Group Title: investigation of operant elements in desensitization
Title: An investigation of operant elements in desensitization
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 Material Information
Title: An investigation of operant elements in desensitization a comparison of differential reinforcement of other behaviors and desensitization in the reduction of phobic responses in rats
Alternate Title: Desensitation
Physical Description: ix, 58 leaves : ill. ; 28 cm.
Language: English
Creator: Wells, Arthur MacClelland, 1939-
Publisher: s.n.
Place of Publication: Gainesville FL. ;
Publication Date: 1970
Copyright Date: 1970
Subject: Reinforcement (Psychology)   ( lcsh )
Extinction (Psychology)   ( lcsh )
Conditioned response   ( lcsh )
Rats   ( lcsh )
Genre: bibliography   ( marcgt )
theses   ( marcgt )
non-fiction   ( marcgt )
Thesis: Thesis--University of Florida.
Bibliography: Bibliography: leaves 51-53.
General Note: Manuscript copy.
General Note: Vita.
 Record Information
Bibliographic ID: UF00098435
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000574286
notis - ADA1650
oclc - 13846670


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An Investigation of Operant Elements in Desensitization: A
Comparison of Differential Reinforcement of Other

Behaviors and Desensitization in the Reduction

of Phobic Responses in Rats





My Wife


The author wishes to acknowledge his indebtedness and to ex-

press his gratitude to those who gave so willingly of their guidance,

support, and patience. First of all appreciation is due to the

Supervisory Committee Chairman, Dr. Harry A. Grater, Jr., and to all

members of the Supervisory Committee, Dr. Benjamin Barger, Dr. Hugh

C. Davis, Jr., Dr. Mary lou McEver, and Dr. Henry S. Pennypacker.

Appreciation is also due Dr. Frederick A. Kins for his kind assistance

with experimental equipment and to Dr. Edward F. Malagodi, Jr., for

his lean of equipment and laboratory facilities.

Thanks are due also to Mrs. Irma Smith for her careful

preparation of the manuscript.

Finally, special gratitude goes to the author's wift, Anastasia,

to whom this study is dedicated. She provides an invaluable source of

meaning to this work and to the achievement it represents.



ACKOOW;LIGEQaE7TS ....................... iii

LIST OF TABLES ..... . . . . ......... v

LIST OF FIGURES ........... . . . . .. vi

AB3TRACT ........... . . . vii

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

METHOD .. .. .. . . . . .. .. . 13

RESULTS ...... . . . . ..... 25

DISCUSSION .. . . . . .. . . .. . 'i1

RK-EI CESCI ............ . . . ..* 51

APPENDICS ......... . .... .. ... 54

APPENDIX A........... . . . . . 55
APPENDIX 3B. .... ....... ** ** ..* 56
APPIE:DIX C ......************ 57

BIOGRAPHICL SKTC . . . . . . . . 58


Table Pago

TREATMEIT .... . . . . . .. 19



EXTINCTION PHASE ............... ... 32




OVER FIVE EXTINCTION DAYS. .... . . ..... . 39



Figure Page

1. Mean number of avoidance responses of three groups of
nine subjects over five days of conditioning ..... 26

2. Mean number of avoidance responses of three groups of
nine subjects over five extinction days . . . . 31

3. Average time between CS onset and phobic response of
three groups of nine subjects over five
extinction days ................... 37

Abstract of Dissertation Presented to the Graduate Council in
Partial Fulfillment of the Require-ents for the
Degree of Doctor of Philosophy
at the University of Florida



Arthur M. Wells, Jr.

March, 1970

Chairman: Dr. Harry A. Grater, Jr.
Major Department: Psychology

An animal analogue study was designed to compare the effects of

desensitization and operant conditioning in reducing phobic behaviors.

The intent of this comparison was to investigate oper,-nt icients in

desensitization rather than to evaluate the relative efficacy of the

two treatments.

On the basis of previous research an explanation of desensiti-

zation in terms of operant rather than classical conditioning principles

was thought to be feasible, leading to the following hypotheses:

1. An operant treatment procedure similar to an operant pro-

cedure possible in desensitization and presented within the framework of

desensitization facilitates the extinction of phobic behavicrs more so

than a desensitization treatment in which operant elements are minimized,

thereby demonstrating the dependence of desensitization on operant con-


2. Both the operant and desensitization proceJures facilitate

the extinction of phobic behaviors to a greater extent than does a

control procedure, thereby demonstrating treatment


To test these hypotheses, rats were conditioned to hurdle jiap

in a shuttle box to avoid electric shock which followed a 500 Hz.

tone (CS). After five days of avoidance conditioning the rats were

assigned to two treatment and one control groups, matched according

to their strength of avoidance responding.

Shock then was discontinued and treatment began. Both treat-

ment groups received equal exposure to the CS tones (phobic stimuli)

which were presented in hierarchial arrangement. Initially the treat-

ment CS was an 8,000 Hz., 66 db tone presented for two seconds, follow-

ing two seconds of a seven second food presentation. On subsequent

treatment days the CS became lover, louder and longer. By the fifth

(final) treatment day it was equal to the original CS tone used in

avoidance conditioning. Food presentation increasingly followed CS

onset in the operant procedure and was made contingent upon the animal's

making various inhibitory responses involved in confronting the CS for

increasing periods without making an avoidance (phobic) response. HoweTer,

in desensitization the tone onset followed and was concomitant with food


Following treatment all three groups received five days of

extinction, during which the number and latencies of the phobic responses

were recorded. Statistical analyses revealed the following:

1. The hypothesis of superiority of the oporant procedure as

compared with desensitization in reducing phobic behaviors was rejected.

In fact, the desensitization procedure demonstrated a stronger treat-

ment effect-though not significantly so.

2. Both treatments resulted in less resistance to the

extinction of phobic behaviors than did. the control procedure.

The results of this work are consistent with the view that the

treatment of phobic behavior may be accomplished either by rewarding

phobic object approach behaviors at the motor level or by the desensiti-

zation of anxiety at a more internal level. These results further

support a unified view of behavior and experience which would regard

changes occurring at one level of overt or covert behavior as having

implications for changes at other such levels.

A future determination of the most effective of these two

treatments could be accomplished within the experimental framework

here introduced by rcmeving certain restrictions which were placed on

the operant procedure. These restrictions were regarded as necessary

in this present study in order to make the operant treatment more

comparable to the operant procedure involved in desensitization.

Desensitization with humans could perhaps be made more effective

by employing and maximizing conditioned positive reinforcers, making

rewards contingent upon the subject's report of successful progression

through the hierarchy of threatening stimulus situations.


Desensitization techniques as introduced by Wolpe (1958) have

been successfully employed by many therapists for the relief of pri-

marily psychoneurotic symptoms (Wolpe, 1958; Lazarus, 1961; Lang and

Lazovik, 1963; Lazarus, 1963, and Paul, 1966). This study represents

an attempt to further our understanding of the processes by which

desensitization success is achieved in reducing phobic behaviors.

Fears and phobic behaviors are common distressful problems and the

treatment of these problems is worthy of investigation.

The term phobic behavior is used here in agreement with

Wolpe's (1958) definition as behavior which is persistently mal-

adaptive in view of changed environmental. conditions of reifiorceanct.

According to classical conditioning theory (Pavlov, 1927) sach phobic

behavior is established when a previously neutral stimulus situation

is followed closely by punishment. The neutral stimulus will be

referred to as the conditioned stimulus (CS) while the punishing situ-

ation will be regarded as an unconditioned stimulus (UCS). After re-

peated presentations of the CS, followed closely by the UCS, the

subject (S) reacts to the CS in a manner similar to his reaction to

the UCS. This overt avoidance behavior, termed the conditioned response

(CB), is generally accepted as a measure of fear on the part of the S

learning this phobic behavior. The persistence of phobic behavior in

response to the CS, lorg after removal of the UCS, may be regarded as

unadaptive behavior. Treatment of phobic behavior will be defined here

as any process which facilitates, or otherwise results in, the reduction

of the overt phobic behavior as a response (CR) to the CS when the

UCS ceases to occur. In this study shock (UCS) will be used to con-

dition aulmals to jump (CR) over a hurdle from one end of a shuttle

box to the other in response to a tone (CS). This jumping behavior

following onset of the tone persists long after the shock is discon-

tinued. The jumping is regarded as a phobic response rather than an

avoidance response under these conditions. A particular interest here

is with the explanation of treatment of phobic responses by desensiti-


Counterconditioning or Desensitization

Counsterconditioning is the term sometimes used in describing

experimental laboratory work with animals which is analogous to

desensitization in clinical treatment with humans. However, both terms

describe essentially equivalent processes (Wolpe, 1952; 1953). Wolps

bases his desensitization technique on early animal studies using

shock as the UCS and using eating responses on the part of the S as the

reciprocal inhibitor to the previously conditioned fear (Wolpe, 1952;

1958). This approach was similar to that employed by Watson and Rayner

(1920) and Jones (1924); a previously conditioned phobia in a child was

treated with food given to the child at progressively diminishing

distances to the phobic object.

In a similar vein, flooding (Weinberger, 1965) is the laboratory

animal study equivalent of implosive therapy in treating humans (Stampfl

and Levis, 1967). This latter treatment involves repeated and continued

presentation of the CS until the CR diminishes, in a massed extinction


The treatment procedure of desensitization, as described by

Wolpe (1958), will be employed here with animals. This treatment in-

volves having the phobic animal experience the phobic stimulus while

eating food. The CS or phobic stimulus is presented along a dimension

of stimulus generalization ranging from weakest to strongest in terms

of CR evocative potential. While the animal is eating, the CS is

presented in increasingly stronger forms until the original CS form Is

presented. In working with humans the first step in desensitization is

construction of a hierarchial arrangement of stimulus situations which

evoke the phobic behavior, arranged from weakest to strongest in terms

of their evocative potential. After reli3.ation training, the subject

is asked to iEngine these stimulus situations while remaining relaxed.

Wolpe cautions that the new response to be learned (relaxation) must be

stronger than tle unadaptive response to be elicinatmd (anxiety). Thus,

by presenting weal: portions of the CS first, and by not progressing to

a stronger CS iten until all anxiety in response to that CS item has

been reciprocally inhibited by the reciprocal inhibitor (relaxation),

desensitization will be maintained without hindrance of sensitization

(conditioning instead of removing anxiety in response to the CS). This

caution on Wolpe's part is important, though not necessarily for the

reasons which Wolpe would offer. Gale, Sturmfels, and Gale (1966) found

that though this use of progressive approximations in presenting these

threatening stimuli (CS) facilitates extinction, this method is most

effective when used in conjunction with desensitization. Goldstein's

(1967) carefully controlled study suggests that desensitization is more

effective than extinction alone LonL when progressive approximation in

presenting the CS is employed; without hierarchially arranged presentation

of the CS, there is no significant difference between extinction and

counterconditioning. Thus, the procedure of progressive approximations

in presenting the CS is of therapeutic importance, particularly in

conjunction with the desensitization treatment method.

Classical Conditioninp Exlanation of

Wolpe (1958) offers an explanation of desensitization based

primarily on classical conditioning principles. Volpe's explanation of

desensitization treatment of phobic behavior primarily involves the

"masking" or reciprocal inhibition of anxiety by a reciprocal in-

hibitor, i.e., a response state which is antagonistic to anxiety and

which prevents the occurrence of the anxiety. In desensitization, cues

which originally evcked anxiety and phobic behavior come to be associ-

ated with and come to evoke relaxation, which being antagonistic to

anxiety comes to eliminate the anxiety and phobic behavior.

Wolpe (1961),using his principles of reciprocal inhibition,

clearly suggests that in desensitization it is the inhibiting properties

of the incompatible responses (relaxation) that reduces anxiety and thus

eliminates phobic behavior: "if a response inhibitory to anxiety can

be made to occur in the presence of anxiety-evoking stimuli so that it

is accompanied by a complete or partial suppression of the anxiety

response, the bond between these stimuli and the anxiety

response will be weakened" (Wolpe, 1961, p. 189). Note that ';olpe

believes that :'hat is treated is the anxiety and not its outward mani-

festations in the forr of observable phobic behavior. Also note that

Welpe believes it is the associations between the CS and internal

response states, such as anxiety and relaxation, which are changed in

desensitization treatment.

As previously noted, counterconditioning of laboratory animals

is the equivalent of the desensitization process. In his research

vith animals, Wolpe (1952) used eating responses as a reciprocal in-

hibitor and argued that the neural and physiological responses associ-

ated with eating and those associated with fear cannot occur simul-

taneously because the first are antagonistic to the latter. Thus, in

desensitization, eating responses reciprocally inhibit fear and thereby

decrease and eliminate those behaviors based on such fear. This study

investigates desensitization with animals employing eating responses

as the reciprocal inhibitor.

Cautela (1966) offers an explanation of the desensitization

process in terms of Pavlovian theory. While relaxed, the subject's

cortex is thought to be in a predominantly inhibitory state when the

excitatory stimulus (CS) is presented. The excitatory stimulus thus

loses its anxiety arousing potential after desensitization. This ex-

planation is similar to Wolpe's in that cue-anxiety bonds are weakened

as a result of strengthening of cue-relaxation bonds.

Recidrocal Inhibitors as Rewards

Relaxation responses are nost commonly used in desensitization

as a reciprocal inhibitor of anxiety. However, a wide variety of other

sucd inhibitors have been employed including assertive responses

(Wolpo ad Lazarus, 1966), drugs which induce relaxation (Wolpe and

Lazarus, 1966), a comforting relationship (Bentler, 1962), emotive or

enjoyable imagery (Lazarus and Abramovitz, 1962), playing responses

with children (White, 1959), and eating responses (Wolpe, 1952; 1958).

An element common to all these reciprocal inhibitors is their potential

reinforcement value in operant conditioning.

Solyom and Killer (1967) have used withdrawal of punishment

(termination of shock) instead of relaxation as a "reciprocal inhibitor"

in treating phobias. The fact that reciprocal inhibitors can also be

positive reinforcers suggests the possibility of operant processes

in desensitization treatment of phobic behavior.

OpOrant Processes in Desensitization

Desensitization involves having the subject imagine increasingly

threatening scenes while he is in a state of relaxation. The sequence

occurs as follows: relaxation--therapist's suggestion of the imagination

of an anxiety provoking inage (the CS)-subject's report of having

successfully imagined the scene without disturbance-therapist's

suggestion that the subject relax (Wolpe and Lazarus, 1966, p. 81). The

subject reports whether or not he is disturbed over imagining the scene

by signaling with raising his finger. By slowly progressing through

the hierarchial list of threatening scenes, from least to most threaten-

ing, anxiety experiences on the part of the subject can be eliminated

or kept to minimal levels.

Although Wolpe offers an explanation of this process in terms

of classical conditioning principles as previously described, an

alternate explanation in terms of operant learning principles appears

to be tenable and more parsimonious. Relaxation instructions or any

other "reciprocal inhibitor" would serve as a conditioned reinforced

in such an operant explanation. The behavior rewarded would be the

subject's self-report of having imagined a threatening scene. As

previously noted this self-report is given via finger signal in the

desensitization procedure. As the subject reports that he has suc-

cessfully imagined threatening scenes without experiencing disturbance

he is then operantly conditioned to progressively continue in this

process until he has imagined the most anxiety provoking scene in the

hierarchy. If the subject reports being disturbed in the desensitization

procedure then he is presented with previously given discriminative

stimuli in the hierarchy and must progress back through the hierarchy

again. This procedure could be regarded as operant conditioning of

finger elevatlon (representing the person's report of successful

imagination of the threatening discriminative stimulus) in the presence

of a fading procedure wherein the discriminative stimuli progress in

presentation along a stimulus dimension from least to most threatening

in terms of phobic response evocative potential.

The alternate explanation of desensitization in operant terms

involves modifying a response by bringing behavior under stimulus

control rather than by hypothesizing the reduction or elimination of

anxiety, upon which the phobic behavior is based. The sequence of

events in desensitization plus the reward potential of reciprocal

inhibitors laLe such an alternate explarntion feasible if it can be

shown that reduction of anxiety is not a necessary element in eliminating

phobic behavior. Wolpe, as previously described, attributes treatment

success of phobic behavior as due to reduction or elimination of

anxiety. The successful modification of phobic behavior using an

operant procedure would show that reduction of anxiety is not a

necessary element in the reduction of phobic behavior, though it might

still be regarded as a sufficient element.

Studies Sunportive of an Operant

Studies which have attempted to analyze and study the components

of desensitization have shown that whereas relaxation has no treatment

value alone (Cooke, 1968; Johnson and Sechrest, 1968), presentation o^

the CS in hierarchical form without using relaxation does have treatment

value (Cooke, 1968; Rachman, 1968; and Fachan and Hodgson, 1967).

Thus, it appears that relaxation to counteract anxiety is not a

necessary treatment condition; anxiety does not need to be directly

eliminated in the successful treatment of phobic behavior.

Wolpin and Raines (1966) found that having subjects simply

imagine the original full CS (most threatening scene in the hierarchy)

for more than two minutes resulted in extinction of the phobic behavior.

Implosive therapy, which involves the technique of flooding whereby

the subject is repeatedly presented with the CS in massed and prolonged

extinction trials, has been successfully used in eliminating phobic

behavior (Hogan and Kirchner, 1968; Stampfl and Levis, 1967). These

procedures also make no attempt to minimize or reciprocally inhibit

anxiety. folpo and Lazarus (1966, p. 140) believe that when such

treatment is sometimes successful, it is only because of "transmarginal

(protective) inhibition . the diminution of response that is ob-

served when stimulus intensity exceeds a certain limit." However, this

does not explain the lasting effect of such treatment to all degrees

of stimulus intensity in CS confrontation.

Reduction of phobic behavior is facilitated or phobic behavior

is successfully treated when the subject is prevented from making the

unadaptive response with repeated presentations of the CS without

any presentations of the UCS (Carlson and Black, 1959; Weinberger, 1965).

In these studies the subject was prevented from making the unadaptive

response (phobic behavior) by utilizing a barrier in a shuttle box,

where jumping front one end of the box to the other upon presentation

of the CS was defined as the phobic behavior. An operant method of

reinforcing the subject to stay in the situation when the CS is presented

without the UCS should be equally successful in facilitating climina-

tion of such phobic behavior, demonstrating the possibility of operant

processes in desensitization.

Lang and Lazovik (1963) reported that following desensitization

of snake phobia, using relaxation as a reciprocal inhibitor, some sub-

jects were able to demonstrate treatment success by touching a snake,

in spite of the fact that after treatment they reported no decrease

in their pre-treatment anxiety concerning touching a snake. This Is

exactly what would be expected in terms of an operant learning view of

desensitization technique. Other subjects who reported a decrease in

anxiety levels following treatment may have been responding to the

demand characteristics of the experimental situation (Orne, 1962) or

the expectations of the experimenter (Rosenthal, 1966). Another

possibility for decrement in anxiety is that anxiety was experienced

and then extinguished in the absence of the UCS during desensitization


Results of studies cited in this section all demonstrate that

anxiety does not have to be reciprocally inhibited in the treatment

of phobic behavior. This fact coupled with an alternate explanation of

events in the desensitization procedure in terms of operant conditioning

leads to the hypothesis that at least part of desensitization success

is due to operant procedures.

Formulation of the Hypotheses

Treatment of phobic behavior may involve facilitation of ex-

tinction processes. These extinction processes do not always operate.

When the subject makes an unadaptive response (CR) in response to the

CS, this may preclude the subject from experiencing the absence of the

UCS. Furthermore, the frequently short latency between onset of the

CS and the occurrence of the CR may serve to prevent an anxiety reaction,

thus conserving conditioned anxiety from undergoing extinction (Deltde

and Carlson, 1964 ; Solomon and Wynne, 1954). Desensitization, operant

techniques, flooding/barrier methods, and other procedures used in

treating phobic behavior are considered here to be successful to the

extent that they allow, encourage or force the subject to experience

both the CS and the lack of the occurrence of the UCS, so that extinction

can occur.

Wolpe's explanation of desensitization in terms of a primarily

classical conditioning paradigm, in which anxiety must be eliminated to

eliminate phobic behavior, is questioned here. This explanation

requires inferences as to unobservable internal processes which have

not been experimentally established (Breger and McGraugh, 1965).

This present study concerns an attempt to show that phobic

behavior can be treated effectively by operant methods, concerned only

with bringing the subject's observable behavior under stimulus control,

without attempting to reduce or eliminate internal anxiety. This bears

on the question of the necessity of reciprocally inhibiting anxiety

in treating phobic behavior. The first hypothesis is that an operant

treatment procedure, presented within the framework of the technique

of desensitization, will result in significantly less resistance to

extinction compared to the disuse or controlled rest condition.

Previously an alternate explanation was offered of the desensiti-

zation process in terns of operant principles rather than in terms of

classical conditioning theory. Such an alternate explanation would

find support if an operant procedure proved to be a more effective

treatment procedure than a desensitization procedure in which operant

processes were minimally operative, i.e., restricted to a continuous

and simultaneous presentation of reward with the presentation of the

CS (so that confrontation with the CS is possibly rewarded). The

second hypothesis is that an operant treatment procedure, presented

within the frame'-ork of desensitization, will result in significantly

less resistance to extinction comparedtoadesensitization procedure, in

which operant procedures are minimally involved.

It is assumed that these treatment procedures can be applied

to the previously conditioned phobic behavior of animals in the follow-

ing way. First, using a 500 Hz. tone as the CS, a conditioned avoidance

response to shock (UCS) can be established. This response can then be

treated by using the progressive approximations method in presenting the

CS without the UCS, starting with an 8,000 Hz. tone which does not evoke

the avoidance response, then progressing to the original CS (500 Hz.

tone). Such progressive presentations of the CS, in hierarchial arrange-

ment from weakest to strongest item, can then be combined with either

a desensitization treatment or an operant treatment. In the desensiti-

zation treatment the hierarchially arranged conditioned stimuli can

be gradually introduced in increasing approximation to the original CS

while the animal is eating. The various responses involved in this

eating behavior should serve to reciprocally inhibit the anxiety aroused

by presentation of the CS tone. In the operant treatment the food is

presented in a way such that obtaining it and making an avoidance

response are mutually exclusive. In this operant procedure, obtaining

food requires that the animal inhibit his making an avoidance response,

making instead various other responses which are competitive with the

avoidance response, for increasing periods of time.

Both of these procedures can be called effective treatment

procedures only if they result in significantly less resistance to ex-

tinction than the disuse or controlled rest conditions. Thus, the

third hypothesis is that the desensitization treatment will also

result in significantly less resistance to extinction compared to the

disuse or controlled rest condition.


Thirty experimentally naive, initially 80 days old Long-Evans

male rats were used as subjects. These 30 rats were selected from a

group of 42 on the basis of their overall performance during the

Acquisition Phase. Selection was accomplished by takinC out the four

fastest and eight slowest rats in terms of average reaction tine

between CS onset and CR or hurdle jumping. In the middle of this

study three rats died, leaving data on 27 animals (see discussion

of matching Ss in oeatnent section belod).

Animal Maintenance

Each animal was separately housed in a hanging, metal _age in

a controlled temperature environment. Water was given ad lib iln all

phases of the experiment. Food was presented ad lib for five days

prior to experimentation and then the animals were reduced to 80 per

cent of their normal weight. Nor'cal weight was determined by taking

the median of the daily weights over the last three days of this five

day pre-experimental period. After normal body weight was determined

the animals went on their diet for two days prior to begirning

acquisition training. They were maintained at 80 per cent of normal

body weight during the Acquisition and Treatment Phases of the experi-

nent, but were again placed on an ad lib food schedule during the

Extinction Phase of the experiment. The rationale for placing the

animals on an ad lib focd schedule during the extinction trials is

presented in the Discussion section. All animals were fed each night

at the end of the experimental work Purina Laboratory Chow was used.


The wooden shuttle box was painted black and had interior

dimensions of 24 inches long by 6 inches wide by 18 inches high. The

floor consisted of 4 copper alloy bars spaced one-half inch apart.

The grid floor was divided in half by a four and one-half inch high

wooden hurdle which was in place at all times. Only one end of the

floor was wired for shock. This same "hot" end also contained a food

tray which could be pushed into the side of the box and which was

centered between the hurdle and the end of the box.

During the Treatment Phase, 20 mg n!oyes food pellets were

presented by sliding this tray into the box. The empty tray was kept

out of the box, the end of the tray covering the box tray opening,

during the Acquisition and cEtinction rhases. A plexiglass sheet

covered a rectangular opening on one side of the box and permitted

full observation of St behavior. The other side of the box contained

numerous one-quarter inch holes to permit sound to enter from an

adjacent speaker.

The shock for the grid was delivered by a Lehigh Valley

Electronics Shock Generator and Scrambler unit which reversed the

polarity randomly among the 23 grid bars on the hot side of the box.

Level of shock was set at one and two-tenths milliamperes (D.C.) as

measured by the Simpson meter on the shock unit.

An AR4x speaker was used adjacent to one side of the shuttle

box with the woofer near the "hot" end of the box. The tones were

supplied from a Hewlett-Packard, model 200AB audio Oscillator. Tones

were measured by a General Radio Company Sound-Level Meter, type 1551-B,

inside of the shuttle box with background noise at a 35 db level. A

Hunter interval timer was used to measure event duration to the nearest

hundredth of a second. Manually operated switches controlled the

shock, tone and timer. When appropriate the switches from the tone

generator could be yoked to the timer to measure the duration of the

tone. The running timer was also used to measure food presentation



Acquisition Phase

During this Phase each of the 42 rats received 20 trials of

acquisition training for each of five consecutive days. On the first

trial of each day the animal was placed in the hot end of the shuttle

box and allowed to roam for a period of two minutes. The 500 Hz., 90 db

tone (the original CS) was then turned on If the animal was in the hot

end of the box. If the animal was not in the hot end after the two

minute period then he was gently placed there. After the CS tone had

been turned on for a period of ten seconds shock was delivered. The CS

tone (and shock if turned on) was immediately terminated and time

recorded as soon as the animal jumped, withdrawing all contact from the

hot grid floor. In effect then the animal quit receiving both the

shock and the tone as soon as he jumped. He did not receive shock

prior to ten seconds from the tone onset.

The latency between the onset of the CS tone and the jumping

or avoidance response was recorded to the nearest hundredth of a

second. Recording of latency was accomplished by having the CS tone

duration switch yoked to the timer so that the duration of the CS

tone (which terminated with Ss jumping clear of the hot grid floor)

was timed. A latency of ten seconds or greater indicated that the

animal did not jump before receiving shock.

On trials following the first trial of each day during the

acquisition training, the animals were allowed 20 seconds in the

"cold" end of the shuttle box following hurdle jumping and CS teriina-

tion which ended a trial. They did not receive the CS, marking the

beginning of a new trial, rntil at least ten seconds after being placed

back in the hot end of the box. Animals jumping within ten seconds of

being placed in the hot end of the box to begin a new acquisition

trial did not receive either the CS or the UCS (shock) but were gently

placed back into the hot end to begin the trial again. Following the

20 daily trials each animal was weighed, returned to his cage and fed

an amount of Purina Laboratory Chow based on the deviation of his weight

from 80 per cent of his normal weight.

By the fifth day of training, all animals reached the acquisition

criterion by hurdle jumping at least 75 per cent of the time before the

duration of the CS reached ten seconds (thus avoiding the shock).


Following the five days of acquisition training all 42 animals

were ranked according to their overall average reaction time (between

the CS onset and jumping behavior). The four animals with the fastest

reaction times as well as the eight slowest reacting animals were dis-

carded from further experimentation. Three groups of ten animals each

were then drawn for the two treatment and control groups. The Control

group was comprised of the following ranked animals: 1, 6, 8, 12, 14,

16, 20, 22, 27 and 30. The Operant treatment group was made up of

animals with these ranked numbers: 2, 4, 9, 10, 15, 17, 21, 23, 25

and 29. The Desensiti nation treatment group was composed of the follow-

ing rank numbered animals: 3, 5, 7, 11, 13, 18, 19, 24, 26 and 28.

The average reaction time over the 100 trials of acquisition training,

computed for each group of ten rats aft-r the anisials were formed into

the three groups, was as follows: Control group, 4.93 seconds; Operant

group, 4.94 seconds; and the Desensitization group, 4.94 seconds. The

groups of animals were thus thought to be well matched in terms of the

overall average time it took them to jump the hurdle upon onset of the

CS during acquisition training.

On the third day of treatment three of the experimental animals,

one from each of the three groups, were found dead. Although no autopsy

was performed the presence of blood traces near the external urinary

region of these animals suggested a urinary tract infection. The remain-

Ing 27 Ss survived the experiment, apparently in good health.

The elimination of these three animals did not appear to upset

the previous matching. The ranked positions of these Ss, in terms of

overall reaction time in the acquisition trials, were ?1, 18 and 20.

The average reaction times of the three groups changed as follows with

the elimination of the three animals: Control group, dropped from 4.93

to 4.90 seconds; Operant group, remained the sane at 4.94 seconds; and

the Desensitilation group, dropped from 4.94 to 4.93 seconds. Since

matching appeared to be maintained the study progressed as scheduled with

the remaining 27 Ss.

Treatment Phase

Treatment began the day after completion of the acquisition

trials. Both the Operant and the Desensitization treatment groups

received equal exposure to the CS stimuli components during treatment.

Both groups also received equal exposure to the food pellets used in

treatment. The tonal hierarchy presented during treatment in accord..

ance with the method of progressive approximations consisted of the

following five tones: an 8,000 Hz., 66 db tone presented for two

seconds; a 4,000 Hz., 72 db tone presented for three seconds; a 2,000

Hz., 78 db tone presented for four seconds; a 1,000 Hz., 84 db tone

presented for five and four seconds; and a 500 Hz., 90 db tone (original

CS) presented for four, six and seven seconds. These tones were pre-

sented over the five day Treatment Phase period in a total of 84 treat-

ment trials. Food was also presented. The timing of the food presenta-

tion in relation to the tone presentation defined and distinguished the

Operant and Desensitization treatment groups. Table 1 provides a

detailed description of the tonal hierarchy and the presentation of

these CS tones in relation to food pellet presentation in the two treat-

ment groups.

,. 4-1 .


N CI CI C 0- N

I I I I I a

CN C\ ClN N -



o C

4 c'-C"


N C--

o cl


'o `0,
'0 '

t .-"I .C

N C -4


0 0) -^
o' 4u cS

f rt-i (


o ,*
o 'C C

o m
oC C.J




1 0 e'
3 V3 I

~t 0 C> '-
N ,- .

N 'r\ '3

0, \0 *N 0,C

N~ 0

C"' C,
8 NhO r-I


As can be seen from Table 1, both treatment groups received the

same stimuli conditions during the 16 trials of the first treatment day

and the first four trials of the second treatment day. On the first

treatment day each animal was initially put into the hot end of the

shuttle box (no longer receiving shock, however) and immediately the

filled food tray was pushed inside the box. The animal was allowed

either to eat or to roam freely, but as soon as he had eaten from the

tray for 30 seconds the food tray was withdrawn. After a ten second

delay the tray was reintroduced and two seconds after the animal had

again started eating the 8,000 Hz., 66 db tone was turned on for two

seconds. After completion of this tone the food tray remained in the

box for an additional three seconds and then was withdrawn. There was a

ten second interval between trials and S was always in place in the hot

end of the box at the beginning of a trial. These first 20 trials con-

bined both operant and desensitization treatment elements but on subse-

quent and succeeding trials food presentation became increasingly de-

layed in the operant treatment in a shaping procedure designed to rein-

force S's confronting the CS stimulus component, making various other

and unmeasured competitive responses, without making the phobic response.

The Desensitization group never received the CS tone without prior and

concomitant food presentation.

Beginning with the twenty-first trial, which was the fifth

trial of the second treatment day, timing of the onset of food presenta-

tion began with the introduction of the food tray and not, as previously,

with initiation of eating behavior on the part of S. It is impossible

to reliably obtain a constant delay of food presentation relative to

previoustone onset when food presentation is defined in terms of S's

initiation of eating behaviors, but food presentation defined in terms

of food tray introduction can easily be delayed at a fixed period after

a tone onset in a consistent and accurate fashion. There was no

assurance that S would begin eating as soon as the food was presented.

in the initial trials because though deprived he had no previous ex-

perience with the food's availability. This made it necessary to

define the start of food presentation in terms of S's initiation of

eating behaviors in these first 20 trials. Stimulus conditions in

these first trials made such a definition quite feasible in regards to

procedural reliability. After the first 20 trials, So had all become

acquainted with the food tray's location and availability such that

introduction of the food tray was practically equivalent to S's

initiation of eating behavior.

After the first treatment day all treatment trials were con-

ducted in the following manner. First an animal was introduced into

the hot end of the shuttle box and after a period of at least ten

seconds, and while the animal was in the hot end of the box (being

gently put back there if he had roamed over the hurdle during the ton

second period), the treatment stimuli were introduced. In the case of

the operant procedure the treatment stimuli introduction consisted of

the onset of the CS tone component followed later by food presentation

which was contingent upon the animal's confronting the CS without

making an avoidance response. In the desensitization method the onset

of the CS tone component followed the food presentation.

As treatment progressed each S was exposed to tones which

increasingly approached the original CS tone in terms of frequency or

pitch, volume level and duration. Thus, after beginning treatment

with a relatively soft, high-pitched and short tone, which had very

weak CR evocative potential, treatment ended with the loud low-

pitched and long lasting tone used as the CS in the acquisition

training. No shock was administered to any animal at any tine follow-

ing the completion of the acquisition training; thus hurdle jumping on

the part of S in response to the tone fulfilled the experimental

definition of a phobic response. Food was presented for a period of

seven seconds in all trials except the last eight trials where it was

presented for eight seconds. The stimulus conditions for the two treat-

ment groups are described more precisely in Table 1.

During the Treatment Phase the control animals were transferred

from their cages to another cage prior to their daily weighing. This

was done to equate all animals for handling. The control animals were

not otherwise manipulated and were kept in the same isolated environment

receiving the saeo stimulus exposure as the treatment animals, except

of course for the treatment stimuli.

Extinction Phase

The extinction trials began on the day after the fifth (final)

treatment day, and consisted of ten trials per day for five consecutive

days. These trials were similar to the acquisition trials in most

respects. Of course neither UCS (shock) nor food was presented as was

the case respectively in the acquisition and treatment trials. Initially

on each day of extinction the animal was placed in the hot end of the

box, then allowed to roam for two minutes. During extinction the

empty food tray was always pulled in the "out" position so that the

end of the tray covered the tray opening in the side of the shuttle-

box. At the end of the two minute exploratory period the animal was

placed again in the hot end of the box (if he was not already there)

and the CS tone (500 Hz., 90 db) was presented and concomitantly was

timed. As soon as the animal made a phobic response (by withdrawing

all physical contact from the grid floor on the hot side of the box)

the CS tone was terminated and simultaneously the timer stopped. If

the animal did not jump at the end of 20 seconds, chosen as the

infinite latency period, then the CS tone was terminated and his

latency was recorded as 20 seconds (indicating that no phobic response

was made). This procedure provided measures for the two dependent

variables, e.g., latency or delay between onset of the CS and the

occurrence of a CR, and whether or not the phobic response or CR was

made. After the first trial of each extinction day S was allowed to

freely roam for a period of 30 seconds before the CS presentation for

the next trial. If an animal made a CR during this pre-trial period

then ten seconds later he was placed back into the hot side to begin

the 30 second exploratory inter-trial period again.


Data obtained from each of the three phases of this study

will be presented in sequential correspondence to the experimental


Acquisition Phase

The latency between CS onset end CR occurrence was recorded

over the 100 trials (20 trials per day) of acquisition training. A

recorded latency of ten seconds or greater indicates that shock was

administered on that trial. These data then provide two measures of

CR acquisition strength in the speed with which a CR was evoked and

in the frequency of CR occurrence prior to UCS onset (or within ten


Figure 1 demonstrates these data graphically showing the mean

number of avoidance responses (CR's) made by each of the three groups

for each day of acquisition training.

Inspection of Figure 1 indicates similarity of conditioning

rates among the three groups. All of the animals achieved the criterion

of avoidance training by making a CR prior to UCS onset at least on

15 of the final 20 acquisition trials.

A one-way analysis of variance on the number of avoidance

responses for the final day of acquisition training supported the

contention that the three groups of Ss had been successfully matched

Control c----
Operant a-----
Desensitization .........-

---I- --T-
1 2 3 4 5

Acquisition Phase: Five Days, Twenty Trials Per Day

Fig. i.-Mean number of avoidance responses of three groups of
nine subjects over five days of conditioning.

on the strength of acquisition variable. This analysis failed to

indicate significant differences anong the three groups in uunber of

avoidance responses for the last 20 acquisition trials, as can be

seen in Table 2 below.



Sources of Variation df Mean Square F

Between 2 .45 .44

Error 24 1.03

Total 26

df (2, 24) .05 = 3.410 .01 = 5.61

Matching was accomplished not on the basis of the number of

avoidance responses made prior to the UCS, but rather on the latency

of these avoidance responses. The average CS CR latency by group

over all five days of acquisition training was as follows: Operant

group, 4.94; Desensitization group, 4.93; and the Control group, 4.90

seconds. These mean latencies for the fifth and final day of acquisition

training were as follows: Control group, 3.63; Operant group, 3.27; and

Desensitization group, 3.22 seconds. Note that although the Control

group demonstrates the fastest overall mean reaction time, indicating

strong acquisition of the avoidance response, the Control group's

reaction time for the fifth and final day of acquisition training (just

prior to treatment attempts to increase this reaction time) is the

slowest of the three groups. As in the case of the number of avoidance

responses made during acquisition, the speed with which these responses

were made is essentially equivalent among the three experimental groups.

Treatment Phase

The only recording made during the treatment trials was the

number of avoidance or phobic responses made by Ss during CS tone

component presentation. In the Desensitization group, which received

food prior to and continuing throughout exposure to the CS tones, only

two of the nine animals made phobic responses. These two animals only

made one such response each for a total of two, and these two responses

were both made only on the first treatment day. In the Operant group,

which received food usually seconds after tho onset of the CS tones,

eight of the nine Ss made a total of 21 (of a possible 756 total

trials) phobic responses. Table 3 describes the distribution of these

21 phobic responses over the five treatment days. Examination of the

data in Table 3 reveals that the operant fading procedure employed was

generally successful in maintaining the desired behavior, and that a

small percentage of phobic responses occurred.

Both treatments appear to have been accomplished successfully.

The nearly total prevention of CR occurrence in the desensitization

procedure attests to the effectiveness of the hierarchy used. Probably

the only way to have eliminated CR occurrence in the operant treatment

would have been to make food presentation less delayed relative to CS

onset, but this would have blurred the distinction between the two



Treatment Day Number and Nunber of Treatment Trials
Per Each Animal
Day 1 Day 2 Day 3 Day 4 Day 5
Animal 16 Trials 16 Trials 16 Trials 16 Trials 20 Trials

1 0 0 0 0 1

2 1 1 2 1 0

3 0 0 0 0 2

4 2 0 1 0 3

5 0 0 0 1 2

6 1 0 1 0 0

7 0 0 0 0 0
8 0 0 0 0 1

9 0 0 0 0 1

treatment groups; the operant treatment would have become more of a

desensitization treatment.

Extinction Phase

Treatment effects were measured during the extinction trials

both by the number of phobic responses made and by the latency in

responding. These data can be found in Appendices A, B and C.

Considering the number of avoidant responses made by the three

groups in the extinction curves in Figure 2, differences among the

groups are readily noted. These differences are further reflected

in the means and standard deviations of the avoidance responses as

contained in Table 4. Both treatment groups made less phobic responses

during post-treatment extinction trials than did the nontreated con-

trols. This difference was most evident on the first day of extinction,

immediately following the last treatment day. A two-way, mixed model

(Hays, 1966) analysis of variance is summarized in Table 5. These

results require the rejection of the hypothesis that the three groups

were sampled from the same population. To further describe differences

attributable to treatment, a Newman-Keuls test is presented in Table 6.

These results indicate that both the Desensitization and Operant treat-

ment groups are significantly different from the Control group, but

that the Operant and Desensitization groups are not significantly

different from each other. Thus, the significant treatment effect is

primarily due to differences between the treated and untreated groups.

Changes over "days" of the extinction trials are to be expected; the

significant effect of this variable is of little concern to this



1 2 3 4 5
Extinction Phase: Five Days of Ten Trials Each
Fig. 2.-Mean number of avoidance responses of three groups of
nine subjects over five extinction days.





Extinction Day
Group 1 2 3 4 5

Desensitization T 3.2 4.7 6.8 5.4 5.6

SD 3.18 3.64 2.47 1.72 2.70
Operant X 4.2 6.0 7.3 6.7 6.7

S 3.35 2.58 2.99 2.79 2.94
Control X 8.9 8.6 8.7 9.3 9.4

SD .89 1.61 1.59 1.03 1.14


Source of Variation df Mean Square F

Trcatnent 2 177.80 36.14-a
Days 4 19.85 2.93*b
Interaction 8 4.92 .73c
Error 120 (128)d 6.90 (6.78)d
Totals 134

adf (2, 8) .05 = 4.46 .01. 8.65

bdf (4, 128) .05 = 2.42
Cdf (8, 128) .05 = 2.01

dPooled MS error, used to test Days and Interaction effects



Treatment Methods
zation Operant Control

Treatment Totals 231 278 404

Differences 47 126

Differences 4
t/ H3error 2.72b 7.15-'c

aNewman.ecum s Test
bQ.95 (2, 120) = 2.80

CQ.99 (2, 120) = 3.70

investigation. It should be noted that complete extinction did not occur,

and that the treatment effects were measured during but not throughout

the extinction process. The "days" factor in the analysis of variance of

number of phobic responses was regarded statistically as a random factor,

sampled from all possible extinction days.

Turning now to the second dependent variable, phobic response

latency, differences among the three groups can be seen in the ex-

tinction curves of Figure 3. These differences are most evident, as

in the case of the phobic response occurrence variable, immediately

after treatment on the first day of extinction. Also, as in the case

of the first dependent variable, both treatment groups appear to be

clearly superior to the Control group in decrement of phobic behavior

and the densensitization treatment appears perhaps more effective than

does the operant procedure. The means and standard deviations of these

latency data are presented in Table 7. Analysis of the variance of

these results, summarized in Table 8, again as in the case of the

first dependent variable, demonstrates a strong treatment effect. A

two-way, mixed model analysis was employed with an error term for test-

ing interaction and row effects (the random effects variable) derived

by pooling the interaction and error mean squares, again as was done in

the first dependent variable analysis of variance.

To more precisely delineate the effect of treatments on latency

of the phobic response during extinction another Newman-Keuls test was

calculated (Table 9). These results again parallel those obtained with

the CR occurrence data previously described in that either the Desensiti-

zation or Operant groups were significantly slower in responding to the


CS than was the Control group, but that the two treatment groups mis.

being significantly different.

The effect of desensitization and operant procedures in the

reduction of two behavioral indices of phobic behavior appears to be

highly facilitative as compared with no treatment procedure at all,

but the hypothesis that the two successful treatment procedures

differed in effectiveness escaped rejection and the differences found

in this study must await future investigation for clarification.

Control o-----
Operant o-- - 0-
16 Desensitization -..........

e. "**.

S14 -'

a, .I
3\ *
S 12 '" "



9 9-

1 2 3 4 5
Extinction Phase: Five Days of Ten Trials Each

Fig. 3.-Average time between CS onset and phobic response of
three groups of nine subjects over five extinction days.



Extirction ___
Group 1 2 3 4 5

Desensitization y 16.09 14.83 11.97 13.63 12.44
s 4.68 5.35 3.69 3.50 6.03
Operant i 15.24 13.73 11.10 12.31 11.16
SD 3.91 3.45 4.08 3.48 4.01
Control y 7.55 9.72 8.87 8.85 7.09
SD 2.18 4.33 2.74 3.58 4.58



Source of Variation df Mean Square F

Treatment 2 356.08 28.72**

Days 4 39.08 2.20b

Interaction 8 12.40 .70c

Error 120 (128)d 18.12 (17.76)d

Total 134

adf (2, 8) .05 = 4.46 .01 = 8.65

bdf (4, 128) .05 = 2.42

Cdf (8, 128) .05 = 2.01
dpocled MS error, used to test Days and Interaction effects.



Treatment Methods
zation Operant Control

Treatment Totals 620.63 572.85 381.43

Differences 47.78 191.42

Differences -:-
is error 1.67a 6.70 -b

aQ.95 (2,

bQ.99 (2,

120) = 2.80

120) = 3.70


Analysis of the acquisition data indicates that successful

matching of groups was achieved in this investigation so that the three

groups of animals had approximately equal conditioned avoidance

response tendency prior to the treatment phase. Thus the three groups

were probably nearly equal in the strength of their phobic response

tendency, and were probably also nearly equal in their ability to

"unlearn" the previously conditioned avoidance response, when treat-

ment began.

Data obtained during the Treatment Phase indicate that both

treatments changed the rate of the avoidance responses of the eaimals

during treatment trials. Both treatment groups received a nearly

equal exposure to the CS throughout this experiment, so that the treat-

ment effect involved in CS exposure was equivalent among treatment

groups. Treatment effects due to extinction were considered minor since

the phobic behaviors of the Control group on the fifth (final) day of

extinction trials were nearly equal to those on the first day of ex-

tinction, and since the phobic behaviors of the Control group on the

final day of extinction were much greater than those of either the

Operant group or the Desensitization group on the first day of extinction.

Both treatment groups also received an equal opportunity to eat during

treatment. All Ss were maintained on similar food deprivation schedules

prior to and during the first two phases of this study, and all the

groups were fed ad lib during the final phase.

The reason for changing to an ad lib food schedule in the final

experimental phase was to achieve what was thought to be a more pure

measure of the effects of treatment by reducing deprivation effects on

response maintenance. Under food deprivation conditions the operant

treatment would have measured out as more effective than was the case.

The fact that the measures of phobic behavior on the final two days

of extinction, when any food expectation should have extinguished to a

large degree, are very similar to these same measures over all five

days of extinction suggests that food expectation played a minor role

in the effects of treatment (as measured with vell-fed animals).

Effects of operant proceduroc are typically measured after

removal of previous reinforcement, but not necessarily while needs

satisfied by the reward are reduced to a state of satiation. In attempt-

ing to measure more lasting effects of treatment, rather than temporary

and perhaps artificial effects, the operant treatment was Beapered in

this investigation.

The operant procedure employed was a discriminative differential

reinforcement of other behaviors. The desired event in the operant

procedure, not jumping, involved a variety of inhibitory responses

(largely superstitious in nature). It was these varied urneasured

inhibitory responses which were actually reinforced. These reinforced

responses, which were somewhat incompatible and antagonistic to the

phobic response, were brought under the control of discriminative

stimuli presented along stimulus dimensions (frequency, loudness, and

duration of tone) through a fading procedure. The tone came to serve

as a discriminative stimulus for food presentation in the operant

procedure. During the extinction trials, when the animals were satiated

for food, the tone was irrelevant as a discriminative stimulus, making

the operant animal nuch more likely to make the phobic response than

would have been the case had the food-deprivation schedule been continued.

However, by providing all animals with food during the Extinction Phase,

the operant treatment procedure more closely approximated the hypothe-

sized operant elements in the desensitization treatment. The desensitized

animal demonstrates his treatment effect whether food deprived or food

satiated and any operant procedure involved in the desensitization

treatment must also stand up under food-satiation conditions.

A one-way shuttle box was used Each that one side consistently

received shock during acquisition, food during treatment, and the CS

during all experimental phases. If a two-'.ay shuttle box had been

used, in which both sides alternately received shock, then both ends

of the box would have taken or an aversive quality for the anzials.

This potential source of confusion for the animals was avoided, though

thereby probably making treatment more difficult, by consistently offer-

ing the animals a sanctuary in the no-Ehock end of the box. Thus the

quick phobic response was always clearly associated with avoidance of

shock, and was always an available course of action to the animal.

The operant treatment involved the reinforcement of responses

involved in an animal's confronting the CS without making a phobic

response. These reinforced responses were shaped in that their occurrence

over increasing periods of tine was required in order to obtain food.

Operant treatments usually attempt to increase the rates of more active

and positive responses. However, in the experimental procedure employed

here, the reinforcement of a single, active response might have intro-

duced desensitization elements in that the active responses would have

involved inhibition of anxiety. Wolpe (1958) describes hoIT an active

motor response can reduce anxiety, even though this motor response

does nothing toward the avoidance of the threatening stimulus. The

choice of rewarding a passive CS confrontation response avoided these

problems Paid thus more clearly offered a test of motor level operant

conditioning versus more central (perhaps) autonomic level anxiety

inhibition. If an active, positive, clearly defined competing motor

response had been positively reinforced then the operant treatment would

probably have measured out as more effective than was the case. Eut

again this does not correspond to the hypothesized role of an operant

procedure in desensitization in that desensitization does not involve

the occurrence of an active, positive noter response. In human de-

sensitization, finger raising serves as a signal rather than as a compet-

ing response antagonistic to the phobic response. Thus, to make the

operant procedure most comparable to the operant procedure that might

operate in desensitization, no clearly defined rewarded response was


Results from the Extinction Phase suggest that contrary to

our hypothesis the operant treatment is not superior to the desensitization

procedure. However, and as hypothesized, both treatments were signifi-

cantly effective as compared to a no treatment condition. Before dis..

cussing possible implications of these results it must be pointed out

that the measures of treatment effect were taken from extinction trials

that did not continue to completion. The question arises as to whether

the treatment differences demonstrated would have continued in the

same form if the trials had gone on to total extinction. Statistically

this was controlled to an extent by regarding the "days" factor in the

analysis of variance as having a random rather than fixed effect,

thus taking the five days measured as a sample rather than as exhaustive

of the universe of "Days." It is most likely that data obtained from

all possible extinction trials would have yielded the same results as

the data actually obtained. The most probable exception to this is

that the desensitization treatment night have been shown to be sig-

nificantly superior to the operant procedure employed in terms of

reducing number of phobic responses made, since this was nearly so

with the data obtained.

A major finding in this study is that an operant procedure,

which most closely approximated such a possible procedure in desensiti-

zation, was found to be slightly less effective (though this was not

statistically significant) than a desensitization procedure in the

reduction of phobic behaviors. All other sources of treatment effect,

not specifically and uniquely a part of the two treatment procedures

employed, were equivalent in the two treatments. Such sources of

treatment effect which were equivalent in both treatments include

(1) extinction possibilities, (2) change from conditioned aversive

qualities to conditioned adient qualities of the hot end of the shuttle

box through food presentation in treatment, and (3) opportunities for

making various motor responses. The CS tone was of different stimulus

value for the two treatment groups, serving as a discriminative stimulus

for food presentation in the operant procedure while serving as a CS

for response states involved in eating (presumedly incompatible with

previously conditioned anxiety response states) in the desensitization

procedure. However, these differences in the tone's value, primarily in

its value as a conditioned reinforcer, are differences inherent in the

differences between the two treatment procedures. And whereas the CS

tone's value as a discriminative stimulus was much reduced during the

extinction trials (when the food schedule became ad lib) this again

more closely approximated any possible operant procedure involved

in desensitization. Therefore, the desensitization treatment effect

may involve some possible operant conditioning treatment effect, but

it is not dependent upon such operant elements. At any rate this study

supports the view that either the operant or the desensiti nation pro-

cedure is similarly effective in reducing phobic behavior. This find-

ing has some implications for further elucidation of the desensitization

process and for treatment of phobic behavior in general.

In regard to the nature of the desensitization process, contrary

to the view initially offered here, it appears that the desensitization

treatment effect involves more than either rewarded confrontation

with the phobic object or reinforced induction of competing motor

responses. The operant treatment contained these two elements plus the

additional advantage of a more efficient use of reward in using fading

and shaping procedures designed to more strongly condition motor responses

than could be accomplished by the continuous and simultaneous "reward"

offered as part of the desensitization treatment. The additional

treatment effect element, which is necessarily a part of the desensiti-

zation treatment to a greater extent than in the operant treatment,

could be a deconditioning of anxiety previously conditioned to the

stimulus represented by the phobic object. This deconditioning might

occur as a result of two processes: the weakening or reciprocal in-

hibition of conditioned bonds between anxiety affect and the phobic

stimulus, and a simultaneous strengthening or reconditioning of bonds

between the phobic stimulus and pleasant affect (a process which could

also serve to reciprocally inhibit anxiety). This night involve a

response state substitution to the sane stimulus via classical con-


But regardless of such conjecture, it doos appear that phobic

behavior can be treated by changing motor behavior in the direction of

approach rather than avoidance, without dealing with anxiety directly.

Phobic behavior treatment is also enhanced by reducing phobic anxiety,

perhaps by a process involving the substitution of conditioned adient

affect for previously conditioned aversive affect.

There is currently a continuing debate between behavior modifi-

cation learning theorists and analytically oriented theorists regard-

ing the necessity of dealing with internal "causes" in treatment of

neurotic symptoms (Ullmann and Krasner, 1965). Related to this issue

is the differing view of phobias held by psychoanalysts and behavior

modifiers. Psychoanalysis traditionally regards phobias as generated

from anxiety which is displaced onto the phobic object, whereby avoid-

ance of the phobic object while being fearful of that object becomes a

means by which the anxiety is kept in check. Analytic treatment of

phobias is accomplished through uncovering the source of the anxiety

in terms of the unconscious dynamics and intrapsychic conflicts in-

volved. After this underlying material is brought into full cognitive

and emotional awareness then the anxiety is dispelled and the phobia is

reduced. In contradistinction to this view, the behavior modification

approach would regard phobias in terms of behavior that originates

from prior aversive conditioning which is best treated by elimination of

the phobic behavior or modification of verbal behavior. Thus Eysenck's

(1960) dictua: "Get rid of the symptom and you have eliminated the

neurosis" (p. 9).

Wolpe, in arguing for the progressive deconditioning or in-

hibition of the phobic anxiety in treating phobic behavior stands some-

where between the analyst, who would resolve the underlying conditions

which give rise to the displaced phobic anxiety, and the behavior

modifier, who would change the phobic (notor level) behavior. The

differences in these three approaches to the treatment of phobic behavior

can then be regarded in terms of the level of the phobic experience at

which attempted change is primarily focused. The results of this

research suggest that either motor level behavior or more central

levels of response states can be the primary change target in effective

treatment of phobic behavior. However, it must be remebered that our

definition of phobic behavior is based on a learning theory model and

not on the psychoanalytic "phobia." There may well be different types

of phobias corresponding to the differing definitions of phobias found

in psychoanalysis and learning theory.

Treatment of phobic behavior may best be accomplished by in-

ducing changes at all levels of experience and behavior. But in

recent years there has been increasing support for the view that be-

havior, however conveniently studied at isolated and restricted levels,

is very much unified.

Social psychologists, particularly the cognitive dissonance

researchers, have well demonstrated how changes in overt behavior can

bring about internal changes in cognition, attitude, and affect. The

operant animal in this study who was rewarded for confronting threat-

ening stinuli probably experienced a fear reaction which likely under-

went some extinction so that changes in affect followed motor level

changes. Likewise, the subject whose fear was diminished was enabled

to make subsequent rotor level changes. Freud (1925) found it most

helpful in treating phobias to make his phobic patients expose them-

selves to previously avoided and painful situations. The results of

this study are consistent with a unified view of behavioral change

such that change at any level of experience has important implications

for subsequent changes at other levels of overt and covert behavior.

The method presented here, of equitably comparing operant with

desensitization methods, would seem worthy of further extension and

exploration. Hopefully, with more sophisticated measuring techniques

and more refined procedures, future research will be able to demonstrate

how much the treatment of phobic behavior depends on the resolution of

anxiety engendering deep-seated conflicts versus reduction in specific

conditioned anxiety versus change in motor level behavior. It might

also be possible to more precisely determine ho;w much desensitization

depends on the inhibition of general anxiety versus specific conditioned

anxiety, and to determine how much desensitization involves instrumental

conditioning of either approach behaviors or competing motor responses.

Such research is particularly neededvith human subjects.

Although the purpose of this study was not to determine the

comparative efficacy of the two treatments employed, such an evaluation

could be accomplished within the experimental framework here intro-

duced. In all fairness to the operant procedure, such a study would

require tie reinforcement of a clearly defined, active motor response

(competitive to the phobic response). In the same vein, food deprivation

conditions should continue throughout the extinction trials in any

such treatment comparison.

Since operant procedures are effective in bringing about con-

frontation with a phobic stimulus, desensitization with humans could

perhaps be modAe nore effective by maximally employing verbal reinforce-

ment which could be iade contingent upon the subject's self-report of

having imagined an item in the hierarchy of threatening stimulus situ-

ations. Therapist reinforcement of the subject's actual confrontations

with the phobic object could also be combined with desensitization in

an attempt to bring about changes at many levels of behavior and ex-

periencein eliminating human phobias.


Bentler, P. An infant's phobia treated with reciprocal inhibition
therapy. Journal of Child Psychology and Psychiatry, 1962, 3,

Breger, L. and McGraugh, J. L. Critique and reformulation of "learning
theory" approaches to psychotherapy and neurosis. Psycological
bulletin, 1965, 338-358.

Carlson, V. J. and Elack, A. H. Traumatic avoidance learning: note
on the effect of response prevention during extinction.
Psychological Renorts, 1959, 5, 409-412.

Cautela, J. The Pavlovian basis of reciprocal inhibition therapy.
Conditioned Reflex, 1966, 1, 293-330.

Cooke, G. Evaluation of the efficacy of components of reciprocal in-
hibition psychotherapy. Journal of Abnormal Psycholog, 1983,
73, 464-467.

Cooper, A., Furst, J. 2,, and Bridger, '. H. A brief conmentary on the
usefulncs of studying fears of snakes. Jourrail of Abnoral
PsicpoloL, 1969, 74, 413-414.
Delude, L. A. and Carlson, N. J. A test of the conservation of anxiety
and partial Irreversibility hypotheses. Canadian Journal of
Psychology, 1964, 18, 15-22.
rseonck, H. J. (Sd.) Behavior therapy and the neurosis. Oxford:
Pergamon Press, 1960.

Freud, S. Turnings in the way of psychoanalytic therapy. In Collected
anSerS,, Yol. 3, 392-402. London: Hogarth Press, 1925.
Gale, Diana, Sturofels, Gloria, and Gale, E. N. A comparison of
reciprocal inhibition and experimental extinction in the
psychotherapeutic process. Behavior; Research and Therany,
1966, 3, 209-219.

Goldstein, A. J. A comnrison of two methods of overcomingavoidance
behavior. Doctoral disoertation, University of 'lorida, 157.

Eays, W. I,. Sttlistics for sycholo-ists. New York: Holt, Rinehart
anid ;iston, 193


Hogan, R. and Kirchner, J. Implosive, electric, verbal and bibliotherapy
in the treatment of fears of snakes. Behavior Research and
Therapy, 1968, 6, 167-171.

Hussian, A. Behavior therapy using hypnosis. In Wolpe, J., Salter, A.
and Rayna, L. J. The conditioning therapies. New York: Holt,
Rinehart and Winston, 1964.

Johnson, S. and Sechrest, L. Comparison of desensitization and progres-
sive relaxation in treating test anxiety. Journal of Consult-
in and Clinical Psychology, 1968, 2, 280-2 '6.

Jones, Mary C. A laboratory study of fear: the case of Peter. Journal
of Genetics and Psycholoj, 1924, 31, 308.

Lang, P. and Lalovik, A. The experimental desensitization of a phobia.
Journal of Abnormal and Social Psychologr, 1963, 66, 519-525.

Lazasus, A. Group therapy of phobic disorders by systematic desensiti-
zation. Journal of Abnormal and Social Pschology, 1961, .3,

Lazarus, A. and Abrmovitz, A. The use of "emotive imagery" in the
treatment of children's phobias. Journal of Mental Science,
1962, 108, 191-195.

Lazarus, A. The results of behavior therapy in 126 cases of severe
neurosis. Behavior Research and Therapy, 1963, 0, 69-79.

Orne, M. On the social psychology of the psychological experiment:
with particular reference to demand characteristics and their
implications. American Psychologist, 1962, 17, 776-783.

Pavlov, I. P. Conditioned reflexes. London: Oxford University Press,

Paul, G. Insipht versus desensitiation in psychotherapy. Stanford:
Stanford Press, 1966.

Rachman, S. The role of muscular relaxation in desensitization therapy.
Behavior Research and Therapy, 1968, 6, 159-166.

Rachmni, S. and Hodgson, R. Studies in desensitization: IV. Optimum
degree anxiety reduction. Behavior Research and Therapy,
196?, J, 249-250.

Roseathal, R. Exorimenter effects in behavioral research. New York:
Appleton-Century-Crofts, 196.-

Solomon, R. L. and Wynne, 1. C. Traumatic avoidance learning: the
principles of anxiety conservation and partial irreversibility.
Psychological Revie, 1954, 61, 353-395.
Solyom, L. and Miller, S. Reciprocal inhibition by aversion relief
in the treatment of phobias. Behavior Research and Therapy,
1967, i, 313-324.

Stampfl, T. and Levis, D. Essentials of implosive therapy: A learn-
ing theory based psychodynamic behavioral therapy. Journal of
Abnormal Psycholooy, 1967, 72, 496-503.

Ullmann, L. P. and Krasner, L. (ils.) Case studies in behavior
modification. New York: Holt, Rinehart and Winston, 1965.

Watson, J. B. and Rayner, Rosalie. Conditioned emotional reactions.
Journal of Fxnerimental Psychology, 1920, 3, 1-14.

Weinberger, N. M. Effects of detainment on extinction of avoidance
responses. Journal of Comnarative and Physiological sycholo ,
1965, 6, 135-138.

White, J. The use of learning theory in the psychological treatenr.t
of children. Journal of Clinical Psychologg, 1959, 15,

Winer, B. J. Statistical Drincioles in experimental desisn. New
York: IMcraw-Hill, iT -.-

Wolpe, J. Experimental neurosis as learned behavior. British Journal
of Psycho 1952, 43, 192-206.

Wolpe, J. Psychotherapy byrecinrocal inhibition. Stanford: Stanford
Press, 1?5 .

Wolpe, J. The systematic desensitization treatment of neuroses. Journal
of Nervous and Mental Disease, 1961, 132, 139-203.

Wolpe, J. and Lazarus, A. Behavior therapy techniques. New York:
Pergamon Press, 196.

Wolpin, 1. and Rales, J. Visual imagery, expected roles, and extinction
as possible factors in reducing fear and avoidance behavior.
Behavior Research and Therany, 1966, 4, 25-37.



Days __
Animals 1 2 3 4 5

1 10.85 (8) 11.32 (8) 9.01 (9) 12.38 (9) 5.56 (10)
2 4.42 (10) 5.38 (10) 8.73 (9) 8.76 (9) 6.46 (9)

3 5.69 (9) 1.82 (10) 5.68 (10) 3.43 (10) 1.94 (10)
4 7.58 (10) 9.72 (10) 10.40 (10) 9.74 (9) 7.88 (10)

5 5.79 (9) 7.98 (10) 3.93 (10) 7.04 (10) 2.48 (10)
6 6.89 (9) 12.74 (6) 12.50 (6) 8.53 (10) 12.22 (9)

7 9.75 (8) 14.01 (6) 6.41 (10) 12.89 (10) 9.55 (9)
8 10.57 (8) 14.65 (8) 13.07 (5) 10.82 (8) 11.10 (8)
9 6.38 (10) 9.86 (10) 9.90 (9) 8.82 (9) 6.60 (10)


~ ____n__ ___Days __________
Animals 1 2 3 4 5

1 17.33 (2) 12.33 (6) 11.25 (8) 16.23 (4) 10.80 (7)
2 10.68 (8) 9.62 (8) 9.14 (10) 11.24 (8) 6.60 (10)

3 10.11 (9) 12.07 (7) 6.40 (10) 11.36 (9) 8.26 (8)
4 18.70 (1) 15.01 (7) 8.76 (9) 9.81 (8) 11.34 (8)

5 15.59 (5) 8.98 (8) 8.33 (9) 10.08 (8) 7.53 (10)
6 20.00 (0) 18.42 (3) 10.68 (?) 10.79 (7) 8.20 (7)

? 20.00 (0) 20.00 (0) 20.00 (0) 20.00 (0) 20.00 (0)
8 13.50 (7) 13.22 (7) 12.96 (7) 8.12 (10) 12.98 (5)

9 11.24 (7) 13.90 (7) 13.41 (6) 13.19 (6) 14.69 (6)


Animals 1 2 3 4 5

1 13.17 (4) 17.69 (2) 9.01 (9) 12.38 (7) 18.90 (1)
2 19.57 (1) 16.88 (8) 12.30 (6) 18.55 (2) 18.33 (1)

3 19.53 (1) 8.59 (7) 13.60 (6) 11.02 (7) 10.86 (7)
4 19.53 (1) 17.05 (4) 15.71 (5) 14.06 (5) 8.74 (8)

5 20.00 (0) 20.00 (0) 12.36 (8) 19.30 (1) 13.10 (4)
6 20.00 (0) 19.40 (2) 14.20 (5) 16.34 (4) 12.00 (6)

7 7.69 (9) 5.89 (10) 7.16 (10) 11.59 (8) 8.72 (9)
8 15.c9 (3) 20.00 (0) 17.53 (2) 11.12 (7) 15.00 (4)

9 9.61 (7) 8.00 (9) 5.88 (10) 8.27 (8) 14.69 (9)


Arthur I. Wells, Jr., was born on October 9, 1939, at Birming-

han, Alabama. He moved to Florida in 1949, where he attended public

schools. He was graduated from Ft. Lauderdale High School in June,

1958. In August, 1962, he received the degree of Bachelor of Arts

from the University of Florida. During the summer of 1961, he worked

with maladjusted children under David Wineman while attending the

University of Michigan. In August, 1965, he received his Master of

Rehabilitation Counseling degree from the University of Florida.

After working for one year in Miani, Florida, as a Rehabilitation

Counselor, he returned to the University of florida to work toward

his doctorate in psychology. During his graduate studiess in psychology,

he vas a Vocational Rehabilitation Administration fellow. In August,

1969, he completed a one year's internship in clinical psychology at

the J. Hillis Hiller Health Center. Since September, 1969, he has

worked as a psychologist at the Northeast Florida State Hospital in

Macclenny, Florida.

He was honorably discharged from service in the U. S. Air


Arthur M. Wells is married to the former Anastasia E. Lawlor.

He is a member of Psi Chi and Phi Kappa Phi.

Thi.s dissertation was prepared under the direction of the
cda.irman of the candidate's supervisory committee and hs been approved
by all members of that committee. It was submitted to the Dean of the
College of Arts and Sciencesanl to the Graduate Council, and was
approved as partial fulfillment of the requirements for the degree of
Doctor of Philosophy.

l!arch, 1970

Dean, College of Arts and Scip -

Dean, Graduat6 School

Supervisory ConLittec:

-m y /'
A^/ -^


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