- Email: [email protected]
Behavior therapy for weight reduction
Addictive Behaviors, Vol. I, pp. 73-82. Pergamon Press 1975. Printed in Great Britain
BEHAVIOR THERAPY FOR WEIGHT REDUCTION ALAN S. BELLACK* University of Pittsburgh Abstract--Behavioral approaches to obesity were reviewed and empirical support for the procedures was evaluated. Treatments were categorized on the basis of a primary foGuson the antecedents or consequences of eating behavior. It was concluded that the most effective approach was a combination of antecedent stimulus control procedures supplemented by any of a variety of contingency managementtechniques. The application of self-control procedures was especiallyeffective. Recommendationswere made for the use of contingency contracting and for the sequential application of treatment techniques. The importance of identifying individual differences in responsiveness to treatments was discussed. A research strategy was presented and the results of two studies based on the strategy were described. Several recent reviews have concluded that behavior therapy is the most efficacious approach for the treatment of obesityt (Abramson, 1974; Hall & Hall, 1974; Stunkard, 1972). This conclusion is supported by a general comparison of behavioral and non-behavioral treatments. It does not, however, adequately reflect the actual utility of each of the specific behavior therapy techniques that have been applied to obese populations. A large number of procedures have been utilized individually and in combination with varying degrees of control and success. The purpose of the present paper is to examine the current status of those procedures and to evaluate their application. The review will encompass empirical studies and controlled single subjects reports of outpatient applications of behavioral techniques with adults. BEHAVIORAL CONCEPTION OF OBESITY Behavioral treatments are based on a common conception of the cause and nature of obesity. Obesity is presumed to be a result of a positive energy balance: consumption of more energy (as calories in food) than is expended. A small proportion of obese individuals suffer from dysfunctions of hormonal or metabolic systems which affect energy usage. Mayer (1968) reported, however, that the relationship of food intake to energy expenditure is critical even for those individuals. People who gain weight overeat in relation to their activity level. Individuals with weight problems persist in overeating despite the many aversive consequences of such behavior. There are two factors that mitigate the effects of those consequences. First, eating has immediate positive reinforcing consequences as well. Characteristically, immediate positive reinforcement has greater control over behavior than delayed aversive rehfforcement. Second, the eating behavior of the obese is under the control of external antecedent stimuli as well as the reinforcing properties of food. Obese individuals eat in response to such external cues as where they are, what they are doing, who they are with and time of day, rather than in response to internal, hunger cues such as gastric motility (Schachter, 1971 ; Stunkard, 1959). The multiplicity of external stimuli that can instigate eating and the reduced level of inhibition resulting from satiety result in a high frequence of eating and the consumption of large amounts at each meal. Almost all treatment approaches, regardless of theoretical orientation, have recognized the need to alter the energy balance in order for weight reduction to occur. Behavioral treatments typically include recommendations for reduction of caloric intake and increased activity. The major focus of behavior therapy has been to modify the energy balance indirectly by altering the antecedent and consequent stimuli that control eating. The primary strategies to affect consequent control have been the addition of more immediate aversive consequences for inappropriate eating or of more immediate positive consequences for appropriate eating. The strategy for antecedent control has been to interrupt stimulus-eating sequences and bring eating *Requests for reprints should be addressed to Alan S. Bellack, Clinical PsychologyCenter, Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A. tMayer (1968) differentiates obesity (excess fat) from overweight (excess weight). The two terms are used interchangeably in the behavior therapy literature and will be used synonymouslyin this paper. 73
74
A.S. BELLACK
under the control of internal, hunger cues. (This approach has typically been referred to as "stimulus control". That convention will be followed throughout the remainder of this paper.) These two strategies have been examined both as independent treatment approaches and in conjunction with one another. Studies emphasizing modification of the consequences of eating will be reviewed first, followed by those emphasizing stimulus control and those utilizing both approaches. MODIFICATION OF THE CONSEQUENCES OF EATING There are several reports in the literature on the application of aversive reinforcement for eating, for thoughts of eating, or for failure to lose weight. Tyler & Straughan (1970) instructed subjects recruited from a weight loss club to hold their breath while thinking about eating fattening foods. No other treatment procedure was utilized and subjects did not lose a significant amount of weight. Stollak (1967) required subjects to record their food intake and report for brief bi-weekly meetings. The experimenter discussed the records with his subjects and administered electric shocks while discussing the eating of high calorie foods. Subjects in this group lost no more weight than those in a control group. The administration of electric shock in this procedure was not contingent upon eating behavior. It was probably associated with the experimental situation and with the recording and reporting of eating. Foreyt & Kennedy (1971) reported the successful use of aversive conditioning by pairing noxious odors with the smell of preferred, fattening foods. Weight loss was moderate, but subjects had maintained the loss by the time of a 48 week follow-up. No strong conclusions can be drawn from this study because of several design flaws. The authors did not control for contact with subjects: the only control group failed to receive ongoing contact. Second, aversive conditioning subjects were required to self-monitor (SM) all food intake. B ellack, Rozensky & Schwartz (1974), Romanczyk (1974), and Stuart (1971) have all demonstrated that self-monitoring is a viable weight reduction procedure by itself. The relative contribution of the aversive conditioning procedure cannot be separated from the effects of SM. Mann (1972) used a contingency contracting procedure in a single subject withdrawal design. He required his subjects to deposit a number of valuables with him and sign a contract authorizing him to return them (or not) contingent on their weight loss. Failure to meet criteria resulted in forfeiture of items. The contract contained options for relatively immediate reinforcement (three times per week) and two forms of delayed reinforcement (every 2 weeks and for the entire treatment period). The procedure was highly effective and punishment (item loss) was more critical than positive reinforcement (item return). A critical component of this approach was that the subjects were willing to make an extreme commitment to the program, thus allowing the therapist to apply meaningfull contingencies. The withdrawal procedure indicated that weight loss was under the control of the therapist-managed contingencies. Subjects even took laxatives and diuretics to meet weight loss criteria. This pattern does not seem conducive to the maintainance of weight losses once the contingencies are terminated. Mann did not conduct a follow-up to examine maintenance. Another example of the use of single subject methodology was a report by Morganstern (1974). He applied cigarette smoke as an aversive stimulus with a non-smoking client. Base rates of eating behavior prior to treatment had indicated that a primary factor in the client's weight problem was excessive consumption of candy, cookies, and doughnuts. Treatment was designed to reduce consumption of those foods. Aversive conditioning trials consisted of the client puffing on a cigarette while she chewed on one of the target foods. Using a multiple baseline design, Morganstern successively reduced consumption of each of the three foods. Weight loss occurred concurrent with the change in eating and was maintained through a six week follow-up. Cautela (1972) suggests the use of covert sensitization for overeating, as an alternative to the use of external aversive stimuli. The effect of covert sensitization on eating behavior was examined by Sachs & Ingram (1972). One group received a standard covert sensitization procedure and a second group received a backward conditioning variation (nausea images followed by images of target food). The two procedures were equally effective in reducing consumption of two foods. However, the study did not include a control for expectancy and demand characteristics of treatment. Subjects were not on diets and might have been able to temporarily reduce the frequency of consumption of two foods simply by request. Rate of consumption was
Behaviortherapyfor weightreduction
75
determined by examination of SM records. The SM procedure has questionable reliability as well as potentially reactive effects. Manno & Marston (1972) compared covert sensitization, covert positive reinforcement, and an attention-placebo condition in an actual treatment study. Both covert conditioning groups lost significantly more ~veight than the control group. The amounts lost were, however, only 4.1 and 5.1 lbs respectively during 8 weeks of treatment. All groups reported further weight losses during a follow-up period, but the follow-up weights were secured from the subjects by telephone. The accuracy and reliability of such data are questionable. Another test of covert sensitization was conducted by Foreyt & Hagen (1973). Subjects in both a covert sensitization and a placebo control condition reported decreased consumption of target foods, but weight changes were non-significant. Estimates of rates of consumption were based on post-treatment self-reports. Janda & Rimm (1972) found no difference between a sensitization group, an attention-placebo group, and no contact controls. Post-treatment interviews indicated that three of the six treated subjects did not find the nausea imagery aversive; they lost a mean of 2.3 lbs. The other three subjects did find the imagery aversive and lost a mean of 2t lbs. Results reported by Mann (1972) and Morganstern (1974) suggest that aversive conditioning can be an effective tool for weight reduction. There are several factors that must be considered if this approach is to be effective. The primary consideration is that aversive stimuli should be applied contingently, while being experienced as aversive by the subject. Berecz (1973) has pointed out that aversiveness cannot be assumed on the basis of face validity, but must be empirically determined for each individual. The results attained by Janda & Rimm (1972) demonstrate the non-universality of "aversive" stimulation. There are several problems specific to the use of aversive conditioning for altering the consumption of specific fattening foods. Overweight for most individuals is not a function of overconsumption of only a few specific foods. Elimination of any one food from the diet will likely result in overeating of some other item. An alternative strategy for these individuals is to focus on the environmental stimuli that control eating. Specific problem situations could be identified and targeted. Images of eating at a desk, while drinking alcohol, while watching television, or while reading could all be paired with aversive stimuli, (See section on financial contingencies for further discussion of this procedure). Aversive conditioning for specific foods is most applicable when it can be determined that such foods are focal to the individual's difficulty. The quality of aversive stimulation must also be considered. Elkins (1974) and Seligman (1970) have reported that persistent flavor aversions can be readily generated in response to such eating related stimuli as nausea, malodorous, and maltasting substances. The use of these stimuli should be examined in contrast to such eating-unrelated stimuli as electric shock and breath holding. Further examination is necessary to clarify the issues involved in the use of this general approach. The focus should be on how the procedures might best be applied rather than on blanket evaluations of effectiveness. A frequently voiced admonition about the use of punishment is that it tells the target what not to do but does not tell him what he should do. The client in a weight control program should know what he can (and should) do in order to best meet his weight loss goals. The application of aversive control without supplemental instruction or training is unlikely to result in maximal, stable losses. MODIFICATION OF THE STIMULUS CONTROL OF EATING Several programs have been developed for altering stimulus control of eating (Ferster, Nurnberger, & Levitt, 1962; Jeffrey, Christensen, & Pappas, 1972; Stuart, 1971; Stuart & Davis, 1972). The emphasis of each of these programs is twofold. The client is instructed in ways to restructure his environment and alter his eating behavior such that he is exposed to fewer eating cues. At the same time, he is also instructed to engage in a variety of procedures to reduce the effect of those cues that he is unable to avoid, while strengthening the effect of internal stimuli (such as hunger). Table 1 contains a list of the most commonly used procedures. Treatment consists of a presentation of the behavioral conception of obesity and a description of the various stimulus control procedures. Instructions on the specific techniques to be applied and the manner of application are ideally based on examination of base rate recordings of the client's particular eating pattern. Most of the studies discussed below involved variants of the basic approach, adapted by the researcher for standardized, group administration. They do not share a common set of instructions and typically do not design individualized applications.
76
A. S. BELLACK Table 1. Proceduresto reduce stimuluscontrol of eating Modificationof meal quantity
I. Eat slowly: gradually increase minimal time allowed for each meal. 2. Take small bite. 3. Put eating utensil (or food item) down while chewing. 4. Take one helping at a time. 5. Leave table for a brief period between helpings. 6. Eat one food item at a time (e.g., finish meat, before taking vegetable). 7. Serve food from kitchen rather than placing platter on table. 8. Use small cups and plates. 9. Leave some food on plate at end of meal. Modificationof meal frequency I. 2. 3. 4. 5. 6. 7.
Do nothing else while eating. Eat in only one place, sitting down (preferably not in kitchen and not where you engage in other activities). Eat only at specifiedtimes. Set the table with a complete place setting whenever eating. Wait a fixed period after urge to eat before actually eating. Engage in an activity incompatiblewith eating when urge to eat appears. Plan a highly liked activity for periods when the urge to eat can be anticipated (e.g., read evening newspaper before bedtime). Modificationof types of food eaten
1. Do not buy prepared foods or snack foods. 2. Prepare lunch after eating breakfast and dinner after lunch (to avoid nibbling). 3. Do grocery shopping soon after eating. 4. Shop from a list. 5. Eat a low calorie meal before leaving for a party. 6. Do not eat while drinking coffee or alcohol.
Evaluations of the stimulus control (SC) package Penick, Filion, & Fox (1971) compared an SC procedure with traditional psychotherapy in a study frequently cited as an example of the effectiveness of stimulus control approaches. While the authors reported that those subjects losing the most weight were in the SC group, there was no overall difference in the effectiveness of the two procedures. Harris & Bruner (1971) reported on two studies. SC was less effective than a financial contingency condition in one comparison and no more effective than a control procedure in another. Hall (1972) also reported negative results for an SC procedure. The findings of these three studies are difficult to evaluate. In the Hall (1972) and Harris & Bruner (1971) studies one therapist saw all groups, while the Penick et al. (1971) study used different therapists for the two treatment groups; therapist factors cannot therefore be discounted in any of the studies. Several studies have reported more positive results. Harris (1969) compared an SC procedure administered in weekly group meetings with a no-contact control condition. Subjects in two similar SC groups lost more weight than subjects in the control group. These results are of questionable impact, as the design did not control for the effects of regular meetings and contact with a therapist (who lost weight along with group members). Bellack, Rozensky, & Schwartz (1974) found no difference between an SC group and a waiting list control group at the end of treatment, but the SC group had lost significantly more weight by the end of a follow-up period. If eating habits are changed by SC procedures, weight loss should be maintained and possibly continue after treatment ends. Apparently, the treatment period in the Bellack et al. study was not long enough for differences in the procedures to become manifest. The best documented study of SC procedures was conducted by Wollersheim (1970). She compared an SC procedure with social pressure only, verbal psychotherapy, and a waiting list control condition. The SC procedure was administered at group meetings during which subjects also received social pressure for weight loss. SC subjects were also required to self-monitor their eating behavior. All three treatment groups lost weight, but the SC group lost significantly more than each of the other groups. The SC condition in this study incorporated two other active treatment elements: self-monitoring and social pressure. The effects of the SC instructions cannot be isolated from the effects of those other elements. Abrahms & Allen (1974) examined the SC program devised by Stuart & Davis (1972). They divided their subjects into four groups: SC supplemented by social reinforcement, SC supplemented by financial contingencies for
Behaviortherapyfor weightreduction
77
weight change, social reinforcement alone, and a no treatment control. There was no difference between the two SC conditions, both of which were more effective than the two non-SC groups. A third study with clearly positive findings was conducted by Hagen (1974). He administered an SC program in three different ways: a bibliothera, py procedure (therapist-subject contact by mail), and two variations of weekly group meetings. Subjects in the bibliotherapy group were required to complete regular homework assignments and subjects in the two contact groups received social pressure for weight change. All three treatment conditions were more effective than a waiting list control. Differences between the treatment groups were non-significant. Wollersheim (1970), Abrahms & Allen (1974), and Hagen (1974) all found a clear superiority for treatment procedures including SC instructions. In each study, SC procedures were supplemented with other supportive factors. Subjects received social or financial reinforcement and were required to self-monitor or complete homework assignments. In contrast, all of the studies failing to report positive findings administered SC alone. It would appear from this set of results that some facilitation is necessary. The SC programs consist essentially of sets of instructions, describing ways in which subjects are to modify their own behavior. Treatment meetings focusing only on these procedures serve an essentially instructional function. It seems unlikely that individuals would be able to change long standing habits simply on the basis of having received new information. Self or externally administered contingencies must be applied to insure the utilization of the information that is provided. The succeeding sections of this paper will focus on techniques that have been used in conjunction with SC procedures.
Financial contingencies (FC) The most widely examined procedure is the use of financial contingencies. Subjects in FC groups are typically required to leave a financial deposit with the therapist at an initial session. The money is then returned or forfeited in fixed amounts contingent on weight loss or changes in eating habits. The contingencies can either be therapist managed or self-managed. Hall (1972) found FC for weight loss to be more effective than SC alone. Her procedure was unusual in that she reinforced subjects with her own money, rather than requiring a deposit. She also conducted a two year follow-up and found that the weight losses were not maintained. Harris & Bruner (1971) permitted their subjects to fix the contingency at either 50¢ or $1.00 per pound. FC was more effective than SC alone, but the losses had dissippated by the time of a 10 month follow-up. Harris & Hallbauer (1973) found a contrasting pattern. They also allowed subjects to establish their own contingencies; rates per pound were as low as five cents and averaged 76¢. FC was no more effective than a placebo condition at the end of treatment but two FC groups registered greater losses after a seven month follow-up. Rozensky & Bellack (1974) compared an FC procedure with a self-control condition and a minimal contact control. All groups were instructed in SC techniques. The two treatment groups were required to monitor their eating immediately prior to actual consumption and to mail their monitoring records to the therapist each day. Subjects reported individually for weekly weight checks, at which time the FC subjects were reinforced at a rate of $2.00/lb. Differences between the treatment groups were non-significant at the end of treatment and after a follow-up period. Both groups did better than the control group at both measurement points. Abrahms & Allen (1974) examined FC as a backup for social reinforcement. A group receiving social reinforcement alone lost as much as a group receiving social reinforcement and FC for weight loss. Both groups lost more than a no treatment control. Mahoney has examined the effects of self-administered financial contingencies. Mahoney, Moura, & Wade (1973) found self-reward for appropriate eating to be more effective than either self-punishment for inappropriate eating or monitoring of eating urges. The comparison of reward and punishment was limited, as the procedure did not allow for control over the frequency with which self-punishment subjects actually self-punished. In a better controlled study, Mahoney (1974) found that self-reward for changes in eating habits was more effective than either self-reward for weight change or monitoring of eating habits. Jeffrey (1974) compared two forms of self-administered financial contingencies with a therapist administered program. He retained deposits and set the criteria and size of reinforcements for all groups. He administered the reinforcements to the external group while the self-control groups were allowed to administer reinforcements to themselves, out of the therapist's view. All groups lost similar amounts of
78
A.S. BELLACK
weight but only the self-control groups maintained the loss through a follow-up period. Reinforcement control was confounded with expectancy attributions, restricting the conclusions that can be drawn from the follow-up results. External control subjects were explicitly informed that success depended on therapist activity, while self-control subjects were told that their own activity was critical. An effective comparison would require that all subjects receive similar (self-control) expectancy instructions. The utility of financial contingencies is still undetermined. FC procedures can increase the effectiveness of SC programs. They have not been shown to be more effective than such procedures as pre-eating, self-monitoring, and social reinforcement, which are simpler to administer. Mahoney, Moura, & Wade (1973) and Mahoney (1974) reported that FC was more effective than self-monitoring, but the specific self-monitoring procedures utilized in those studies have not otherwise been shown to be effective. Several issues about the use of FC require further investigation. Reinforcements have typically been in the range of $1.00-$2.00 per pound. Given that weight losses average less than 2 lb per week, these reinforcers seem quite modest for the support of a week's dieting effort. This factor is confounded by the delay between eating and weigh-in and reinforcement. The application of reinforcement to behavior change rather than weight change might circumvent that difficulty to some extent. Subjects can monitor eating habits on an ongoing basis and immediately quantify their performance in reference to financial reinforcement. While actual reinforcement might still be delayed, the records should have secondary reinforcing properties. A final issue concerns the nature of self-administered FC. A substantial amount of external control is involved when the therapist retains a deposit, establishes reinforcement criteria, and requires attendance at weekly meetings. External control should be compared with an entirely self-administered program, in which the subject has responsibility for maintaining the contract as well as administering reinforcement.
Self-monitoring and self-reinforcement Self-monitoring (SM) has been included as a data gathering procedure in several studies. The current emphasis is on the reactive effects of monitoring procedures. Mahoney, Moura, & Wade (1973) and Mahoney (1974) reported that monitoring of eating urges or eating habits did not result in significant weight loss. More positive results have been attained for the monitoring of food or calorie intake. Stollak (1967) found SM to be more effective than either aversive conditioning or a no contact control condition. Romanczyk, Tracey, Wilson, & Thorpe (1973) and Romanczyk (1974) compared SM of calorie intake with SM of weight, and with stimulus control packages supplemented by a variety of reinforcement procedures. The SM groups did not receive SC instruction. SM of weight was no more effective than a no treatment control condition, while SM of calories was as effective as the stimulus control procedures. Romanczyk et al. (1973) conducted two studies. Differences between SM and SC were similar in both studies. The difference (in favor of SC) was significant in the second study, which did not contain a control condition. The lack of difference between the SM calorie group and the SC groups may partially be a function of the treatment duration, which was only four weeks. Stuart (1971) and Mahoney (1974) have reported that SM is effective when it is first implemented, but that the effect decreases over time. Group differences in the Mahoney study, for example, did not become apparent until the midpoint of treatment. It is possible that the SM and SC groups in the Romanczyk studies were not treated long enough for differential effects to manifest themselves. An alternative to post-eating monitoring of intake or calories is pre-eating monitoring of intended eating. The latter procedure would interrupt the stimulus-eating sequence and allow the individual to make an alternative, non-eating response. Bellack, Rozensky, & Schwartz (1974) compared pre-eating SM, post-eating SM, and an SC therapy group. The pre-eating subjects were required to write down everything they intended to eat immediately prior to eating. If they chose to eat more (or less), at any one time, they were to make a new entry. The pre-monitoring group lost the most weight. The post-eating subjects did no better than a waiting list group. Bellack, Schwartz, & Rozensky (1974) found the pre-monitoring procedure to be effective when contact with the therapist was limited to correspondance through the mail. Rozensky & Bellack (1974) reported that this form of SM was as effective as an FC procedure. The reactive effects of post-behavior monitoring have been attributed to covert self-evaluation and self-reinforcing operations that occur after behavior is observed (Kanfer,
Behavior therapy for weight reduction
79
1970). In the absence of explicit instructions for self-reinforcement (SR), the operation cannot be presumed to occur on a highly contingent basis. Conversely, performance should be improved if subjects are given instructions for the contingent use of SR. Bellack (in press) compared the effects of post-eating SM with SM supplemented by SR, under two levels of therapist contact. SR consisted of a letter grade assigned to every instance of eating, and recorded on the monitoring record. One-half of the subjects mailed monitoring records to the therapist each day and received weekly feedback by mail. The remaining subjects had no ongoing contact with the therapist. There was no difference between the contact and no contact SR groups and both lost significantly more weight than their non-SR counterparts. In a subsequent study, Bellack, Glanz, & Simon (1974) evaluated the use of contingent positive and aversive covert imagery. Both procedures were more effective than a non-reinforcement control condition. The use of such self-reinforcing operations is highly promising. The procedures are easily learned and easily implemented. Reinforcement can be delivered immediately under all circumstances. The techniques can be used by the individual after treatment proper is terminated for weight control or other problem areas. Covert conditioning procedures Clinical observation of dieters suggests that they often lose track of the reasons for dieting. Both the aversive consequences of overweight and the potential positive consequences of lower weight seem to become obscured, adding to the difficulty of dieting. If this observation is accurate, sustaining attention to the two sets of consequences should increase the subject's ability to lose weight. Tyler & Straughan (1970) and Horan & Johnson (1971) have examined the use of coverant conditioning to increase occurrence of diet-relevant thoughts. Coverant control subjects in both studies were instructed to emit negative coverants ("I am fat"; "fat is ugly") followed by positive coverants ("thin people are attractive"; "being thin is healthy") throughout the day. The subjects in the Tyler and Straughan study were required to follow the coverant with a Premack reinforcer (reading the newspaper, watching television). This procedure was not supplemented by any other weight reduction instructions and was not effective. Horan & Johnson (1971) compared a coverant conditioning procedure followed by Premack reinforcement with a non-reinforced approach. The reinforcement group lost the most weight, but the losses for that group were modest (mean loss of 5.66 Ibs in 8 weeks). Subjects were instructed to emit seven coverant sequences each day, but by the fifth week of treatment actual frequency had decreased to 2-3 per day. A more meaningful test of this technique would be based on a higher rate of emission of coverants. Ongoing attention to the reasons for dieting is probably an important factor in maintaining appropriate behavior. It seems unlikely that such attention is sufficient to generate weight loss by itself. Coverant conditioning approaches would appear to be most useful as components of a treatment battery. The emission of coverants might also be tied to the occurrence of thoughts about eating, rather than made randomly during the day. Harris (1969), Romanczyk (1974), and Romanczyk et al. (1973) have all examined the utility of covert sensitization as a supplement for other procedures. The results of all three studies were negative. In each case subjects received only from 2-6 conditioning trials and no test was made of the aversiveness of the stimuli used. As with the research on coverant conditioning, evaluations of covert sensitization have not been based on optimal utilization of the technique. The number of conditioning trials should be increased and the adequacy of the imagery should be assessed. DISCUSSION
An overview of the studies reviewed suggests that the most effective approach is the use of stimulus control procedures in combination with other treatment techniques. The results of almost all well-controlled studies of multiple component approaches were positive. In contrast, there have been few demonstrations of the utility of either stimulus control or other procedures by themselves. Ferster et al. (1962) have emphasized that new eating habits are difficult to establish and require shaping as well as the judicious application of new contingencies. Stimulus control packages are essentially sets of instructions for self-modification of behavior. They are no more likely to be applied than exhortations to eat less. Some contingent consequation must be applied by the individual himself or the environment, in order to insure that the instructions are followed. Conversely, the application of contingencies to weight loss will be most effective when the individual knows the best way to lose weight.
80
A.S.
BELLACK
There are several unresolved issues about this approach. Stimulus control instructions have generally been administered as a package. Subjects are encouraged to adopt the most useful component and the procedure is evaluated in toto. The utility of the specific components and the degree to which they are followed has not been determined. Subjects in the Bellack, Rozensky, & Schwartz (1974) study reported that engaging in activities incompatible with eating was the most effective technique, but it was not as widely followed as others. Hagen (1974), Mahoney (1974), and Wollersheim (1970) all found a relationship between weight loss and reported change in eating habits. In all four studies, these findings were based on post hoc self-reports rather than on external observation or ongoing SM. While the data are suggestive, such retrospective reports cannot be presumed reliable. A general statement about the utility of a specific directive is not critical for individual treatment, in which specific problems and solutions can be identified. This issue is of more concern for group treatment. Subjects provided with a "smorgasboard" of recommendations will select a few to follow. They are at least as likely to make inappropriate as appropriate choices. A restricted list of highly effective techniques should be identified and provided to subjects in order to maximize their efforts. The role of the therapist is to provide information and to establish some contingencies for behavior change. The results of several studies using self-control techniques suggest that the need for therapist contact and control is minimal. Bellack, Schwartz, & Rozensky (1974) and Hagen (1974) found that bibliotherapy procedures were as effective as weekly personal contact. Jeffrey (1974), Mahoney (1974) and Mahoney et al. (1973) found that subjects could successfully apply self-administered financial contingencies. Bellack (in press) reported that a no-contact SR procedure was as effective as a bibliotherapy SR'approach. These studies all emphasized self-control but varying degrees of external control was applied. Subjects were bound to programs by financial deposits, were required to submit performance records or be weighed regularly, and had to report in for an end of treatment evaluation. If external control were not a factor, subjects should continue to lose weight between the end of the defined treatment period and the follow-up weigh-in. The results of most studies indicate that weight loss rarely continues after treatment and when it does, it occurs at a reduced rate. One possible factor in this pattern is the treatment contract made by the client and the therapist (Kanfer & Karoly, 1972; Mann, 1972). The client agrees, overtly or covertly, to follow certain procedures during the course of the treatment period. Failure to fulfill the contract would result in self-censure and/or therapist censure. This contract and the associated reinforcements are terminated during the follow-up period, allowing for a change in behavior. This hypothesis and the use of contracts in general requires further examination. If contracts are a factor, more explicit contracts can be written and added to treatment. The amount of external control needed and the format in which it is administered are not absolutes: they vary with the individual subject and the nature of treatment. Combinations of treatments and contact schemata should be examined. A considerable amount of research has focused on the simultaneous presentation of stimulus control and one other treatment procedure. An alternative approach is the successive presentation of a number of approaches. Different procedures could be applied at different points in treatment to maximize their impact. Bellack, Glanz, & Simon (1974) found greater weight losses during the first three weeks of treatment than the second three. Stuart (1971) and Mahoney (1974) reported that SM had reactive effects only for the first few weeks of treatment. These data suggest that it is easier to lose weight at the beginning of treatment. If that is the case, treatment could be initiated with instruction and a contract for self-application. High levels of external control or overt self-reinforcement could be reserved until the rate of loss begins to decrease. This sequential strategy is applicable for the evaluation of techniques as well as for clinical programming. Targeted procedures could be initiated after a base rate period in which rate of loss decreased or stabilized at a low level. The effect of the treatment would not then be masked by the effects of non-specific, temporary factors. The procedures described by Ferster et al. (1962) presumed a functional analysis of the behavior of each individual subject. Most research has ignored individual differences and focused instead on group applications. The primary acknowledgement of differential response patterns has come in the form of correlational analyses of weight loss with a variety of independent variables. Relationships have been examined for age, sex, history of weight problem, history of dieting, marital status, motivation, anxiety, depression, and locus of control.
Behavior therapy for weight reduction
8]
There is some suggestion that younger subjects without a history of overweight do better (Hall & Hall, 1974), but for the most part the relationships have not been significant. Conducting post hoc correlations with the results of both effective and ineffective treatment procedures combined is not likely to yield useful information. A better strategy would be to determine the characteristics necessary for utilization of specific procedures and then to examine the procedures with people high and low on the characteristic. Recent studies by Bellack, Glanz, & Simon (1974) and Rozensky & Bellack (1974) have found positive results with this approach. A self-reinforcement task was administered to subjects in both studies and base rates were secured. High and low SR groups were then identified. Rozensky, & Bellack (1974) found that high SR subjects lost more weight than low SR subjects in a self-monitoring condition, and lost considerably less in a therapist managed financial contingency condition. Bellack, Glanz, & Simon (1974) found that high self-reinforcers lost more than lows in two SC procedures. These results suggest differential treatment for individuals differing in the ability or inclination to use self-reinforcement. There are a number of other factors in which individual differences might be explored, including responsivity to positive and aversive control and to covert conditioning procedures. Ikard & Tomkins (1973) suggested a categorization of smoking styles which included smoking to facilitate positive affect, smoking to reduce negative affect, and addictive smoking. Similar patterns might exist for overeaters. Leon & Chamberlain (1973a, 1973b), for example, reported that individuals who regained weight after dieting were more likely to eat between meals and in response to emotional cues than non-regainers or control subjects. In contrast, Abramson & Wunderlich (1972) and Schacter, Goldman, & Gordon (1968) reported that the obese did not eat differently in anxiety and non-anxiety situations. These contradictory findings might reflect the recruitment of subjects populations with different eating styles. Leon and Chamberlain studied middle aged women recruited from a weight reduction club, while Abramson & Wunderlich (1972) and Schachter et al. (1968) examined college students. If younger subjects do lose weight more easily than older subjects, it might be a function of different eating problems and the applicability of treatments used. The results of reviewed studies have been discussed primarily in terms of group differences, with little mention of actual weight changes. This procedure has been adopted for two reasons. First, there is a tremendous variability in data reporting and analysis procedures, precluding consistent between study comparisons. Continued progress in the development of treatment procedures requires the adoption of some evaluation convention (Bellack & Rozensky, 1974). Second, the absolute changes achieved in most controlled studies misrepresent the clinical utility of the procedures. Techniques that can generate significant losses over brief intervals when presented in standardized group format should be considerably more effective in individualized clinical applications. The importance of a functional analysis of the client's specific eating behavior has already been discussed. Notoriously high drop-out rates should be reduced if goals and expectancies are realistic and mutually agreed upon by client and therapist (Ferster et al. 1962; Mahoney, 1974). Finally, treatment duration would be longer, providing more practice of new habits and thereby reducing recidivism. REFERENCES Abrahms, J. & Allen, G., Comparative effectiveness of situational programming, financial pay-offs and group pressure in weight reduction. Behavior Therapy, 1974, S, 391--400. Abr~'unson, E. E., A review of behavioral approaches to weight control. BehaviourResearch and Therapy, 1973, 11,547-556. Abramson, E. & Wunderlich, R., Anxiety, fear and eating: A test of the psychosomatic concept of obesity. Journal of Abnormal Psychology, 1972, 79, 317-321. Bellack. A. S., Self-monitoring and self-reinforcement in weight reduction. Behavior Therapy, in press. Bellack, A. S., Glanz, L., & Simon, R., Positive and negative covert reinforcement in the treatment of obesity. Unpublished manuscript, 1974. Bellack, A. S. & Rozensky, R. H., Selection of dependent variables in weight reduction research. Paper read at Association for Advancement of Behavior Therapy, Chicago, 1974. Bellack, A. S., Rozensky, R. H., & Schwartz, J., A comparison of two forms of self-monitoring in a behavioral weight reduction program. Behavior Therapy, 1974, 5, 523-530. Bellack, A. S., Schwartz, J., & Rozensky, R., The contribution of external control to self-control in a weight reduction program, Behavior Therapy and Experimental Psychiatry, 1974, 5, 245-249. Berecz. J., Aversion by fiat: The problem of "face validity" in behavior therapy. Behavior Therapy, 1973, 4, 110-116. Cautela, J. R., The treatment of over-eating by covert conditioning. Psychotherapy: Theory, Research and Practice, 1972, 9, 211-216. EIkins, R. L., Conditional flavor aversions to familiar tap water in rats: An adjustment with implications for aversion therapy treatment of alcoholism and obesity. Journal of Abnormal Psychology, 1974, 83, 411-417.
A.B. Vot. I, No. I--F
82
A.S. BELLACK
Ferster, C. B., Nurnberger, J. I., & Levitt, E. B., The control of eating. Journal o[Mathetics, 1962, I, 87-109. Foreyt, J. P. & Hagen, R., Covert sensitization: Conditioning or suggestion? Journal of Abnormal Psychology, 1973, 82, 17-23. Foreyt, J. P. & Kennedy, W. A., Treatment of overweight by aversion therapy. Behaviour Research and Therapy, 1971, 9, 29-34. Hagen, R. L., Group therapy vs. bibliotherapy in weight reduction. Behavior Therapy, 1974, 5, 222-234. Hall, S. M., Behavioral treatment of obesity: A two year follow-up. BehaviourResearch and Therapy, 1973, 1I, 647-648. Hall, S. M., Self-control and therapist control in the behavioral treatment of overweight women. Behaviour Research and Therapy, 1972, 10, 59-68. Hall, S. M. & Hall, R. G., Outcome and methodological considerations in the behavioral treatment of obesity. Behavior Therapy, 1974, 5, 352-364. Harris, M. B., Seff-directed program for weight control: A pilot study. Journal of Abnormal Psychology, 1969, 74(2), 263-270. Harris, M. B. & Bruner, C. G., A comparison of a self-control and a contract procedure for weight control. Behaviour Research and Therapy, 1971, 9, 347-354. Harris, M. B. & Hallbauer, E. S., Self-directed weight control through eating and exercise. BehaviourResearch and Therapy, 1973, 11,523-529. Horan, J. J. & Johnson, R. G., Coverant conditioning through a self-management application of the Premack Principle: Its effect on weight reduction. Journal of Behavior Therapy and Experimental Psychiatry, 1971, 2, 243-249. Ikard, F. F. & Tomkins, S., The experience of affect as a determinant of smoking behavior: a series of validity studies. Journal of Abnormal Psychology, 1973, 81, 172-181. Janda, L. W. & Rimm, D. C., Covert sensitization in the treatment of obesity. Journal of Abnormal Psychology, 1972, 80, 37--42. Jeffrey. D. J., A comparison of the effects of external control and self-control on the modification and maintainance of weight. Journal of Abnormal Psychology, 1974, 83, 4(14-410. Jeffrey, D. B., Christenson, E. R., & Pappas, J. R., Developing a behavioral program and therapist manual for the treatment of obesity. Paper read at the American College Health Association meeting, Atlanta, 1972. Kanfer, F., Maintainance of behavior by self-generated stimuli and reinforcement. In A. Jacobs & L. Sachs (Ed). The psychology o[ private events: Perspectives on covert response systems. New York: Academic Press, 1971. Kanfer, F. H. & Karoly, P., Self-control: A behavioristic excursion into the lion's den. Behavior Therapy, 1972, 3, 398--416. Leon, G. & Chamberlain, K., Emotional arousal, eating patterns and body image as differential factors associated with varying success in maintaining a weight loss. Journal o[ Consulting and Clinical Psychology, 1973a, 40, 474--480. Leon, G. & Chamberlain, K., Comparison of daily eating habits and emotional states of overweight persons successful or unsuccessful in maintaining a weight loss. Journal o[ Consulting and Clinical Psychology, 1973b, 41, 108-115. Mahoney, M., Self-reward and self-monitoring techniques for weight control. Behavior Therapy, 1974, 5, 48-57. Mahoney, M., Moura, N., & Wade, T., The relative efficacy of self-reward, self-punishment and self-monitoring techniques. Journal o[ Consulting and Clinical Psychology, 1973, 40, 404--407. Mann, R. A., The behavior-therapeutic use of contingency contracting to control an adult behavior problem: weight control. Journal of Applied Behavior Analysis, 1972, 5, 9%109. Manno, B. & Marston, A. R., Weight reduction as a function of negative covert reinforcement (sensitization) vs positive covert reinforcement. Behaviour Research and Therapy, 1972, 10 (3), 201-208. Meyer, J., Overweight: Causes, cost and control. Prentice-Hall: Englewood Cliffs, New Jersey, 1968. Morganstern, K. P., Cigarette smoke as a norious stimulus in self-managed aversion therapy for compulsive eating: technique and case illustration. Behavior Therapy, 1974, 5, 255-260. Penick, S. B., Filion, R., Fox S., & Stunkard, A. J., Behavior modification in the treatment of obesity. Psychosomatic Medicine, 1971, 33, 49-55. Romanczyk, R. G., Self-monitoring in the treatment of obesity: Parameters of reactivity. Behavior Therapy, 1974.5, 531-540. Romanczyk, R. G., Tracey, D., Wilson, G. T., & Thorpe, G., Behavioral techniques in the treatment of obesity; a comparative analysis. Behaviour Research and Therapy, 1973, 11,629--640. Rozensky, R. & Bellack, A. S., Subjects' self-reinforcement tendencies and their responses to behavioral weight reduction programs. Paper read at the European Association for Behavioral Therapy Conference, London, 1974. Sachs, L. & Ingram, G., Covert sensitization as a treatment for weight control. PsychologicalReports, 1972, 30, 971-974. Schachter, S. Some extraordinary facts about obese humans and rats. American Psychologist, 1971, 26, (2), 129-144. Schacter, S., Goldman, R., & Gordon, A. Effects of fear, food depreviation and obesity on eating. Journal of Personality and Social Psychology, 1968, I0, 91-97. Seligman, M. E., On the generality of the laws of learning. Psychological Review, 1970, 77, 406-418. Stollak, G. E., Weight loss obtained under different experimental procedures. Psychotherapy: Theory, Research and Practice, 1967, 4, 61-64. Stuart, R. B., A three-dimensional program for the treatment of obesity. BehaviourResearch & Therapy, 1971,9, 177-186. Stuart, R. B. and Davis, B., Slim chance in a fat world. Champaigne: Research Press, 1972. Stunkard, A., New therapies for the eating disorders. Archives of General Psychiatry, 1972, 26, 391-398. Stunkard, A., Obesity and the denial of hunger. Psychosomatic Medicine, 1959, 21,281-289. Tyler, V. & Straughan, J. H., Coverant control and breath holding as techniques for the treatment of obesity. Psychological Record, 1970, 20, 473-.-478. Wollersheim, J. P., Effectiveness of group therapy based upon learning principles in the treatment of overweight women. Journal of Abnormal Psychology, 1970, 76, 462--474.
BEHAVIOR THERAPY FOR WEIGHT REDUCTION ALAN S. BELLACK* University of Pittsburgh Abstract--Behavioral approaches to obesity were reviewed and empirical support for the procedures was evaluated. Treatments were categorized on the basis of a primary foGuson the antecedents or consequences of eating behavior. It was concluded that the most effective approach was a combination of antecedent stimulus control procedures supplemented by any of a variety of contingency managementtechniques. The application of self-control procedures was especiallyeffective. Recommendationswere made for the use of contingency contracting and for the sequential application of treatment techniques. The importance of identifying individual differences in responsiveness to treatments was discussed. A research strategy was presented and the results of two studies based on the strategy were described. Several recent reviews have concluded that behavior therapy is the most efficacious approach for the treatment of obesityt (Abramson, 1974; Hall & Hall, 1974; Stunkard, 1972). This conclusion is supported by a general comparison of behavioral and non-behavioral treatments. It does not, however, adequately reflect the actual utility of each of the specific behavior therapy techniques that have been applied to obese populations. A large number of procedures have been utilized individually and in combination with varying degrees of control and success. The purpose of the present paper is to examine the current status of those procedures and to evaluate their application. The review will encompass empirical studies and controlled single subjects reports of outpatient applications of behavioral techniques with adults. BEHAVIORAL CONCEPTION OF OBESITY Behavioral treatments are based on a common conception of the cause and nature of obesity. Obesity is presumed to be a result of a positive energy balance: consumption of more energy (as calories in food) than is expended. A small proportion of obese individuals suffer from dysfunctions of hormonal or metabolic systems which affect energy usage. Mayer (1968) reported, however, that the relationship of food intake to energy expenditure is critical even for those individuals. People who gain weight overeat in relation to their activity level. Individuals with weight problems persist in overeating despite the many aversive consequences of such behavior. There are two factors that mitigate the effects of those consequences. First, eating has immediate positive reinforcing consequences as well. Characteristically, immediate positive reinforcement has greater control over behavior than delayed aversive rehfforcement. Second, the eating behavior of the obese is under the control of external antecedent stimuli as well as the reinforcing properties of food. Obese individuals eat in response to such external cues as where they are, what they are doing, who they are with and time of day, rather than in response to internal, hunger cues such as gastric motility (Schachter, 1971 ; Stunkard, 1959). The multiplicity of external stimuli that can instigate eating and the reduced level of inhibition resulting from satiety result in a high frequence of eating and the consumption of large amounts at each meal. Almost all treatment approaches, regardless of theoretical orientation, have recognized the need to alter the energy balance in order for weight reduction to occur. Behavioral treatments typically include recommendations for reduction of caloric intake and increased activity. The major focus of behavior therapy has been to modify the energy balance indirectly by altering the antecedent and consequent stimuli that control eating. The primary strategies to affect consequent control have been the addition of more immediate aversive consequences for inappropriate eating or of more immediate positive consequences for appropriate eating. The strategy for antecedent control has been to interrupt stimulus-eating sequences and bring eating *Requests for reprints should be addressed to Alan S. Bellack, Clinical PsychologyCenter, Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, U.S.A. tMayer (1968) differentiates obesity (excess fat) from overweight (excess weight). The two terms are used interchangeably in the behavior therapy literature and will be used synonymouslyin this paper. 73
74
A.S. BELLACK
under the control of internal, hunger cues. (This approach has typically been referred to as "stimulus control". That convention will be followed throughout the remainder of this paper.) These two strategies have been examined both as independent treatment approaches and in conjunction with one another. Studies emphasizing modification of the consequences of eating will be reviewed first, followed by those emphasizing stimulus control and those utilizing both approaches. MODIFICATION OF THE CONSEQUENCES OF EATING There are several reports in the literature on the application of aversive reinforcement for eating, for thoughts of eating, or for failure to lose weight. Tyler & Straughan (1970) instructed subjects recruited from a weight loss club to hold their breath while thinking about eating fattening foods. No other treatment procedure was utilized and subjects did not lose a significant amount of weight. Stollak (1967) required subjects to record their food intake and report for brief bi-weekly meetings. The experimenter discussed the records with his subjects and administered electric shocks while discussing the eating of high calorie foods. Subjects in this group lost no more weight than those in a control group. The administration of electric shock in this procedure was not contingent upon eating behavior. It was probably associated with the experimental situation and with the recording and reporting of eating. Foreyt & Kennedy (1971) reported the successful use of aversive conditioning by pairing noxious odors with the smell of preferred, fattening foods. Weight loss was moderate, but subjects had maintained the loss by the time of a 48 week follow-up. No strong conclusions can be drawn from this study because of several design flaws. The authors did not control for contact with subjects: the only control group failed to receive ongoing contact. Second, aversive conditioning subjects were required to self-monitor (SM) all food intake. B ellack, Rozensky & Schwartz (1974), Romanczyk (1974), and Stuart (1971) have all demonstrated that self-monitoring is a viable weight reduction procedure by itself. The relative contribution of the aversive conditioning procedure cannot be separated from the effects of SM. Mann (1972) used a contingency contracting procedure in a single subject withdrawal design. He required his subjects to deposit a number of valuables with him and sign a contract authorizing him to return them (or not) contingent on their weight loss. Failure to meet criteria resulted in forfeiture of items. The contract contained options for relatively immediate reinforcement (three times per week) and two forms of delayed reinforcement (every 2 weeks and for the entire treatment period). The procedure was highly effective and punishment (item loss) was more critical than positive reinforcement (item return). A critical component of this approach was that the subjects were willing to make an extreme commitment to the program, thus allowing the therapist to apply meaningfull contingencies. The withdrawal procedure indicated that weight loss was under the control of the therapist-managed contingencies. Subjects even took laxatives and diuretics to meet weight loss criteria. This pattern does not seem conducive to the maintainance of weight losses once the contingencies are terminated. Mann did not conduct a follow-up to examine maintenance. Another example of the use of single subject methodology was a report by Morganstern (1974). He applied cigarette smoke as an aversive stimulus with a non-smoking client. Base rates of eating behavior prior to treatment had indicated that a primary factor in the client's weight problem was excessive consumption of candy, cookies, and doughnuts. Treatment was designed to reduce consumption of those foods. Aversive conditioning trials consisted of the client puffing on a cigarette while she chewed on one of the target foods. Using a multiple baseline design, Morganstern successively reduced consumption of each of the three foods. Weight loss occurred concurrent with the change in eating and was maintained through a six week follow-up. Cautela (1972) suggests the use of covert sensitization for overeating, as an alternative to the use of external aversive stimuli. The effect of covert sensitization on eating behavior was examined by Sachs & Ingram (1972). One group received a standard covert sensitization procedure and a second group received a backward conditioning variation (nausea images followed by images of target food). The two procedures were equally effective in reducing consumption of two foods. However, the study did not include a control for expectancy and demand characteristics of treatment. Subjects were not on diets and might have been able to temporarily reduce the frequency of consumption of two foods simply by request. Rate of consumption was
Behaviortherapyfor weightreduction
75
determined by examination of SM records. The SM procedure has questionable reliability as well as potentially reactive effects. Manno & Marston (1972) compared covert sensitization, covert positive reinforcement, and an attention-placebo condition in an actual treatment study. Both covert conditioning groups lost significantly more ~veight than the control group. The amounts lost were, however, only 4.1 and 5.1 lbs respectively during 8 weeks of treatment. All groups reported further weight losses during a follow-up period, but the follow-up weights were secured from the subjects by telephone. The accuracy and reliability of such data are questionable. Another test of covert sensitization was conducted by Foreyt & Hagen (1973). Subjects in both a covert sensitization and a placebo control condition reported decreased consumption of target foods, but weight changes were non-significant. Estimates of rates of consumption were based on post-treatment self-reports. Janda & Rimm (1972) found no difference between a sensitization group, an attention-placebo group, and no contact controls. Post-treatment interviews indicated that three of the six treated subjects did not find the nausea imagery aversive; they lost a mean of 2.3 lbs. The other three subjects did find the imagery aversive and lost a mean of 2t lbs. Results reported by Mann (1972) and Morganstern (1974) suggest that aversive conditioning can be an effective tool for weight reduction. There are several factors that must be considered if this approach is to be effective. The primary consideration is that aversive stimuli should be applied contingently, while being experienced as aversive by the subject. Berecz (1973) has pointed out that aversiveness cannot be assumed on the basis of face validity, but must be empirically determined for each individual. The results attained by Janda & Rimm (1972) demonstrate the non-universality of "aversive" stimulation. There are several problems specific to the use of aversive conditioning for altering the consumption of specific fattening foods. Overweight for most individuals is not a function of overconsumption of only a few specific foods. Elimination of any one food from the diet will likely result in overeating of some other item. An alternative strategy for these individuals is to focus on the environmental stimuli that control eating. Specific problem situations could be identified and targeted. Images of eating at a desk, while drinking alcohol, while watching television, or while reading could all be paired with aversive stimuli, (See section on financial contingencies for further discussion of this procedure). Aversive conditioning for specific foods is most applicable when it can be determined that such foods are focal to the individual's difficulty. The quality of aversive stimulation must also be considered. Elkins (1974) and Seligman (1970) have reported that persistent flavor aversions can be readily generated in response to such eating related stimuli as nausea, malodorous, and maltasting substances. The use of these stimuli should be examined in contrast to such eating-unrelated stimuli as electric shock and breath holding. Further examination is necessary to clarify the issues involved in the use of this general approach. The focus should be on how the procedures might best be applied rather than on blanket evaluations of effectiveness. A frequently voiced admonition about the use of punishment is that it tells the target what not to do but does not tell him what he should do. The client in a weight control program should know what he can (and should) do in order to best meet his weight loss goals. The application of aversive control without supplemental instruction or training is unlikely to result in maximal, stable losses. MODIFICATION OF THE STIMULUS CONTROL OF EATING Several programs have been developed for altering stimulus control of eating (Ferster, Nurnberger, & Levitt, 1962; Jeffrey, Christensen, & Pappas, 1972; Stuart, 1971; Stuart & Davis, 1972). The emphasis of each of these programs is twofold. The client is instructed in ways to restructure his environment and alter his eating behavior such that he is exposed to fewer eating cues. At the same time, he is also instructed to engage in a variety of procedures to reduce the effect of those cues that he is unable to avoid, while strengthening the effect of internal stimuli (such as hunger). Table 1 contains a list of the most commonly used procedures. Treatment consists of a presentation of the behavioral conception of obesity and a description of the various stimulus control procedures. Instructions on the specific techniques to be applied and the manner of application are ideally based on examination of base rate recordings of the client's particular eating pattern. Most of the studies discussed below involved variants of the basic approach, adapted by the researcher for standardized, group administration. They do not share a common set of instructions and typically do not design individualized applications.
76
A. S. BELLACK Table 1. Proceduresto reduce stimuluscontrol of eating Modificationof meal quantity
I. Eat slowly: gradually increase minimal time allowed for each meal. 2. Take small bite. 3. Put eating utensil (or food item) down while chewing. 4. Take one helping at a time. 5. Leave table for a brief period between helpings. 6. Eat one food item at a time (e.g., finish meat, before taking vegetable). 7. Serve food from kitchen rather than placing platter on table. 8. Use small cups and plates. 9. Leave some food on plate at end of meal. Modificationof meal frequency I. 2. 3. 4. 5. 6. 7.
Do nothing else while eating. Eat in only one place, sitting down (preferably not in kitchen and not where you engage in other activities). Eat only at specifiedtimes. Set the table with a complete place setting whenever eating. Wait a fixed period after urge to eat before actually eating. Engage in an activity incompatiblewith eating when urge to eat appears. Plan a highly liked activity for periods when the urge to eat can be anticipated (e.g., read evening newspaper before bedtime). Modificationof types of food eaten
1. Do not buy prepared foods or snack foods. 2. Prepare lunch after eating breakfast and dinner after lunch (to avoid nibbling). 3. Do grocery shopping soon after eating. 4. Shop from a list. 5. Eat a low calorie meal before leaving for a party. 6. Do not eat while drinking coffee or alcohol.
Evaluations of the stimulus control (SC) package Penick, Filion, & Fox (1971) compared an SC procedure with traditional psychotherapy in a study frequently cited as an example of the effectiveness of stimulus control approaches. While the authors reported that those subjects losing the most weight were in the SC group, there was no overall difference in the effectiveness of the two procedures. Harris & Bruner (1971) reported on two studies. SC was less effective than a financial contingency condition in one comparison and no more effective than a control procedure in another. Hall (1972) also reported negative results for an SC procedure. The findings of these three studies are difficult to evaluate. In the Hall (1972) and Harris & Bruner (1971) studies one therapist saw all groups, while the Penick et al. (1971) study used different therapists for the two treatment groups; therapist factors cannot therefore be discounted in any of the studies. Several studies have reported more positive results. Harris (1969) compared an SC procedure administered in weekly group meetings with a no-contact control condition. Subjects in two similar SC groups lost more weight than subjects in the control group. These results are of questionable impact, as the design did not control for the effects of regular meetings and contact with a therapist (who lost weight along with group members). Bellack, Rozensky, & Schwartz (1974) found no difference between an SC group and a waiting list control group at the end of treatment, but the SC group had lost significantly more weight by the end of a follow-up period. If eating habits are changed by SC procedures, weight loss should be maintained and possibly continue after treatment ends. Apparently, the treatment period in the Bellack et al. study was not long enough for differences in the procedures to become manifest. The best documented study of SC procedures was conducted by Wollersheim (1970). She compared an SC procedure with social pressure only, verbal psychotherapy, and a waiting list control condition. The SC procedure was administered at group meetings during which subjects also received social pressure for weight loss. SC subjects were also required to self-monitor their eating behavior. All three treatment groups lost weight, but the SC group lost significantly more than each of the other groups. The SC condition in this study incorporated two other active treatment elements: self-monitoring and social pressure. The effects of the SC instructions cannot be isolated from the effects of those other elements. Abrahms & Allen (1974) examined the SC program devised by Stuart & Davis (1972). They divided their subjects into four groups: SC supplemented by social reinforcement, SC supplemented by financial contingencies for
Behaviortherapyfor weightreduction
77
weight change, social reinforcement alone, and a no treatment control. There was no difference between the two SC conditions, both of which were more effective than the two non-SC groups. A third study with clearly positive findings was conducted by Hagen (1974). He administered an SC program in three different ways: a bibliothera, py procedure (therapist-subject contact by mail), and two variations of weekly group meetings. Subjects in the bibliotherapy group were required to complete regular homework assignments and subjects in the two contact groups received social pressure for weight change. All three treatment conditions were more effective than a waiting list control. Differences between the treatment groups were non-significant. Wollersheim (1970), Abrahms & Allen (1974), and Hagen (1974) all found a clear superiority for treatment procedures including SC instructions. In each study, SC procedures were supplemented with other supportive factors. Subjects received social or financial reinforcement and were required to self-monitor or complete homework assignments. In contrast, all of the studies failing to report positive findings administered SC alone. It would appear from this set of results that some facilitation is necessary. The SC programs consist essentially of sets of instructions, describing ways in which subjects are to modify their own behavior. Treatment meetings focusing only on these procedures serve an essentially instructional function. It seems unlikely that individuals would be able to change long standing habits simply on the basis of having received new information. Self or externally administered contingencies must be applied to insure the utilization of the information that is provided. The succeeding sections of this paper will focus on techniques that have been used in conjunction with SC procedures.
Financial contingencies (FC) The most widely examined procedure is the use of financial contingencies. Subjects in FC groups are typically required to leave a financial deposit with the therapist at an initial session. The money is then returned or forfeited in fixed amounts contingent on weight loss or changes in eating habits. The contingencies can either be therapist managed or self-managed. Hall (1972) found FC for weight loss to be more effective than SC alone. Her procedure was unusual in that she reinforced subjects with her own money, rather than requiring a deposit. She also conducted a two year follow-up and found that the weight losses were not maintained. Harris & Bruner (1971) permitted their subjects to fix the contingency at either 50¢ or $1.00 per pound. FC was more effective than SC alone, but the losses had dissippated by the time of a 10 month follow-up. Harris & Hallbauer (1973) found a contrasting pattern. They also allowed subjects to establish their own contingencies; rates per pound were as low as five cents and averaged 76¢. FC was no more effective than a placebo condition at the end of treatment but two FC groups registered greater losses after a seven month follow-up. Rozensky & Bellack (1974) compared an FC procedure with a self-control condition and a minimal contact control. All groups were instructed in SC techniques. The two treatment groups were required to monitor their eating immediately prior to actual consumption and to mail their monitoring records to the therapist each day. Subjects reported individually for weekly weight checks, at which time the FC subjects were reinforced at a rate of $2.00/lb. Differences between the treatment groups were non-significant at the end of treatment and after a follow-up period. Both groups did better than the control group at both measurement points. Abrahms & Allen (1974) examined FC as a backup for social reinforcement. A group receiving social reinforcement alone lost as much as a group receiving social reinforcement and FC for weight loss. Both groups lost more than a no treatment control. Mahoney has examined the effects of self-administered financial contingencies. Mahoney, Moura, & Wade (1973) found self-reward for appropriate eating to be more effective than either self-punishment for inappropriate eating or monitoring of eating urges. The comparison of reward and punishment was limited, as the procedure did not allow for control over the frequency with which self-punishment subjects actually self-punished. In a better controlled study, Mahoney (1974) found that self-reward for changes in eating habits was more effective than either self-reward for weight change or monitoring of eating habits. Jeffrey (1974) compared two forms of self-administered financial contingencies with a therapist administered program. He retained deposits and set the criteria and size of reinforcements for all groups. He administered the reinforcements to the external group while the self-control groups were allowed to administer reinforcements to themselves, out of the therapist's view. All groups lost similar amounts of
78
A.S. BELLACK
weight but only the self-control groups maintained the loss through a follow-up period. Reinforcement control was confounded with expectancy attributions, restricting the conclusions that can be drawn from the follow-up results. External control subjects were explicitly informed that success depended on therapist activity, while self-control subjects were told that their own activity was critical. An effective comparison would require that all subjects receive similar (self-control) expectancy instructions. The utility of financial contingencies is still undetermined. FC procedures can increase the effectiveness of SC programs. They have not been shown to be more effective than such procedures as pre-eating, self-monitoring, and social reinforcement, which are simpler to administer. Mahoney, Moura, & Wade (1973) and Mahoney (1974) reported that FC was more effective than self-monitoring, but the specific self-monitoring procedures utilized in those studies have not otherwise been shown to be effective. Several issues about the use of FC require further investigation. Reinforcements have typically been in the range of $1.00-$2.00 per pound. Given that weight losses average less than 2 lb per week, these reinforcers seem quite modest for the support of a week's dieting effort. This factor is confounded by the delay between eating and weigh-in and reinforcement. The application of reinforcement to behavior change rather than weight change might circumvent that difficulty to some extent. Subjects can monitor eating habits on an ongoing basis and immediately quantify their performance in reference to financial reinforcement. While actual reinforcement might still be delayed, the records should have secondary reinforcing properties. A final issue concerns the nature of self-administered FC. A substantial amount of external control is involved when the therapist retains a deposit, establishes reinforcement criteria, and requires attendance at weekly meetings. External control should be compared with an entirely self-administered program, in which the subject has responsibility for maintaining the contract as well as administering reinforcement.
Self-monitoring and self-reinforcement Self-monitoring (SM) has been included as a data gathering procedure in several studies. The current emphasis is on the reactive effects of monitoring procedures. Mahoney, Moura, & Wade (1973) and Mahoney (1974) reported that monitoring of eating urges or eating habits did not result in significant weight loss. More positive results have been attained for the monitoring of food or calorie intake. Stollak (1967) found SM to be more effective than either aversive conditioning or a no contact control condition. Romanczyk, Tracey, Wilson, & Thorpe (1973) and Romanczyk (1974) compared SM of calorie intake with SM of weight, and with stimulus control packages supplemented by a variety of reinforcement procedures. The SM groups did not receive SC instruction. SM of weight was no more effective than a no treatment control condition, while SM of calories was as effective as the stimulus control procedures. Romanczyk et al. (1973) conducted two studies. Differences between SM and SC were similar in both studies. The difference (in favor of SC) was significant in the second study, which did not contain a control condition. The lack of difference between the SM calorie group and the SC groups may partially be a function of the treatment duration, which was only four weeks. Stuart (1971) and Mahoney (1974) have reported that SM is effective when it is first implemented, but that the effect decreases over time. Group differences in the Mahoney study, for example, did not become apparent until the midpoint of treatment. It is possible that the SM and SC groups in the Romanczyk studies were not treated long enough for differential effects to manifest themselves. An alternative to post-eating monitoring of intake or calories is pre-eating monitoring of intended eating. The latter procedure would interrupt the stimulus-eating sequence and allow the individual to make an alternative, non-eating response. Bellack, Rozensky, & Schwartz (1974) compared pre-eating SM, post-eating SM, and an SC therapy group. The pre-eating subjects were required to write down everything they intended to eat immediately prior to eating. If they chose to eat more (or less), at any one time, they were to make a new entry. The pre-monitoring group lost the most weight. The post-eating subjects did no better than a waiting list group. Bellack, Schwartz, & Rozensky (1974) found the pre-monitoring procedure to be effective when contact with the therapist was limited to correspondance through the mail. Rozensky & Bellack (1974) reported that this form of SM was as effective as an FC procedure. The reactive effects of post-behavior monitoring have been attributed to covert self-evaluation and self-reinforcing operations that occur after behavior is observed (Kanfer,
Behavior therapy for weight reduction
79
1970). In the absence of explicit instructions for self-reinforcement (SR), the operation cannot be presumed to occur on a highly contingent basis. Conversely, performance should be improved if subjects are given instructions for the contingent use of SR. Bellack (in press) compared the effects of post-eating SM with SM supplemented by SR, under two levels of therapist contact. SR consisted of a letter grade assigned to every instance of eating, and recorded on the monitoring record. One-half of the subjects mailed monitoring records to the therapist each day and received weekly feedback by mail. The remaining subjects had no ongoing contact with the therapist. There was no difference between the contact and no contact SR groups and both lost significantly more weight than their non-SR counterparts. In a subsequent study, Bellack, Glanz, & Simon (1974) evaluated the use of contingent positive and aversive covert imagery. Both procedures were more effective than a non-reinforcement control condition. The use of such self-reinforcing operations is highly promising. The procedures are easily learned and easily implemented. Reinforcement can be delivered immediately under all circumstances. The techniques can be used by the individual after treatment proper is terminated for weight control or other problem areas. Covert conditioning procedures Clinical observation of dieters suggests that they often lose track of the reasons for dieting. Both the aversive consequences of overweight and the potential positive consequences of lower weight seem to become obscured, adding to the difficulty of dieting. If this observation is accurate, sustaining attention to the two sets of consequences should increase the subject's ability to lose weight. Tyler & Straughan (1970) and Horan & Johnson (1971) have examined the use of coverant conditioning to increase occurrence of diet-relevant thoughts. Coverant control subjects in both studies were instructed to emit negative coverants ("I am fat"; "fat is ugly") followed by positive coverants ("thin people are attractive"; "being thin is healthy") throughout the day. The subjects in the Tyler and Straughan study were required to follow the coverant with a Premack reinforcer (reading the newspaper, watching television). This procedure was not supplemented by any other weight reduction instructions and was not effective. Horan & Johnson (1971) compared a coverant conditioning procedure followed by Premack reinforcement with a non-reinforced approach. The reinforcement group lost the most weight, but the losses for that group were modest (mean loss of 5.66 Ibs in 8 weeks). Subjects were instructed to emit seven coverant sequences each day, but by the fifth week of treatment actual frequency had decreased to 2-3 per day. A more meaningful test of this technique would be based on a higher rate of emission of coverants. Ongoing attention to the reasons for dieting is probably an important factor in maintaining appropriate behavior. It seems unlikely that such attention is sufficient to generate weight loss by itself. Coverant conditioning approaches would appear to be most useful as components of a treatment battery. The emission of coverants might also be tied to the occurrence of thoughts about eating, rather than made randomly during the day. Harris (1969), Romanczyk (1974), and Romanczyk et al. (1973) have all examined the utility of covert sensitization as a supplement for other procedures. The results of all three studies were negative. In each case subjects received only from 2-6 conditioning trials and no test was made of the aversiveness of the stimuli used. As with the research on coverant conditioning, evaluations of covert sensitization have not been based on optimal utilization of the technique. The number of conditioning trials should be increased and the adequacy of the imagery should be assessed. DISCUSSION
An overview of the studies reviewed suggests that the most effective approach is the use of stimulus control procedures in combination with other treatment techniques. The results of almost all well-controlled studies of multiple component approaches were positive. In contrast, there have been few demonstrations of the utility of either stimulus control or other procedures by themselves. Ferster et al. (1962) have emphasized that new eating habits are difficult to establish and require shaping as well as the judicious application of new contingencies. Stimulus control packages are essentially sets of instructions for self-modification of behavior. They are no more likely to be applied than exhortations to eat less. Some contingent consequation must be applied by the individual himself or the environment, in order to insure that the instructions are followed. Conversely, the application of contingencies to weight loss will be most effective when the individual knows the best way to lose weight.
80
A.S.
BELLACK
There are several unresolved issues about this approach. Stimulus control instructions have generally been administered as a package. Subjects are encouraged to adopt the most useful component and the procedure is evaluated in toto. The utility of the specific components and the degree to which they are followed has not been determined. Subjects in the Bellack, Rozensky, & Schwartz (1974) study reported that engaging in activities incompatible with eating was the most effective technique, but it was not as widely followed as others. Hagen (1974), Mahoney (1974), and Wollersheim (1970) all found a relationship between weight loss and reported change in eating habits. In all four studies, these findings were based on post hoc self-reports rather than on external observation or ongoing SM. While the data are suggestive, such retrospective reports cannot be presumed reliable. A general statement about the utility of a specific directive is not critical for individual treatment, in which specific problems and solutions can be identified. This issue is of more concern for group treatment. Subjects provided with a "smorgasboard" of recommendations will select a few to follow. They are at least as likely to make inappropriate as appropriate choices. A restricted list of highly effective techniques should be identified and provided to subjects in order to maximize their efforts. The role of the therapist is to provide information and to establish some contingencies for behavior change. The results of several studies using self-control techniques suggest that the need for therapist contact and control is minimal. Bellack, Schwartz, & Rozensky (1974) and Hagen (1974) found that bibliotherapy procedures were as effective as weekly personal contact. Jeffrey (1974), Mahoney (1974) and Mahoney et al. (1973) found that subjects could successfully apply self-administered financial contingencies. Bellack (in press) reported that a no-contact SR procedure was as effective as a bibliotherapy SR'approach. These studies all emphasized self-control but varying degrees of external control was applied. Subjects were bound to programs by financial deposits, were required to submit performance records or be weighed regularly, and had to report in for an end of treatment evaluation. If external control were not a factor, subjects should continue to lose weight between the end of the defined treatment period and the follow-up weigh-in. The results of most studies indicate that weight loss rarely continues after treatment and when it does, it occurs at a reduced rate. One possible factor in this pattern is the treatment contract made by the client and the therapist (Kanfer & Karoly, 1972; Mann, 1972). The client agrees, overtly or covertly, to follow certain procedures during the course of the treatment period. Failure to fulfill the contract would result in self-censure and/or therapist censure. This contract and the associated reinforcements are terminated during the follow-up period, allowing for a change in behavior. This hypothesis and the use of contracts in general requires further examination. If contracts are a factor, more explicit contracts can be written and added to treatment. The amount of external control needed and the format in which it is administered are not absolutes: they vary with the individual subject and the nature of treatment. Combinations of treatments and contact schemata should be examined. A considerable amount of research has focused on the simultaneous presentation of stimulus control and one other treatment procedure. An alternative approach is the successive presentation of a number of approaches. Different procedures could be applied at different points in treatment to maximize their impact. Bellack, Glanz, & Simon (1974) found greater weight losses during the first three weeks of treatment than the second three. Stuart (1971) and Mahoney (1974) reported that SM had reactive effects only for the first few weeks of treatment. These data suggest that it is easier to lose weight at the beginning of treatment. If that is the case, treatment could be initiated with instruction and a contract for self-application. High levels of external control or overt self-reinforcement could be reserved until the rate of loss begins to decrease. This sequential strategy is applicable for the evaluation of techniques as well as for clinical programming. Targeted procedures could be initiated after a base rate period in which rate of loss decreased or stabilized at a low level. The effect of the treatment would not then be masked by the effects of non-specific, temporary factors. The procedures described by Ferster et al. (1962) presumed a functional analysis of the behavior of each individual subject. Most research has ignored individual differences and focused instead on group applications. The primary acknowledgement of differential response patterns has come in the form of correlational analyses of weight loss with a variety of independent variables. Relationships have been examined for age, sex, history of weight problem, history of dieting, marital status, motivation, anxiety, depression, and locus of control.
Behavior therapy for weight reduction
8]
There is some suggestion that younger subjects without a history of overweight do better (Hall & Hall, 1974), but for the most part the relationships have not been significant. Conducting post hoc correlations with the results of both effective and ineffective treatment procedures combined is not likely to yield useful information. A better strategy would be to determine the characteristics necessary for utilization of specific procedures and then to examine the procedures with people high and low on the characteristic. Recent studies by Bellack, Glanz, & Simon (1974) and Rozensky & Bellack (1974) have found positive results with this approach. A self-reinforcement task was administered to subjects in both studies and base rates were secured. High and low SR groups were then identified. Rozensky, & Bellack (1974) found that high SR subjects lost more weight than low SR subjects in a self-monitoring condition, and lost considerably less in a therapist managed financial contingency condition. Bellack, Glanz, & Simon (1974) found that high self-reinforcers lost more than lows in two SC procedures. These results suggest differential treatment for individuals differing in the ability or inclination to use self-reinforcement. There are a number of other factors in which individual differences might be explored, including responsivity to positive and aversive control and to covert conditioning procedures. Ikard & Tomkins (1973) suggested a categorization of smoking styles which included smoking to facilitate positive affect, smoking to reduce negative affect, and addictive smoking. Similar patterns might exist for overeaters. Leon & Chamberlain (1973a, 1973b), for example, reported that individuals who regained weight after dieting were more likely to eat between meals and in response to emotional cues than non-regainers or control subjects. In contrast, Abramson & Wunderlich (1972) and Schacter, Goldman, & Gordon (1968) reported that the obese did not eat differently in anxiety and non-anxiety situations. These contradictory findings might reflect the recruitment of subjects populations with different eating styles. Leon and Chamberlain studied middle aged women recruited from a weight reduction club, while Abramson & Wunderlich (1972) and Schachter et al. (1968) examined college students. If younger subjects do lose weight more easily than older subjects, it might be a function of different eating problems and the applicability of treatments used. The results of reviewed studies have been discussed primarily in terms of group differences, with little mention of actual weight changes. This procedure has been adopted for two reasons. First, there is a tremendous variability in data reporting and analysis procedures, precluding consistent between study comparisons. Continued progress in the development of treatment procedures requires the adoption of some evaluation convention (Bellack & Rozensky, 1974). Second, the absolute changes achieved in most controlled studies misrepresent the clinical utility of the procedures. Techniques that can generate significant losses over brief intervals when presented in standardized group format should be considerably more effective in individualized clinical applications. The importance of a functional analysis of the client's specific eating behavior has already been discussed. Notoriously high drop-out rates should be reduced if goals and expectancies are realistic and mutually agreed upon by client and therapist (Ferster et al. 1962; Mahoney, 1974). Finally, treatment duration would be longer, providing more practice of new habits and thereby reducing recidivism. REFERENCES Abrahms, J. & Allen, G., Comparative effectiveness of situational programming, financial pay-offs and group pressure in weight reduction. Behavior Therapy, 1974, S, 391--400. Abr~'unson, E. E., A review of behavioral approaches to weight control. BehaviourResearch and Therapy, 1973, 11,547-556. Abramson, E. & Wunderlich, R., Anxiety, fear and eating: A test of the psychosomatic concept of obesity. Journal of Abnormal Psychology, 1972, 79, 317-321. Bellack. A. S., Self-monitoring and self-reinforcement in weight reduction. Behavior Therapy, in press. Bellack, A. S., Glanz, L., & Simon, R., Positive and negative covert reinforcement in the treatment of obesity. Unpublished manuscript, 1974. Bellack, A. S. & Rozensky, R. H., Selection of dependent variables in weight reduction research. Paper read at Association for Advancement of Behavior Therapy, Chicago, 1974. Bellack, A. S., Rozensky, R. H., & Schwartz, J., A comparison of two forms of self-monitoring in a behavioral weight reduction program. Behavior Therapy, 1974, 5, 523-530. Bellack, A. S., Schwartz, J., & Rozensky, R., The contribution of external control to self-control in a weight reduction program, Behavior Therapy and Experimental Psychiatry, 1974, 5, 245-249. Berecz. J., Aversion by fiat: The problem of "face validity" in behavior therapy. Behavior Therapy, 1973, 4, 110-116. Cautela, J. R., The treatment of over-eating by covert conditioning. Psychotherapy: Theory, Research and Practice, 1972, 9, 211-216. EIkins, R. L., Conditional flavor aversions to familiar tap water in rats: An adjustment with implications for aversion therapy treatment of alcoholism and obesity. Journal of Abnormal Psychology, 1974, 83, 411-417.
A.B. Vot. I, No. I--F
82
A.S. BELLACK
Ferster, C. B., Nurnberger, J. I., & Levitt, E. B., The control of eating. Journal o[Mathetics, 1962, I, 87-109. Foreyt, J. P. & Hagen, R., Covert sensitization: Conditioning or suggestion? Journal of Abnormal Psychology, 1973, 82, 17-23. Foreyt, J. P. & Kennedy, W. A., Treatment of overweight by aversion therapy. Behaviour Research and Therapy, 1971, 9, 29-34. Hagen, R. L., Group therapy vs. bibliotherapy in weight reduction. Behavior Therapy, 1974, 5, 222-234. Hall, S. M., Behavioral treatment of obesity: A two year follow-up. BehaviourResearch and Therapy, 1973, 1I, 647-648. Hall, S. M., Self-control and therapist control in the behavioral treatment of overweight women. Behaviour Research and Therapy, 1972, 10, 59-68. Hall, S. M. & Hall, R. G., Outcome and methodological considerations in the behavioral treatment of obesity. Behavior Therapy, 1974, 5, 352-364. Harris, M. B., Seff-directed program for weight control: A pilot study. Journal of Abnormal Psychology, 1969, 74(2), 263-270. Harris, M. B. & Bruner, C. G., A comparison of a self-control and a contract procedure for weight control. Behaviour Research and Therapy, 1971, 9, 347-354. Harris, M. B. & Hallbauer, E. S., Self-directed weight control through eating and exercise. BehaviourResearch and Therapy, 1973, 11,523-529. Horan, J. J. & Johnson, R. G., Coverant conditioning through a self-management application of the Premack Principle: Its effect on weight reduction. Journal of Behavior Therapy and Experimental Psychiatry, 1971, 2, 243-249. Ikard, F. F. & Tomkins, S., The experience of affect as a determinant of smoking behavior: a series of validity studies. Journal of Abnormal Psychology, 1973, 81, 172-181. Janda, L. W. & Rimm, D. C., Covert sensitization in the treatment of obesity. Journal of Abnormal Psychology, 1972, 80, 37--42. Jeffrey. D. J., A comparison of the effects of external control and self-control on the modification and maintainance of weight. Journal of Abnormal Psychology, 1974, 83, 4(14-410. Jeffrey, D. B., Christenson, E. R., & Pappas, J. R., Developing a behavioral program and therapist manual for the treatment of obesity. Paper read at the American College Health Association meeting, Atlanta, 1972. Kanfer, F., Maintainance of behavior by self-generated stimuli and reinforcement. In A. Jacobs & L. Sachs (Ed). The psychology o[ private events: Perspectives on covert response systems. New York: Academic Press, 1971. Kanfer, F. H. & Karoly, P., Self-control: A behavioristic excursion into the lion's den. Behavior Therapy, 1972, 3, 398--416. Leon, G. & Chamberlain, K., Emotional arousal, eating patterns and body image as differential factors associated with varying success in maintaining a weight loss. Journal o[ Consulting and Clinical Psychology, 1973a, 40, 474--480. Leon, G. & Chamberlain, K., Comparison of daily eating habits and emotional states of overweight persons successful or unsuccessful in maintaining a weight loss. Journal o[ Consulting and Clinical Psychology, 1973b, 41, 108-115. Mahoney, M., Self-reward and self-monitoring techniques for weight control. Behavior Therapy, 1974, 5, 48-57. Mahoney, M., Moura, N., & Wade, T., The relative efficacy of self-reward, self-punishment and self-monitoring techniques. Journal o[ Consulting and Clinical Psychology, 1973, 40, 404--407. Mann, R. A., The behavior-therapeutic use of contingency contracting to control an adult behavior problem: weight control. Journal of Applied Behavior Analysis, 1972, 5, 9%109. Manno, B. & Marston, A. R., Weight reduction as a function of negative covert reinforcement (sensitization) vs positive covert reinforcement. Behaviour Research and Therapy, 1972, 10 (3), 201-208. Meyer, J., Overweight: Causes, cost and control. Prentice-Hall: Englewood Cliffs, New Jersey, 1968. Morganstern, K. P., Cigarette smoke as a norious stimulus in self-managed aversion therapy for compulsive eating: technique and case illustration. Behavior Therapy, 1974, 5, 255-260. Penick, S. B., Filion, R., Fox S., & Stunkard, A. J., Behavior modification in the treatment of obesity. Psychosomatic Medicine, 1971, 33, 49-55. Romanczyk, R. G., Self-monitoring in the treatment of obesity: Parameters of reactivity. Behavior Therapy, 1974.5, 531-540. Romanczyk, R. G., Tracey, D., Wilson, G. T., & Thorpe, G., Behavioral techniques in the treatment of obesity; a comparative analysis. Behaviour Research and Therapy, 1973, 11,629--640. Rozensky, R. & Bellack, A. S., Subjects' self-reinforcement tendencies and their responses to behavioral weight reduction programs. Paper read at the European Association for Behavioral Therapy Conference, London, 1974. Sachs, L. & Ingram, G., Covert sensitization as a treatment for weight control. PsychologicalReports, 1972, 30, 971-974. Schachter, S. Some extraordinary facts about obese humans and rats. American Psychologist, 1971, 26, (2), 129-144. Schacter, S., Goldman, R., & Gordon, A. Effects of fear, food depreviation and obesity on eating. Journal of Personality and Social Psychology, 1968, I0, 91-97. Seligman, M. E., On the generality of the laws of learning. Psychological Review, 1970, 77, 406-418. Stollak, G. E., Weight loss obtained under different experimental procedures. Psychotherapy: Theory, Research and Practice, 1967, 4, 61-64. Stuart, R. B., A three-dimensional program for the treatment of obesity. BehaviourResearch & Therapy, 1971,9, 177-186. Stuart, R. B. and Davis, B., Slim chance in a fat world. Champaigne: Research Press, 1972. Stunkard, A., New therapies for the eating disorders. Archives of General Psychiatry, 1972, 26, 391-398. Stunkard, A., Obesity and the denial of hunger. Psychosomatic Medicine, 1959, 21,281-289. Tyler, V. & Straughan, J. H., Coverant control and breath holding as techniques for the treatment of obesity. Psychological Record, 1970, 20, 473-.-478. Wollersheim, J. P., Effectiveness of group therapy based upon learning principles in the treatment of overweight women. Journal of Abnormal Psychology, 1970, 76, 462--474.