Variability and utilization deficiencies in children's memory strategies : a developmental study

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Variability and utilization deficiencies in children's memory strategies : a developmental study
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xiii, 108 leaves : ill. ; 29 cm.
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Coyle, Thomas, 1968-
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Thesis (Ph. D.)--University of Florida, 1997.
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Includes bibliographical references (leaves 104-107).
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Vita.
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by Thomas R. Coyle.

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Table of Contents
    Title Page
        Page i
    Dedication
        Page ii
    Acknowledgement
        Page iii
        Page iv
        Page v
        Page vi
    Table of Contents
        Page vii
        Page viii
    List of Tables
        Page ix
        Page x
    Abstract
        Page xi
        Page xii
        Page xiii
    Introduction
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
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    Method
        Page 26
        Page 27
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        Page 29
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        Page 32
        Page 33
    Results
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
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        Page 77
    Discussion
        Page 78
        Page 79
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        Page 103
    References
        Page 104
        Page 105
        Page 106
        Page 107
    Biographical sketch
        Page 108
        Page 109
        Page 110
Full Text











VARIABILITY AND UTILIZATION DEFICIENCIES IN CHILDREN'S MEMORY
STRATEGIES: A DEVELOPMENTAL STUDY
















By

THOMAS R. COYLE
















A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1997



































For my parents,

Oceania and Roger Coyle















ACKNOWLEDGMENTS

Dissertation acknowledgments typically say little about how those acknowledged contributed to the student's academic development. Perhaps this is how it should be, for the main purpose of a dissertation is to present a student's original contribution to a recognized body of knowledge. I will adhere to the academic tradition of brevity in these Acknowledgments, but do so in a way that allows me to recognize specific contributions of individuals who helped and supported me in completing this dissertation. I first acknowledge faculty, and then acknowledge my family.

I wish to thank Dr. James Algina for his contribution in teaching me how to do some of the statistics in this dissertation, particularly the analysis in which measures of variability were converted to z-scores and analyzed simultaneously. I also thank Dr. Algina for discussions, which I initiated, on issues pertaining to tenure in the university and E. D. Hirsch's notion of cultural literacy.

I wish to thank Dr. David Bjorklund for convincing me to devote my life to studying developmental psychology. Dr. Bjorklund was instrumental in my training during the early part of my career, and he deserves much credit for my achievements. Dr. Bjorklund has shown me that the most exciting aspect of science is discovery, that description is a reasonable goal for science, that the best research questions are those that can account for the most data, and that Peter Kapista knew



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what he was talking about when he said, "Theory is a good thing but a good experiment lasts forever."

I wish to thank Dr. Shari Ellis for suggesting that I examine

patterns of variability within individual subjects and the effectiveness of individual strategy combinations. Dr. Ellis's suggestions were incorporated into this dissertation and into Coyle and Bjorklund (1997). I also thank Dr. Ellis for discussions, which I initiated, on funding for education and on cross-cultural research.

I wish to thank Dr. Ira Fischler for bringing to my attention several articles in the adult literature that utilize procedures for assessing intentionality in cognition, notably Jacoby's (1991) processdisassociation approach. The intentionality issue is often neglected in strategy research, even though some researchers have made intentionality the sine qua non of strategy use.

I wish to thank Dr. Patricia Miller for emphasizing the continuous nature of strategy classifications. Her contribution is acknowledged in Bjorklund and Coyle (1995, p. 166), and can be identified in the analyses presented in this dissertation. I also thank Dr. Miller for suggesting that I analyze qualitative differences in strategy use. Such an analysis was performed for this dissertation, and it yielded some interesting results.

I wish to thank Dr. Scott Miller for suggestion g that I think carefully about defining and measuring cognitive strategies. It is interesting that defining cognitive strategies never has been a favorite pastime of strategy researchers who study them. I also thank Dr. Miller for his careful and timely reviews of my manuscripts, including my dissertation. I have yet to find anyone whose knowledge of iv








APA guidelines is as expansive as Dr. Miller's, and I probably never will. I also wish to thank Dr. Miller for his contribution to the Developmental area while he was on sabbatical.

I wish to thank Jennifer L. Slawiniski for her suggestions

regarding the design of my dissertation. I also thank Miss Slawinski for the clever idea of applying a sequential design in the context of a microgenetic experiment. Finally, I thank Miss Slawinski for her incisive comments on examining gender effects and on reanalyzing archival data.

I wish to thank the research assistants who helped with data

collection, analyses, and interpretation. These include Joshua List, Chad Colbert, Victoria Otero, and Jerusha Azel. I suspect I learned as much from them as they learned from me.

I wish to thank my mother and father, Oceania and Roger Coyle, for their enduring support during my academic career. My mother and father have taught me that hard work and perseverance will in the end always pay off. Most important, my mother and father have taught me that the most important thing in secular life is family. Their marriage of 35 years (and counting) is why I have acknowledged them together. This dissertation is a testament to their love and support throughout the years.

I wish to thank my brother, James Coyle, for his interest in my work and his continued support of my goals, including the completion of this dissertation. James is an exceptional guitar player, partly because of exceptional talent, and partly because of exceptional practice. I have learned much from observing his work ethic and dedication to the instrument he loves so much.

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I wish to thank my cousin, Annette Fields, for providing me with support and guidance throughout the years. Annette is an accomplished lawyer and she has taught me by example the rules and standards of good argumentation. She has shown me that anyone can rise to the top with lots of hard work and discipline. Annette's best friend and confidant, Ellen Ross, always has believed in me and my talents, and her support is appreciated.

I wish to thank Deborah Hooks for loving me for what I am and,

more importantly, for what I can become. Deborah entered nearly all of the data for this dissertation, and she provided numerous useful suggestions about possible analyses. One of her suggestions, to examine intrusions in children's recall protocols, turned out to be very promising and provides a possible basis for a new view of strategy development that includes developmental differences in resistance to interference. Deborah has taught me that love is the best part of life, and without it, you really don't have much of a life at all.

To all the members of my family, I love you all.





















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TABLE OF CONTENTS


page
ACKNOWLEDGMENTS ..................................................... iii

LIST OF TABLES ...................................................... ix

ABSTRACT ............................................................ xi

INTRODUCTION ........................................................ 1

Memory Strategies Enhance Performance .............................. 2
Memory Strategy Development is Stagelike .......................... 8
Evaluation of Research on Variability and Utilization
Deficiencies .................................................... 12
The Current Study ................................................. 18
Goals of the Current Study ........................................ 21

METHOD .............................................................. 26

Participants ...................................................... 26
Stimuli and Design ................................................ 26
Procedure ......................................................... 29
Coding ............................................................ 31

RESULTS ............................................................. 34

Preliminary Analyses .............................................. 34
Off-Task Behavior and Examination ............................... 34
Recall .......................................................... 35
Strategy Use .................................................... 39
Variability in Strategy Use ....................................... 41
Multiple-Strategy Use ........................................... 41
Strategy Change ................................................. 45
Relation Between Strategy Use and Recall .......................... 56
Utilization Deficiencies ........................................ 56
Strategy Change and Recall ...................................... 64

DISCUSSION .......................................................... 78

Variability in Strategy Use ....................................... 79
Multiple-Strategy Use ........................................... 79
Strategy Changes ................................................ 82
Relation Between Multiple-Strategy Use and Recall ................. 86
Relation Between Strategy Changes and Recall ...................... 93
Conclusions ....................................................... 98

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REFERENCES .................................................... page
...... 104

BIOGRAPHICAL SKETCH ................................................. 108






















































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LIST OF TABLES

Table page

1. Word lists by category membership .............................. 27

2. Mean proportion recall by condition, grade, and trial, and by
condition and trial (i.e., collapsed across grade), and
grade differences in recall at each trial by condition ....... 37

3. Percentage (and number) of trials on which each strategy was
used, by condition and grade ................................. 40

4. Mean number of strategies used, by grade and trial, and by
condition, grade, and trial .................................. 43

5. Mean number of trial-by-trial strategy changes, by grade and
trial transition, and by condition, grade, and trial
transition .................................................... 47

6. Mean z-scores and raw scores for unique combinations, trials
with changes, and total changes, by grade (standard
deviations in parentheses) .................................... 50

7. Percentage (and number) of children classified as stable or
unstable across all trials, on early trials, and on later
trials, by grade .............................................. 52

8. Percentage (and number) of children changing or not changing
their stability classification across trial blocks, by
grade ........................................................ 54

9. Correlations between number of words recalled and number of
strategies used, by condition, grade, and trial .............. 57

10. Mean proportion recall when strategy use was perfect, by grade and type of strategy used ..................................... 60

11. Percentage (and number) of trials on which each strategy combination was used, and mean proportion recall (and
standard deviations) for each combination, by grade (Codes for strategies: S, sorting; R, rehearsal; C, clustering; N,
category naming) ............................................. 62

12. Correlations between measures of strategy change and recall, by condition and grade ....................................... 66


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Table page

13. Correlations among measures of strategy change, by condition and grade .................................................... 67

14. Mean proportion recall (and standard deviations) for children classified as stable or unstable across all trials, on early
trials, and on later trials, by grade ........................ 70

15. Percentage (and number) of trials on which strategy changes did and did not occur immediately after recall was perfect
or not perfect ............................................... 73

16. Percentage (and number) of trials on which strategy changes did and did not occur immediately after recall was perfect
or not perfect, by condition ................................. 75






































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Abstract of Dissertation Presented to the Graduate School of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

VARIABILITY AND UTILIZATION DEFICIENCIES IN CHILDREN'S MEMORY STRATEGIES: A DEVELOPMENTAL STUDY By

Thomas R. Coyle

August, 1997

Chair: Patricia H. Miller
Cochair: Shari A. Ellis
Major Department: Psychology

The goal of this study was to examine variability in memory

strategy use, and the relation between such variability and recall, as a function of age and a measure of task difficulty (number of words to remember). Second and fourth graders received seven sort-recall trials of different categorizable words (e.g., nurse, lawyer, wall, roof, rose, lily). The number of words presented varied across trials, whereas the number of categories represented in all word lists remained constant. Variability in strategy use was measured in terms of multiple-strategy use (e.g., number of strategies used across trials) and strategy changes (e.g., number of trial-by-trial changes in the types of strategies used). Consistent with previous research, (a) older children used more strategies and made fewer trial-by-trial changes than younger children;

(b) older children recalled more than comparably strategic younger children, indicating a utilization deficiency for the younger children; and (c) older children showed significant and positive relations between xi









stable-strategy use (i.e., few trial-by-trial changes) and recall, whereas younger children showed no reliable relation between stability and recall. This study extended previous research by showing that (a) stable-strategy use emerges with experience (i.e., over trials) for older children but not younger children, (b) utilization deficiencies occur for some but not all instances of perfect strategy use, and (c) memory benefits from stability occur on early trials (i.e., Trials 1 to 4) for older children but not for younger children, who show memory benefits from stability on later trials (i.e., Trials 4 to 7) only. Surprisingly, the results revealed few significant effects related to changes in the measure of task difficulty (i.e., number of words to remember). The findings are discussed in terms of how they advance our knowledge and understanding of utilization deficiencies and variability in strategy use.



























xii


































Nature is not economical of structures--only of principles Abdus Salam


























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INTRODUCTION

All scientific disciplines are based on a set of core assumptions (Gholson & Barker, 1985). These assumptions are rarely stated explicitly and rarely questioned. They serve to direct a researcher's choice of research questions, data collection procedures, statistical analyses, and interpretation of research findings.

Two such assumptions were central in early research on children's memory strategies. The first was that memory strategies usually enhance memory performance. The second was that memory strategy development proceeds through a series of stages in which a unique strategy is used fairly consistently in each stage. These assumptions were implicit in much of the memory strategy research conducted throughout the 1960s and 1970s.

There are now a number of studies demonstrating that these assumptions are at best misleading, and at worst, empirically inaccurate. The next two sections provide a brief history of events that led to the rise and fall of the view that memory strategies generally enhance performance and that memory strategy development is stagelike. The discussion will focus on two concepts central to this dissertation. The first is the concept of utilization deficiency, which refers to strategy use with no performance benefit. The second is the concept of variability in strategy use, which refers to the use of not one but several different approaches.


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Memory Strategies Enhance Performance

The origin of the assumption that memory strategies usually

facilitate memory performance can be traced to strategy training studies (for a review, see Flavell, 1970). In a typical training study, children who did not spontaneously use a strategy (e.g., rehearsal) were trained to do so, frequently showing marked improvements in memory performance. Such children were said to be production deficient because they were unable to spontaneously produce a strategy, even though they could do so and show memory benefits when instructed,

The discovery of production deficiencies was followed by a number of studies that examined the effectiveness of strategy training. In general, these studies, like the earlier ones, demonstrated that children who do not produce a strategy initially can be trained to do so and show corresponding memory improvements. These findings led to the assumption that memory strategies typically improve performance and that the failure to use memory strategies is associated with relatively low levels of performance (for examples, see Flavell, 1970). This view was not limited to memory strategies but was implicit in the descriptions of other cognitive strategies, including those used in analogical reasoning, arithmetic, and reading (for a historical review, see Bjorklund, 1992).

The view that memory strategies generally improve performance began to be questioned in the middle to late 1980s. A number of developmental studies during this period examined the effectiveness of various mnemonics. Several of these studies showed that memory strategies sometimes resulted in no or little benefit to memory,









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particularly for younger, less practiced strategy users. For example, research by Miller and her colleagues (reviewed in Miller & Seier, 1994) demonstrated that young children using a selective attention strategy had lower levels of recall than equally strategic older children. Such findings were not limited to selective attention strategies. Similar patterns were found in tasks assessing organizational and elaboration strategies (Bjorklund & Harnishfeger, 1987; Kee & Davies, 1990).

Why did these studies show ineffective strategy use when earlier research on production deficiencies showed effective strategy use? The answer may have to do with how strategy use was measured. Production deficiency research inferred strategy use from patterns of recall following training. Improvements in recall were interpreted as indicating the effective use of a mnemonic. No improvements in recall were interpreted as indicating ineffective strategy training. This latter pattern of data is ambiguous, however. No improvement in recall may indicate ineffective training, but it may also indicate ineffective strategy use. The only sure way to discriminate between these alternatives is to assess recall and strategy use independently. Later research on strategy effectiveness did assess recall and strategy use independently. As mentioned above, these studies showed that increases in strategy use do not always result in benefits to memory.

In 1990, Miller formally identified evidence of strategy use with no recall benefits, and labeled such evidence a utilization deficiency (Miller, 1990). According to Miller, utilization deficiencies occur when a child produces an appropriate strategy but does not benefit from it in terms of recall, or benefits less than an equally strategic older








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child. Utilization deficiencies are inferred empirically when (a) the correlation between strategy use and recall is nonsignificant for younger children but significant for older children, (b) young strategy users recall no more than their nonstrategic peers, (c) older children recall more than comparably strategic younger children, and (d) strategy use increases over trials with no corresponding improvements in memory performance (for additional examples of utilization deficiencies, see Miller & Seier, 1994). Evidence for utilization deficiencies has been found in studies using a variety of memory paradigms and involving participants ranging in age from preschool to late adolescence (for reviews, see Bjorklund & Coyle, 1995; Miller & Seier, 1994).

Recent reviews of memory development research have revealed the ubiquity of utilization deficiencies (Bjorklund & Coyle, 1995; Miller & Seier, 1994). One such review was conducted by Miller and Seier (1994), who examined the memory development literature from 1974 through mid1992 for evidence of utilization deficiencies in normal populations (e.g., greater recall for older than comparably strategic younger children). Miller and Seier used three criteria to select studies appropriate for the examination of utilization deficiencies: (a) independent measures of strategy use and recall, (b) spontaneous strategy production (i.e., training studies were excluded), and (c) analyses examining age differences in strategy use and performance. Of the 59 studies they evaluated, 56 (95%) provided evidence for a utilization deficiency.

Although Miller and Seier limited their review to spontaneous strategy use, a more recent review by Bjorklund, Miller, Coyle, and








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Slawinski (in press) examined utilization deficiencies (e.g., increases in strategy use but not recall following training) in memory strategy training studies published between 1968 and 1994. Like Miller and Seier, Bjorklund et al. selected only studies that included children from normal populations and reported independent measures of strategy use and recall. Because studies with multiple-training conditions could provide multiple cases of evidence of utilization deficiencies, training conditions within studies (rather than the studies themselves) served as the units of analysis. Of the 76 relevant training conditions identified, 39 (51%) showed evidence for utilization deficiencies.

Why did it take the field so long to identify utilization

deficiencies? The most parsimonious explanation, I believe, is that utilization deficiencies did not make any sense given the dominant assumption prevalent in much of the early research on production deficiencies (i.e., strategies help performance). Consequently, evidence for a utilization deficiency was often ignored or overlooked. A conceptual shift occurred in the mid-1980s when a number of studies examined independent measures of strategy use and recall (for a review of these studies, see Miller & Seier, 1994). Several studies during this period reported that strategy use resulted in no or little recall benefit. The accumulation of such evidence made it difficult to ignore data indicating that strategies did not always enhance memory performance. A new view of strategy use emerged, one that considered the possibility of ineffective strategy use. This view made possible the discovery of utilization deficiencies in research on memory strategies.








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Contemporary research has investigated the causes and consequences of utilization deficiencies. Possible causes of utilization deficiencies include inadequate capacity for both strategy production and effective encoding, limited knowledge of stimulus items or task requirements, and insufficient metamnemonic knowledge of when and how to use strategies (Miller & Seier, 1994). Empirical support for these causes has been demonstrated in studies showing that utilization deficiencies are reduced or eliminated when (a) the capacity required for accessing or executing a strategy is eliminated by having an experimenter carry out the strategy (Miller, Woody-Ramsey, & Aloise, 1991); (b) the stimulus items or task requirements are highly familiar and embedded in a meaningful context (Miller, Seier, Barron, & Probert, & 1994); and (c) metamnemonic instruction is provided regarding the cause-and-effect relati on between strategy use and recall (Ringel & Springer, 1980). Of the three causes mentioned, inadequate mental capacity and limited knowledge base have received the most empirical support. Other potential causes of utilization deficiencies, including inadequate strategic monitoring, failure to link one strategy with another, and failure to inhibit an earlier, ineffective strategy (see Bjorklund & Coyle, 1995; Miller & Seier, 1994), have received little attention.

Contemporary research has also examined the development of

utilization deficiencies. The general finding is that young children are more apt to show a utilization deficiency than older children. Compared to older children, young children (a) recall less when using the same strategies, (b) show lower correlations between strategy use








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and recall, and (c) show more instances of strategy increases over trials with no corresponding increases in recall (see Miller & Seier, 1994). These findings demonstrate that young children are less likely to benefit from strategy use than older children, which is evidence of a utilization deficiency for young children.

A recent study by Coyle and Bjorklund (1996) showed that

utilization deficiencies have different developmental consequences for memory depending on when they occur. In this study, children in second through fourth grade received a multitrial sort-recall task, with different sets of categorizable words on each trial. Children were classified as utilizationally deficient or not based on their pattern of clustering and recall over trials. Children were classified as utilizationally deficient if they showed increases in clustering over trials with no corresponding increases in recall. All other children were classified as nonutilizationally deficient. Mean recall varied as a function of grade and utilization deficiency classification. Secondand third-grade utilizationally deficient children recalled more on average than their nonutilizationally deficient agemates, most of whom used no strategy at all. Conversely, fourth-grade utilizationally deficient children recalled less than their nonutilizationally deficient agemates, most of whom were using strategies effectively.

The Coyle and Bjorklund findings demonstrate that utilization

deficiencies have different memory consequences depending on when they occur in development. Utilization deficiencies that occur early in development are associated with relatively high levels of memory performance, because the dominant alternative pattern is no strategy use









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and low levels of recall. Conversely, utilization deficiencies that occur later in development are associated with relatively poor recall, because the dominant alternative pattern is effective strategy use and high levels of recall.

Memory Strategy Development is Stagelike

The origin of the assumption that memory strategy development is stagelike can be traced to research on spontaneous (i.e., uninstructed) strategy use in the late 1960s and 1970s. One goal of this research was to identify the types of strategies used by different age groups. To do this, children of different ages were presented with a memory task and their mnemonic behaviors were recorded and compared. The general finding was that children in each age group typically used a different and unique strategy for remembering. This finding was remarkably consistent across a variety of research paradigms. Serial recall studies showed that young children often use no rehearsal strategy, older children often use single-word rehearsal, and still older children use cumulative rehearsal (Flavell, Beach, & Chinsky, 1966; Ornstein, Naus, & Liberty, 1975). Organizational memory tasks showed that young children often organize words along thematic dimensions whereas older children often organize words along taxonomic dimensions (Ceci & Howe, 1978). Paired-associate learning tasks showed that young children often form arbitrary links between word pairs whereas older children often form relational links between word pairs (for a review, see Kee, 1994).

These early findings depicted memory strategy development as a stagelike progression (Siegler, 1995). Stage descriptions were not limited to memory strategies but included strategies in such diverse








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domains as arithmetic, number conservation, and scientific reasoning (Siegler, 1996). Young children were described as using one approach, older children as using a different approach, and still older children as using yet another approach. At each age children were described as using a single and unique strategy. Strategy development consisted of one strategy being replaced by another more advanced strategy.

Although a stagelike pattern of strategy development appeared to describe well the pattern of data in early studies, evidence inconsistent with a stagelike progression was reported in the mid- to late-1980s. Several studies during this period demonstrated that children of a particular age used not one but several strategies. Such variability was found across a variety of tasks, including ones assessing memory strategies. For example, children asked to remember a series of digits sometimes used no rehearsal strategy, sometimes rehearsed only one digit at a time, and sometimes rehearsed all digits together (McGilly & Siegler, 1989). Children asked to remember the location of a hidden object sometimes talked about where the object was hidden, sometimes stayed near the hiding place, and sometimes pointed to the hiding location (DeLoache, 1984). Children presented with a pairedassociate learning task sometimes repeated the names of the items and sometimes formed a sentence or image linking the word pairs (reviewed in Kee, 1994). Children asked to remember a series of objects sometimes visually inspected the objects, sometimes named the objects, and sometimes physically manipulated the objects (Baker-Ward, Ornstein, & Holden, 1984; Lange, MacKinnon, & Nida, 1989).








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Why was variability reported in these studies when early research on strategy development had reported a stagelike progression? As with utilization deficiencies, the answer has to do with how strategies were assessed. Early research on memory strategy development typically classified children as using a single strategy only. Children might be identified as rehearsing, sorting, or elaborating, but no child was identified as using more than one strategy. Although variability was present across individuals, data were often presented in terms of the dominant strategy used at each age (Flavell, Beach, & Chinsky, 1966). This type of data presentation, along with the strategy assessment procedures, depicted memory strategy development as a series of stages. Later research on memory strategy development assessed the possibility of intraindividual variability in strategy use (i.e., multiple strategies being used by a particular individual). This research assessed several strategies on a particular trial or different strategies across trials. Under these conditions, children showed considerable variability in strategy use, often using a variety of approaches within and across trials.

Evidence for variability in strategy use led to a new view of strategy development championed by Robert Siegler (1996). Siegler argued that strategy development does not involve the replacement of different strategies, as implied by stage theories. Instead, he argued that strategy development involves changes over time in the frequency of occurrence of several strategic approaches. According to Siegler, at any given age children use not one but a variety of strategies. Strategy development consists of changes in the frequency of use of each









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individual strategy, with some strategies being used more than others. At no point in development is a single strategy used exclusively. Rather, multiple strategies are used throughout development.

Considerable evidence supports the view of strategy development championed by Siegler. Variability in strategy use has been found for children differing in race, nationality, and intelligence; for problem domains including arithmetic, serial recall, scientific reasoning, reading, spelling, and tic-tac-toe; for participants ranging in age from one year to adulthood; and for analyses examining both group and individual subject data (Siegler, 1996). In sum, variability in strategy development appears to be the rule in development, not the exception.

Contemporary research has investigated possible correlates of variability in memory strategy use. Possible correlates include knowledge of the stimulus items and task, psychometrically-measured intelligence, and the history of effectiveness of a particular strategy. Empirical support for these correlates has been demonstrated in studies showing that variability in strategy use is reduced when (a) highly familiar stimulus items are used (Bjorklund & Bernholtz, 1986; Frankel & Rollins, 1985), (b) children have very high-IQs (Coyle, Colbert, & Read, 1997), and (c) a strategy yields perfect memory performance (McGilly & Siegler, 1989).

Contemporary research also has examined the developmental course of variability in strategy use. Siegler has shown that the number of strategies used depends on amount of experience on a task (Siegler, 1996). In general, few strategies are used when task experience is








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limited, several different strategies are used when experience is moderate, and few strategies are again used when experience is extensive. Thus, the number of strategies used, plotted as a function of task experience, produces an inverted-U shaped pattern. This pattern has been found across a variety of strategic tasks.

Finally, contemporary research has shown that initial levels of variability have implications for subsequent learning. For example, Goldin-Meadow and her colleagues (Goldin-Meadow, Alibali, & Church, 1993) have shown that children who displayed high levels of variability on a conceptual learning task showed increases in task performance following instruction or practice. In contrast, children who displayed low levels of variability typically showed no or relatively little improvement in performance. Similarly, Siegler (1995) has shown that children who used several strategies on a number conservation task showed increases in subsequent learning. In contrast, children who used few strategies on a number conservation task showed relatively little change in subsequent learning. These findings raise the intriguing possibility that variability may provide an index of when change is likely to occur and when change can be induced to occur (cf. Thelen & Smith, 1994).

Evaluation of Research on Variability and Utilization Deficiencies

The discovery of utilization deficiencies and variability has had two important consequences in strategy development research. First, several models of memory strategy development now explicitly account for utilization deficiencies and variability. These models assume that variability is present at all points in development (Siegler, 1996;








13

Thelen & Smith, 1994), and that memory strategies have costs as well as benefits (Bjorklund & Coyle, 1995; Miller & Seier, 1994). Second, several studies have been designed with the explicit intent of assessing utilization deficiencies and variability (Bjorklund, Coyle, & Gaultney, 1992; Coyle & Bjorklund, 1996; Miller, Seier, Barron, & Probert, 1994; Siegler & Jenkins, 1989). These studies do not view utilization deficiencies and variability as anomalies to be discounted, but consider them as being worthy of study in their own right and deserving of explanation.

Although utilization deficiencies and variability have received considerable attention in contemporary strategy research, current research investigating these phenomena is limited in at least three ways. First, utilization deficiencies have been described almost exclusively on tasks in which only a single strategy is assessed on all trials. In most studies, children are said to be utilizationally deficient when they use a particular strategy (e.g., rehearsal or elaboration) and show no or little memory benefit or less benefit than that shown by more experienced strategy users. Because only a single strategy is assessed, the possibility of utilization deficiencies in multiple-strategy use cannot be examined. Instead, the focus is on the ineffective use of a particular strategy.

Second, variability generally has been assessed on multitrial

tasks in which only one strategy per problem solving trial is assessed. In most studies, children are credited with using a single strategy each time they are presented with a problem, although they can (and usually do) use a variety of strategies across different problems. Because only








14

one strategy per trial is assessed, the possibility of variability within a particular trial (i.e., intratrial variability) cannot be examined. Instead, the focus is on variability across trials (i.e., intertrial variability).

Third, variability has been measured almost exclusively in terms of the number of strategies used. Although the number of strategies used is one measure of variability, it is not the only one. A handful of other studies have shown that variability can be measured in other ways, including the number of trial-by-trial changes in strategy use, the degree of stability in the sequence of strategy production across several trials, and the number of instances when one strategy is expressed in gesture and a different one in speech (Coyle & Bjorklund, 1997; Coyle, Colbert, & Read, 1997; Goldin-Meadow et al., 1993). These studies demonstrate that variability can be measured in not one but several ways. A single measure, such as the number of strategies used, does not capture all possible patterns of variability, and different kinds of variability may have different causes and consequences.

A recent study by Coyle and Bjorklund (1997) addressed these

limitations. Some time will be spent describing this study because its design and findings figure prominently in the study developed for this dissertation. Children in second through fourth grade received five sort-recall trials of categorizable words. Unlike other multitrial experiments (e.g., Bjorklund, 1988), different items and categories were used on each trial, so that any increases in strategy use could not be attributed to increased familiarity with a particular set of stimulus items.








15

Multiple strategies were assessed on each trial. This permitted assessment of variability within trials, as well as variability across trials. It also permitted assessment of utilization deficiencies in multiple-strategy use. The four strategies assessed on each trial were sorting, physically moving or arranging the words into groups; rehearsing, saying out loud or mouthing the items; category naming, saying the category name of a group of words; and clustering, recalling the words by categories. Each strategy was coded as occurring or not on each trial. The measure of performance was the number of words recalled on each trial.

Unlike previous studies, variability was measured in not one but several ways. Variability was measured in terms of (a) average number of strategies used across trials, (b) number of trials on which multiple strategies were used, (c) number on trials that the combination of strategies differed from the preceding trial, and (d) total number of strategy changes on consecutive trials, counting both strategy additions and deletions as changes. The first two measures (average number of strategies and number of trials with multiple strategies) are examples of multiple-strategy use. These are the most frequently reported measures of variability. The last two measures (trials with changes and total number of changes) are examples of strategy change. These measures assess changes over time and are reported less frequently.

Coyle and Bjorklund predicted age differences in variability.

Multiple-strategy use (e.g., number of strategies used) was predicted to increase with age. The basis for this prediction was that strategy use would be less effortful for older than for younger children, and so








16

older children would have the capacity to produce additional strategies. Strategy changes (e.g., trial-by-trial changes in strategy use) were predicted to be high and comparable for both age groups. This prediction was based on research showing that strategy changes occur frequently in development, across a wide range of ages and on a variety of tasks (Siegler, 1995, 1996).

Coyle and Bjorklund also predicted age differences in the relation between variability and recall. Multiple-strategy use was predicted to correlate with recall for older but not younger children. This prediction was based on the assumption that older children would have the mental capacity to produce and use effectively multiple strategies. In contrast, multiple-strategy use was expected to consume so much of young children's limited mental capacity that little would remain for recall, resulting in a utilization deficiency. Strategy change, in particular stable-strategy use (i.e., few trial-by-trial changes in strategy use), was predicted to correlate with recall for older but not younger children. This prediction was based on research showing that older children are likely to stick with a single approach that yields optimal performance, whereas younger children frequently use a variety of ineffective approaches (Lemaire & Siegler, 1995).

The findings were generally consistent with the predictions.

Multiple-strategy use was greater for older than for younger children. Although children of all ages used more than one strategy across trials, older children used more strategies and had more trials with multiple strategies than did younger children. Strategy changes were high and comparable for children in all age groups. Although considerable









17

variability was observed for all age groups, a (nonsignificant) agerelated decline in variability was observed. Older children showed fewer changes on consecutive trials and had fewer trials with changes than younger children. These findings were confirmed in an analysis of strategy change within individual subjects. Although Coyle and Bjorklund (1997) paid little attention to the age-related declines in strategy changes, emphasizing instead pervasive variability at all ages, subsequent research has found considerable evidence for age-related declines in variability across a variety of tasks and for children varying widely in age (Coyle, Colbert, & Read, 1997; for a review, see Siegler, 1996). In general, older and more experienced strategy users show fewer strategy changes than younger and less experienced strategy users.

Further analysis revealed relations between variability and memory performance. As predicted, multiple-strategy use was related to recall for older children, who showed significant and positive relations between number of strategies used and recall. Younger children showed no reliable relation between number of strategies used and recall, indicating a utilization deficiency. In addition, stable-strategy use (i.e., few strategy changes across trials) was significantly related to high levels of recall, but only for the older age groups. That is, third- and fourth-grade children who consistently used a particular strategy combination had higher levels of recall than their peers whose strategy use was less consistent. No reliable relation between variability and recall was found for the youngest children.









18

Taken together, these findings extend current research on

utilization deficiency and variability in several ways. Specifically, they provide evidence for (a) utilization deficiencies in multiplestrategy use, (b) several different types of variability, including multiple-strategy use and strategy change, and (c) variability in strategy use within a particular trial, as well as between trials.

The Current Study

The purpose of the current study was to further examine issues

concerning utilization deficiencies and variability using the procedures developed by Coyle and Bjorklund (1997). As in Coyle and Bjorklund, children received a multitrial sort-recall task with different words and categories on each trial. Also as before, multiple strategies were assessed on each trial and variability was measured in several ways. The strategies assessed were sorting, rehearsal, clustering, and category naming. The measures of strategy variability were number of strategies used on each trial, number of strategy changes on consecutive trials, number of unique combinations, and number of trials with strategy changes.

The current study differed from the study by Coyle and Bjorklund in two important ways, each of which permitted new research questions concerning utilization deficiencies and variability in strategy use. First, in the current study children received seven sort-recall trials, two more than in Coyle and Bjorklund. The additional trials permitted a more detailed analysis of strategy change during the testing session. It was now possible to assess periods of stability and instability within individual children during early trials and again during later








19

trials. In contrast, the study by Coyle and Bjorklund assessed stability and instability using data on all trials.

Second, in the current study the number of words presented varied across trials from six to fifteen, whereas in Coyle and Bjorkiund the number of words presented remained constant across trials at eighteen. Although the number of words varied across trials in the current study, the number of categories represented on each trial remained constant at three. This eliminated the possibility that changes in strategy use and recall would result from changes in the number of categories represented across trials, and ensured that such changes could be attributed to variation in the number of words presented. The design permitted an examination of whether children adapt their strategy use to changes in the number of words on each trial. It was now possible to assess measures of variability, including multiple-strategy use and strategy changes, when children were presented with relatively few words or many words. In contrast, the study by Coyle and Bjorklund assessed variability under conditions in which task demands (i.e., number of words on each trial) remained constant.

Apart from the differences mentioned above, the design of the

current study was very similar to the one used by Coyle and Bjorklund. Second- and fourth-grade children were given seven sort-recall trials of categorizable words. As in Coyle and Bjorklund, different words and categories were used on each trial to minimize the likelihood that increases in strategy use would result from practice with a particular set of categorizable items. Also as in Coyle and Bjorklund, category items were chosen to avoid high associations between words, thus








20

minimizing the likelihood of clustering as a result of the automatic activation of semantic memory relations.

Approximately half the children in each grade were assigned to one of two conditions, labeled ascending/descending and descending/ascending. In the ascending/descending condition, children received an increasing number of words on each successive trial until Trial 4, and then received a decreasing number on each successive trial (number of words on Trials 1-7, respectively, was 6, 9, 12, 15, 12, 9, and 6). The descending/ascending condition was the complement of the ascending/descending condition. In the descending/ascending condition, children received a decreasing number of words on each successive trial until Trial 4, and then received an increasing number of words on each successive trial (number of words on Trials 1-7, respectively, was 15, 12, 9, 6, 9, 12, 15). Each condition had trials with the same number of words, so that effects concerning number of words presented could be teased apart from effects concerning the ascending or descending order in which words in each condition were presented.

These conditions were developed to examine changes in strategy use and performance as a function of the number of words presented on successive trials. Two additional sets of conditions were considered but not selected. The first involved presenting trials in the ascending/descending and descending/ascending condition randomly, without having a constant rate of increase or decrease across trials. For example, Trials 1 to 7 in the ascending/descending condition might be ordered 12, 15, 9, 9, 6, 12, and 6, respectively, whereas Trials 1 to

7 in the descending/ascending condition might be ordered 9, 15, 15, 6,








21

12, 9, and 12, respectively. Unlike the conditions in the current study, these presentation orders would vary randomly the amount of increase or decrease on successive trials. Consequently, they would confound changes in the number of words presented on successive trials with the magnitude of such changes. The design of the current study eliminated this confound by holding constant the rate of change at three words.

A second possible set of conditions that were considered included an ascending only series and a descending only series. The idea was to extend the pattern in the early trials of each condition in the current study. Thus, Trials 1 to 7 in the ascending series would have 6, 9, 12, 15, 18, 21, and 24 words, respectively, whereas Trials 1 to 7 in the descending series would have 24, 21, 18, 15, 12, 9, and 6 words, respectively. Unlike the conditions in the current study, these presentation orders do not reverse the pattern of change in the latter trials. Consequently, effects regarding possible strategic adaptation to reversal of presentation order could not be assessed. Furthermore, it was not clear why differences in strategic adaptation and recall performance would vary beyond 15 words, when the number of words presented would exceed children's memory capacity (Miller, 1956).

Goals of the Current Study

The current study had three goals. The first was to examine

differences in measures of strategy variability (e.g., multiple-strategy use and strategy change) as a function of grade and number of words presented on each trial. As in Coyle and Bjorklund (1997), multiplestrategy use (e.g., number of strategies used per trial) was predicted








22

to increase with age. This prediction was based on research showing that strategies are capacity-demanding operations and that strategy production consumes less capacity with age (Kee, 1994). Thus, older children, who use relatively little capacity during strategy production, should produce more capacity-consuming strategies than younger children.

In addition, multiple-strategy use was predicted to be greater on trials with relatively many words (i.e., 12 or 15 words) than on trials with relatively few words (i.e., 6 or 9). This prediction was based on the assumption that trials with many words would induce children to use additional memory strategies because recall of all words on these trials is beyond children's memory capacity (Miller, 1956). In contrast, trials with few words should not have this effect because recall of all words is within children's memory capacity. Thus, children are expected to use multiple-strategies only when they cannot perform optimally without doing so (cf. McGilly & Siegler, 1989). These predictions may be qualified by age, with older children having greater capacity for using multiple strategies than younger children.

On the basis of the findings in Coyle and Bjorklund (1997) and in other studies (Coyle, Colbert, & Read, 1997; Lemaire & Siegler, 1995), strategy changes (e.g., trial-by-trial changes in strategy use) were predicted to decrease with age. In addition, strategy changes were predicted to decrease over the course of the testing session, especially for older children. This latter prediction was based on models of strategy variability proposing that task-relevant experience is associated with decreases in trial-by-trial changes in strategy use (Siegler, 1996; Thelen & Smith, 1994). Thus, children should show









23

relatively few strategy changes during the later trials of the sortrecall task, when they have had considerable task-related experience.

Strategy changes were predicted to vary according to the number of words presented on each trial. Specifically, strategy changes were predicted to rarely follow trials with relatively few words (i.e., trials with 6 and 9 words), but to frequently follow trials with relatively many words (i.e., trials with 12 and 15 words). These predictions were based on research showing that strategy changes rarely follow perfect performance but frequently follow less than perfect performance (McGilly & Siegler, 1989). Because perfect recall was likely on trials with few words but not on trials with many words, it was predicted that strategy changes would be less frequent on trials with few words compared to trials with many words.

The second goal of the current study was to examine the relation between multiple-strategy use and recall as a function of age and number of words on each trial. A specific aim was to examine data for possible evidence of utilization deficiencies. Utilization deficiencies were predicted to be less frequent for older children than for younger children. This prediction was based on research examining evidence of utilization deficiencies for children of different ages. For example, Miller and Seier (1994) have shown that correlations between strategy use and recall are often positive and significant for older but not younger children, and have interpreted this as evidence of a utilization deficiency for the younger children. Similarly, Coyle and Bjorklund (1996) have shown that younger children recall less than comparably strategic older children and have interpreted this finding as








24

demonstrating a utilization deficiency for younger children. To date, research on utilization deficiencies has examined the effectiveness of a single strategy (e.g., clustering or rehearsal), or, in a few cases, the effectiveness of multiple strategies. The current study examines the effectiveness of both single- and multiple-strategy use in a single paradigm, and compares directly the incidence of utilization deficiency when children use one or several strategies.

Utilization deficiencies were predicted to be less frequent on trials with relatively few words (i.e., 6 or 9 words) than on trials with relatively many words (i.e., 12 or 15 words). This prediction was based on the assumption that trials with few words would consume less of children's limited mental capacity than trials with many words. Thus, additional capacity should be available for efficient strategy utilization on trials with few words. Consequently, utilization deficiencies should be less frequent on trials with few words compared to trials with many words. This prediction may be qualified by age, with older children's superior processing capacity permitting effective strategy use on all trials, irrespective of the number of words presented.

The third and final goal of the current study was to examine the relation between strategy changes and recall as a function of age. On the basis of the findings in Coyle and Bjorklund (1997) and other studies (Lemaire & Siegler, 1995), the relation between strategy change and recall was predicted to be negative and significant for older but not younger children. That is, few strategy changes across trials (i.e., stable-strategy use) were predicted to result in high levels of








25

recall for fourth graders but not second graders. A further prediction was that the relation between stability and recall may be more apt to occur on later trials (Trials 4 to 7) than on early trials (Trials 1 to 4). This prediction was based on research showing that children initially show inconsistent and ineffective strategy use, but later settle into a stable and optimal state of strategic responding (Siegler, 1996; Thelen & Smith, 1994). Because the measures of strategy variability were computed from data aggregated across trials, no predictions concerning the impact of number of words on the relation between strategy change and recall could be made.

A final prediction concerned the conditions under which strategy

changes occur. Strategy changes were predicted to occur less frequently when recall was perfect on the immediately preceding trial than when recall was not perfect on the immediately preceding trial. This prediction was based on the findings of a serial-recall study by McGilly and Siegler (1989). In that study, children who had been given a series of serial-recall trials tended to switch strategies when their performance was less than perfect on the preceding trial, but not when their performance was perfect on the preceding trial. That is, children tended to stick with a particular approach when it had yielded optimal performance but switched approaches when the previous one had yielded less than optimal performance. This pattern is known as the winstay/lose-shift approach in the decision-making literature (Eimas, 1969). Such a pattern may vary with the number of words presented on each trial. Trials with few words should provide greater opportunity for perfect recall, which should result in few strategy changes.















METHOD

Participants

Participants were 69 second graders, 36 boys and 33 girls (mean age = 7 years 8 months, SD =6.42 months), and 51 fourth graders, 21 boys and 30 girls (mean age =9 years 7 months, SD =5.00 months). Children were recruited from schools and recreation centers in Gainesville, Florida. The majority of children were White (80%) and came from middle- and upper-middle-income households.

Stimuli and Design

Seven lists of categorically related words were constructed (three categories per list, five words per category; see Table 1). The lists were composed of words reported in three analyses of category norms (Bjorklund, Thompson, & Ornstein, 1983; Posnansky, 1978; Uyeda & Mandler, 1980). Each word was printed on a 3 x 5 in. (7.6 x 12.7 cm) index card. Different words and categories were used on each list. Items in each list varied in category typicality, with most items being in the top-third frequency ranking for a particular category. Highly associated words within a particular category (e.g., dog, cat; salt, pepper) were avoided, thus minimizing the likelihood that clustering would result from the automatic activation of semantic memory relations (Frankel & Rollins, 1985; Schneider, 1986). Previous research has shown that children in the age range tested here had little difficulty




26









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Table 1

Word Lists By Category Membership



List I List 2 List 3 List 4


Occupations Trees Metals Buildings


Carpenter Willow Copper Tepee

Lawyer Maple Brass Castle

Nurse Palm Tin Igloo

Dentist Oak Iron Church

Farmer Pine Silver Barn


Parts of a Reading
House Beverages Weapons Material


Window Tea Sword Book

Roof Milk Grenade Journal

Door Soda Cannon Newspaper

Stairs Water Spear Magazine

Ceiling Coffee Knife Letter


Sports Jewelry Vegetables Birds


Soccer Earrings Cabbage Sparrow

Golf Necklace Onion Eagle

Tennis Crown Celery Parrot

Football Watch Peas Dove

Hockey Bracelet Corn Owl









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Table 1--continued

List 5 List 6 List 7


Weather
Flowers Animals Phenomenon


Daisy Horse Wind

Orchid Zebra Snow

Tulip Pig Rain

Lily Tiger Fog

Rose Cat Hail


Furniture Vehicles Cloth


Couch Bus Cotton

Lamp Plane Satin

Chair Boat Silk

Bed Car Wool

Dresser Motorcycle Velvet


Musical
Instruments Time Body Parts


Drums Year Foot

Tuba Decade Elbow

Violin Month Neck

Flute Hour Mouth

Piano Century Hand








29

defining items like the ones used in the current study (Coyle & Bjorklund, 1997).

Each child received seven sort-recall trials. A different list of words was presented on each trial. Children were assigned to one of two conditions. In both conditions, three categories were represented in the word lists on all trials. However, the number of words in each category varied systematically across trials. In the ascending/descending condition, the number of items in each category was 2, 3, 4, 5, 4, 3, and 2 on trials 1 through 7, respectively. Thus, the total number of items presented on trials 1 through 7 was 6, 9, 12, 15, 12, 9, and 6. In the descending/ascending condition, the number of items in each category was 5, 4, 3, 2, 3, 4, and 5 on trials 1 through 7, respectively. Thus, the total number of items presented on trials 1 through 7 was 15, 12, 9, 6, 9, 12, and 15. The sum of all items in the descending/ascending condition was greater than the sum of all items in the ascending/descending condition. In each condition, the seven lists were presented in 1 of 10 predetermined random orders. Each list was presented on each of the seven trials approximately equally, and all items within a list were used approximately equally. This resulted in a 2 (grade: second vs. fourth) x 2 (condition: ascending/descending vs. descending/ascending) x 7 (trial) design, with repeated measures on the trial factor.

Procedure

Children were tested by the author of this dissertation and two

undergraduate research assistants. Each child was seen individually in a session lasting approximately 30 min. Prior to the presentation of








30

the first list, children were told that they would be presented seven lists of words (each printed on a 3 x 7 in. [7.6 x 12.7 cm] index card) to remember and later recall in any order they wished. They were told that the lists and items would be presented one at a time and that some lists would have a different number of words. They were not told how many words would be presented on each list, nor were they told about the categorical structure of the lists.

The experimenter presented each card (on which a word was printed) to the child at a rate of about one card every 2 s. The experimenter named the item and children repeated the name. Cards were placed in front on children in rows, with the stipulation that no two items from the same category were presented contiguously. Each row contained six cards, unless the number of cards presented was not a multiple of six (i.e., 9 or 15 cards). In this case, the row closest to the child contained three cards. After the cards were presented, children were instructed to "study the words and do whatever you want to remember them later." After 1 min 30 s, the cards were covered with an opaque cloth and then children solved problems on the Matching Familiar Figures Test (Kagan, 1965) for approximately 30 s. Children were then asked to recall as many items as they could in any order they wished. If the child was silent for 10 s, the experimenter asked if there were any more words that he or she could remember. When either another 10 s interval elapsed with no more words recalled or the child stated that he or she could remember no more words, the trial was ended. Trials 2-7 followed immediately after Trial 1, using the same procedure with different sets








31

of items. The experimenter recorded children's sorting patterns on each trial and the entire session was audiotapes.

Coding

During the 1 min 30 s study period on each trial, the experimenter observed the incidence of sorting, rehearsal, category naming, examination, and off-task behavior for each of three separate 30-s intervals. Each type of study behavior was coded as occurring or not during each of the three intervals. Sorting was recorded when children physically moved or arranged cards. Rehearsal was recorded when children verbalized out loud or mouthed the list items (no distinction was made between single-word and cumulative rehearsal). Category naming was recorded when children said the category name of a group of items (e.g., FRUIT for apple, banana, peach). Examination was recorded when children visually scanned the cards. Off-task behavior was recorded when children looked away from the cards and were visually inattentive to the task for a total of 5 consecutive seconds. Clustering during recall was recorded when children recalled words by adult-defined categories.

Following Coyle and Bjorklund (1997), three of the five study behaviors were classified and analyzed as strategies. These were sorting, rehearsal, and category naming. Clustering during recall was classified as a fourth strategy. Examination was not considered a strategy because by itself examination reflects only attention to the target information. Although children may be covertly using a strategy (e.g., rehearsal) while examining the items, this cannot be discerned from their overt behavior. For these reasons, examination was not








32

included as a strategy for purposes of analyses. Unless specified otherwise, strategy data were coded dichotomously, with each strategy being coded as occurring or not occurring on each trial.

The strategies assessed during the study period (i.e., sorting,

rehearsal, and category naming) could be observed between zero and three times during the 1 min 30 s study period. A child was credited with using a strategy on a trial if he or she was observed to use that strategy during at least one of the three 30-s intervals. The strategy assessed during recall, clustering, was measured by the adjusted ratio of clustering (ARC) score (Roenker, Thompson, & Brown, 1971). Following Coyle and Bjorklund (1997), a child was credited with using a clustering strategy if his or her ARC score was .50 or greater. This represents a value of slightly more than one standard deviation greater than clustering expected by chance. Children could be classified as using any one of the four strategies or any combination of the four strategies on a particular trial.

Reliability has been assessed in previous research that examined the same study behaviors and strategies (Coyle & Bjorklund, 1997). This research demonstrated that percentage of agreement for two independent coders coding the study behaviors (i.e., sorting, rehearsal, category naming, examination, and off-task behavior) was very high (92%). Percentage agreement for coding the strategies of sorting, rehearsal, and category naming was even higher (97%). These data, along with data from other studies reporting reliability for similar strategies (Lange, MacKinnon, & Nida, 1989; Wellman, Ritter, & Flavell, 1975), demonstrate








33

high intercoder agreement for the types of strategies coded in the current study.














RESULTS

All analyses are reported at p < .05, with post-hoc tests evaluated with t-tests unless otherwise specified.

Preliminary Analyses

Some of the results were pertinent to general issues in cognition and memory development but not to the focus of the current study. These results are presented here. The next section reports results concerning issues of strategy variability and the relation between variability and recall.

Off-Task Behavior and Examination

off-task behavior and examination were observed during each of the three 30-s intervals of the study period (range: 0 to 3 per trial). Each type of data was analyzed separately using 2 (grade) x 2 (condition) x 7 (trial) analyses of variance (ANOVAs), with repeated measures on the trial factor. The analysis of off-task behavior revealed no significant main effects or interactions. As shown in previous research (Coyle & Bjorklund, 1997), off-task behavior was slightly greater for younger than for older children (mean frequency of off-task behavior per trial: .29 and .16 for second and fourth grade, respectively). The analysis of examination revealed significant main effects of condition, F(l, 116) = 5.51 (mean number of intervals of examination per trial: 1.87 and 2.27 for ascending/descending and descending/ascending conditions, respectively), and trial, F(6, 696)


34








35

5.68 (mean number of intervals of examination per trial: 2.28, 2.19,

2.10, 1.98, 2.03, 2.00, 1.85 for Trials 1-7, respectively). These main effects were qualified by a significant Condition x Trial interaction, f(6, 696) = 2.91. Inspection of the significant interaction revealed that ascending/descending versus descending/ascending comparisons were significant at Trial 2 (1.89 versus 2.54), Trial 3 (1.81 versus 2.43), and Trial 4 (1.69 versus 2.30), but not significant at Trial 1 (2.13 versus 2.46), Trial 5 (1.91 versus 2.16), Trial 6 (1.88 versus 2.14), and Trial 7 (1.81 versus 1.89). These data demonstrate that attention to the task materials was somewhat greater on the initial descending/ascending trials than on the corresponding ascending/descending trials.

Recall

Before presenting preliminary analysis of the recall data, data concerning repetitions and intrusions in recall are examined. Repetitions refer to recall of the same word more than once. Intrusions refer to utterances of words not on the target list. The frequency of occurrence of each type of data was analyzed separately using 2 (grade) x 2 (condition) x 7 (trial) ANOVAs, with repeated measures on the trial factor. Analysis of the repetition data revealed no significant main effects or interactions. Repetitions were slightly greater for fourth graders (M = .49) than for second graders (LI = .40). Analysis of the intrusion data revealed a significant main effect of grade, F(l, 116) 5.64, with intrusions being greater for second graders (M = .22) than for fourth graders (M = .05). All other main effects and interactions for the intrusion data were not significant. The significant grade








36

difference in intrusions is consistent with findings demonstrating that younger children have problems inhibiting task-inappropriate responses (Dempster, 1992). The repetition and intrusion data are excluded from all subsequent analyses.

Because possible recall varied trial-by-trial, the number of words recalled on each trial was converted to the proportion of words recalled relative to possible recall. Mean proportion recall on each trial, by grade and condition, is presented in Table 2, which also shows mean proportion recall by condition and trial (i.e., collapsed across grade) and fourth grade minus second grade recall differences by condition and trial. Proportion recall was examined by a 2 (grade) x 2 (condition) x

7 (trial) ANOVA, with repeated measures on the trial factor. The analysis revealed significant main effects of grade, F(l, 116) = 10-08 (mean proportion recall: .54 and .75 for second and fourth grade, respectively), condition, F(1, 116) = 6.83 (mean proportion recall: .65 and .60 for ascending/descending and descending/ascending conditions, respectively), and trial, F(6, 696) = 3.69 (mean proportion recall: .65, .61, .61, .67, .60, .60, and .65 for trials 1-7, respectively). Also significant were interactions of grade x trial, F(6, 696) = 7.01, and condition x trial, F(6, 696) = 57.68, both of which were qualified by a significant interaction of grade x condition x trial, F(6, 696) = 2.85.

The significant three-way interaction was evaluated by comparing grade differences in recall at each trial, separately for each condition. In the ascending/descending condition, significant grade differences in recall were observed on all trials except Trial 1, when only six words were presented. In the descending/ascending condition,








37

Table 2

Mean Proportion Recall By Condition, Grade, and Trial, and By Condition and Trial (i.e., Collapsed Across Grade), and Grade Differences in Recall at Each Trial By Condition



Trial


1 2 3 4 5 6 7


Ascending/Descending

Maximum Recall 6 9 12 15 12 9 6

Grade 2

M .81 .59 .49 .45 .42 .50 .71

SD .17 .22 .16 .18 .19 .28 .22

Grade 4

M .84 .73 .69 .70 .76 .89 .94

SD .18 .16 .23 .23 .21 .17 .14

Collapsed Across Grade

M .82 .64 .57 .55 .55 .65 .80

SD .17 .21 .21 .24 .26 .31 .22

Grade 4 Grade 2

Difference .03 .14 .20 .25 .34 .39 .24



Descending/Ascending

Maximum Recall 15 12 9 6 9 12 15

Grade 2

M .38 .48 .53 .76 .56 .41 .36

SD .18 .24 .24 .22 .30 .24 .18








38

Table 2--continued

Grade 4

M .55 .66 .80 .90 .80 .69 .61

SD .19 .21 .21 .22 .22 .24 .24

Collapsed Across Grade

M .46 .56 .66 .82 .67 .54 .48

SD .20 .25 .26 .23 .29 .28 .24

Grade 4 Grade 2

Difference .17 .18 .27 .14 .24 .28 .25



Note. Maximum recall indicates the maximum number of words that could be recalled on a particular trial.








39

grade differences in recall were found on all trials. As shown in Table 2, the magnitude of grade differences in recall was least pronounced on trials with the fewest words presented (Trials I and 7 in ascending/ descending and Trial 4 in descending/ascending), compared to the data on adjacent trials.

Strategy Use

The percentage and mean number of trials on which children in each grade used each strategy is presented by condition in Table 3. The percentages within each grade do not sum to 100 because multiple strategies were frequently used in combination on a single trial. The number of trials on which each strategy was used (range = 0 to 7) was examined by a 2 (grade) x 2 (condition) x 4 (strategy) ANOVA. The analysis revealed a significant main effect of strategy, E(l, 116) = 73.09, and significant interactions of grade x strategy, f(3, 348) = 4.63, and condition x strategy, L(3, 348) = 5.72. Inspection of the significant main effect of strategy revealed that sorting, rehearsal, and clustering were used more often than category naming, with all other strategy comparisons being nonsignificant (mean number of trials on which each strategy was used: 3.18, 3.44, 3.23, and .12 for sorting, rehearsal, clustering, and category naming, respectively). The floor levels of category naming are inconsistent with previous research showing that category naming was used relatively frequently by fourth graders who received a sort-recall task similar to the one used here. Although category naming was almost never used in the current study, the near absence of this strategy did not prevent the detection of








40

Table 3

Percentage (and Number) of Trials on Which Each Strategy Was Used, By Condition and Grade



Strategy


Category
Sorting Rehearsal Clustering Naming


Ascending/Descending

Grade 2 36 (2.54) 60 (4.21) 37 (2-56) 2 ( .15)

Grade 4 58 (4.04) 58 (4.04) 49 (3.40) <1 ( .04)

Descending/Ascending

Grade 2 35 (2.47) 38 (2.67) 50 (3.53) 3 ( .20)

Grade 4 59 (4.15) 37 (2.62) 53 (3.69) <1 ( .04)








41

significant effects concerning measures of strategy variability, as shown in later analyses.

Data relevant for the significant interactions concerning strategy use are presented in Table 3. Inspection of the Grade x Strategy interaction revealed that sorting was used more by fourth graders

4.13) than by second graders (M = 2.51), with grade comparisons for the other strategies being nonsignificant. Evaluation of the Condition x Strategy interaction revealed that rehearsal was used more in the ascending/descending condition (M = 4.13) than in the descending/ascending condition Q = 2.65), with the other strategies being used approximately equally in both conditions.

These strategy data provide information concerning the frequency of occurrence of each individual strategy. Subsequent analyses examine the possibility of several strategies being used in combination on a single trial, and changes in the mixture of strategies used across trials.

Variability in Strategy Use

Two general types of variability were examined: multiple-strategy use and strategy change. Multiple-strategy use refers to the number of strategies used within a given trial. Strategy change refers to the number of different strategies used across trials and trial-by-trial changes in strategy use.

Multiple-Strategy Use

An initial analysis examined the prediction that multiple-strategy use would increase with age and that the number of strategies used would be greatest for trials on which relatively many words were presented








42

(i.e., Trials 3-5 in the ascending/descending series and Trials 1, 2, 6, and 7 in the descending/ascending series). The number of strategies used on each trial was analyzed by a 2 (grade) x 2 (condition) x 7 (trial) ANOVA, with repeated measures on the trial factor. The analysis revealed a marginally significant effect of grade, F(l, 116) = 3.31, P .07, with fourth graders using more strategies (M = 1.57) than second graders Qj = 1.32). Also significant was the main effect of trial, F(6, 696) = 12.33, and the Grade x Trial interaction, F(6, 696) = 3.23. No other significant effects were found. Inspection of the significant main effect of trial revealed that the number of strategies used on Trial I (E = 1.14) and Trial 2 (N = 1.18) was significantly less than that used on Trials 3-7 (mean number of strategies used: 1.46, 1.49,

1.58, 1.57, and 1.58 for Trials 3-7, respectively). No other significant comparisons across trials were found.

Data pertaining to the significant Grade x Trial interaction are presented in Table 4, which also shows the number of strategies used for each Condition x Grade x Trial cell. Examination of grade differences in number of strategies used on each trial revealed that fourth graders used more strategies than second graders on Trials 3, 4, and 6, with strategy use being comparable for both grades on all other trials. These data, along with the data presented immediately above, are consistent with the predicted grade differences. In all cases where grade differences were found, fourth graders used more strategies than second graders. The absence of a significant Condition x Trial interaction indicates that strategy use did not vary across trials with different numbers of words presented.








43

Table 4

Mean Number of Strategies Used. By Grade and Trial, and By Condition. Grade, and Trial


Trial


1 2 3 4 5 6 7


Grade 2

M 1.22 1.12 1.30 1.32 1.44 1.38 1.48

SD .78 .83 .77 .85 .87 1.01 1.01

Grade 4

m 1.04 1.28 1.67 1.73 1.77 1.82 1.71

SD .96 .96 1.07 1.08 .99 1.14 1.17



Ascending/Descending

Grade 2

m 1.36 1.15 1.39 1.33 1.41 1.36 1.54

SD .81 .81 .78 .84 .79 1.04 .94

Grade 4

m 1.00 1.28 1.68 1.96 1.88 2.00 1.76

SD .96 .94 1.03 1.10 1.17 1.12 1.20



Descending/Ascending

Grade 2

N 1.03 1.07 1.20 1.30 1.47 1.40 1.40

SD .72 .87 .76 .88 .97 .97 1.10








44


Table 4--continued

Grade 4

m 1.08 1.27 1.65 1.50 1.65 1.65 1.65

SD .98 1.00 1.13 1.03 .80 1.16 1.16








45

Strategy Change

Number of strategy changes across trials. Although the analysis above demonstrates that fourth graders used more strategies than second graders, it did not examine possible changes in strategy use across trials (i.e., additions and deletions in strategy use on consecutive trials). For example, a child using two strategies across all trials could be using sorting and rehearsal on all seven trials, sorting and rehearsal on Trials 1-4 and sorting and clustering on Trials 5-7, or sorting and rehearsal on all even trials and sorting and clustering on all odd trials. In each case the child uses two strategies on all trials but shows a different number of strategy changes. A child using sorting and rehearsal on all trials shows no strategy changes; a child using sorting and rehearsal on Trials 1-4 and sorting and clustering on Trials 5-7 shows two strategy changes (i.e., dropping rehearsal and adding clustering from Trial 4 to Trial 5); and a child using sorting and rehearsal on all even trials and sorting and clustering on all odd trials shows 12 changes (i.e., dropping a strategy and adding a strategy on each of the six trial transitions (Trials 1 to 2, 2 to 3, 3 to 4, 4 to 5, 5 to 6, 6 to 7).

An analysis of strategy change evaluated the prediction that

strategy changes would decrease with age and that strategy changes would occur most frequently on transitions to trials with more words (i.e., Trials 2 to 3 and 3 to 4 in the ascending/descending series and Trials 5 to 6 and 6 to 7 in the descending/ascending series). The number of strategy changes on each of the six trial transitions was analyzed by a

2 (grade) x 2 (condition) x 6 (trial transition) ANOVA, with repeated








46

measures on the trial transition factor. The analysis revealed a significant main effect of grade, F(1, 116) = 11.41 (mean number of strategy changes: .78 and .54 for second and fourth grade, respectively), and a significant Grade x Trial Transition interaction, E(5, 580) = 2.67. No other significant effects were found.

Data relevant to the significant Grade x Trial Transition

interaction are presented in Table 5, which also shows the number of strategy changes for each Condition x Grade x Trial cell. Inspection of grade differences in strategy changes on each trial transition revealed that fourth graders had significantly fewer changes than second graders on all trial transitions except transitions 2 to 3 and 3 to 4. These data demonstrate that the grade difference mentioned above is primarily a result of fourth graders having fewer strategy changes than second graders on later rather than earlier trials. These findings are consistent with the hypothesis that strategy changes decrease with age. The absence of a significant Condition x Trial interaction indicates that strategy changes did not vary across trials with different numbers of words presented.

Other types of variability. Although number of strategy changes across trials is one measure of strategy change, other measures of strategy change are possible. Two additional measures of strategy change are examined here: number of unique strategy combinations used across all trials (range: 0 to 7), and number of consecutive trials with strategy changes (range: 0 to 6). These measures, along with the average number of strategy changes across trials (an average of the measure analyzed above), were converted to z-scores and entered into a 2








47

Table 5

Mean Number of Trial-by-Trial Strategy Changes, By Grade and Trial Transition, and By Condition, Grade, and Trial Transition



Trial Transition


Ilto 2 2 to 3 3 to 4 4 to 5 5 to 6 6 to 7


Grade 2

m .77 .68 .73 .93 .87 .70

SD .75 .58 .75 .85 .89 .69

Grade 4

M .49 .80 .57 .47 .45 .43

SD .64 .83 .67 .83 .50 .61



Ascending/Descending

Grade 2

M .87 .64 .67 .95 .82 .69

SD .83 .63 .74 .79 .82 .69

Grade 4

m .40 .76 .64 .60 .40 .44

SD .50 .78 .76 1.08 .50 .65



Descending/Ascending

Grade 2

14 .63 .73 .80 .90 .93 .70

SD .62 .52 .76 .92 .98 .70








48

Table 5--continued

Grade 4

m .58 .85 .50 .35 .50 .42

SD .76 .88 .58 .49 .51 .58








49

(grade) x 2 (condition) x 3 (strategy change type) ANOVA, with repeated measures on the strategy change type factor. This analysis permitted examination of possible grade and condition differences across the three measures of strategy change.

The analysis revealed a significant main effect of grade, F(l,

116) = 10.65 (mean z-scores summed across the three measures of strategy change: .22 and -.30 for second and fourth grade, respectively), which was qualified by a significant Grade x Strategy Change Type interaction, f(2, 232) = 3.90. No other significant main effects or interactions were found. Data pertaining to the significant Grade x Strategy Change Type interaction are presented in Table 6. Fourth graders had significantly lower levels of strategy change than second graders for two of the three measures (trials with changes and total changes). The grade difference for unique combinations was in the predicted direction but only approached significance, p < .10. Paired comparisons among the change measures within each grade revealed that fourth graders had significantly fewer total strategy changes than unique combinations. No other comparisons among the change measures within each grade were found. These data, along with the data in the preceding section, demonstrate that older children show fewer strategy changes than younger children across a variety of measures of strategy change, with the exception of unique combinations.

Variability within individual children. Although these findings demonstrate that strategy changes decline with age, they are based on analyses of group data, which often mask patterns of individual strategy use. Thus, children were classified as stable or unstable based on








50

Table 6

Mean Z-scores and Raw Scores for Unique Combinations, Trials with Changes, and Total Changes, By Grade (Standard Deviations in Parentheses)



Strategy Change Type


Unique Trials Total
Combinations with Changes Changes


Grade 2

Z-Score .13 (1.00) .25 (1.00) .29 (1.04)

Raw Score 2.64 (1.11) 3.51 (1.56) 4.67 (2.45)

Grade 4

Z-Score -.18 ( .99) -.34 ( .91) -.39 ( .80)

Raw Score 2.29 (1.10) 2.59 (1.43) 3.06 (1.87)








51

their pattern of strategy change across trials. Children were classified as stable if they used the same combination of strategies on at least four pairs of consecutive trials (of a possible six pairs of consecutive trials). Children were classified as unstable if they used the same combination of strategies on fewer than fours pairs of consecutive trials. These classifications were based on changes in the mixture (rather than the number) of strategies used over trials.

The percentage of children in each grade classified as stable or unstable is shown in the first and second columns of Table 7. Fourth graders were significantly more likely to be classified as stable than second graders, who showed considerable variability in strategy use 2j2(l, N = 120) = 7.52. These data are consistent with the findings reported in the previous section. However, the findings in the previous section showed that although both groups tended to show variability on early trials, only the second graders showed variability on later trials. Thus, a second analysis examined the possibility that the observed grade differences in stability classification were primarily attributed to differences in variability on later rather than earlier trials. Children were classified as stable or unstable on early trials (Trials 1 to 4) and separately on later trials (Trials 4 to 7). (Trial 4 is both the last trial in the set of early trials and the first trial in the set of later trials.) For each block of trials, children were classified as stable if they used the same combination of strategies on two or three pairs of consecutive trials (of a possible total of three pairs of consecutive trials). Children were classified as unstable if








52

Table 7

Percentage (and Number) of Children Classified as Stable or Unstable Across All Trials, on Early Trials, and on Later Trials, By Grade



All Trials Early Trials Later Trials


Grade Stable Unstable Stable Unstable Stable Unstable


2 23 (16) 77 (53) 39 (27) 61 (42) 38 (26) 62 (43)

4 47 (24) 53 (27) 43 (22) 57 (29) 63 (32) 37 (19)








53

they used the same combination of strategies on only one of three pairs of consecutive trials.

The percentage of children in each grade classified as stable and unstable on early trials and separately on later trials is presented in columns three through six in Table 7. For the early trials, no grade difference in the distribution of children classified as stable or unstable was found, X2(l, N = 120) < 1, with most children showing unstable strategy use. For the later trials, fourth graders were significantly more likely to be classified as stable than second graders, who frequently showed unstable strategy use, X2(l, N = 120)

7.38. These findings demonstrate that both groups of children showed considerable variability in strategy use on early trials. In contrast, only second graders showed unstable strategy use on later trials; most fourth graders showed stable strategy use.

These findings were extended in an analysis that examined changes in stability classification from early to later trials for individual children. Children were classified as showing one of four possible patterns of stability classification from early trials (i.e., Trials 1 to 4) to later trials (Trials 4 to 7): unstable on early trials, unstable on later trials (unstable/unstable); unstable on early trials, stable on later trials (unstable/stable); stable on early trials, stable on later trials (stable/stable); stable on early trials, unstable on later trials (stable/unstable).

The percentage of children in each of the four pattern

classifications is shown by grade in Table 8. The data are presented in terms of children whose stability classification did or did not change








54

Table 8

Percentage (and Number) of Children Changing or Not Changing Their Stabilit Classification Across Trial Blocks, By Grade



No Change Change


Unstable/ Stable/ Unstable/ Stable/
Grade Unstable Stable Stable Unstable


2 41 (28) 17 (12) 20 (14) 22 (15)

4 18 ( 9) 24 (12) 39 (20) 20 (10)








55

from early to later trials. The distribution of fourth and second graders in each of the four pattern classifications was significantly different, X2(3, N = 120) = 9.33. Analysis of data for children who did not change pattern classifications revealed that second graders were significantly more likely to show the unstable/unstable pattern than fourth graders, who frequently showed the stable/stable pattern, X2(l, N = 61) = 4.25. Analysis of data for children who did change pattern classifications revealed that the distribution of second and fourth graders in the unstable/stable and stable/unstable groups was not significant, X2(l, N = 59) = 2.04. The analysis of children who did not change classifications demonstrates that fourth graders were more likely to maintain an initial pattern of stable-strategy use than second graders, who frequently maintained an initial pattern of unstablestrategy use.

Analyses were also performed on the distribution of second and

fourth graders whose initial classification (on Trials 1-4) was unstable (unstable/unstable and unstable/stable), and separately on the distribution of second and fourth graders whose initial classification was stable (stable/stable and stable/unstable). In the analysis of children whose initial classification was unstable, fourth graders were significantly more likely to show the unstable/stable pattern than second graders, who frequently showed the unstable/unstable pattern, L( 2(l, N = 71) = 8.73. The distribution of second and fourth graders whose initial classification was stable (stable/stable and stable/unstable) was not significant, X2(l, N = 49) < 1. The analysis of children whose initial classification was unstable demonstrates that








56

fourth graders frequently switched from unstable-strategy use on early trials (i.e., Trials 1 to 4) to stable-strategy use on later trials (i.e., Trials 4 to 7). In contrast, second graders who showed unstablestrategy use on early trials frequently also showed unstable-strategy use on later trials.

Relation Between Strategy Use and Recall Utilization Deficiencies

Correlations between number of strategies used and recall. Miller and Seier (1994) have argued that significant and positive correlations between strategy use and recall for older but not younger children indicate a utilization deficiency for younger children. In the current study, utilization deficiencies of this type were expected on most trials for second graders. However, second graders were predicted to overcome a utilization deficiency on trials with relatively few words, when capacity requirements for strategy use were presumably minimal.

Utilization deficiencies were evaluated by computing correlations between number of strategies used and percentage of words recalled, separately for each Condition x Grade x Trial cell (see Table 9). The pattern of correlations in the ascending/descending condition showed clear age differences in the significance and magnitude of the relation between strategy use and recall. Fourth graders showed significant and positive correlations on all trials, whereas second graders showed significant and positive correlations on only three of seven trials. The magnitude of correlations for the fourth graders was higher than that for second graders on all Trials except Trial 6. These data provide evidence of utilization deficiency for the youngest children.








57

Table 9

Correlations Between Number of Words Recalled and Number of Strategies Used, By Condition, Grade, and Trial



Trial


1 2 3 4 5 6 7


Ascending/Descending

Grade 2 .31 .29 .42** .32* .16 .50** .30

Grade 4 .41* .46* .41* .65** .73** .45* .55**

Descending/Ascending

Grade 2 -.18 .50** .43* .34 .60** .65** .57**

Grade 4 .31 .37 .38 .06 .43* .46* .36


* p < .05, ** p < .01








58

Contrary to predictions, second graders did not overcome a utilization deficiency on three of four trials with nine or fewer words presented (i.e., Trials 1, 2, and 7).

The pattern of correlations in the descending/ascending condition was nearly opposite to that observed in the ascending/descending condition. Fourth graders now had significant correlations on only two of seven trials. Second graders had significant correlations on five of seven trials, with two of these correlations being found on trials with nine or fewer words presented (i.e., Trials 3 and 5). The magnitude of correlations for second graders was higher than that for fourth graders on all trials except Trial 1. These data do not provide evidence of a utilization deficiency for the younger children.

The failure to find significant correlations for fourth graders in the descending/ascending condition, when such correlations were significant in the ascending/descending condition, cannot be attributed to restricted variance in number of words recalled or number of strategies used. The standard deviations for number of strategies used on Trials 1-7 were very similar for fourth graders in the ascending/descending condition (SDs = .96, .94, 1.03, 1.10, 1.17, 1.12, and 1.20) and in the descending/ascending condition ( Ds = .98, 1.01, 1.13, 1.03, .80, 1.16, and 1.16). The standard deviations for recall were also similar for both groups of fourth graders (see Table 2).

Recall for perfectly Strategic children. Coyle and Bjorklund

(1996), as well as Miller and Seier (1994), have argued that utilization deficiencies can be inferred when grade differences in recall are observed despite comparable strategy use. In the current study, this








59

type of utilization deficiency was evaluated by analyzing mean proportion recall for trials on which children showed perfect sorting only, perfect clustering only, and perfect sorting and clustering. Clustering and sorting data on each trial were measured continuously by ARC scores for this analysis. ARC scores can range from 1 to -1, with 1 indicating perfect sorting or clustering and 0 indicating chance sorting or clustering. Because children rarely showed multiple trials with perfect strategy use (i.e., two or more trials with sorting or clustering scores of 1), repeated measures analysis of recall across trials with perfect strategy use was not performed. Instead, each child received a single score averaging recall across trials with perfect strategy use. Such a recall score was computed separately for trials with perfect clustering only, perfect sorting only, and perfect clustering and sorting.

Mean proportion recall for children in each grade showing each

measure of perfect strategy use is presented in Table 10, along with the number of subjects in each grade who had at least one trial of perfect strategy use. Separate 2 (grade) x 2 (condition) ANOVAs were performed on proportion recall for trials with perfect sorting only, perfect clustering only, and perfect sorting and clustering. The analysis of recall on trials with perfect clustering revealed a significant main effect of grade, F(l, 83) = 5.59. No other significant main effects or interactions were found for any measure of perfect strategy use.

These findings demonstrate that second graders who clustered

perfectly recalled fewer words than comparably strategic fourth graders, which is evidence for a utilization deficiency for the second graders.









60

Table 10

Mean Proportion Recall When Strategy Use Was Perfect, By Grade and Type of Strategy Used



Strategies Used Perfectly


Sorting Clustering Sorting and
Only Only Clustering


Grade 2

M .72 .50 .87

SD .19 .17 .17

n 15 63 14

Grade 4

M .80 .60 .89

SD .15 .23 .10

n 14 24 28


Note. ns are number of children who showed at least one trial of perfect strategy use.








61

In contrast, second graders who sorted perfectly or sorted and clustered perfectly recalled just as many words as comparably strategic fourth graders. Thus, utilization deficiencies occurred for some but not all instances of perfect strategy use. The absence of a significant effect of condition demonstrates that recall in each condition did not vary for children who showed comparable and perfect strategy use.

Utilization deficiencies for individual strategies. The findings described above were confirmed and extended in a descriptive analysis of recall for children in each grade who used each of the 15 possible strategy combinations or no strategy (see Table 11). The first part of this analysis examined grade differences in the percentage of trials on which each combination was used. As shown in Table 11, second graders were more likely than fourth graders to use rehearsal only, clustering only, and both rehearsal and clustering. In contrast, fourth graders were more likely than second graders to use no strategy, both sorting and clustering, and sorting, rehearsal, and clustering.

Utilization deficiencies were evaluated by analyzing grade

differences in recall when children used the same strategies. Analyses were conducted only on the seven strategy combinations for which sufficient data were available for a significance test. (Recall data for no strategy use were not included in this analysis because children who use no strategy cannot be evaluated for a utilization deficiency.) Of these seven comparisons, four showed that fourth graders recalled significantly more than second graders when strategy use was comparable. The remaining three comparisons were not significant but had means in the predicted direction. Consistent with the findings in the previous








62

Table 11

Percentage (and Number) of Trials on Which Each Strategy Combination Was Used, and Mean Proportion Recall (and Standard Deviations) for Each Combination, By Grade (Codes for Strategies: S. Sorting; R, Rehearsal; C, Clustering; N, Category Naming)



Percentage of Trials Mean Recall


Strategy Grade 2 Grade 4 Grade 2 Grade 4


None 16 ( 78) 22 (77) .41 (.25) .65 (.23)

S 8 ( 39) 8 (30) .50 (.23) .60 (.21)

R 24 (115) 10 (34) .53 (.25) .81 (.19)

C 14 68) 5 (18) .47 (.19) .54 (.17)

N 0 0) 0 ( 0)

SR 8 37) 10 (34) .65 (.23) .76 (.22)

SC 10 50) 17 (61) .70 (.26) .80 (.22)

SN <1 2) 0 ( 0)

RC 10 49) 5 (17) .48 (.20) .69 (.27)

RN <1 1) 0 0)

CN 0 0) 0 0)

SRC 7 35) 23 (83) .74 (.23) .90 (.13)

SRN <1 1) <1 1)

SCN <1 1) <1 2)

RCN <1 1) 0 0)

SRCN 1 6) 0 0)








63

Table 11--continued

Note. Boldface denotes significant age differences in recall or percentage of trials on which a particular strategy combination was used, with all significant results reported at p .05. Recall data are omitted for combinations used on one or zero trials. Grade differences in percentage of trials on which each combination was used are evaluated using Yates corrected chi-squares with one degree of freedom. Grade differences in mean recall for each combination are evaluated using t-tests.








64

section, these data demonstrate that fourth graders outperform comparably strategic second graders, which is evidence of a utilization deficiency for the second graders. Strategy Change and Recall

Correlations between strategy change and recall. Previous

research (Coyle & Bjorklund, 1997) involving procedures and age groups similar to those in the current study has shown that measures of strategy change are significantly and negatively correlated with recall for older but not younger children. That is, older children who showed the fewest strategy changes across trials (i.e., high levels of stability in strategy use) had the highest levels of recall. The current study attempted to replicate this finding with a different sample.

Correlations were computed separately between each measure of strategy change and mean proportion recall across trials. The three measures of strategy change were number of unique strategy combinations, number of consecutive trials with strategy changes, and total number of strategy changes on consecutive trials.

Correlations computed separately for each grade revealed a pattern very similar to that observed in previous research. Fourth graders showed significant and negative relations between recall and strategy change for two of the three measures (trials with changes, r(51) = -.42, p < .01, and total changes, r(51) = -.36, p < .05), but not for unique combinations, r(51) = -.11, p > .10. Second graders showed no reliable relation between recall and any measure of strategy change (Ls(69) = .23, -.15, and -.13 for unique combinations, trials with changes, and








65

total changes, respectively). These findings were qualified by correlations computed separately within each Grade x Condition cell and reported in Table 12. These correlations showed that only fourth graders in the descending/ascending condition showed significant and negative relations between recall and strategy change, with correlations involving all three measures of strategy change being significantly related to recall. These latter findings demonstrate that the grade differences reported above can be attributed to correlational data for fourth graders in the descending/ascending condition. Fourth graders in the ascending/descending condition showed no reliable relation between recall and strategy change.

The data in Table 12 reveal that the difference between

correlations involving trials with changes and total changes was always lower than the difference between correlations involving each of these variables and unique combinations. This suggested possible differences in the relations among the various measures of strategy change. To assess this possibility, pairwise correlations among each of the three measures of strategy change were computed, separately within each Grade x Condition cell. These correlations are reported Table 13.

As shown in Table 13, all correlations among the three measures of strategy change were significant. However, the magnitude of correlations involving unique combinations (i.e., unique combinations and trials with changes; unique combinations and total changes) was lower than the magnitude of correlations not involving unique combinations (i.e., trials with changes and total changes). Correlations between trials with changes and total changes were near








66

Table 12

Correlations Between Measures of Strategy Change and Recall. By Condition and Grade


Measure of Strategy Change Unique Trials Total
Combinations with Changes Changes

Ascending/Descending

Grade 2 .23 -.21 -.06

Grade 4 .28 -.16 -.05

Descending/Ascending

Grade 2 .22 -.13 -.18

Grade 4 -.53** -. 66** .66**


**Q < .01








67

Table 13

Correlations Among Measures of Strategy Change, By Condition and Grade



Correlation


Combinations and Combinations and Trials with Changes
Trials with Changes Total Changes Total Changes


Ascending/Descending

Grade 2 .33* .49** .77***

Grade 4 .60** .65*** .93***

Descending/Ascending

Grade 2 .66*** .64*** .94***

Grade 4 .69*** .68*** .91**


*Q < .05, **p < .01, ***D < .001








68

perfect for all Grade x Condition cells except one (second graders in the ascending/descending condition).

Relation between strategy change and recall for individual

children. The finding that stability was related to high levels of recall only for fourth graders in the descending/ascending condition was only partially confirmed in an analysis of recall for children classified as stable or unstable (see Table 7 for stability classification data). A 2 (grade) x 2 (stability classification) x 2 (condition) x 7 (trial) ANOVA was conducted on mean proportion recall. Because significant main effects and interactions involving the Grade, Condition, and Trial factors have already been reported, only significant main effects and interactions involving the Stability Classification factor are reported here.

The analysis revealed a marginally significant main effect of stability classification, F(l, 112) = 3.02, p = .09 (mean proportion recall: .59 and .70, for unstable and stable, respectively), which was qualified by a significant grade x stability classification interaction, F(l, 112) = 3.78. No other significant effects involving the stability classification factor were found, including effects involving the condition factor. The failure to find a significant Grade x Stability Classification x Condition interaction is inconsistent with the correlational results reported in the previous section. Those results showed that, in the descending/ascending condition, fourth graders showing stable-strategy use had higher recall than fourth graders showing unstable-strategy use. The findings in the current section, along with those of the previous one, demonstrate that findings








69

pertaining to analyses that examine patterns of variability for individual subjects may not always be consistent with those pertaining to analyses that examine patterns of variability in group data.

Data relevant to the significant Grade x Stability Classification interaction are reported in columns one and two of Table 14. Differences in recall between stable and unstable children were analyzed separately within each grade. Second-grade children in each stability classification showed equivalent levels of recall. In contrast, fourth graders classified as stable recalled significantly more than fourth graders classified as unstable. A further analysis examined grade differences.in recall separately within each stability group. Fourth graders recalled significantly more than second graders within both stability groups. However, the magnitude of this grade difference in recall was greater for stable children than for unstable children (mean fourth grade minus second grade recall difference: .28 and .16, for stable and unstable children, respectively).

These findings were confirmed and extended in a final set of analyses that examined grade differences in recall for children classified as stable and unstable on early trials (Trials 1-4) and separately on later trials (Trials 4-7). A 2 (grade) x 2 (condition) x

2 (stability classification) ANOVA was performed on mean proportion recall on early trials and separately on later trials. As before, only significant effects involving the stability classification factor are reported. The recall data for these analyses are reported in columns three through six in Table 14.








70

Table 14

Mean Proportion Recall (and Standard Deviations) for Children Classified as Stable or Unstable Across All Trials, on Early Trials, and on Later Trials, By Grade



All Trials Early Trials Later Trials


Grade Stable Unstable Stable Unstable Stable Unstable


2 .53 (.18) .54 (.15) .53 (.15) .59 (.15) .59 (.18) .47 (.15)

4 .81 (.12) .70 (.16) .78 (.12) .70 (.16) .82 (.16) .72 (.20)








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The analysis involving data on early trials revealed a significant grade x stability classification interaction, F(l, 112) = 5.62. No other significant effects involving stability classification were found. Examination of the significant interaction revealed a pattern of results very similar to that observed the analysis involving all trials. No differences in recall were found for second graders classified as stable or unstable, whereas recall for fourth graders classified as stable was marginally greater than that for fourth graders classified as unstable, P < .07. Separate grade comparisons within each stability classification revealed that fourth graders recalled significantly more than second graders, although the magnitude of this grade difference was again greater for stable children than for unstable children (mean fourth grade minus second grade recall difference: .25 and .11 for stable and unstable children, respectively).

The comparable analysis involving data on later trials revealed a significant main effect of stability classification, F(l, 112) = 11.10 (mean proportion recall: .72 and .55 for stable and unstable, respectively). No other significant differences involving stability classification were found. These findings, along with those for early trials, demonstrate that stability on early trials is associated with high levels of recall for older but not younger children, whereas stability on later trials is associated with high levels of recall for both age groups.

Conditions of strategy changes. Why do strategy changes occur? McGilly and Siegler (1989) addressed this question by analyzing the number of trials on which children showed strategy changes immediately








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after serial recall performance that was perfect or less than perfect. They found that children were more likely to show strategy changes when recall was less than perfect than when recall was perfect. That is, children tended to stick with a particular strategy on the next trial when it had yielded perfect performance, but changed strategies on the next trial when it had yielded less than perfect performance. This pattern is consistent with the win-stay/lose-shift approach that has been reported in decision-making literature (Eimas, 1969).

In the current study, evidence for the win-stay/lose-shift

approach was examined by classifying each trial as a trial on which recall was perfect or not perfect and on which strategy changes were or were not observed on the next trial. This resulted in four possible classifications: recall perfect/strategy change; recall perfect/no strategy change; recall not perfect/strategy change; recall not perfect/no strategy change. Classifications were performed separately for Trials 1-6, with each child contributing a single data point at each trial. (Trial 7 was omitted from the analysis because a strategy change following Trial 7 is not possible.)

The percentage of trials on which recall was perfect or not and followed by a strategy change or not is shown in Table 15. The classification data on each trial were analyzed separately by 2 (recall perfect vs. recall not perfect) x 2 (strategy change vs. no strategy change) chi-squares. For Trials 1 through 3, perfect recall was followed by strategy changes or no strategy change approximately equally, 2j2s(l, N = 120) < 1. For Trials 4 through 6, however, perfect recall was followed by no strategy change more frequently than by









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Table 15

Percentage (and Number) of Trials on Which Strategy Changes Did and Did Not Occur Immediately After Recall was Perfect or Not Perfect



Trial


1 2 3 4 5 6


Recall Perfect

Strategy
Change 42 ( 8) 57 ( 4) 31 ( 4) 30 ( 9) 29 ( 6) 25 ( 5)

No Strategy
Change 58 (11) 43 ( 3) 69 ( 9) 70 (21) 71 (15) 75 (15)

Recall Not Perfect

Strategy
Change 53 (54) 61 (69) 54 (58) 62 (56) 57 (56) 54 (54)

No Strategy
Change 47 (47) 39 (44) 46 (49) 38 (34) 43 (43) 46 (46)


Note. Percentages computed separately at each trial.








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strategy changes, X2s(l, N = 120) > 5.43. These results demonstrate that children were more likely to continue to use a strategy that yielded perfect performance on later but not earlier trials.

Additional analyses examined the prediction that trials with

relatively few words (i.e., Trials 1, 2, and 6 in ascending/descending and Trials 3, 4, and 5 in descending/ascending) would provide greater opportunity for perfect recall, and consequently result in relatively few strategy changes. To test this prediction, a series of 2 (recall perfect vs. recall not perfect) x 2 (strategy change vs. no strategy change) chi-squares were performed separately at each trial in each condition (see Table 16). This resulted in a total of 12 individual chi-squares (2 conditions x 6 trials). (Because including the grade factor would have resulted in insufficient data to perform significance tests for several of the grade x condition x trial combinations, the grade factor was excluded from these analyses.) One of the 12 chisquares (Trial 1 in the descending/ascending condition) did not contain sufficient data for a significance test. Of the remaining 11, only two were significant. As predicted, the pattern of data on trials 4 and 5 in the descending/ascending condition revealed that perfect recall was followed by no strategy change more frequently than by strategy changes, X2s(l, N = 56) > 5.18. The four other trials on which this pattern was predicted (i.e., Trials 1, 2, and 6 in ascending/descending and Trial 3 in descending ascending) showed that perfect recall and strategy changes did not vary as a function of number of words presented. These data provide little evidence for the prediction that trials with relatively









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Table 16

Percentage (and Number) of Trials on Which Strategy Changes Did and Did Not Occur Immediately After Recall was Perfect or Not Perfect, By Condition



Trial


1 2 3 4 5 6


Ascending/Descending Number of Words
Presented 6 9 12 15 12 9

Recall Perfect

Strategy
Change 42 ( 8) 50 ( 3) 33 ( 1) 67 ( 2) 33 ( 2) 29 ( 5)

No Strategy
Change 58 (11) 50 ( 3) 67 ( 2) 33 ( 1) 67 ( 4) 71 (12)

Recall Not Perfect

Strategy
Change 56 (25) 57 (33) 51 (31) 59 (36) 53 (31) 55 (26)

No Strategy
Change 44 (20) 43 (25) 49 (30) 41 (25) 47 (27) 45 (21)


Descending/Ascending Number of Words
Presented 15 12 9 6 9 12

Recall Perfect

Strategy
Change 0 ( 0) 100 ( 1) 30 ( 3) 26 ( 7) 27 ( 4) 0 ( 0)

No Strategy
Change 0 ( 0) 0 ( 0) 70 ( 7) 74 (20) 73 (11) 100 ( 3)









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Table 16--continued

Recall Not Perfect

Strategy
Change 52 (29) 65 (36) 59 (27) 69 (20) 61 (25) 53 (28)

No Strategy
Change 48 (27) 35 (19) 41 (19) 31 ( 9) 39 (16) 47 (25)


Note. Percentages computed separately at each trial.








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few words would provide greater opportunity for perfect recall, and consequently result in few strategy changes.















DISCUSSION

The current study examined several measures of variability in strategy use, relating each measure to memory performance. Whereas previous investigations of variability in strategy use have assessed only one strategy on each trial and one type of variability (Siegler, 1996), the current study examined the possibility of multiple strategies on each trial and two different types of variability (multiple-strategy use and strategy changes). The current study was very similar in design to a study by Coyle and Bjorklund (1997). However, it had additional trials with which to evaluate changes in variability over time and included trials varying widely in the number of words to be recalled. Strategy variability was assessed within and across trials and related to mean levels of recall, with analyses focusing on utilization deficiencies and stability-recall relations. The results revealed developmental differences in multiple-strategy use and strategy change, and more important, age-related changes in the relation between measures of variability and recall. Surprisingly, the results revealed few significant effects related to the number of words presented on each trial or the pattern of increases and decreases in the number of words presented across trials.

The goals of the current study were to examine the impact of age and number of words presented on each trial on (a) measures of strategy variability, including multiple-strategy use and strategy changes; (b)


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the relation between multiple-strategy use and recall, with particular attention to patterns indicative of utilization deficiencies; (c) and the relation between strategy changes and recall, with particular attention to stability-recall relations. The pages that follow are organized around these goals.

Variability in Strategy Use

Multiple-Strategy Use

As predicted, fourth graders tended to use more strategies than

second graders, with the number of strategies used increasing from Trial

2 to Trial 3 and remaining stable thereafter. These results were confirmed and extended in the analysis of grade differences in the use of each of the 15 unique strategy combinations (Table 11). In that analysis, second graders used the strategies of rehearsal and clustering and the two-strategy combination of rehearsal and clustering more than fourth graders. In contrast, fourth graders used the two-strategy combination of sorting and clustering and the three-strategy combination of sorting, rehearsal, and clustering more often than second graders. These data demonstrate that, when grade differences in strategy use were found, second graders tended to use combinations with the fewest strategies (i.e., single-strategy combinations) whereas fourth graders tended to use combinations with the most strategies (i.e., threestrategy combinations).

The very low frequency of category naming in the current study is inconsistent with the results obtained by Coyle and Bjorklund (1997). Whereas category naming was observed on only 2% of all trials in the current study, it was observed on almost 31% of all trials in Coyle and








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Bjorklund (1997). The reason for this difference is not clear. Both studies used similar tasks and designs, had very similar testing procedures, and involved children in the same age range. One possible explanation for the disparity is that children in each study attended different types of schools. Whereas children in the current study attended public schools, children in Coyle and Bjorklund attended a university-affiliated laboratory school. The curriculums at public schools and laboratory schools may differ in ways that promote or inhibit organizational strategy use. For example, children who attend the university-affiliated schools may receive explicit instruction in organizing items by taxonomic categories, whereas children who attend public schools may receive such instruction less often, if at all. Such a curriculum difference would affect children's use of organizational strategies, particularly category naming.

The near absence of category naming in the current study resulted in fewer strategies being available for analyses of variability in strategy use. Although a reduction in the total number of strategies available for analyses could affect statistical outcomes, the agerelated patterns of variability and performance found in the current study are comparable to those found in the very similar sort-recall study by Coyle and Bjorklund (1997). Older children in both studies used more strategies than younger children. Also, as reported later in the Discussion, older children in both studies showed lower levels of strategy change, and stronger relations between stable-strategy use and recall, than did younger children. These results suggest that age-








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related patterns in variability are relatively uninfluenced by changes in the total number of strategies being assessed.

Children were expected to show increases in the number of

strategies used on trials with more words. The results revealed that multiple-strategy use did not vary as a function of the number of words on each trial, with strategy use being comparable across both the ascending/descending and descending/ascending conditions. The absence of any effects involving trial or condition cannot be attributed to ceiling effects or children not being able to use the target strategies. Children of all ages used an average of fewer than two strategies across trials (of a possible four strategies), leaving ample opportunity for increases in the number of strategies used. Furthermore, children in the age range studied have demonstrated competence in using all strategies assessed.

The absence of any effect of condition and trial on the number of strategies used demonstrates that children did not modify their strategic behavior in response to being presented with different number of words. Why did children stick with using a certain number of strategies when presented varying number of words? Perhaps the most parsimonious explanation is that children did not consider altering their strategic behavior on trials with different numbers of words. Although children in the age range tested could use all the strategies assessed in the current study, metacognitive limitations concerning when and how to use strategies may have prevented them from doing so. An implication is that children who do not produce strategies spontaneously might do so if they are instructed to (Ringle & Springer, 1980). In








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addition to metacognitive limitations, capacity limitations may have prevented the use of additional strategies. Children have limited mental capacity for executing cognitive operations such as strategies, and such capacity constraints may impose limits on the number of strategies that can be used (Guttentag, 1984). Capacity limits can change as a result of task experience or familiarization, as may have occurred when strategy use increased from Trial 2 to 3. However, capacity limits probably place an upper limit on the number of strategies used, resulting in changes that occur in a restricted range. Strategy Changes

In addition to the observed age differences in multiple-strategy use, the current study also revealed age differences in strategy changes. Fourth graders showed fewer strategy changes than second graders for two of the three measures of strategy change (number of trials with changes and number of trial-by-trial changes). No grade difference was found for the third measure of strategy change, number of unique strategy combinations, although the pattern was in the predicted direction. Although age-related declines in variability have been noted elsewhere (Siegler, 1996), these are the first results to demonstrate empirically that strategy changes decline with age. More importantly, these results, along with the results pertaining to multiple-strategy use described above, demonstrate that different measures of variability show different developmental patterns. Number of strategies used increased with age, number of trials with changes and total strategy changes decreased with age, and number of unique strategy combinations was comparable across age. These results suggest considerable diversity








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in the developmental pathways of different measures of variability, with no one pattern accounting for all measures of strategy change and multiple-strategy use.

Correlations among the various measures of strategy changes

differed in magnitude. Although correlations among all measures of strategy change were significant, correlations between number of trials with changes and total number of changes were consistently higher than correlations between each of these measures and number of unique combinations. Moreover, correlations between trials with changes and total changes were near perfect (rs > .90) for 3 of the possible 4 correlations involving these measures, whereas none of the 8 correlations involving unique combinations was near perfect. These data are the first to my knowledge to show differences in the strength of relations among different measures of strategy change.

Differences in the relations among the various measures of

strategy change can be attributed to how each measure was computed. The two most closely related measures, trials with changes and total changes, both were computed based on the number of consecutive trials on which different strategies were used. The third measure, unique combinations, was computed based on the number of different strategy combinations used, irrespective of whether the different strategies were used on consecutive trials. These computational differences resulted in differences in the magnitude of the correlations among the various measures of strategy change, with correlations among measures based on the same underlying index of strategy change being higher than









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correlations among measures based on different indexes of strategy change.

Mean levels of variability for each strategy change measure in the current study were lower than those observed in the similar study by Coyle and Bjorklund (1997). In the current study, percentage of unique combinations, trials with changes, and total changes across trials (collapsed across grade) was 35, 51, and 55, respectively. In Coyle and Bjorklund, the corresponding percentages were 46, 54, and 62, respectively. This slight disparity in strategy change scores can be attributed to the current study using more trials than the Coyle and Bjorklund study. As shown in Table 5, the additional trials in the current study allowed fourth graders to maintain a pattern of stablestrategy use (i.e., few strategy changes) that began after Trial 4, whereas second graders showed unstable-strategy use across all trials. Consequently, the mean number of strategy changes averaged across grade can be attributed to fourth graders showing substantially lower strategy change scores on the later trials. Although Coyle and Bjorklund did analyze strategy change patterns across trials, the fewer trials used in that study limited the amount of stability that older children could display and probably contributed to the slight disparity in strategy change scores.

The age-related decline in strategy change was confirmed and extended in analyses of trial-by-trial changes in strategy use for individual children. An initial analysis revealed that fourth graders were more likely to be classified as showing stable-strategy use than second graders, who often switched strategies on adjacent trials.








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Subsequent analyses revealed that this grade difference in stability classification was attributed to a disproportionate number of fourth graders being classified as stable on later trials (i.e., Trials 4 to 7). The distribution of children in each grade classified as stable and unstable was comparable on early trials (i.e., Trials 1 to 4). These findings were extended in an analysis of changes in individual-subject stability classification across early and later trial blocks for children whose initial stability classification was unstable. In that analysis, fourth graders who showed unstable-strategy use on early trials frequently showed stable-strategy use on later trials. In contrast, second graders who showed unstable-strategy use on early trials often remained unstable on later trials. These findings demonstrate that stable-strategy use emerged during the later trials for fourth graders but not for second graders. The fourth-grade data are consistent with research demonstrating that variability in strategy use declines with experience on a task (Coyle & Bjorklund, 1997; Siegler, 1996). Presumably, the second-grade children eventually would have shown stability in strategy use if they had been given additional practice and experience on the task. Microgenetic studies, assessing children's strategy use over longer periods of time, are needed to evaluate this hypothesis.

Children in all grades were predicted to show relatively few

strategy changes following trials with few words (i.e., trials with 6 or

9 words) and more frequent strategy changes following trials with many words (i.e., trials with 12 or 15). Contrary to this prediction, the results revealed that strategy changes did not vary with trials with








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different numbers of words. Children of all ages showed comparable numbers of strategy changes after trials with relatively few words or many words.

Why did children fail to show strategy changes on trials with many words when they were predicted to do so and when such changes may have benefited their performance? The answer to this question may involve the same factors that were reviewed in the section on multiple-strategy use: metacognitive limitations and capacity limitations. Metacognitive limitations may have limited children's ability to monitor changes in the number of words presented on each trial and to alter their strategy use in response to such changes. Capacity limitations may have limited children's ability to add strategies on successive trials even if they had the metacognitive awareness to do so. Future research, providing metacognitive instruction on when and how to use strategies and reducing the capacity demands for strategy production and utilization, is needed to assess these possibilities.

Relation Between Multiple-Strategy Use and Recall

An important purpose of the current study was to investigate the relation between multiple-strategy use and recall, identifying possible evidence for utilization deficiencies. An initial analysis examined age differences in correlations between multiple-strategy use (i.e., number of strategies used) and recall, computed separately in each condition and across trials. The findings in the ascending/descending condition were very similar to those observed in previous research examining age differences in the relation between strategy use and recall (Coyle & Bjorklund, 1996, 1997). Fourth graders showed significant correlations








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on all trials, whereas second graders showed significant correlations on only three of the seven trials (Trials 3, 4, and 6). The pattern of correlations for the fourth graders indicated that they were able to benefit from using multiple strategies from the beginning of the task. The second graders' pattern indicated that strategy use was rarely linked to recall performance, which is evidence of a utilization deficiency.

The findings in the descending/ascending condition revealed a pattern opposite to that found in the ascending/descending condition. Fourth graders now showed significant correlations on only two of the seven trials (Trials 6 and 7), whereas second graders showed significant correlations on five of the seven trials (Trials 2, 3, 5, 6, and 7). The pattern of correlations for the second graders indicated that they were using multiple strategies effectively. The fourth graders, pattern was more difficult to interpret. Although it could be argued that fourth graders were utilizationally deficient, such an interpretation is probably incorrect because, with few exceptions, mean recall and strategy use were higher for fourth graders than for second graders (see Tables 2 and 4). Thus, fourth graders were probably not using strategies ineffectively but likely using other means to recall the list items, perhaps relying on nonstrategic factors (e.g., capacity, speed of processing).

A comparison of the correlational data in each condition

demonstrates different patterns of strategy-recall relations across trials for each age group. Fourth graders tended to use multiple strategies effectively when an increasing number of words was presented