BEHAVIOR THERAPY 9, 185--188 (1978)

Effects of Therapy Set on Electrical Aversion Therapy and Covert Sensitization

PAUL M. G, EMMELKAMP AND CLEMENS WALTA

University of Groningen, The Netherlands

Type of treatment (covert sensitization or electrical aversion therapy) and instructional set (therapy set or research set) were varied within a 2 × 2 factorial design plus a no-treatment control group. Subjects were 34 smokers. A significant instruction effect was found: Therapeutically oriented subjects improved more than experimentally oriented subjects. No significant difference was found be- tween covert sensitization and electrical aversion therapy.

Studies in which aversive procedures have been compared with placebo conditions have produced equivocal results (Diament & Wilson, 1975; Foreyt & Hagen, 1973; Janda & Rimm, 1972; Miller, Hersen, Eisler, & Hemphill, 1973; Sachs, Bean, & Morrow, 1970; Sipich, Russell, & To- bias, 1974; Vogler, Lunde, Johnson, & Martin, 1970; Wisocki & Rooney, 1974). The conflicting results are difficult to interpret because the credibil- ity of the attention placebo controls has not been adequately assessed. Borkovec and Nau (1972), McGlynn and McDonell (1974), and Nau, Caputo, and Borkovec (1974) have demonstrated that the "expectancy of improvement" produced by a placebo therapy must be assessed rather than assumed. In many cases placebo rationales have not been as credible as the rationales of true clinical procedures.

A different, and probably more fertile, approach to the study of the influence of expectancy on treatment outcome is to vary instructional sets: Subjects can be given a therapeutically oriented instructional set and compared with subjects who are led to believe that they are participating in experimental procedures concerned with physiological reactions. While a large number of investigations into the influence of such expec- tancy manipulations on systematic desensitization and flooding have been conducted (see Emmelkamp, 1975), no well-designed study on the influ- ence of expectancy on aversive procedures such as electrical aversion

Requests for reprints should be sent to Paul M. G. Emmelkamp, Department of Clinical Psychology, Academic Hospital, Oostersingel 59, Groningen, The Netherlands.

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0005-7894/78/0092-0185501.00/0 Copyright © 1978 by Association for Advancement of Behavior Therapy.

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186 EMMELKAMP AND WALTA

t h e r a p y a n d c o v e r t s e n s i t i z a t i o n h a s b e e n p u b l i s h e d . T h e a i m of t h e

p r e s e n t s t u d y w a s to d e t e r m i n e w h a t t h e i n f l u e n c e o f t h e r a p y se t o n t h e s e

a v e r s i v e t r e a t m e n t s w o u l d be . T y p e o f t r e a t m e n t ( c o v e r t s e n s i t i z a t i o n o r

e l e c t r i c a l a v e r s i o n t h e r a p y ) a n d i n s t r u c t i o n a l se t ( t h e r a p y se t o r r e s e a r c h

se t ) w e r e v a r i e d w i t h i n a 2 z 2 f a c t o r i a l d e s i g n . C i g a r e t t e s m o k e r s w e r e

r a n d o m l y a s s i g n e d to t h e s e f o u r c o n d i t i o n s o r to a n o - t r e a t m e n t c o n t r o l

g r o u p .

METHOD Subjects. Students (n = 608) filled out a questionnaire, created by the authors, which lists

40 experiences, including smoking, receiving electric shock, and vomiting. Subjects had to indicate on five-point scales for each experience (I) how often it occurred and (2) if they wanted it to occur more or less often. Sixty-four subjects indicated that they (1) smoked "'much" or "very much," (2) wished to smoke "less" or "much less," and (3) were prepared to cooperate in further experiments. Of these, 22 males and 16 females were randomly chosen for the study, of whom 34 subjects completed the project. The mean base rate of these subjects was 17.8 cigarettes per day.

Procedure. Six sessions were held: one instruction session, four therapy sessions, and one posttest session. Therapy sessions were held twice a week, each lasting 30 min. In the instruction session, held at least 5 days before the first therapy session, the subjects were given one of two instructions: (a) Therapy instruction, which informed the subjects that they would receive a therapy which had proved to be very effective with smokers, or (b) Research instruction, which informed the subjects that the aim of the experiment was to investigate whether pleasant experiences (smoking) and unpleasant experiences (vomiting or receiving electric shocks) produced different physiological reactions. No-treatment control subjects were told that the actual experiment would only begin after 3 weeks. Moreover, the subjects were given forms on which to chart their daily smoking behavior.

At the beginning of the following sessions, the instruction that the therapy or the experi- ment, respectively, would be continued was repeated once more. Then the experimenter took the subject to the room where the treatment was given. Therapists were two assistants who attended to the technical aspects of the therapy sessions, such as applying electrodes, switching on the tape recorder, and operating the apparatus. The therapists were unaware of the experimental manipulations.

At the posttest, the subjects handed in the forms of the preceding week. In addition, they had to give a written answer to the following question: "'What was, according to you, the object of this investigation?" Then the real purpose of the experiment was revealed.

Treatment. Before the treatment started, two electrodes were fixed onto the left arm. The subjects were told that the electrodes were connected by wire to recording equipment in another room. Actually, there was no recording equipment there at all. With the electrical aversion therapy another pair of electrodes was fixed onto the fight arm. Before each session, the maximum level of bearable shock was determined (averaging 3.8 mA). Both therapies were recorded on tape. The use of prerecorded treatment eliminated the possibility that any group differences would arise as a function of therapist biases or expectancies.

Covert sensitization consisted of a short relaxation instruction and 10 different scenes. Half of the scenes were punishment trims in which the subjects had to imagine becoming sick and vomiting uncontrollably: the other half were avoidance trials in which the subjects obtained relief from feeling of nausea by ceasing smoking behavior.

EtectricM aversion therapy also consisted of a short relaxation instruction and the same 10 scenes as those for covert sensitization. Instead of instructing the subjects to imagine feeling sick, the therapist administered an electric shock. All scenes were punishment trials.

EFFECTS OF THERAPY SET 187

RESULTS

A 2 × 2 analysis of variance revealed no significant pretreatment group differences. The main treatment effects were tested with one-tailed t tests for dependent samples. Treatment led to significant reduction of daily cigarette consumption in the condition therapy instruction, t (12) = -1.98, p < .05, and covert sensitizatiom t (13) = -I .79, p < .05. Research instruction, electrical aversion therapy, and no-treatment con- trol did not lead to significant improvements.

A 2 x 2 analysis of variance for change scores indicated a significant instruction effect, F (1, 29) = 4.23, p < .05. Compared to subjects receiving the research instruction, subjects receiving the therapy instruc- tion improved significantly more. No significant difference was found between covert sensitization and electrical aversion therapy, F (1, 29) = 2.86, p > .05.

DISCUSSION

The primary aim of this study was to evaluate the contribution of therapeutic instructional sets to covert sensitization and electrical aver- sion therapy. At the posttest, a significant instruction effect was found. Subjects with a therapeutically oriented instructional set improved more than experimentally oriented subjects. In fact, research instruction did not lead to a significant reduction in the number of cigarettes smoked. At the posttest it was checked whether the instructional manipulations had affected subjects' actual expectancies. The instructions given had actually induced a therapy set and a research set, respectively; of the subjects who had received the research instruction, not one was aware of therapeutic goals.

In a review of expectancy studies, Wilkins (1973) concluded that the studies reporting an expectancy effect involved therapists who were not blind to the experimental manipulation, whereas in studies failing to demonstrate expectancy effects, therapists were blind. The present study demonstrates an "expectancy" effect, when the therapists were blind to the experimental manipulation, which corroborates the results from an earlier study (Emmelkamp & Straatman, 1976). Thus, experimenter bias does not adequately account for observed differences between therapeut- ically and experimentally oriented subjects.

The comparison of covert sensitization with electrical aversion therapy was of only secondary importance. Although covert sensitization did result in a significant improvement and electrical aversion therapy did not, no significant difference between these two procedures was observed.

The diminution of smoking by the subjects in the condition which produced the greatest improvement (therapy instruction-covert sensitiza- tion) averaged only 21.5%. However, meaningful reductions in smoking

188 EMMELKAMP AND WALTA

were not expected because of subjects' low motivation to stop smoking, the use of prerecorded treatment tapes, and the relatively small number of aversive sessions. The main purpose of this study was theoretical rather than clinical or therapeutic. If the latter were the case, many more things than self-recording would have to be included, not the least of which would be some kind of follow-up. Finally, it should be noted that the role therapy instructional sets play in covert sensitization or electrical aver- sion therapy is yet to be demonstrated with other clinically defined popu- lations.

REFERENCES Borkovec, T. D., & Nau, S. D. Credibility of analogue therapy rationales. Journal of

Behavior Therapy and Experimental Psychiatry., 1972, 3, 257-260. Diament, C., & Wilson, G. T. An experimental investigation of the effects of covert

sensitization in an analogue eating situation. Behavior Therapy, 1975, 4, 499-509. Emmelkamp, P. M. G. Effects of expectancy on systematic desensitization and flooding.

European Journal of Behavioral Analysis and Modification, 1975, 1, 1-11. Emmelkamp, P. M. G., & Straatman, H. A psychoanalytic reinterpretation of the effective-

ness of systematic desensitization: Fact or fiction? Behaviour Research and Therapy, 1976, 14, 245-249.

Foreyt, J. P., & Hagen, R. L, Covert sensitization: Conditioning or suggestion? Journal of Abnormal Psychology, 1973, 82, 17-23.

Janda, L. H., & Rimm. D. C. Covert sensitization in the treatment of obesity. Journal of Abnormal Psychology, 1972, 80, 37-42.

McGlynn, F. D., & McDonell, R. M. Subjective ratings of credibility following brief exposures to desensitization and pseudotherapy. Behaviour Research and Therapy, 1974, 12, 141-146.

Miller, P. M., Hersen, M., Eisler, R. M., & Hemphill, D. P. Electrical aversion therapy with alcoholics: An analogue study. Behaviour Research and Therapy, 1973, 11, 491-497.

Nau, S. D., Caputo, J. A., & Borkovec, T. D. The relationship between therapy credibility and simulated therapy response. Journal of Behavior Therapy and Experimental Psychiatry., 1974, 5, 129-134.

Sachs, L. B., Bean, H., & Morrow, J. E. Comparison of smoking treatments. Behavior Therapy, 1970, 1, 465-472.

Sipich, J. F., Russell, R. K., & Tobias, L. L. A comparison of covert sensitization and "nonspecific" treatment in the modification of smoking behavior. Journal of Behavior Therapy and Experimental Psychiatry, 1974, 5, 201-203.

Vogler, R. E., Lunde, S. E., Johnson, G. R., & Martin, P. L. Electrical aversion condition- ing with chronic alcoholics. Journal of Consulting and Clinical Psychology, 1970.34, 302-307.

Wilkins. W. Expectancy of therapeutic gain: An empirical and conceptual critique. Journal of Consulting and Clinical Psychology, 1973, 40, 69-77.

Wisocki, P. A., & Rooney, E. J. A comparison of thought stopping and covert sensitization techniques in the treatment of smoking: A brief report. The Psychological Record, 1974, 24, 191-192.

RECEIVED: September 30, 1976; aEVlSED: April 5, 1977 FINAL ACCEPTANCE: April 17, 1977