PSYCHOPHYSICAL METHOD AND PHORIA
AS VARIABLES DETERMINING
ALAN WAIS RUSNAK
A DISSERTATION PRESENTED TO THE GRADUATE COUNCIL OF
THE UNIVERSITY OF FLORIDA
IN PARTIAL. FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
The writer wishes to express his appreciation to the many
people who have contributed to the preparation of this dissertation.
Thanks are due to Dr. M. E. Shau, Dr. J. C. Dixon, Dr. A.
Schunacher, and Dr. G. R. Bartlett, members of the supervisory committee,
for the guidance and interest they have shown.
The writer would particularly like to express his gratitude
and appreciation to Dr. E. P. Home, chairman of the supervisory
committee, for his consultation, effort, support, and guidance in
making this dissertation a reality.
Thanks are also due to Dr. A. E. Brandt of the University Com-
puting Center for his consultation on the statistical procedures in
TABLE OF CONTENTS
ACKNOWLEDGIENTS . . . . . . . . ... .... ii
LIST OF TABLES . . . . . . . .... . . iv
I. IT ODUCTIO . . . . . . . . . 1
II. ETOD . . . . . . . . . . . 6
Design . . . . . . . . .. .. 6
Subjects . . . . . . . . . .
V. S Apparatus . .COC . . . . . . . 21
Procedure . . . . . . . . . . 10
III. RESULTS . . . . . . . . . . . 12
IV. DISCUSSION . . . . . . . . . . 17
V. SU:IHARY AND CONCLUSIONS . . . . . . . 21
APPENDIX . . . . . . . . .. . . . . 23
REFEPRSECES . . .. . . .. .. . . . 26
BIOGRAPHICAL SKETCH . . . . . . . . ... 28
LIST OF TABLES
1. Sumnary of Analysis of Variance for iale Data . . 13
2. Summary of Analysis of Variance for Female Data . . 16
3. Central Tendency and Variability for Hales . . . 24
4. Central Tendency and Variability for Fenales . . 25
The purpose of this study is to examine the effects of psycho-
physical method, variables of phoria, and their interactions on the
perception of apparent motion. The specific type of apparent notion
to be utilized is called beta notion. Beta motion is defined as the
perception of short lateral movement when two intermittently illuminated
objects are presented in succession.
The phenomenon of apparent notion has played a controversial
role in some theories of perception. It is differentiated from the
perception of real movement in that the perception of real movement
involves the physical movement of a stimulus object over a given period
of time. Apparent motion is that which is perceived when there is
actually no moving stimulus in the visual field.
Experimental and theoretical work in the area of the perception
of motion was done by Purkinje as early as 1820 (Boring, 1942). In
1870 Dvorak (Boring, 1942) hypothesized that the perception of motion
was dependent on the simple interaction of neurons in the retina.
Following this, Exner (Neff, 1936) maintained Dvorak's notions of
retinal interaction processes, but extended them to state that the inter-
actions can also involve areas of the retina not immediately adjacent
to one another.
The major contribution to contemporary theories of perception
regarding notion was made by Wertheiner (1912). At that time he pro-
duced irhat he called pure movement or phi movement without the
succession of stimuli. On the basis of his findings he discarded the
notion that perceived movement was dependent on simple retinal pro-
cesses alone and posited a cortical interactive or integrative process
as the physiological substrate of notion perception. A study by
Gengerelli (1940) supported Wertheimer's theoretical formulation.
Wertheimer, and those who followed him in the Gestalt school,
also rejected the previous notions that perceptions could be broken
down into minute or microscopic physiological processes resulting in
specific sensations. They concluded that the perception of motion,
real or apparent, was a unitary phenomenon which could not be broken
doun into simpler analyzable constituents (Ilelson, 1925). The Gestalt-
ists have insisted that perception is not completely tied to the sepa-
rate physical characteristics of the external world. They propose that
there is an organizational characteristic which is imposed on sensory
input by the processes of the perceptual system. In a recent form
(Klhler, 1958) Gestalt theory presupposes that the more important cor-
tical correlates of perceptual experience are electrical brain currents
rather than neural impulses.
Kenkel (1913) described three types of apparent motion in addi-
tion to Wertheimer's phi. Of these, beta motion has received the
greatest amount of experimental attention. Neff (1936) distinguishes
two classes of experimental variables connected with apparent motion
perception: intre-organic variables and extra-organic variables.
Subsumed under intro-organic variables are dark adaptation, instruction,
past experience, attention, and attitude. Saucer (1950) and Uilson
(1957), in independent studies, found dark adaptation to be a signifi-
cant variable in perception of apparent notion. With regard to the
other intra-organic variables there is little conclusive evidence.
Reichenberg (1957) found instruction to be conditionally effective as
an experimental variable. Under extra-organic variables Neff (1936)
cites interval between successive presentations of the stimuli, inten-
sity of the stimuli, exposure time of the stimuli, and similarity of
form of the stimuli.
Korte (Ieff, 1936) formulated a set of laws relating the variables
of interval between stimuli, stimulus intensity and distance between
stimuli. Although Korte's laws hold up well within certain limits,
they have been shown to break down at the extremes of the dimensions.
Orlansky (1940) and Reichenberg (1957) have studied the effects
of similarity and difference between stimulus forms and have found that
similar forms facilitate apparent motion.
Flash rate (Saucer, 1954; Lane and Home, In Press; Home and
Deabler, 1962) has also been studied and has been found to be an impor-
tant variable in apparent motion.
Research findings by lotokawa (1953) have been interpreted to
indicate that retinal responses during the perception of real and
apparent motion are identical. This finding lends additional support
to the Gestaltist's contention that motion perception is dependent on
a cortical interactive or integrative mechanism.
Following this, it may be proposed that interference with an
observer's normal approach in perceiving his environment will result in
a disruption of the integrative process and a disruption of the ability
to perceive apparent motion.
Part of this study is concerned with an investigation of the
effect of varying normal visual processes on the perception of appar-
ent motion. This is to be accomplished by the means of experimentally
inducing dysphoria in "normal" subjects.
A second part of this study is concerned with the effects of
psychophysical method on the ability to perceive apparent motion. It
may be predicted that the method of serial exploration would yield a
predictable shift in the upper limit of apparent notion. This assum-p-
tion is made on the grounds that with an ascending series of change in
phoria, the method of serial exploration (limits) permits series effects
(habituation of movement) to become operable, extending the range of
movement upward in pulse rate. With the method of constant stimuli,
habituation would not be systematically introduced although a randomly
ordered, discrete set of phoric changes, adjusting for convergence, might
also have a systematic effect on the upper limit.
The following specific hypotheses are to be investigated in this
1. Experimentally induced dysphoria may disrupt an observer's per-
ception of apparent motion. This effect will be shown in de-
creased mean durations of perceived motion as the artificially
induced dysphoria becomes progressively more severe. An increase
in phoric imbalance, or dysphoria, will produce a decrease in
mean duration of perceived apparent motion.
2. For a horizontal direction of movement a condition of horizontal
dysphoria may be more disruptive to the perception of apparent
notion than t~ill a condition of vertical dysphoria. This will
be shown by greater mean durations of perceived apparent motion
for the condition of vertical orientation of dysphoria than for
the condition of horizontal dysphoria.
3. The psychophysical method of serial exploration may extend the
range, thereby raising the upper threshold of apparent notion.
The method of constant stimuli is to be used as a comparison
The independent variables to be examined in this study were
psychophysical method [method of serial exploration (Cl) and method of
constant stimuli (C2)], horizontal (Bl) and vertical (B2) orientation
of dysphoria, and degree of dysphoria (A). The dependent variables
were: (1) the number of key presses made by a subject during an
observation, and (2) the duration of perceived movement which was
recorded on tape. The first variable was, therefore, the number of
times motion was perceive during a trial. The second was the length
of time motion was perceived at each occurrence, and from these variables
the mean duration of apparent motion was obtained.
The design of the study was such that all subjects received all
treatment combinations (ABC) in the same order of presentation for each
of the two psychophysical methods. One major treatment variable was
the effect of the psychophysical method, i.e., the constant stimulus
method and the method of serial exploration. In each method all subjects
received two directional dysphoric effects, horizontal and vertical.
Clinically, dysphoria is a condition in which a person is unable
binocularly to fixate a given point so as to produce a single visual
image. Symptomatically, dysphoria is generally described as double vision.
In ophthalmological terms, the particular condition of horizontal
dysphoria used in this study is called esophoria (an excessive con-
vergence of one eye towards the other, or "crossed" eyes). The
ophthalmological term fcr the vertical orientation of dysphoria is
hyperphoria, a condition in which one eye diverges vertically From the
line of sight of the other. Under each directional condition, hori-
zontal and vertical, all the subjects received varying degrees of
dysphoria, with the rotary prism set from zero to 28 prins diopters.
These degrees of dysphoria were experimentally, i.e., optically, pro-
duced by adjusting only one (left) of the two rotary prisms of an AO
phorometer. The AO phorometer and its method of use in this study is
described below. Under the method of constant stimuli the phorometer
settings determining the degree of dysphoria were varied by a randomly
selected order which was unchanged for each of the 50 subjects. Under
the serial exploration method the degree of dysphoria was increased in
eight ascending steps of four diopters from zero to 28 prism diopters.
For any single observation the combination of A, B, C variables
was complete. Every level of one variable was combined with all
levels of the other two variables. Each subject completed 32 observa-
tions. For a total of 50 subjects there were 1600 measurements of the
obtained dependent variable, mean duration.
All subjects received the method of constant stimuli (C2) first
and, in order the horizontal (Bl) and then the vertical (B2) series.
For this order of presentation (00, 24, 08, 20, 16, 28, 04, 12 prism
diopters), consecutive settings were not progressively increasing in
Then each subject observed under the method of serial explora-
tion (CO) for the eight graduated settings of horizontal and vertical
dysphoria. Under this method these dioptric settings were ordered in
an ascending series from zero to 28 diopters. For each consecutive
trial the setting was increased by four diopters.
The following experimental conditions were held constant:
1. rate of alternation (2.7 alternations per sec.)
2. center-to-center distance between stimulus figures (6.5 en.).
3. luminance level (0.4487 foot lamberts)
4. distance between subject and stimulus figure (76.5 cm.)
5. binocular viewing
6. the illuminated circular stimulus figures
7. length of viewing time (27 sec. per trial)
The geometric form of the stimulus figures and the pulse rate
of alternation used in this study were within optimal or near optimal
conditions for inducing the perception of apparent motion (Roichenberg,
Fifty subjects were used in this study, 25 males and 25 females.
All subjects were students enrolled in introductory psychology courses
at the University of Florida. All subjects were "volunteers" who were
fulfilling course requirements. All subjects wearing glasses with
corrections were required to wear them during the experimental proce-
dure. Subjects ranged from 17 to 24 years of age, the mean age being
An electronic apparatus was used which controlled the duration
and rate of visual stimuli necessary to induce the perception of appa-
rent notion. Light sources were two one-watt, neon filled, incandescent
Westinghouse Nite-Lite bulbs which alternately illuminated two separate
apertures, 6.5 cm. center-to-center and presented horizontally to the
subjects. These illuminated circular stimulus figures were 2.5 cm. in
diameter and were engraved on clear plastic with an opaque black plastic
backing so that only the engraved forms transmitted light providing an
illuminated figure. The recording units included a Gerbrands constant
speed recorder and two telegraph keys. The AO phorometer provided for
experimental variables A and B. A subject's head rest and a manually
controlled shutter completed the inventory.
The AO phorometer is characteristically used in ophthalmclogical
examinations. For purposes of this study only those portions of the
apparatus for visual phoria testing were used. The necessary apparatus
consisted of two rotary prisms mounted separately, each having a
maximum power of 30 prism diopters. Although 60 prism diopters were
available, only 30 were used so that maximal adduction was not obtained.
The prisms were situated one in front of each of the subject's eyes, in
a vertical plane which was perpendicular to the subject's line oF sight.
The prism rotation created a converging or diverging line of sight of
one of the subject's eyes with respect to the line of sight of the other
eye. Only convergence, or esophoria, was used in this study in deter-
mining the horizontal condition of dysphoria. When one or both of the
prisms were rotated 90 degrees with the "zero" horizontal, a condition
of vertical displacement of the line of sight of one eye with respect
to the other (hyperphoria) was made, thereby resulting in a condition
of vertical dysphoria. Here only an upward deviation in the line of
vision of one eye was used. Also, only the left prism was manipulated
to produce the experimental conditions for all subjects, while the
other prism was maintained in a zero position. The phororneter was
adjusted to a line-of-sight level and the head rest also adjusted to
maintain a fixed position which was comfortable for the experimental
Two telegraph keys were connected to two channels of the con-
stant speed recorder. They were located so that one of them could be
operated by the subject and the other by the experimenter. The experi-
menter's key was used to record the onset and termination of each
trial, and the subject's key recorded the responses as defined.
The shutter device was opened to start a trial and was closed to
terminate it. The duration of each single trial was 27 sec. Total
viewing time for each subject was 864 sec.
The complete apparatus was housed in a light-tipht room and
illumination was maintained at a darkroom level during the experiment.
Subjects were brought into the experimental room and seated in
front of the apparatus. Each subject was asked to place his head in
the adjusted rest. The instructions were given on the use of the key
with the shutter closed. Room lights were then turned off and the
subject was given a three-minute dark adaptation period.
Following dark adaptation the shutter was opened and the subject
was asked to describe what he saw. If he reported a perception of
motion, the shutter was again closed and the experimental procedure
begun. If the subject's renort indicated that he did not perceive
apparent motion, he -ra. excused rfro: further participation in the study.
Subjects who reported an initial perception of apparent motion
were instructed as follows: whenever r you see the lights) moving,
you are to press your key do'rn and hold it down as lonc as the lights)
appear to move. When the lights) do not appear to nove, release
your key. You are to repeat this procedure whenever the lights)
appear as though they are moving."
The major variables under investigation in this study were:
(1) degree of dysphoria; zero prism diopters (A1) to 28 prism diopters
(A8) in equal steps; (2) horizontal convergence-adduction test (Bl),
vertical vergence-hyperphoric infraduction test (B2); and (3) psycho-
physical method (method of constant stimuli C2 and method of serial
exploration CI). After calculation of a mean duration for each subject
the data were treated by means of analysis of variance in order to
determine, for these averages, the significance of the effects of
the main variables and their interactions.
Two separate analyses of variance were performed, one for the
data on male subjects and a second for the data on female subjects.
The analyses were carried out by IBM 709 computer at the University
Computing Center of the University of Florida.
The summary of the analysis of variance for male subjects is given
in Table 1.
Bartlett's chi-square test for homogeneity of variance in the
male sample, with 31 degrees of freedom, was found to be non-signifi-
cant, indicating that the variance in this analysis was homogeneous.
The results indicated that horizontal-vertical orientation of
dysphoria had a significant effect (p < .005) on the mean duration of
Summary of Analysis of Variance for Male Data
Source df Sum of Squares Mean Square F p
Degree of Dysphoria (A) 7 710.5804 101.5515 1.256 NS
Dysphoria (B) 1 836.4056 836.4056 10.348 .005
Method (C) 1 406.1250 406.1250 5.024 .05
A x B 7 543.3942 77.6277 0.960 US
A x C 7 431.7549 61.6793 0.763 NS
B x C 1 24.4994 24.4994 0.303 US
A x B x C 7 312.6601 44.6657 0.553 HS
Error 768 62,075.3730 80.8273
Total 799 65,340.7813
apparent motion reported by the iale subjects. The duration of appa-
rent motion perception was higher (15.3675 sec.) under the condition
of vertical dysphoria (hyperphoria) than under the condition (13.3225
sec.) of horizontal dysphoria (csophoria). These results supported a
second hypothesis in this study, namely that a main effect of horizon-
tal dysphoria is more disruptive to the perception of apparent motion
than a condition of vertical dysphoria.
The analysis of male subjects also indicated that psychophysical
method was a significant factor (p < .05) influencing the duration of
apparent notion reported by the male subjects. The nean duration of
perceived apparent motion under the method of constant stimuli was
15.0575 sec., while the mean duration for the method of limits (serial
exploration) was 13.6325 sec. The third hypothesis, that the psycho-
physical method of serial exploration (limits) extended the range, and
thereby enhanced a series effect,was not supported. The method of
constant stimuli resulted in greater mean duration of perceived appa-
rent motion than did the method of serial exploration for the male
The main variable, degree of dysphoria, was not found to be
significant as an overall factor influencing the duration of apparent
motion perceived by the 25 male subjects. Variations in the severity
of artificially induced dysphoria did not significantly affect mean
duration times for the perception of apparent notion, indicating that
conditions of phoric imbalance did not significantly change the duration
of reported apparent motion.
All interactions between main variables were found to be non-
significant for the male subjects, suggesting that the main variables
under consideration nay be independent and unrelated to one another.
Table 2 illustrates the summary of the analysis of variance for
the female subjects.
Bartlett's chi-square test for homogeneity of variance in the
female group, with 31 degrees of freedom, was non-significant for this
analysis also, indicating homogeneity of variance in this analysis.
In the analysis of the female subjects' data it was found, as
with the male subjects, that the horizontal-vertical orientation of
dysphoria was a significant factor influencing the amount of reported
apparent motion (p < .01). The mean duration of perceived apparent
notion under the horizontal orientation of dysphoria was 8.2425 sec.,
while the mean duration for the vertical orientation was 9.8150 sec.
These findings again indicated that the mean duration for the percep-
tion of apparent motion was higher under the condition of vertical
dysphoria than under the condition of horizontal dysphoria, giving
additional support to the second hypothesis in this study.
The other main variables in this second analysis, degree of
dysphoria and psychophysical method, were found to be non-significant
in affecting the amount of apparent motion perceived by the female
subjects. Neither of these variables significantly affected the mean
durations of perceived apparent motion for this subject group.
All interactions between major variables were found to be non-
significant for the female subjects, indicating that the main variables
were independent and unrelated to one another in any systematic way.
Certain supplementary results in the form of statistical tables
for means and standard deviations by sex have been included in an
Sumnary of Analysis of Variance for Female Data
Source df Sun of Squares Nean Square F p
Degree of Dysphoria (A) 7 G8.0087 9.7155 0.148 ITS
Dysphoria (B) 1 494.5513 494.5513 7.550 .01
Hethod (C) 1 1.5313 1.5313 0.023 lNS
A x B 7 429.9987 61.4284 0.938 ;S
A x C 7 116.7388 16.6770 0.255 US
B x C 1 6.6612 6.6612 0.010 US
A x B x C 7 355.8887 50.8412 0.777 IS
Error 768 50,304.9639 65.5013
Total 799 51,778.3389
Of the three major experimental variables, degree of dysphoria,
horizontal-vertical figure orientation, and psychophysical method, the
only one which significantly affected the mean duration times for the
perception of apparent motion for both males and females was horizontal
(esophoric) and vertical (hyperphoric) orientation. The second hypo-
thesis, that a horizontal (esophoric) condition of dysphoria would be
more disruptive to an observer's perception of apparent motion than
would a vertical (hyperphoric) condition, was supported.
That directional orientation of the phoric imbalance should
affect mean durations for perceived apparent motion may be accounted
for in terms of enhanced binocular imbalance in the visual field,
greater for esophoria than for hyperphoria. The human eye, with its
extrinsic musculature, is able to accommodate for more esophoric distor-
tion than it is for hyperphoric distortion. When hyperphoria is artifi-
cially induced by prismatically deviating the line of sight of one eye
from the other, it is necessary for a deviation of only two prism diop-
ters to be present before binocular visual fusion is broken with the
result that two separate and distinct images are seen. Then, as in
this study, the apparent motion was presented with the visual stimuli
effecting movement in a horizontal plane, the visual result may have
been the appearance of two moving objects (lights), one above the other.
When esophoria was induced, and the visual. stimuli moved horizontally,
overlapping visual images were produced. The overlapping movement
effects beyond a fusion limit wcre confusing a-nd disruptive '- --
ccption and naintainance of apparent notion.
The A variable, degree of dysphoria (ranging from zero to 28
prism diopters), was non-significant as a factor influencing the mean
duration of perceived apparent motion for both males and females. This
hypothesis, that an increase in phoric imbalance would produce a de-
crease in the mean duration of perceived potion, was not confirmed.
The result may be a basis for an inference that the phenomenon of beta
motion is highly stable and not readily disrupted by the manipulation
of the balancing extraocular mechanisms orienting the peripheral recep-
tors. That a peripheral interference with an observer's normal means
of perceiving his world through the introduction of varying degrees of
dysphoria did not result in decreased mean duration times for the per-
ception of apparent motion seemed to indicate some support for a
Gestalt contention that the perception of motion is dependent on the
functioning of some central integrative mechanism at a cortical level.
It was found that the subjects in this study, when faced with varying
degrees of dysphoria, continued to report apparent motion regardless
of the severity of the phoric ir.balance and that the mean duration was
not significantly reduced. Subjects may have blocked or suppressed the
sensory input from one eye in order to continue perceiving apparent
motion, thereby reporting monocular beta movement. However, even this
mechanism may be centrally organized rather than peripherally determined.
The subjects were integrating the sensory information permitting them to
continue their perception of apparent motion at a fairly stable level.
The third hypothesis, as it was stated, was not generally sup-
ported. For the female subjects, psychophysical method was found not to
be a significant variable affecting the mean duration of perceived appar-
ent motion. For the male subjects, psychophysical method was found to
have a significant effect (p < .05) on the mean duration of perceived
motion, with the greater mean duration for the method of constant
stimuli. These results were contrary to the original hypothesis, that
the method of limits would produce longer mean duration times in terms
of more habituation effect, probably extending the range of perceived
apparent motion upward. It must be noted that no rate change was
directly introduced to determine the upward extension. With this experi-
ment, the duration was investigated and there was no implication of
the elevation of the notion-no motion threshold. Only a study of
change in alternation rate may assess the upper limit directly.
The inconsistent conclusion for male and female data may indi-
cate that series effects were not "eliminated" by the constant stimulus
method but were spread by the particular sequence selected for this
application of the method.
The main effects by two analyses of variance have already been
indicated, but certain additional statistical details have also been in-
cluded in an Appendix, e.g., means and standard deviations by conditions.
The mean duration for males, disregarding specific treatment effects,
was 14.3500 sec., whereas for females the corresponding mean was 9.0300
sec. This difference was not noted by Reichenberg (1953) in a study of
the effect of stimulus form, for a constant rate, in which nean dura-
tions were obtained. In the study by Rouse (1960) with a sample of men-
tally retarded subjects of ages 15 to 25 years of ago, the upper thres-
hold of movement, in terms of flash rate, w;as significantly higher for
male subjects. This variable, rate of alternation, cannot be directly
compared with the mean duration. Rouse pointed out the difference in
perception which involved the sex of the subject may be involved in
test-sex interactions and direction-sex interactions.
Other perceptual studies by Witkin and Uapner (1950) and by
Wapner and Witkin (1950) relating factors in the visual field to the
maintenance of upright posture and body balance reported some significant
differences in the performance of their male and female subjects. In
their research,performances for both males and females were poorest
under conditions of unstable visual fields, with performance for females
being more strongly affected than for males. They reported that females
were more highly dependent on the visual field than were males and they
also reported great individual differences among both their male and
female subjects. With reference to the results of the present study, it
is possible that the females' greater "field dependence" may account for
their lower mean durations of perceived apparent motion, especially under
conditions of ambiguous or unstable visual fields. If field dependence
is involved (this research did not establish such reference), the
difference may be attributed to unknown field factors.
SUMMARY AND CONCLUSIONS
The purpose of this study was to determine the effects of
psychophysical method (method of constant stimuli and method of limits),
degree of dysphoria (ranging from zero to 28 prism diopters in eight
equal steps), horizontal (esophoria)-vertical (hyperphoria) orienta-
tion in dysphoria, and the interactions of these variables on the
perception of (beta) apparent motion.
Data from 50 subjects, 25 males and 25 females, were obtained.
The design of the study provided that all subjects receive all
treatment combinations in the same order of presentation. Of the three
major variables there were eight levels of degree of dysphoria (variable
A), two levels of variable B (horizontal-vertical orientation of
dysphoria), and two levels of variable C methodd of constant stimuli
and method of limits). An AO phorometer was used to experimentally in-
duce dysphoria in the subjects. The eight levels of variable A were
obtained by eight settings, in prism diopters, of one (left) of the
prisms of the phorometer. The prism positions also produced the hori-
zontal (esophoric) and vertical (hyperphoric) orientaticns.
The data were treated by means of two analyses of variance, one
analysis pertaining to the data for each sex, male and female. The
analyses were performed by the University Computing Center of the
University of Florida.
Three hypotheses c yere examined in this study: (1) an increase
in phoric imbalance may further a decrease in the mean duration of
perceived apparent notion; (2) for a horizontal movement direction,
horizontal dysphoria may be more disruptive to the perception of
apparent motion than a condition of vertical dysphoria; and (3) the
serial exploration (limits) nay extend the range of apparent motion.
Results of the study indicated support of the second hypothesis
for both males and females. For male subjects it was found tha psycho-
physical method was a significant factor influencing the mean duration
of perceived apparent motion, but a higher mean duration was obtained
for the method of constant stimuli than for the method of limits. The
degree of dysphoria was found to be non-significant for both males and
Perceptual theory concerned with apparent movement classically
has been oriented to a central integrative process. The results of this
research have not altered the theory. It was also concluded that
apparent motion is a highly stable phenomenon, seemingly unaffected by
induced peripheral changes in an observer's normal method of perceiving
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Boring, E. G. Sensation and perception in the history of experimental
psychology. New York: Appleton-Century-Crofts, 1942.
Gengerelli, J. A. Apparent movement in relation to homonymous and
heteronymous stimulation of the cerebral hemispheres. J. exp.
Psychol., 1948, 38, 592-599.
Helson, H. The psychology of gestalt. Amer. J. Psychol., 1925, 36,
Home, E. P., and Deabler, H. L. Optimal beta notion in patients re-
ceiving insulin and chlorpromazine treatment. J. gen. Psychol.,
1962, 67, 265-269.
Kenkel, F. Untersuchungen dber den zusammenhang zwischen erscheinunga-
gr6dse und erscheinungsbewegung beim einigen sogenannten
optischen tauschungen. Zcit. f. Psychol., 1913, 61, 358-449.
Kdbhler, W. The present situation in brain physiology. Amer. Psychol.,
1958, 13, 150-154.
Lane, J. P., and Horne, E. P. Stimulus intensity and position effects
on apparent movement. J. gen. Psychol., in press.
Motokawa, K. Retinal traces and visual perception of movement. J. exp.
Psychol., 1953, 45, 360-377.
Neff, U. S. A critical investigation of the visual apprehension of
movement. Amer. J. Psychol., 1936, 48, 1-42.
Orlansky, J. The effect of similarity and difference in form on appa-
rent visual movement. Arch. Psychol., 1940, No. 246.
Reichenberg, IT. Apparent motion as a function of form. Unpublished
master's thesis, University of Florida, 1953.
Reichenberg, N. Apparent motion as a function of instruction, form and
rate. Unpublished doctoral dissertation, University of Florida,
Rouse, U. S. Thresholds of beta motion reported by mental detectives.
Unpublished master's thesis, University of Florida, 1960.
Saucer, R. T. The effect of dark adaptation upon the perception of
apparent notion. Unpublished master's thesis, University of
Saucer, R. T. The effect of rate and energy upon the perception of
apparent motion. Unpublished doctoral dissertation, University
of Florida, 1954.
Wapner, i., and Witkin, H. A. The role of visual factors in the main-
tenance of body balance. Amer. J. Psychol., 1950, 63, 385-408.
Wertheimer, I. Experimentelle studies Uber das schen von bewegung.
Zeit. f. Psychol., 1912, 61, 161-265.
Wilson, S. R. Rate and dark adaptation as determinants of apparent
notion. Unpublished doctoral dissertation, University of
Witkin, H. A., and Wapner, S. Visual factors in the maintenance of
upright posture. Amer. J. Psychol., 1950, 63, 31-50.
Alan W. Pusnak was born in Chicago, Illinois, on June 3, 1937.
He attended public schools in Mliami, Florida, and received a Bachelor
of Arts degree from the University of Miami in June, 1959.
He entered the Graduate School of the University of Florida in
September, 1959, and received the Master of Arts degree in psychology
in August, 1961. He is a charter member of the University of Florida
chapter of Psi Chi.
He is presently on a post-internship grant from the National
Institutes of Vental Health, and a candidate for the Doctor of
Philosophy degree in psychology.
This dissertation was prepared under the direction of the
chairman of the candidate's supervisory committee and has been approved
by all members of that committee. It was submitted to the Dean of the
College of Arts and Sciences and to the Graduate Council, and was
approved as partial fulfillment of the requirements for the degree of
Doctor of Philosophy.
April 13, 1964
Dean, College of Arts nd Sciences
Dean, Graduate School
^ /. -^*.