cognitive bias in eating disorders implications for theory and treatment

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1999 23: 556Behav ModifDonald A. Williamson, Stephanie L. Muller, Deborah L. Reas and Jean M. Thaw

Cognitive Bias in Eating Disorders: : Implications for Theory and Treatment

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BEHAVIOR MODIFICATION / October 1999Williamson et al. / BIAS IN EATING DISORDERS

Research testing the predictions of cognitive-behavioral theory related to the psychopathologyof eating disorders has lagged behind treatment outcome research. Central to cognitive theoriesof eating disorders is the hypothesis that beliefs and expectancies pertaining to body size and toeating are biased in favor of selectively processing information related to fatness/thinness, diet-ing, and control of food intake or body weight. In recent years, controlled investigations of thepredictions of cognitive theories of eating disorders have yielded empirical support for thesetheories. This paper reviews research which has tested the predictions of cognitive-behavioraltheory and discusses the implications of these findings for the treatment of eating disorders.Understanding of information processing biases may assist the clinician in understanding arange of psychopathological features of anorexia and bulimia nervosa, including denial, resis-tance to treatment, and misinterpretation of therapeutic interventions.

Cognitive Bias in Eating Disorders:

Implications for Theory and Treatment

DONALD A. WILLIAMSONSTEPHANIE L. MULLER

DEBORAH L. REASJEAN M. THAW

Louisiana State University

During the past 15 years,clinical research with eating disorders hasfound cognitive-behavior therapy to be highly efficacious (William-son, Sebastian, & Varnado, 1995). Reviews of the treatment literaturehave concluded that this approach should be included in lists ofempirically validated psychotherapeutic approaches for psychiatricdisorders (Sanderson & Woody, 1995). Research testing predictionsof cognitive-behavioral theory of eating disorders has lagged behindadvances in treatment. Most earlier theoretical research focused onbehavioral predictions of cognitive-behavioral theory. These studies

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AUTHORS’NOTE: Address correspondence and requests for reprints to: Donald A. Williamson,Ph.D., Department of Psychology, Louisiana State University, Baton Rouge, LA 70803.

BEHAVIOR MODIFICATION, Vol. 23 No. 4, October 1999 556-577© 1999 Sage Publications, Inc.



(e.g., W. P. Johnson, Jarrell, Chupurdia, & Williamson, 1994; Rosen,Leitenberg, Fondacaro, Gross, & Willmuth, 1985; Williamson,Prather, Goreczny, Davis, & McKenzie, 1989) found that anxietyexperienced by bulimics increased after eating large amounts of foodor after eating forbidden foods and decreased after purging. Also,studies of the association of dietary restraint and binge eating or over-eating have found that overeating often occurs after breaking dietaryrestraint (Polivy & Herman, 1995) but only when there is an opportu-nity to purge to prevent weight gain (Duchmann, Williamson, &Stricker, 1989).

Most earlier research on the cognitive features of eating disordersemphasized the study of body image disturbances, which was viewedas a “perceptual distortion” (Slade, 1985). This line of researchyielded very mixed findings, leading some researchers to view thestudy of body image as misguided (Hsu & Sobkiewicz, 1989). Othercognitive studies used various self-report inventories to test hypothe-ses that persons with eating disorders hold maladaptive or irrationalbeliefs related to eating and body shape and weight (e.g., McGlone &Ollendick, 1989). In recent years, research has applied the laboratorymethods of cognitive psychology to the study of predictions derivedfrom cognitive-behavioral theory of eating disorders. These studieshave a methodological advantage over use of self-report inventories inthat the interpretation of biased cognitive processing is based on overtbehavior in response to controlled laboratory stimuli as opposed toretrospective self-report. These investigations have studied cognitivebiases related to attention, memory, and judgment. This body ofresearch will be the primary focus of this article. Several basicassumptions are made in all of these studies: (a) individual differenceson cognitive tasks reveal underlying psychopathology; (b) cognitivebiases associated with the eating disorders are specific to self-referenced (not other-referenced) eating and body shape; and (c) cog-nitive biases are primarily a function of the obsession with thinnessand/or fear of fatness and therefore can be observed in nonclinicalsubjects who are normal weight but express preoccupation with bodyshape and are very dissatisfied with physical appearance of their body.In this research, the authors have referred to this condition asbodydysphoriato distinguish it frombody dissatisfactionin persons who

Williamson et al. / BIAS IN EATING DISORDERS 557



are overweight. Based on the results of a factor analytic study by Wil-liamson, Barker, Bertman, and Gleaves (1995), the authors selected theBody Shape Questionnaire (C. G. Cooper, Taylor, Cooper, & Fairburn,1987) to define body dysphoria. In this chapter, body dysphoria willrefer to normal weight persons with high scores on the Body ShapeQuestionnaire.

Before reviewing research pertaining to the predictions of cogni-tive theories of eating disorders and before discussing the implicationsof this research for treatment, the authors first describe the basic tenetsof cognitive-behavioral theory of eating disorders and the basic com-ponents of cognitive-behavior therapy for eating disorders.

COGNITIVE BEHAVIORAL THEORYOF EATING DISORDERS

Cognitive-behavioral theory of eating disorders describes the influ-ence of cognition on the development and maintenance of pathologi-cal eating and weight control behaviors. A central concept of cogni-tive theory is the structure of thinking as organized by schemata. Incognitive psychology, a schema is viewed as a highly efficient knowl-edge structure; its purpose is to direct attention, perception, and howinformation is processed (Vitousek & Hollon, 1990). Schemata arepresumed to exist for all information that requires organization inmemory and cognitive processing; however, these knowledge struc-tures can just as easily serve a dysfunctional purpose if they bias judg-ment, thought, and behavior in a way that is self-destructive ormaladaptive.

In individuals with eating disorders, this is precisely what occursaccording to cognitive-behavioral theory. Persons diagnosed with aneating disorder are hypothesized to have developed a disorderedschema that centers on overconcern with body size and eating (M. J.Cooper & Fairburn, 1993). This schema is hypothesized to containstereotyped, affectively loaded, and overvalued information concern-ing weight and shape, especially as it applies to self. The informationis overvalued in that it is given central importance among other cogni-tive structures. The body shape schema is considered to be a personalschema. As the schema begins to take an active role in information

558 BEHAVIOR MODIFICATION / October 1999



processing, ambiguous stimuli are biased by the strict personal mean-ings of the body schema. This process is presumed to occur automati-cally with no conscious attention to the actions. Occurring beyond therange of conscious awareness lends the biased, schematic cognitionan air of reality; therefore, the bias becomes insipid within all func-tions of the dominant schema including attention, judgment, memory,and body image. Environmental events related to body shape andweight are processed with a bias toward a fatness interpretation. Oneimplication of this theory is that cognitive bias is presumed to be afunction of a disordered body schema, not disordered eating behavior.Therefore, cognitive-behavioral theory predicts the presence of cog-nitive biases related to body weight/shape and eating in nonclinicalsubjects who are highly preoccupied with body weight/shape but donot meet diagnostic criteria for an eating disorder. This hypothesis hasbeen tested and supported in many studies of cognitive bias associatedwith eating disorders and body dysphoria (Williamson, 1996).

Cognitive-behavioral theory hypothesizes that cognition influ-ences eating and weight control behaviors as shown in Figure 1. Theglobal automatic biasing of information processing related to bodyshape and size leads to dietary restriction, purging (i.e., self-inducedvomiting, laxative abuse, diuretics, etc.), excessive exercise, bodychecking, and ritualistic eating behaviors. Binge eating is hypothe-sized to be an indirect result of cognitive bias because binges typicallyare a reaction to excessive dietary restriction. Cognitive-behavioral


Figure 1. Cognitive influences on eating and weight control behaviors.



theory also postulates that binge eating is determined by hunger andthe hedonic effects of eating (Williamson, 1990).

COGNITIVE-BEHAVIOR THERAPYFOR EATING DISORDERS

Disturbed eating habits and pathological weight control strategiesare the most obvious signs of an eating disorder. Because of the theo-rized link between cognition and behavior, cognitive-behavior ther-apy for eating disorders emphasizes modification of both disturbedeating behavior and cognition related to body and to eating. One set ofbehavioral techniques is calledstimulus control procedures. Usingstimulus control procedures, antecedents of disturbed eating patternsare narrowed to include only those that promote healthy eating. Forexample, the patient may be instructed to eat only when seated at atable to alter the stimuli that set the occasion for binge eating (e.g.,standing in the kitchen or when watching television). Changes instimulus to control overeating are modified using meal planning,altering the pace of eating, and self-monitoring eating and purgativebehaviors. Other behavioral methods are Exposure with ResponsePrevention (ERP) and Temptation with Exposure Response Preven-tion (TERP). ERP is based on the theory that purging produces areduction of eating-related anxiety; therefore, patients are allowed toeat, but compensatory behaviors are prevented. Anxiety concerningweight gain is gradually reduced using this approach (Rosen &Leitenberg, 1982). TERP is similar to ERP but it is binge eating, notpurging, that is prevented. Patients are allowed the sensory experienceof their favorite foods but binge eating is prevented (W. G. Johnson &Corrigan, 1987). This technique weakens the association of the sightand smell of certain foods and the occurrence of binge eating.

The cognitive components of therapy focus on altering dysfunc-tional thoughts, beliefs, and expectancies (Fairburn, Marcus, & Wil-son, 1993). One such method is calledcognitive restructuring. Usingthis method, irrational thoughts are identified, challenged, andreplaced with alternative rational ways of thinking. Another type oftreatment that is a combination of cognitive restructuring and behav-




ioral techniques is calledbody image therapy(Cash & Grant, 1996).This type of treatment involves exposure to body image stimuli (e.g.,looking at body in a mirror), elimination of body checking, and therestructuring of intrusive thoughts related to body shape (Rosen,Reiter, & Orosan, 1995).

The cognitive components of treatment assume that persons diag-nosed with eating disorders automatically process information relatedto body and eating with a biased interpretation. It also assumes thatattention is drawn to body and food stimuli and that memory for eventsrelated to these topics is easily activated and readily recalled. Theseassumptions have not been tested until recently. The following sectionreviews cognitive bias research related to predictions from cognitive-behavioral theory. The cognitive aspects of this theory predicts thatattention, memory, and interpretation of ambiguous stimuli of personswith eating disorders are biased in favor of information related to con-cerns pertaining to a disturbed body schema. Four types of cognitivebias have been studied: (a) attentional bias, (b) memory bias, (c) judg-ment (or selective interpretation) bias, and (d) body image (William-son, 1996).

RESEARCH ON COGNITIVE BIAS

ATTENTIONAL BIAS

Attentional bias refers to increased sensitivity to and absorptionwith relevant environmental cues. With eating disorders, it is pre-sumed that attention is biased toward stimuli related to body fatnessand to fattening foods because both types of stimuli are threatening topersons who are overconcerned with gaining weight. Biases of atten-tion are presumed to maintain preoccupation with body appearancebecause stimuli related to body predominate all competing stimuli(Fairburn, Cooper, Cooper, McKenna, & Anastasiades,1991). Aware-ness of threatening stimuli enables a person to avoid situations thatelicit anxiety and negative affect (Mathews, Richards, & Eysenck,1989). Individuals with eating disorders fear weight gain and there-fore process stimuli related to fatness as threatening (Fairburn et al.,




1991). Such stimuli should capture attention more readily than stimulithat are emotionally neutral.

Two experimental strategies have been used in the research con-cerning the relation between attentional bias and emotion. Bothapproaches measure performance on laboratory tasks; however, per-formance can be either facilitated or impaired due to the selectiveprocessing of information related to the person’s concerns. The mostfrequently used measure of impaired performance is the Stroop ColorNaming test (Mathews & MacLeod, 1985). Earlier research found thatcolor naming was significantly slowed if the ink color and meaning ofthe presented word differ (e.g., the wordbrownwritten in red ink iscolor named more slowly that the wordred written in red ink). Suchinterference is believed to be caused by the antagonistic characteris-tics of the stimulus (i.e., differences in semantic meaning and color).More recent research has found the color-naming interference effectwith words that are personally and emotionally salient. These studieshave found that emotional Stroop interference is found across a rangeclinical conditions (Williams, Mathews, & MacLeod, 1996) in whichperformance is disrupted when the words to be color named arerelated to specific psychopathology (Watts, McKenna, Sharrock, &Trezise, 1986). This interference effect has been shown in numerousstudies on anorexia nervosa (Ben-Tovim, Walker, Fok, & Yap, 1989;Long, Hinton, & Gillespie, 1994) and bulimia nervosa (M. J. Cooper,Anastasiades, & Fairburn, 1992; Fairburn et al., 1991; for a completereview, see Williamson, 1996).

The selective bias toward processing body size and shape and foodinformation is not, however, specific to those with eating disorders.Certain subgroups (e.g., restrained eaters and normal weight womenwith high body dysphoria) of the nonclinical population have strongconcerns about eating, weight, and shape. Research using the Strooptask with these subgroups has consistently found an interferenceeffect for nonclinical subjects who are preoccupied with dieting orbody size (Williamson, 1996), which is consistent with predictionsfrom cognitive theories.

Studies using the Stroop test do not provide definitive evidence ofattentional biases (Mogg, Bradley, & Williams, 1995). A more strin-gent measure of attentional bias is the dichotic listening task. Subjects




are simultaneously presented with two prose passages, one to each ear.They are then asked to repeat aloud the passage presented to one earbut not the other. Target words are inserted in each passage; subjectsare asked to detect the target words presented in both ears. Researchhas shown that subjects readily detect target words in the attended pas-sage but not the unattended passage unless the target words are emo-tionally significant (Burgess, Jones, Robertson, Radcliffe, & Emer-son, 1981; Foa & McNally, 1986). Schotte, McNally, and Turner(1990) used this task to determine selective attention in bulimics.Results showed that bulimics detected a body-related word (i.e.,fat) inthe unattended passage more frequently than normal controls, a find-ing that is consistent with predictions from cognitive-behavioraltheory.

Enhanced sensitivity to information related to a person’s specialconcerns can also be tested using lexical decision tasks (Hill &Kemp-Wheeler, 1989). In this task, subjects are instructed to deter-mine if a string of letters (displayed quickly) is a word or nonword;accuracy is predicted to improve with increased salience of words.Thus, in the lexical decision task, performance is enhanced (ratherthan impaired, as seen in the emotional Stroop test) by attentional bias.Fuller, Williamson, and Anderson (1995) used this method to com-pare three groups of women who differed on degree of body dyspho-ria. Body size words, food words, and matched control words werepresented randomly, each displayed for 35 ms on a computer monitor.The study found that the high body dysphoric group more accuratelydetected body size and food words in comparison to the low body dys-phoric group, a finding consistent with predictions of cognitive-behavioral theory. In summary, these studies have found that overcon-cern with eating, weight, and shape appears to direct attention towardrelevant stimuli, which may function to maintain preoccupation withbody size/shape and/or food.

MEMORY BIAS

Cognitive-behavioral theory predicts that information related to theconcerns of an individual will be more readily encoded in memory andmore easily accessed in recall. Baker, Williamson, and Sylve (1995)




investigated a recall bias for fatness and thinness stimuli using a self-referent encoding task. Because research has shown that stimuli needemotional as well as content relevance for expression of recall bias(Mogg & Marden, 1990), the authors also examined the effects ofnegative mood induction on recall. Subjects included normal weightfemales differing in level of body dysphoria. All subjects wereinstructed to imagine themselves in situation using four types ofwords presented one at a time by computer. The four types of wordswere: fatness body words, thinness body words, depressive words,and neutral words. Half of the subjects in each group were adminis-tered a negative mood induction procedure. Subjects with high bodydysphoria recalled significantly more fatness words and fewer thin-ness words than low body dysphoric subjects. The mood inductionprocedure was effective for inducing negative mood, and changes inmood enhanced the recall of depressive words but not fatness, thin-ness, or control words.

Sebastian, Williamson, and Blouin (1996) used a self-referentencoding task to determine the presence of a memory bias for emo-tional body-related words in eating disorders. They compared threegroups of women: eating disorder, high body dysphoria, and controls.Subjects were presented with three word types (fatness, nonemotionalbody-related, and neutral). They found increased recall for fatnesswords by the eating disorder group and no differences in recallbetween groups for the nonemotional body-related words and neutralwords.

Watkins, Martin, Muller, and Day (1995) compared high and lowbody dysphoric subjects on recall of items seen in an office. Subjectswere left in an office for 45 seconds and then asked to recall objects inthe room. Objects consisted of office items, food-related items, body-related items, and items not characteristic of an office. They found thathigh body dysphoric subjects recalled more body-related items thansubjects with low body dysphoria; however, there were no group dif-ferences found in recall of the other items.

Results of these three studies suggest that recall of fatness words isenhanced in persons diagnosed with an eating disorder and in personswho are preoccupied with body size and shape. Baker et al. (1995)




found that high body dysphoric subjects had difficulty recalling thin-ness words, a finding that was interpreted as evidence of an encodingerror where high body dysphoric subjects had difficulty imaginingthemselves as thin. Results of these studies of memory bias are sup-portive of predictions of cognitive-behavioral theory of eating disor-ders. Finding that persons with eating disorders selectively recallinformation related to fatness and have difficulty recalling informa-tion related to being thin suggests that body image may be viewed as atype of cognitive bias (Williamson, 1996), with many differentaspects, including attention, memory, and as discussed in the next sec-tion, biases of judgment.

JUDGMENT BIAS

In addition to memory and attentional biases, selective interpreta-tion of stimuli related to body size and shape and to food has recentlybeen investigated. The central premise of this line of research is thatwhen people who are preoccupied with body size are presented withan ambiguous situation, information will be selectively interpreted tobe congruent with their concerns. Three studies have investigated ajudgment (or selective interpretation) bias related to body size andshape. Jackman, Williamson, Netemeyer, and Anderson (1995) usedan ambiguous sentence task to investigate judgment errors in bodydysphoric women. In their study, 30 ambiguous sentences were pre-sented via audiotape to female college athletes who differed in degreeof body dysphoria. Sentences were designed to be relevant to the con-cerns of women who were very preoccupied with body size and couldbe interpreted with either a fatness or thinness meaning. In addition,sentences related to other common concerns of athletes (i.e., concernspertaining to health and athletic performance) were used as controlstimuli. Subjects were instructed to imagine themselves in theseambiguous situations as they listened to the audiotape. Followingpresentation of ambiguous sentences, subjects’ interpretations weremeasured using an unobtrusive memory task. Results suggested thatbody dysphoric subjects recalled body-related ambiguous situationswith a fatness interpretation; however, subjects in the low body dys-




phoric group recalled these same sentences with a thinness interpreta-tion. The two groups did not differ on measures of their interpretationof ambiguous situations regarding health and performance concerns.

Watkins et al. (1995) also investigated a judgment bias related tooverconcern with body size. They presented words that could be inter-preted with either a body shape or nonbody-shape meaning to bothhigh and low body dysphoric subjects. Words were either polysemous(e.g., chest) or homophones (e.g., waist or waste). After presentationof a word, subjects were instructed to write a sentence as quickly aspossible using the word that they had heard. Results suggested thathigh body dysphoric subjects interpreted ambiguous words consistentwith a body shape meaning significantly more frequently than the lowbody dysphoric subjects. The two groups did not differ in their inter-pretations of neutral words.

Perrin (1995) extended the results of Jackman et al. (1995) to eatingdisordered patients. This study used an ambiguous sentence task thatwas very similar to that employed by Jackman et al. Results indicatedthat eating disorder and body dysphoric subjects recalled theirimagery of the body-related situations with a fatness interpretation. Incontrast, nonsymptomatic control subjects recalled their imagery witha thinness interpretation. In a second phase of this experiment, theability of subjects to intentionally modify cognitive biases was exam-ined. Subjects were again instructed to imagine themselves in thesame ambiguous situations; however, they were asked to imagine thescenes with either a positive or a negative meaning. Half of the sub-jects in each group received positive instructions and the remaininghalf of the subjects received negative instructions. Results suggestedthat the eating disorder and body dysphoric groups were able to mod-ify their imagery when instructed to do so, although the effect of thisinstructional intervention was small. The findings of this study illus-trate how cognitive components of therapy may operate. If eating dis-order patients process self-referent body-related ambiguous informa-tion without therapeutic intervention, they automatically interpret thisinformation with a fatness meaning. However, with prompting, theycan alter this biased interpretation. This effort is volitional, however,and probably does not seem natural. Perhaps this is one reason that it




appears so difficult for them to make consistent changes in their pro-cessing of body-related information, especially as it pertains to theirown body.

Three studies have investigated judgment biases related to foodintake by bulimics. Hadigan, Walsh, Devlin, and LaChaussee (1992)found that bulimic women overestimated dietary intake one day aftereating. This finding is especially meaningful given the general findingof underestimation of food intake by most people (Wolper, Heshka, &Heymsfield, 1995). Williamson, Gleaves, and Lawson (1991) foundthat as caloric intake increased, bulimics reported overeating at amuch higher rate than controls. Gleaves, Williamson, and Barker(1993) extended these findings to show that negative mood and thetype of food that was consumed interacted with caloric intake to deter-mine biased judgment of overeating.

Cognitive biases, such as memory, attention, and selective interpre-tation, are thought to play a determining role in the development andmaintenance of eating disorders. Results of studies investigating cog-nitive biases lend support to cognitive-behavioral theory of eating dis-orders. These studies provide evidence that situations that are ambigu-ous and of emotional concern to the individual may bring aboutmisinterpretation of body-related stimuli by persons diagnosed withan eating disorder. Misinterpretation of stimuli, in turn, may functionto maintain or worsen disturbed patterns of eating. Bulimic patientsapparently misinterpret the consumption of normal amounts of foodas overeating. This misperception, no doubt, serves to increase emo-tional distress, which in turn, motivates purgative behavior.

BODY IMAGE

Body image disturbances represent a primary diagnostic feature ofeating disorders. The fourth edition of theDiagnostic and StatisticalManual of Mental Disorders(DSM-IV) includes body image concernsamong the diagnostic criteria for both anorexia and bulimia nervosa(American Psychiatric Association, 1994). Considerable evidenceexists that negative body image may predict severity of eating disordersymptoms and may play an important role in the development of eat-




ing disorders (Cash & Grant, 1996; Rosen, 1990; Thompson, 1992).Therefore, a clear understanding of the concept of body image isessential for effective management of eating disorders.

Bruch (1962) is recognized as being the first to describe negativebody image as a primary feature of eating disorders. Some years later,Slade and Russell (1973) investigated the perceptual accuracy of esti-mation of body size in eating disorder patients. They found thatpatients with eating disorders overestimated their body size whencompared with control subjects. Slade and Russell conceptualizedthis body image disturbance as a perceptual phenomenon. The percep-tual construct pertains to the accuracy or distortion of an individual’sestimates of their physical size (Cash & Grant, 1996). Subsequentresearch focused primarily on measuring the accuracy of size percep-tion (Cash & Brown, 1987; Garner & Garfinkel, 1981; Slade, 1985;Thompson, 1992, 1995).

In recent years, researchers have proposed that body image is bestconceptualized as a complex form of cognitive bias rather than as aperceptual process (Smeets & Panhuysen, 1995; Vitousek & Hollon,1990; Williamson, Cubic, & Gleaves, 1993). The findings of Jackmanet al. (1995), Watkins et al. (1995), and Perrin (1995) suggest that eat-ing disorder patients infer a negative meaning when information abouttheir own body shape is presented within an ambiguous context. Wil-liamson (1996) observed that most body size estimation tasks involvejudgment of an ambiguous stimulus (i.e., the size of a body part,manipulation of their picture on a video screen, or selection of a sil-houette that matches their body shape). Such tasks would be expectedto activate the body self-schema and judgments of body size wouldlikely be biased in the direction of a fatness interpretation. Using thislogic, Williamson reasoned that body size estimation tasks may beconceptualized as an ambiguous situation susceptible to biased judge-ments. Similarly, vague comments in a clinical context such as, “Howdo you feel about your body today?” probably function to elicit thesame types of biased judgment. From this perspective, earlier researchon body image has some relevance to this discussion of cognitive bias.Recent meta-analyses of body size estimation in eating disorders haveconcluded that there is a general phenomenon of body size overesti-mation inanorexiaandbulimianervosa (Cash&Deagle,1995;Smeets&




Panhuysen, 1995). It is suspected that the variability of findings acrossstudies (Hsu & Sobkiewicz, 1989) may in part be due to the impreci-sion of body size estimation tasks as a measure of judgment bias.

Williamson (1996) suggested that the structure of these body-related self-schemata should involve a dense network of associationsbetween self and body size and appearance. Memory theories assertthat highly elaborated memories associated with body should also beassociated with emotional memories of body (Bower, 1981). Conse-quently, if body memories are activated, then emotional memories ofbody should also be activated. One implication of this theory is thatbody size estimation should be labile in persons with high body dys-phoria. Empirical tests of this hypothesis have generally provided sup-port (Baker et al., 1995; McKenzie, Williamson, & Cubic, 1993;Slade, 1985). Results of these studies suggest that it is the activation ofnegative emotion that determines lability of body size overestimationin persons who are preoccupied with body size and shape. A similarrelationship between the presence of negative emotion and biasedestimation of overeating was reported by Gleaves et al. (1993).Whether the eating disorder patient feels fatter or bloated, it is sus-pected that the result will be increased probability of using extrememethods for controlling body weight. Perhaps, presence of depressionand anxiety complicate the treatment of eating disorder patients viathis type of influence on subjective states of fatness.

IMPLICATIONS FOR TREATMENT

Results of these studies of cognitive bias support the theoreticalbasis of cognitive-behavior therapy for anorexia and bulimia nervosa.The following section summarizes implications of these findings forapplications of cognitive-behavioral treatment approaches.

CONTENT SPECIFICITY

Research evidence from a variety of sources has suggested that theprimary pathological concerns of eating disordered patients relate tobody size and shape and fattening foods. As noted by Fairburn and




Cooper (1993), these concerns take the form of overvalued ideationabout thinness and fatness. Body dissatisfaction is a common but notuniversal feature of eating disorders. Studies of cognitive bias havefound similar biases in women of normal weight with extreme bodydissatisfaction and patients with eating disorders. It is believed that itis the overconcern with body size and shape that is the central psycho-pathological feature of anorexia and bulimia nervosa. If this assump-tion is correct, then a major focus of cognitive-behavior therapy mustbe to modify cognitive biases and obsessional thinking related to theseconcerns. Also, efforts to prevent the development of eating disordersin preadolescents should focus on body dysphoria and obsession withthinness as an ideal body shape.

SITUATIONAL SPECIFICITY AND SELF-REFERENCE

Most studies of cognitive bias and body image disturbances in eat-ing disorders have found positive effects only when instructions askthe subject to apply the experimental task to themselves (e.g., imagin-ing themselves in an ambiguous situation as opposed to some otherperson). It is presumed that such tasks activate the self-schema, whichis highly associated with memories associated with fear of fatness andstrong drive for thinness. Also, these tasks usually require the personto recall situations involving evaluation of body size, decidingwhether to eat, or some similar type of circumstance. These studieshave consistently found that such combination of environmental stim-uli activates cognitive biases of memory, attention, and judgment.Results of these studies offer an explanation for the common observa-tion that patients with eating disorders accurately perceive the size ofother person’s bodies and are less concerned with the eating habits ofothers. Therefore, it is important for the therapist to avoid the beliefthat because patients are reasonable about the body size of others thatthey are simply being intentionally resistant to viewing their own bod-ies in a realistic manner.

AUTOMATICITY OF REACTIONS

Most of the studies of cognitive bias and eating disorders have usedrelatively ambiguous encoding or activating tasks. These tasks have




generated cognitive and emotional reactions that appear to be auto-matic in the sense that they occur very rapidly and appear to be outsidethe volitional control of the subject. This same type of automatic reac-tion is reported by clinical subjects in their day-to-day activities. Infact, these reactions are so automatic that persons with eating disor-ders cannot imagine not having reactions of fearing weight gain, per-ceiving themselves to be bloated after eating normally, and so on. Theclinician should never underestimate the strength and seeming realityof these reactions.

APPARENT REALITY

Frijda (1988) observed that “emotions are elicited by eventsappraised as real and their intensity corresponds to the degree to whichthis is the case” (p. 51). Persons with eating disorders perceive theiremotional reactions to be in response to real situations (e.g., theyreally have gained weight because they feel full or they will gain largeamounts of weight because they have been unable to exercise accord-ing to their rigid rules). Efforts to convince them of their mispercep-tion of reality, as the therapist or family member sees it, are met withstiff resistance. It is as if others do not understand them, which is abso-lutely true because others do not share their apparent reality. It isimportant for the clinician to recognize this fundamental difference inapparent realities and to openly acknowledge the different appraisal ofthe situation to the patient.

DENIAL AND RESISTANCE TO TREATMENT

Much of what is seen as denial of the severity of the problems asso-ciated with anorexia and bulimia nervosa and resistance to treatmentstems from the problem of apparent reality. This phenomenon is oftencalledovervalued ideation. The essential feature of this phenomenonis an inability to understand the issue of discussion in terms differentfrom those held by the person. This type of discussion between patientand therapist usually has the feel of stubborn resistance to changes inattitude or behavior. It is important that the therapist understand thatthe patient may be unable to formulate a new belief or expectation due




to the biased memories that are central to the psychopathology of ano-rexia and bulimia nervosa. Armed with this understanding, the thera-pist may be able to manage his or her own frustrations with the pati-ent’s apparent denial and/or resistance.

MISINTERPRETATION OF THERAPEUTIC INTERVENTIONS

Patients with eating disorders often misinterpret the intent or pur-pose of many therapeutic interventions. Misunderstandings oftenoccur outside of the patient’s awareness and are experienced as auto-matic thoughts or reactions. For example, therapists have patients turntheir backs when being weighed because they exaggerate the signifi-cance of minor fluctuations of weight. They are provided with generalinformation about changes in body weight to reduce the likelihood ofmisinterpretation. But, even this intervention can lead to misunder-standing and catastrophic reactions because the information that theyreceive is inherently ambiguous. Therefore, it is important to con-stantly evaluate the interpretations of the patient and to assist them inthinking about even mundane events in more rational terms.

HEDONIC ASYMMETRY

Frijda (1988) also noted that “pleasure is always contingent uponchange and disappears with continuous satisfaction. Pain may persistunder persisting adverse conditions” (p. 52). Recovery from an eatingdisorder is a painful experience for the patient. The anorexic patientmust gain weight and the bulimic patient must learn to eat normallywithout purging. This treatment process is necessarily painful for thepatient because it activates all of his or her fears of weight gain, loss ofcontrol over eating, and threatens overvalued ideas concerning thesanctity of thinness. What positive reinforcement does the patientobtain from complying with a treatment program? Therapists smileand praise the patient. Parents who are often distrusted or dislikedshow their approval. Restoration of healthy nutrition may be associ-ated with fleeting feelings of better health, but all of these experiencesare rather brief moments of pleasure. In the meantime, emotional painof weight gain or eating without the compensation of purging persists,




especially when the person is alone and there are no competing activi-ties (e.g., working on therapeutic activities or engaging in otherattention-demanding activities). It is no wonder that patients some-times feel as though they suffer without understanding or compassion.Without a clear understanding of the cognitive basis of this emotionalanguish, the therapist may wonder what else can I do? Where have Igone wrong? Such feelings can be detrimental to the therapist and tothe therapeutic process.

CAN COGNITIVE BIASES BE CHANGED?

The good news is that there is an abundance of evidence that cogni-tive biases associated with eating disorders can be modified. Availablescientific evidence suggests that this process of change is slow andfilled with stops and starts. Persistence on the part of the treatmentteam is clearly a virtue and the therapist needs to continually remindhimself or herself that the patient may not always retain new informa-tion related to eating, body, and self in therapy sessions. Often, thesame basic concept must be presented many times in slightly differentcontexts for it to find a permanent place in the person’s self-schema. Arecent review of the literature (Williamson, Womble, & Zucker, 1998)found strong evidence in support of the efficacy of cognitive-behaviortherapy for bulimia nervosa. Length of outpatient therapy for bulimianervosa is generally 4 to 6 months with about 60% of subjects signifi-cantly improved. Anorexia nervosa patients often require hospitali-zation, followed by partial day hospitalization, and lengthy outpa-tient therapy (Williamson, Duchmann, Barker, & Bruno, 1998). Ithas been found that many cases require several years of treatment toachieve stable recovery. It has become increasingly apparent thatchanges in cognitive bias are an important part of successful recovery.

CONCLUSIONS

In this paper, the authors have reviewed the recent literature per-taining to cognitive biases associated with anorexia and bulimia ner-vosa and in nonclinical subjects who are preoccupied with body sizeand shape. Also, implications of these research findings for the treat-




ment of eating disorders were discussed. At present, it is concludedthat cognitive biases are quite pervasive, involving attention, memory,and judgment, or selective interpretation of information pertaining toeating fattening foods and to body size and shape. Current evidencesuggests that these cognitive biases may be specific to eating andbody-related information. As noted in an earlier article (Williamson,1996), earlier research on body image disturbances in eating disorderscan also be interpreted within the context of cognitive bias, which mayserve to bring new direction to this field of research.

Pervasiveness of these cognitive biases suggests that they mayinfluence many of the cognitive, emotional, and behavioral reactionsof eating disordered patients. Therefore, the authors feel that it isessential for clinicians to understand the cognitive processes thatdetermine the patient’s reactions to the therapeutic process and to inte-grate this knowledge into their practice of cognitive-behavior therapy.

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Donald A. Williamson is a professor of psychology at Louisiana State University (LSU)and is director of the LSU Psychological Services Center. He is an adjunct faculty mem-ber at Pennington Biomedical Research Center. His interests are in eating disorders,obesity, and behavioral medicine.

Stephanie L. Muller is a doctoral candidate in clinical psychology at Louisiana StateUniversity. She completed her master’s degree in clinical psychology at Eastern Wash-ington University. Her interests include cognitive biases in eating disorders anddepression.

Deborah L. Reas is a doctoral candidate in clinical psychology at Louisiana State Uni-versity. Her research interests are in the areas of eating disorders and obesity.

Jean M. Thaw is a doctoral candidate in clinical psychology at Louisiana State Univer-sity. Her research interests are in the areas of eating disorders, obesity, and anxiety.




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