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The physiological basis of implosive therapy
tkhav
ks.
& Therapy.
1975. Vol.
13. pp. 93-100. Pergamon Press. Printed m Great Bream
THE PHYSIOLOGICAL
BASIS
OF IMPLOSIVE
THERAPY*
BETH A. MCCUTCHEONt Brenau
College. Gainesville.
Georgia.
USA
and HENRY University
of Georgia.
E. ADAMS Athens, Georgia.
(Rrcrived 19 Auyust
U.S.A
1974)
Summary-Two analog studies were designed to investigate the differential effects of length of implosion session. theoretical concepts underlying IT. and the physiological, subjective, and behavioral responses to relevant and irrelevant fear stimuli in implosion. Subjects were selected who were unable to pass a behavioral test of viewing a.film of surgical operations. The results indicated that IT is a feasible method of behavior modification if subjects are ‘flooded’ to a point of physiological habituation to specific relevant. symptomatic cues. Implosion with irrelevant fear cues did not produce a significant change in the behavioral test. An extinction hypothesis emphasizing elicitation of the fear response without reinforcement was supported by the present data. The ‘behavioral contrast’ and exhaustion hypotheses of implosion were not supported.
Stampfl and his colleagues (Levis and Carrera, 1967; Stampfl and Levis, 1967a, 1967h) assume that if an individual is exposed repeatedly to stimuli which he has been conditioned to fear and if that exposure occurs in a situation which the subject cannot avoid, the fear behavior elicited by the conditioned stimuli will be extinguished. This assumption is the basis of implosive therapy (IT), and IT theorists stress that the extinction process progresses more rapidly when the individual is kept in a state of high arousal (Stampfl and Levis, 1967b; Hogan and Kirchner, 1967). As a result of the theory that high levels of arousal lead to more rapid extinction, the IT therapist floods the individual with a series of cues progressively more intense in order to achieve a consistently increasing level of anxiety. Both the theory and the therapeutic effects of IT have been questioned by numerous investigators (Bandura, 1969; Eysenck, 1968; Lader and Mathews, 1968; Lader and Wing, 1966; Morganstern, 1973; Wolpe, 1969). For example. the theory of maximal habituation (Lader and Mathews, 1968; Lader and Wing, 1966) suggests that rapid habituation occurs with low rather than high levels of arousal. In fact, Lader (1967) stresses that after the S reaches a pathological state of fear arousal, even a low level arousal stimulus maintains the critical level of anxiety, thus interfering with the habituation process. According to Rachman (1969) IT may depend on the therapist’s ability to achieve high levels of anxiety arousal in the S until a point of stimulus satiation is reached. Habituation occurs because the S is at a level where he can no longer overtly or covertly respond, and the level of arousal rapidly diminishes. In addition to the exhaustion hypothesis, Hodgson * This article is based on a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree from the Department of Psychology, University of Georgia. by the first author under the direction of the second author. t Requests for reprints should be sent to Beth A. McCutcheon. Brenau College, Gainesville, Georgia 30501, U.S.A. 93
94
BETH A. MCCUTCHEON and HENRY E. ADAMS
and Rachman (1970) state that ‘behavioral contrast’ may be an alternate explanation for the reported success of IT since the behavioral criteria (e.g.. touching a snake in the presence of another person) may be less threatening or anxiety provoking than the actual therapeutic process (e.g. the anxiety-producing snake imagery with which the S is flooded). Both the theoretical formulations of behavioral contrast and of exhaustion suggest that the individual need not be flooded with stimuli highly relevant to the situation that generates anxiety. The principal goals of the following analog studies were to clarify further these theoretical issues and to devise a procedure which would simultaneously investigate the subjective, behavioral, and psychophysiological indices of implosion while controlling for demand characteristics of the situation. EXPERIMENT
I
METHOD
Subjects
The 219 male and female students who were enrolled in an introductory psychology course at the University of Georgia were administered the Fear Survey Schedule III (Wolpe and Lang, 1964) in a group testing session. Those who indicated that they were ‘very much afraid’ of watching a surgical operation* were asked to participate further in the experiment. The first twelve female Ss who did not pass the behavioral test, a film depicting surgical procedures, were assigned on a rotation basis to one of three groups. Apparatus
The experimental chamber was a dimly lit, sound resistant, constant temperature room containing a reclining chair equipped for the attachment of GSR electrodes. An intercom. system and a one-way viewing mirror enabled the experimenter to hear and view any unusual movement or activity which might create artifactual skin resistance changes. The GSR located on the outside of the chamber was recorded as d.c. resistance change on a 7PIA preamplifier of a Grass Model 7 polygraph. Two GSR electrodes which conform to specifications suggested by Venables and Sayer (1963) were used. An electrode paste of 0.05~ NaCl as recommended by Edelbert (1967) was used. Surface oils were removed by swabbing the electrode sites with acetone until the skin became mildly erythematous. GSR nonspecifics were recorded continuously throughout the experiment from these electrodes. A 16-mm film entitled ‘Multiple Wounds, Report of a Battle Casualty’ (U.S. Department of the Navy, 1945) which could be stopped by a switch available to the subject was utilized as the behavioral test. All Ss were urged to watch the film as long as possible. Subjects who did not stop the film within 3 min were eliminated from the study. The Ss were also administered a lOO-point fear thermometer (FT) in the experimental chamber immediately before and after completion of the experiment. The Ss in the relevant and irrelevant imagery groups also indicated on a 5-point scale the degree of anxiety and fear that they experienced during the film and during the implosive tapes. * Pilot data indicated that fear of surgical operations is the most common at the University of Georgia. A total of 35 subjects were given the behavioral
fear among female college students test in order to obtain the subjects.
The phsyiological
basis of implosive
therapq
95
Procedure
Upon arrival at the laboratory, Ss, after completing the FT, were given general instructions about the behavioral assessment procedure as the GSR electrodes were being attached. A basal GSR was obtained during a 5-min silent adaptation period (Baseline I). The behavioral test was then administered to the subject who had the option of switching off the film at any time. They were then assigned to treatment groups as previously mentioned. Relecanr Imagery’ (RI) Group. The first 5 min after the film were devoted to giving the Ss information concerning IT and the relevant imagery implosive tape. Subjects were then given another 5-min adaptation period in order to obtain the basal GSR (Baseline II). A 20-min tape-recorded implosion session depicting fear-provoking imagery of witnessing a surgical operation was then administered. Continuous GSR recoding monitored the Ss autonomic responses throughout the entire experiment. At the end of the implosion tape, subjects were given another 5-min adaptation period to obtain the resting GSR basal level (Baseline III). They were then shown the film for the second time. Irreleoant Imagery (II) Group. The first 5 min after reviewing the film were devoted to giving Ss information concerning IT and the irrelevant imagery implosive tape. The GSR procedure and the adaptation periods are identical to those in Group RI. Instead of the implosive tape dealing with surgical operations. however, Ss in Group II were given a 20min tape-recorded implosion session depicting anxiety-provoking imagery of snakes. Control Group (CC). The procedure for the control group was essentially the same as for Groups RI and II, with the exception that subjects were told to lie back in the chair, close their eyes, but not to go to sleep. After a basal GSR was obtained during the first 5 min, the nonspecific fluctuations of the GSR were recorded for 20 min. Data reduction
A nonspecific response or fluctuation was defined as a decrease in skin resistance as indicated on the polygraph by a downward deflection of the pen (ascending limb) or a change in direction, if the deflection of the ascending limb was at least 1 mm amplitude at an angle of 15” at a chart speed of Smmisec. Any response was counted if there was a change in direction of the existing oscillograph line between two responses regardless of direction. In other words, two responses occurred, both in a downward direction, if there was a leveling or a change in angle of the slope between those two responses. Any change in direction or angle of slope constituted the end of a response, and a continued decrease in skin resistance was tabulated as another response. All responses that occurred smoothly at an angle to the existing baseline were tabulated. Those changes which did not occur smoothly were considered to be movement or other artifactual events and were omitted from the tabulation. Changes in basal skin resistance were also analyzed using the data reduction procedure suggested by Edelberg (1967) in both studies. However, this measure was nonreactive to treatment conditions and will not be further discussed. This is not surprising since Kilpatrick (1972) has indicated that changes in basal skin resistance indicates cognitive activity while changes in nonspecific responses are related to emotional arousal. The stimulus periods during the tapes and no-stimulation control were divided into lomin trial blocks. The Baseline II period was multiplied by two in order to equate the amount of time during the rest periods with the trial blocks.
BETH A. MCCUTCHEON and HENRY E. ADAMS
96 35
/‘R’
r
PRE TREATMENT
POST TREATMENT
EXPERIMENT
Fig. 1. Mean number
of nonspecific
PRE TRELTMENT
POS’
EXPERIMENT
I
GSR responses during iments I and II.
observation
TREATMENT
II
of criterion
film in Exper-
RESULTS
Analyses of variance of the duration of time observing the film (behavioral test) and the FT indicated no significant differences in treatment groups, pre-versus post-test or the interaction of these two variables. However, the analysis of variance of nonspecific fluctuations of the GSR during the behavioral test indicated a significant interaction between treatment groups and pre- versus post-test (F = 3.24, df = 2/9, p < O.lO).* There appeared to be a tendency for the implosion Ss to show more arousal after being exposed to 20 min of implosion, as may be seen in Fig. 1. while the CG group showed less arousal. An analysis of variance of nonspecific fluctuations during the presentation of the implosive tapes or the no-stimulation control period was conducted and indicated a significant difference between treatment groups (F = 8.84, df‘= 2/9, p < 0.05) and the interaction of * Because of the small N and the exploratory cant.
/
nature
BASELINE
of nonspecitic
a p value of 0.10 was considered
II
TRIAL
Fig. 2. Mean number
of these studies.
BLOCKS
GSR responses
during
control
and treatment
periods.
signifi-
The phsyiological
basis of implosive
therapy
97
time periods with treatment groups (F = 2.57. df = 4/18. p < 0.10). Both treatment groups showed a definite increase in nonspecific fluctuations as a result of implosion, while the control group exhibited a decrease in arousal. as may be seen in Fig. 2. EXPERIMENT
11
The results of the first experiment strongly suggest that a 20-min period of implosion was not sufficient to eliminate the avoidance or fear responses to anxiety-arousing stimuli. In fact, the RI subjects appeared to show more arousal during the post-treatment behavioral test. The second experiment was conducted imploying 60 min of IT to investigate further this phenomenon. METHOD
Eighteen female Ss of the original sample who did not pass the behavioral test were assigned on a rotation basis as in Experiment I to one of three groups. Group RI received 60 min of relevant implosion, Group II received 60 min of irrelevant implosion. and Group CG sat quietly for 60 min. In all other respects, Experiment II was identical to Experiment I. RESULTS
Behavioral test
In contrast to Experiment I, the general finding in Experiment II was that the RI condition resulted in a greater decrease in anxiety than did either the II condition or the nostimulation control condition when Ss were exposed to 60 min rather than 20 min of IT. The analysis of variance of the mean exposure time for the behavioral criterion tests indicated a significant difference between the pre- and the post-tests (F = 8.50, df = l/15, p < 0.05) and significant treatment conditions by pre- versus post-test interaction (F = 4.64, df = 2/15, p < 0.05). An analysis of the simple main effects indicated an increase in exposure for the RI Group, as may be seen in Table 1. No significant changes, however, were observed for the II or CG Groups. There were no significant differences between groups at pre-test, but the differences between groups were significant at post-test. The RI Group was significantly different from both the II and the CG Groups, but these groups did not differ from each other. Subjective report
The analysis of variance of the FT scores showed that there were no significant differences between treatment conditions. There was a tendency for those Ss in the RI Group Table
Group RI I1 CG F tests
1. Analysis of simple effects of the treatment pre- versus post-treatment interaction Mean Exposure Pre-treatment 50.5 57.2 68.5
Time (set) Post-treatment 166.2 78.7 12.3 6.37**
* p < 0.05. **p < 0.01
groups
F tests 5.73’ cl
by
98
BETH A. MCCUT~HEON and HENRY E. ADAMS
I I I BASELINE n I 2
TRIAL
Fig. 3. Mean number
of nonspecific
GSR responses
,
I
3 4
I
5 6
BLOCKS
during
control
and treatment
periods.
(four of six) to ascribe to less subjective anxiety after treatment than Ss in the II Group (one of six) and the CG Group (none). Psychophysiological responses
Nonspecific responses (fluctuations) were analyzed for Rest Period II and for the six lomin trial blocks during the presentation of implosive tapes or, in the case of the CG group, during the no-stimulation period. The results of the analysis of variance indicated that there were significant changes as a function of trial blocks (F = 22.01, df = 6/90, p < 0.01) as well as a significant treatment groups by trial blocks interaction (F = 5.18, df = 12/90, p < 0.01). Figure 3 illustrates that there was a sharp initial increase then a decrease in nonspecific fluctuations in both implosion groups while the CG Group decreased over time. The first 20 min essentially replicate the results of Experiment I. An analysis of variance of nonspecific fluctuations during the behavioral tests indicated a significant difference between the first and second observation of the film (F = 20.68, df= l/15, p < 0.01). The interaction of this variable with treatment groups was also significant (F = 3.98, df = 2/15, p -C 0.10) as shown in Fig. 1. This figure indicates that habituation was much greater in the RI Group than in either the CG of the II Group.
Behavioral contrast and exhaustiorl
In order to explore the possibility that the film was less threatening than implosion, the amount of subjective fear and anxiety experienced during these events was rated by Ss on a 5-point scale. Analyses of variance of these data indicated that subjects in both RI and II Groups rated the film as being more anxiety-evoking or fearful than the implosive session (F = 125.32, df = l/10, p < 0.01: F = 50.00. df= l/10. p < 0.01, respectively). There were no significant differences between the implosion groups nor was there a significant interaction of implosion groups with film versus implosion. An analysis of variance was performed on the mean number of nonspecific fluctuations during Rest Periods I. II. and III for treatment groups. Rest Period I occurred before any experimental manipulations had been applied to Ss: Rest Period II occurred immediately
The phsyiological
basis of implosive
therapy
99
preceding the implosion session. and Rest Period III occurred immediately after the implosion session. There were no significant differences between these rest periods, treatment groups, or the interaction of the two variables, indicating that there was no lowering of arousal level as a function of time of treatment condition.
DISCUSSION
The experiments have indicated that 20 min of relevant or irrelevant implosion does increase arousal during treatment as measured by fluctuations of basal skin resistance, but this effect had no influence on subjective, psychophysiological. or behavioral indices of anxiety during the behavioral test. As a matter of fact, relevant implosion seemed to increase physiological arousal during the behavior test. which suggests that a ‘sensitization’ phenomenon occurred. Sensitization to anxiety-eliciting cues would appear to be antitherapeutic and could be a negative side effect of incomplete implosion, but this remains to be demonstrated. With 60 min of implosion. arousal increased in the first 20 min. as in the first experiment; then habituation to the anxiety-eliciting cues occurred. Changes in psychophysiological and behavioral indices during the behavioral test did occur but only when relevant cues were used. The changes in subjective fear ratings were not significant but were in the proper direction. Several conclusions are suggested by these data. It would appear that physiological arousal. observed in the Irrelevant Imagery Group, is not sufficient for change in the behavioral test to occur. Rather, there has to be physiological arousal in IT to anxiety-provoking cues which are relevant to the conditioned fear, and IT has to be continued until physiological habituation to these cues has taken place. These data suggest that the degree of generalization of fear reduction from IT to the behavioral test (or actual situation) is a function of the similarity of cues in each situation. A behavioral contrast explanation of IT is not supported by these results since the behavioral test (i.e., the film of surgical operations) was consistently rated as more anxietyand fear-provoking than the implosion session. This conclusion is further supported by the fact that the mean number of fluctuations of basal skin resistance was much greater during the fear-provoking film than in IT. Further, since there was no significant change in fluctuations of basal skin resistance over Rest Periods, and there were significantly more fluctuations of GSR in the post-test observation of the film than during IT, the ‘exhaustion’ hypothesis of IT also appears unlikely. An advantage of the present studies is a clear control for demand characteristics and subject expectancies (Bernstein 1973). Because of the divergent results of the two experiments, it is unlikely that these results can be explained by demand characteristics or other situational biases unless time in treatment alters these biases-an unlikely possibility. A further advantage in this design is that the replication of Experiment I in the first 20 min of Experiment II increased the credibility of the findings of Experiment I. These experiments were designed to evaluate the basic processes in IT but have not demonstrated how these processes are related to clinical treatment. Further research is needed to determine if these results are observed in actual phobic cases, whether IT generalizes to the natural environment. and the permanence of the behavioral changes on followup. In conclusion, these studies suggest that the most feasible explanation of IT is extinction of conditioned emotional responses by repeated elicitation of the conditioned responses without reinforcement.
IO0
BETH A. M~C~TCHEON and HENRY E. ADAMS
REFERENCES BANDURA A. (1969) ~~jf7ei~~~.~~~~~~ff~~~r ~~~~j~~arj#~l. Hoft. Rinehart & Winston. New York. BERNSTEIND. A. (1973) Behavioral fear assessment: Anxiety or artifact? In Isru~s und Trends iii Beharinr Therap.t (Eds. H. E. ADAMS and 1. P. UXIEEL). Springfield. Ill. EDELBERGR. (1967) Electrical properties of the skin. In ,bfethods o~Ps~chaph~siolo~~,(Ed. C. C. BROWN). Williams & Wilkins, Baltimore. EYSENCK H. J. (1968) A theory of the incubation of anxiety,fear responses. Rc~har-. I&. & 7Irerap! 6, 309-321. HODGSON R. J. and RA~HMAX S. (1970) An experim~nta1 investigation of the implosion technique. Bchur. RL’s. & Thrrapv8, 21-27. HOGAN R. A. and KIRCHNER J. H. (1968) Implosive. eclectic verbal and bibliotherapy in the treatment of fears of snakes. Brhar. Res. & Therapy 6. 167--171. KILPATRICK D. G. (1972) Ditferential responsiveness of two electodermal Indices to psychological stress in performance of a complex cognitive task..P.s!,chopk!,siol. 9, 218-226. LADER M. H. (1967)Palm~r skin conductance measures in anxietv . and nhobic states. J. Ps~~~7ffs~~l~.Rcs. It, 271. 281. LADER M. H. and MATHEWS A. M. (1968) A physiological model of phobic anxiety and desensitization, &huc. Res. & Thcrupg 6, 4 1 l-42 1. LADER M. H. and WING L. (1966) Phwioloqical Mcmttres Sedatiw Dr~cq.sand Morbid An.xiery. Oxford University Press. London. LEVIS D. and CAKRERA R. (1967) The effects of 10 hours of impiosiv-e therapy in the treatment of outpatients. J. ahnortn. P.yvchol. 72, 504-508. MORGANSTERN K. P. (1973) Implosion therapy and flooding procedures: A critical review. Ps,rchol. Bull. 79, 318334. RACHMAN S. (1969) Treatment by prolonged exposure to high intensity stimulation. Behac. Res. & Thcwp~ 7. 29-5302. STAMPFLT. G. and LEVIS D. J. (1967a) Phobic patients: Treatment with the learning theory approach of implosive therapy. Voices: The Art md Scimcc oj”Psvchothrrapy 6, 23-27. STAMPFLT. G. and LEVIS D. .I. (1967b) The essentials of implosive therapy: A learning theory based on psychodynamic behavioral therapy. .f. uhrioriii. PvJ~cliol. 72, 496-503. VENABLESP. H. and SAYERSE. (1963) On the measurement of the level of skin potential. Br. J. Ps_who/. 54, 251260. WOLPE J. (1969) The Practice ~t’B~,~u~jo~ Thwupy. Pergamon Press, New York. WOLPE J. and LANG P. J. (1964) A fear survey schedule for use in behavior therapy. Behan Rrs. & Thrrqy 2. 27-30.
ks.
& Therapy.
1975. Vol.
13. pp. 93-100. Pergamon Press. Printed m Great Bream
THE PHYSIOLOGICAL
BASIS
OF IMPLOSIVE
THERAPY*
BETH A. MCCUTCHEONt Brenau
College. Gainesville.
Georgia.
USA
and HENRY University
of Georgia.
E. ADAMS Athens, Georgia.
(Rrcrived 19 Auyust
U.S.A
1974)
Summary-Two analog studies were designed to investigate the differential effects of length of implosion session. theoretical concepts underlying IT. and the physiological, subjective, and behavioral responses to relevant and irrelevant fear stimuli in implosion. Subjects were selected who were unable to pass a behavioral test of viewing a.film of surgical operations. The results indicated that IT is a feasible method of behavior modification if subjects are ‘flooded’ to a point of physiological habituation to specific relevant. symptomatic cues. Implosion with irrelevant fear cues did not produce a significant change in the behavioral test. An extinction hypothesis emphasizing elicitation of the fear response without reinforcement was supported by the present data. The ‘behavioral contrast’ and exhaustion hypotheses of implosion were not supported.
Stampfl and his colleagues (Levis and Carrera, 1967; Stampfl and Levis, 1967a, 1967h) assume that if an individual is exposed repeatedly to stimuli which he has been conditioned to fear and if that exposure occurs in a situation which the subject cannot avoid, the fear behavior elicited by the conditioned stimuli will be extinguished. This assumption is the basis of implosive therapy (IT), and IT theorists stress that the extinction process progresses more rapidly when the individual is kept in a state of high arousal (Stampfl and Levis, 1967b; Hogan and Kirchner, 1967). As a result of the theory that high levels of arousal lead to more rapid extinction, the IT therapist floods the individual with a series of cues progressively more intense in order to achieve a consistently increasing level of anxiety. Both the theory and the therapeutic effects of IT have been questioned by numerous investigators (Bandura, 1969; Eysenck, 1968; Lader and Mathews, 1968; Lader and Wing, 1966; Morganstern, 1973; Wolpe, 1969). For example. the theory of maximal habituation (Lader and Mathews, 1968; Lader and Wing, 1966) suggests that rapid habituation occurs with low rather than high levels of arousal. In fact, Lader (1967) stresses that after the S reaches a pathological state of fear arousal, even a low level arousal stimulus maintains the critical level of anxiety, thus interfering with the habituation process. According to Rachman (1969) IT may depend on the therapist’s ability to achieve high levels of anxiety arousal in the S until a point of stimulus satiation is reached. Habituation occurs because the S is at a level where he can no longer overtly or covertly respond, and the level of arousal rapidly diminishes. In addition to the exhaustion hypothesis, Hodgson * This article is based on a dissertation submitted in partial fulfillment of the requirements for the Ph.D. degree from the Department of Psychology, University of Georgia. by the first author under the direction of the second author. t Requests for reprints should be sent to Beth A. McCutcheon. Brenau College, Gainesville, Georgia 30501, U.S.A. 93
94
BETH A. MCCUTCHEON and HENRY E. ADAMS
and Rachman (1970) state that ‘behavioral contrast’ may be an alternate explanation for the reported success of IT since the behavioral criteria (e.g.. touching a snake in the presence of another person) may be less threatening or anxiety provoking than the actual therapeutic process (e.g. the anxiety-producing snake imagery with which the S is flooded). Both the theoretical formulations of behavioral contrast and of exhaustion suggest that the individual need not be flooded with stimuli highly relevant to the situation that generates anxiety. The principal goals of the following analog studies were to clarify further these theoretical issues and to devise a procedure which would simultaneously investigate the subjective, behavioral, and psychophysiological indices of implosion while controlling for demand characteristics of the situation. EXPERIMENT
I
METHOD
Subjects
The 219 male and female students who were enrolled in an introductory psychology course at the University of Georgia were administered the Fear Survey Schedule III (Wolpe and Lang, 1964) in a group testing session. Those who indicated that they were ‘very much afraid’ of watching a surgical operation* were asked to participate further in the experiment. The first twelve female Ss who did not pass the behavioral test, a film depicting surgical procedures, were assigned on a rotation basis to one of three groups. Apparatus
The experimental chamber was a dimly lit, sound resistant, constant temperature room containing a reclining chair equipped for the attachment of GSR electrodes. An intercom. system and a one-way viewing mirror enabled the experimenter to hear and view any unusual movement or activity which might create artifactual skin resistance changes. The GSR located on the outside of the chamber was recorded as d.c. resistance change on a 7PIA preamplifier of a Grass Model 7 polygraph. Two GSR electrodes which conform to specifications suggested by Venables and Sayer (1963) were used. An electrode paste of 0.05~ NaCl as recommended by Edelbert (1967) was used. Surface oils were removed by swabbing the electrode sites with acetone until the skin became mildly erythematous. GSR nonspecifics were recorded continuously throughout the experiment from these electrodes. A 16-mm film entitled ‘Multiple Wounds, Report of a Battle Casualty’ (U.S. Department of the Navy, 1945) which could be stopped by a switch available to the subject was utilized as the behavioral test. All Ss were urged to watch the film as long as possible. Subjects who did not stop the film within 3 min were eliminated from the study. The Ss were also administered a lOO-point fear thermometer (FT) in the experimental chamber immediately before and after completion of the experiment. The Ss in the relevant and irrelevant imagery groups also indicated on a 5-point scale the degree of anxiety and fear that they experienced during the film and during the implosive tapes. * Pilot data indicated that fear of surgical operations is the most common at the University of Georgia. A total of 35 subjects were given the behavioral
fear among female college students test in order to obtain the subjects.
The phsyiological
basis of implosive
therapq
95
Procedure
Upon arrival at the laboratory, Ss, after completing the FT, were given general instructions about the behavioral assessment procedure as the GSR electrodes were being attached. A basal GSR was obtained during a 5-min silent adaptation period (Baseline I). The behavioral test was then administered to the subject who had the option of switching off the film at any time. They were then assigned to treatment groups as previously mentioned. Relecanr Imagery’ (RI) Group. The first 5 min after the film were devoted to giving the Ss information concerning IT and the relevant imagery implosive tape. Subjects were then given another 5-min adaptation period in order to obtain the basal GSR (Baseline II). A 20-min tape-recorded implosion session depicting fear-provoking imagery of witnessing a surgical operation was then administered. Continuous GSR recoding monitored the Ss autonomic responses throughout the entire experiment. At the end of the implosion tape, subjects were given another 5-min adaptation period to obtain the resting GSR basal level (Baseline III). They were then shown the film for the second time. Irreleoant Imagery (II) Group. The first 5 min after reviewing the film were devoted to giving Ss information concerning IT and the irrelevant imagery implosive tape. The GSR procedure and the adaptation periods are identical to those in Group RI. Instead of the implosive tape dealing with surgical operations. however, Ss in Group II were given a 20min tape-recorded implosion session depicting anxiety-provoking imagery of snakes. Control Group (CC). The procedure for the control group was essentially the same as for Groups RI and II, with the exception that subjects were told to lie back in the chair, close their eyes, but not to go to sleep. After a basal GSR was obtained during the first 5 min, the nonspecific fluctuations of the GSR were recorded for 20 min. Data reduction
A nonspecific response or fluctuation was defined as a decrease in skin resistance as indicated on the polygraph by a downward deflection of the pen (ascending limb) or a change in direction, if the deflection of the ascending limb was at least 1 mm amplitude at an angle of 15” at a chart speed of Smmisec. Any response was counted if there was a change in direction of the existing oscillograph line between two responses regardless of direction. In other words, two responses occurred, both in a downward direction, if there was a leveling or a change in angle of the slope between those two responses. Any change in direction or angle of slope constituted the end of a response, and a continued decrease in skin resistance was tabulated as another response. All responses that occurred smoothly at an angle to the existing baseline were tabulated. Those changes which did not occur smoothly were considered to be movement or other artifactual events and were omitted from the tabulation. Changes in basal skin resistance were also analyzed using the data reduction procedure suggested by Edelberg (1967) in both studies. However, this measure was nonreactive to treatment conditions and will not be further discussed. This is not surprising since Kilpatrick (1972) has indicated that changes in basal skin resistance indicates cognitive activity while changes in nonspecific responses are related to emotional arousal. The stimulus periods during the tapes and no-stimulation control were divided into lomin trial blocks. The Baseline II period was multiplied by two in order to equate the amount of time during the rest periods with the trial blocks.
BETH A. MCCUTCHEON and HENRY E. ADAMS
96 35
/‘R’
r
PRE TREATMENT
POST TREATMENT
EXPERIMENT
Fig. 1. Mean number
of nonspecific
PRE TRELTMENT
POS’
EXPERIMENT
I
GSR responses during iments I and II.
observation
TREATMENT
II
of criterion
film in Exper-
RESULTS
Analyses of variance of the duration of time observing the film (behavioral test) and the FT indicated no significant differences in treatment groups, pre-versus post-test or the interaction of these two variables. However, the analysis of variance of nonspecific fluctuations of the GSR during the behavioral test indicated a significant interaction between treatment groups and pre- versus post-test (F = 3.24, df = 2/9, p < O.lO).* There appeared to be a tendency for the implosion Ss to show more arousal after being exposed to 20 min of implosion, as may be seen in Fig. 1. while the CG group showed less arousal. An analysis of variance of nonspecific fluctuations during the presentation of the implosive tapes or the no-stimulation control period was conducted and indicated a significant difference between treatment groups (F = 8.84, df‘= 2/9, p < 0.05) and the interaction of * Because of the small N and the exploratory cant.
/
nature
BASELINE
of nonspecitic
a p value of 0.10 was considered
II
TRIAL
Fig. 2. Mean number
of these studies.
BLOCKS
GSR responses
during
control
and treatment
periods.
signifi-
The phsyiological
basis of implosive
therapy
97
time periods with treatment groups (F = 2.57. df = 4/18. p < 0.10). Both treatment groups showed a definite increase in nonspecific fluctuations as a result of implosion, while the control group exhibited a decrease in arousal. as may be seen in Fig. 2. EXPERIMENT
11
The results of the first experiment strongly suggest that a 20-min period of implosion was not sufficient to eliminate the avoidance or fear responses to anxiety-arousing stimuli. In fact, the RI subjects appeared to show more arousal during the post-treatment behavioral test. The second experiment was conducted imploying 60 min of IT to investigate further this phenomenon. METHOD
Eighteen female Ss of the original sample who did not pass the behavioral test were assigned on a rotation basis as in Experiment I to one of three groups. Group RI received 60 min of relevant implosion, Group II received 60 min of irrelevant implosion. and Group CG sat quietly for 60 min. In all other respects, Experiment II was identical to Experiment I. RESULTS
Behavioral test
In contrast to Experiment I, the general finding in Experiment II was that the RI condition resulted in a greater decrease in anxiety than did either the II condition or the nostimulation control condition when Ss were exposed to 60 min rather than 20 min of IT. The analysis of variance of the mean exposure time for the behavioral criterion tests indicated a significant difference between the pre- and the post-tests (F = 8.50, df = l/15, p < 0.05) and significant treatment conditions by pre- versus post-test interaction (F = 4.64, df = 2/15, p < 0.05). An analysis of the simple main effects indicated an increase in exposure for the RI Group, as may be seen in Table 1. No significant changes, however, were observed for the II or CG Groups. There were no significant differences between groups at pre-test, but the differences between groups were significant at post-test. The RI Group was significantly different from both the II and the CG Groups, but these groups did not differ from each other. Subjective report
The analysis of variance of the FT scores showed that there were no significant differences between treatment conditions. There was a tendency for those Ss in the RI Group Table
Group RI I1 CG F tests
1. Analysis of simple effects of the treatment pre- versus post-treatment interaction Mean Exposure Pre-treatment 50.5 57.2 68.5
Time (set) Post-treatment 166.2 78.7 12.3 6.37**
* p < 0.05. **p < 0.01
groups
F tests 5.73’ cl
by
98
BETH A. MCCUT~HEON and HENRY E. ADAMS
I I I BASELINE n I 2
TRIAL
Fig. 3. Mean number
of nonspecific
GSR responses
,
I
3 4
I
5 6
BLOCKS
during
control
and treatment
periods.
(four of six) to ascribe to less subjective anxiety after treatment than Ss in the II Group (one of six) and the CG Group (none). Psychophysiological responses
Nonspecific responses (fluctuations) were analyzed for Rest Period II and for the six lomin trial blocks during the presentation of implosive tapes or, in the case of the CG group, during the no-stimulation period. The results of the analysis of variance indicated that there were significant changes as a function of trial blocks (F = 22.01, df = 6/90, p < 0.01) as well as a significant treatment groups by trial blocks interaction (F = 5.18, df = 12/90, p < 0.01). Figure 3 illustrates that there was a sharp initial increase then a decrease in nonspecific fluctuations in both implosion groups while the CG Group decreased over time. The first 20 min essentially replicate the results of Experiment I. An analysis of variance of nonspecific fluctuations during the behavioral tests indicated a significant difference between the first and second observation of the film (F = 20.68, df= l/15, p < 0.01). The interaction of this variable with treatment groups was also significant (F = 3.98, df = 2/15, p -C 0.10) as shown in Fig. 1. This figure indicates that habituation was much greater in the RI Group than in either the CG of the II Group.
Behavioral contrast and exhaustiorl
In order to explore the possibility that the film was less threatening than implosion, the amount of subjective fear and anxiety experienced during these events was rated by Ss on a 5-point scale. Analyses of variance of these data indicated that subjects in both RI and II Groups rated the film as being more anxiety-evoking or fearful than the implosive session (F = 125.32, df = l/10, p < 0.01: F = 50.00. df= l/10. p < 0.01, respectively). There were no significant differences between the implosion groups nor was there a significant interaction of implosion groups with film versus implosion. An analysis of variance was performed on the mean number of nonspecific fluctuations during Rest Periods I. II. and III for treatment groups. Rest Period I occurred before any experimental manipulations had been applied to Ss: Rest Period II occurred immediately
The phsyiological
basis of implosive
therapy
99
preceding the implosion session. and Rest Period III occurred immediately after the implosion session. There were no significant differences between these rest periods, treatment groups, or the interaction of the two variables, indicating that there was no lowering of arousal level as a function of time of treatment condition.
DISCUSSION
The experiments have indicated that 20 min of relevant or irrelevant implosion does increase arousal during treatment as measured by fluctuations of basal skin resistance, but this effect had no influence on subjective, psychophysiological. or behavioral indices of anxiety during the behavioral test. As a matter of fact, relevant implosion seemed to increase physiological arousal during the behavior test. which suggests that a ‘sensitization’ phenomenon occurred. Sensitization to anxiety-eliciting cues would appear to be antitherapeutic and could be a negative side effect of incomplete implosion, but this remains to be demonstrated. With 60 min of implosion. arousal increased in the first 20 min. as in the first experiment; then habituation to the anxiety-eliciting cues occurred. Changes in psychophysiological and behavioral indices during the behavioral test did occur but only when relevant cues were used. The changes in subjective fear ratings were not significant but were in the proper direction. Several conclusions are suggested by these data. It would appear that physiological arousal. observed in the Irrelevant Imagery Group, is not sufficient for change in the behavioral test to occur. Rather, there has to be physiological arousal in IT to anxiety-provoking cues which are relevant to the conditioned fear, and IT has to be continued until physiological habituation to these cues has taken place. These data suggest that the degree of generalization of fear reduction from IT to the behavioral test (or actual situation) is a function of the similarity of cues in each situation. A behavioral contrast explanation of IT is not supported by these results since the behavioral test (i.e., the film of surgical operations) was consistently rated as more anxietyand fear-provoking than the implosion session. This conclusion is further supported by the fact that the mean number of fluctuations of basal skin resistance was much greater during the fear-provoking film than in IT. Further, since there was no significant change in fluctuations of basal skin resistance over Rest Periods, and there were significantly more fluctuations of GSR in the post-test observation of the film than during IT, the ‘exhaustion’ hypothesis of IT also appears unlikely. An advantage of the present studies is a clear control for demand characteristics and subject expectancies (Bernstein 1973). Because of the divergent results of the two experiments, it is unlikely that these results can be explained by demand characteristics or other situational biases unless time in treatment alters these biases-an unlikely possibility. A further advantage in this design is that the replication of Experiment I in the first 20 min of Experiment II increased the credibility of the findings of Experiment I. These experiments were designed to evaluate the basic processes in IT but have not demonstrated how these processes are related to clinical treatment. Further research is needed to determine if these results are observed in actual phobic cases, whether IT generalizes to the natural environment. and the permanence of the behavioral changes on followup. In conclusion, these studies suggest that the most feasible explanation of IT is extinction of conditioned emotional responses by repeated elicitation of the conditioned responses without reinforcement.
IO0
BETH A. M~C~TCHEON and HENRY E. ADAMS
REFERENCES BANDURA A. (1969) ~~jf7ei~~~.~~~~~~ff~~~r ~~~~j~~arj#~l. Hoft. Rinehart & Winston. New York. BERNSTEIND. A. (1973) Behavioral fear assessment: Anxiety or artifact? In Isru~s und Trends iii Beharinr Therap.t (Eds. H. E. ADAMS and 1. P. UXIEEL). Springfield. Ill. EDELBERGR. (1967) Electrical properties of the skin. In ,bfethods o~Ps~chaph~siolo~~,(Ed. C. C. BROWN). Williams & Wilkins, Baltimore. EYSENCK H. J. (1968) A theory of the incubation of anxiety,fear responses. Rc~har-. I&. & 7Irerap! 6, 309-321. HODGSON R. J. and RA~HMAX S. (1970) An experim~nta1 investigation of the implosion technique. Bchur. RL’s. & Thrrapv8, 21-27. HOGAN R. A. and KIRCHNER J. H. (1968) Implosive. eclectic verbal and bibliotherapy in the treatment of fears of snakes. Brhar. Res. & Therapy 6. 167--171. KILPATRICK D. G. (1972) Ditferential responsiveness of two electodermal Indices to psychological stress in performance of a complex cognitive task..P.s!,chopk!,siol. 9, 218-226. LADER M. H. (1967)Palm~r skin conductance measures in anxietv . and nhobic states. J. Ps~~~7ffs~~l~.Rcs. It, 271. 281. LADER M. H. and MATHEWS A. M. (1968) A physiological model of phobic anxiety and desensitization, &huc. Res. & Thcrupg 6, 4 1 l-42 1. LADER M. H. and WING L. (1966) Phwioloqical Mcmttres Sedatiw Dr~cq.sand Morbid An.xiery. Oxford University Press. London. LEVIS D. and CAKRERA R. (1967) The effects of 10 hours of impiosiv-e therapy in the treatment of outpatients. J. ahnortn. P.yvchol. 72, 504-508. MORGANSTERN K. P. (1973) Implosion therapy and flooding procedures: A critical review. Ps,rchol. Bull. 79, 318334. RACHMAN S. (1969) Treatment by prolonged exposure to high intensity stimulation. Behac. Res. & Thcwp~ 7. 29-5302. STAMPFLT. G. and LEVIS D. J. (1967a) Phobic patients: Treatment with the learning theory approach of implosive therapy. Voices: The Art md Scimcc oj”Psvchothrrapy 6, 23-27. STAMPFLT. G. and LEVIS D. .I. (1967b) The essentials of implosive therapy: A learning theory based on psychodynamic behavioral therapy. .f. uhrioriii. PvJ~cliol. 72, 496-503. VENABLESP. H. and SAYERSE. (1963) On the measurement of the level of skin potential. Br. J. Ps_who/. 54, 251260. WOLPE J. (1969) The Practice ~t’B~,~u~jo~ Thwupy. Pergamon Press, New York. WOLPE J. and LANG P. J. (1964) A fear survey schedule for use in behavior therapy. Behan Rrs. & Thrrqy 2. 27-30.