Emotional Labeling and Overeating in Obese and Normal Weight Individuals JOYCE SLOCHOWER
It was hypothesized that obese individuals respond to unlabeled high arousal by overeating, while no such response was predicted for labeled high arousal states. Obese and normal weight subjects were led to believe that they were hearing their own heart beat, and that it was either fast or slow. A label for this heart rate either was or was not provided, and subjects' eating behavior was measured unobtrusively. The results supported these hypotheses: aroused obese subjects ate more when they could not identify the cause of their arousal than when a label was known. When obese subjects were calm, the presence or absence of a label did not affect their eating. Furthermore, obese subjects showed significant affect reduction following eating. Normal weight subjects were not affected by the presence or absence of an arousal label. Instead, they ate more when they called themselves calm than when anxious, and more when hungry than when full.
INTRODUCTION
Recent investigations of the psychological factors producing overeating and obesity fall into two theoretical frameworks which stand in apparent conflict. One, initiated by Schachter, posits that overweight individuals are essentially unable to withstand the pressure of external, food-related cues, while their eating is believed to be relatively unaffected by both internal hunger and emotional states. In contrast to this emphasis on the external food environment in determining eating, psychosomatic theorists, most notably Bruch (3), point to the influence of early emotional experiences on the development of overeating as an anxiety-reducing mechanism [see Kaplan and Kaplan (6) for a review of this literature]. The psychosomatic position From the Department of Psychology, Hunter College, City University of New York, New York 10021. Received for publication July 28, 1975; revision received November 7, 1975.
focuses on precisely those internal, emotional factors that are disregarded in the theory of external responsiveness. There is substantial evidence concerning both the role of external cues in obesity (11,13) and the obese person's insensitivity to his internal gastric state (15). However, little experimental support is available for the notion that the obese individual eats when anxious. In one study, Schachter, Goldman, and Gordon (12) hypothesized that normal subjects would reduce their eating when aroused, because arousal inhibits the physiological correlates of hunger. Obese subjects, on the other hand, were thought to be unresponsive to their internal gastric state, and thus would not be affected by manipulations of arousal level. Subjects were threatened with severe or mild shock (high and low fear), and their eating was measured during a cracker "taste test." The results indicated that normal subjects ate more when calm than when frightened, while obese subjects ate the same amount in high and low fear conditions. Since obese subjects
Psychosomatic Medicine Vol. 38, No. 2 (March-April 1976) Copyright ° 1976 by the American Psychosomatic Society, Inc. Published by American Elsevier Publishing Company, Inc.
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did not report fear reduction following eating, it was also concluded that eating did not serve a stress reducing function for them. To clarify these findings, McKenna (7) either threatened subjects with direct physiological measurements or reassured them about the study, and measured their eating using either good or bland tasting food. Normal subjects ate significantly less when aroused than when calm. However, the obese group ate slightly more good food in high than in low arousal conditions (p < 0.10), while they ate nearly identical amounts of bland food independent of arousal state. Obese subjects also did not show arousal reduction following eating. Thus, only marginal support was offered for the psychosomatic position. In a different approach, Abramson and Wunderlich (1) argued that the psychosomatic hypothesis attributes overeating to a variety of neurotic rather than objective emotional reactions, and noted that the former studies had really manipulated objective fear rather than neurotic anxiety. Subjects were therefore either threatened with shock (fear condition) or were told that they would have difficulty forming deep personal relationships (anxiety condition). Eating was measured in a taste test. The results indicated that obese subjects ate about the same amount in all conditions. (Normal subjects did not respond to the anxiety manipulation appropriately, and their data were not discussed.) However, one implication of the psychosomatic notion that obesity is a manifestation of internal (and perhaps unconscious) conflicts is that the experiential anxiety state that triggers eating may be diffuse, and its source frequently not understood by the obese person. It seems
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plausible that it is precisely the "grossness" of the emotional reaction that results in overeating for the obese individual. However, tests of the psychosomatic hypothesis have thus far employed manipulations of the external environment that could allow subjects to label and to interpret their emotional state as, for example, fear of shock (14). Since obese subjects are highly responsive to external cues, they should be even more likely than normals to label their internal state according to the available external information. However, if the obese person experienced a diffuse, or free-floating anxiety state, his idiosyncratic eating response to high arousal might emerge. Furthermore, a likely consequence of overeating may be a reduction in emotional stress. These notions stand in contrast to both the theories discussed above. According to the Schachter position, the externally responsive obese subject should not be affected by either his arousal level or the presence or absence of a label for it; only variations in food salience should alter his eating. The psychosomatic position would predict an increase in eating when obese subjects are aroused; however, there is no direct support for our distinction between labeled and unlabeled arousal states. It is hypothesized that obese subjects will respond to both their arousal level and to the presence or absence of a label for it. Specifically, the aroused obese subject is expected to eat more when he lacks a label for this arousal state than when a label is known. When calm, the presence or absence of a label should not affect his eating, which should be at an intermediate level. Normal subjects' eating should parallel earlier findings; normals should eat more when calm than when aroused, and should not be affected by the label manipulation.
Psychosomatic Medicine Vol. 38, No. 2 (March-April 1976)
EMOTIONAL LABELING AND OVEREATING cesses and were offered $2 to do so, 94% of those requested agreed to participate. Each potential subject completed a short form containing questions about height, weight, participation Overview of the Procedure in athletics, and experience with psychology courses Subjects were tested in a 2X2X2 factorial design: or experiments. Initial selection of subjects was based obese and normal weight subjects were either upon self-report of height and weight. Subjects were aroused or not aroused, and a label for their arousal eliminated if they participated in any sports (N = 6), either was or was not provided. The main dependent because their higher body weight is caused by inmeasure was the amount eaten during a task in which creased muscle rather than fat content (2). Students subjects could eat, doodle, or play with several toys with experience in psychology courses or studies [after Ross (10)]. This situation offered alternative were also eliminated (N = 8). (noneating) response choices to subjects, making eatAt the end of the study, subjects were weighed and ing simply one of several appropriate activities. A measured, and percent overweight was calculated second dependent measure was an index of arousal according to Metropolitan Life Insurance (8) weight reduction following eating. Checks on all manipula- norms. Forty moderately obese subjects, ranging betions were also obtained. However, since it seemed tween + 16% and +40% overweight (M = +25%), possible that asking subjects to introspect about their and 40 normal weight subjects, ranging between emotional state might alter the state itself, only half - 9 % and +9% overweight (M = +1.3%), were the subjects in each condition received these checks. selected. Following procedures outlined by SchachThe effects of receiving manipulation checks were ter, Goldman, and Gordon (12), subjects weighing later examined as a possible experimental effect. between +10% and +15% overweight (N = 5) were To manipulate arousal, subjects received false (fast eliminated, to more clearly differentiate obese from or slow) aural feedback of heart rate, which made it nonobese subjects. appear that they were actually hearing their own heart beat. There is evidence supporting the thesis that this feedback will cause subjects (1) to behave as Procedure if they are appropriately aroused and (2) to actually show physiological responses corresponding to apSubjects were randomly scheduled between 1:00 parent heart rate. In two studies, subjects who heard and 2:30 p.m. in order to minimize the effects of apparently increased heart rates to certain pictures of differential hunger on eating. When the subject arnude females rated those pictures as most desirable rived , he waited for 5 min before the study began (the IValins (16)1, and actually "tracked" the heart rate waiting period was necessary to reduce betweenfeedback, i.e., showed significantly greater deviation subject differences in initial heart rate). Each room from base-line heart rate during presentation of contained a pair of earphones and a complex piece of falsely elevated heart rates [Goldstein, Fink, and Met- electrical equipment (to enhance the believability of tee (5)]. In another study, Frankenhaeuser (4) found the forthcoming manipulations). that subjects who were injected with a placebo they Taped instructions introduced subjects to the exbelieved was a stimulant showed increased perimental concerns, the physiological correlates of physiological arousal, while subjects who thought thinking. The subject learned that his heart rate the placebo was a depressant showed decreased ar- would be measured as an index of physiological arousal. ousal. The experimenter then entered and attached The label manipulation employed a neutral label two electrodes to his arm andfinger,remarking, "By (noise level) to reduce the possibility that subjects the way, our machine doesn't have a sound interwould self-arouse further upon learning the source of mediate, so you'll be able to hear the sound of the their arousal. beats corresponding to your heart rate over the earphones. Just ignore them."
METHOD
Arousal Manipulation. This manipulation was Subjects disguised in a "base-line heart rate measurement." Male undergraduates were recruited from dor- The "heart beats" were actually prerecorded low fremitories at Columbia University. When students were quency tones generated on a moog synthesizer. In requested to participate in a study of cognitive pro- high arousal conditions, subjects heard beats varying
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JOYCE SLOCHOWER between 84 and 92 per minute for 2 min. Low arousal subjects heard beats varying between 66 and 74 per minute for 2 min. [These heart rates were established as high and low arousal by Goldstein, Fink, and Mettee (5)]. At the end of the measurement, subjects received feedback about their heart rate level on a five-item checklist, varying from "very slow heart rate" to "very fast heart rate." High arousal subjects learned their heart rates were "very fast" and low arousal subjects learned their heart rates were "slightly slow." Label Manipulation. Subjects in the label high arousal condition were then told, "We have found that the unusual noise level which is produced by wearing earphones in the laboratory tends to increase heart rate level. That is, your heart rate was probably affected by the sound conditions in your room." Low arousal subjects received identical instructions, except that they believed the noise would decrease rather than increase heart rate. No label subjects received no instructions at this point.
The thinking task lasted for 3 min. Subjects then completed a questionnaire containing checks on posteating arousal as well as secondary measures. After a suspicion probe (which revealed that no subject suspected the validity of the experimental manipulations or measures), subjects were debriefed. However, no references were made to obesity, to avoid upsetting overweight participants.
RESULTS Dependent Measures
The amount eaten by obese and normal subjects is presented in Table 1 and Fig. 1. An analysis of variance (Table 2) indicated first that obese and normal subjects did not differ in the amount of cashews Manipulation Checks. Half the subjects in each eaten overall. Furthermore, no main efcondition then completed a questionnaire containing fects emerged for manipulations of label or of arousal. Instead, a significant Subject x checks on both manipulations. Label interaction and a significant Subject Dependent Measures. The eating measure was x Label x Arousal interaction were redisguised in a "thinking task." The experimenter entered and placed several objects before the subject. vealed. In order to test the relative conThese included a tin containing 800 g of large tributions of obese and normal subjects to cashews. The taped instructions continued: these overall interactions, tests for simple For the next few minutes we would like you to main effects were conducted. The results think about the objects on the table. In this con- indicated that the Subject x Label interacdition, we will not specify which objects you tion was largely accounted for by the reshould think about. . . think about the toy, the sponsiveness of obese subjects, who ate marbles, the ball, the nuts, the paper and pencil, significantly more when they lacked a or think about only one or two of these . . . feel free to touch the objects, to doodle, or to eat the label for their arousal state than when a label was known (for obese subjects, F = nuts. 4.63, p < 0.05; for normals, F = 1.07). TABLE 1. Mean Grams of Cashews Eaten by Obese Furthermore tests for simple interaction and Normal Subjects effects indicated that the obese subject's responsiveness to the presence or absence High arousal Low arousal of a label occurred primarily when he felt Subjects No label Label No label Label aroused (for obese subjects,F = 3.03, p < 6.05 16.38 16.90 16.40 Normal 0.09; for normals,F = 1.3). Taken together, (8) a (9) (9) (8) the data indicate that, as predicted, Obese 26.10 7.60 15.80 13.85 aroused obese subjects ate significantly (10) (8) (9) (9) more when the arousal they experienced N = 10 in each experimental condition. was "free-floating" than when its source 3 Numbers in parentheses, represent the number of subwas known. In low arousal conditions, the jects w h o ate at least 1 g of cashews.
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CASHEWS EATEN
Fig. 1. Mean grams of cashews eaten by obese and normal subjects.
TABLE 2. Analysis of Variance for Grams of Cashews Eaten Source Subjects Arousal Label Subjects x arousa Subjects x label Arousal x label Ss x A x L
F 0.32 0.26 0.62 1.23 5.08" 0.18 4.15*
*p < 0.05. **p < 0.03. For all f tests, df = 1,72.
obese did not respond to the presence or absence of a label for arousal. Normal weight subjects were not significantly affected by either experimental manipulation. Another way to examine subjects' eating behavior is to consider what other, non-
manipulated variables might affect it, in order to gain a more precise picture of those factors that influence this behavior. To do this, stepwise multiple regression analyses were performed for obese and normal subjects separately. Entered into the regressions as additional variables were (1) a measure of hunger, to assess the responsiveness of subjects to their gastric state and (2) a measure of body weight, to provide information about the linearity of the overweight-eating relationship. The index of hunger was the number of hours since the last meal eaten by each subject (a comparison of the amount eaten by subjects in each condition indicated that subjects did not differ in the quantity eaten that day). Percent overweight was entered as the weight measure. In addition, the two experimentally manipulated variables of arousal and label were entered.
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The results indicated that, for both obese and normal subjects, the only variable significantly related to eating was pulled out in the first step. For obese subjects, neither hunger nor percent overweight was significantly related to eating. Only label was significant P 2 = 0.102,F (1,38) = 4.33, p < 0.04], indicating again that obese subjects ate most in unlabeled arousal conditions (R2 represents the multiple correlation squared, and indicates the proportion of variance in the dependent variable "explained" by association with the independent variable). This significant effect clearly masks the interaction of arousal and label for obese subjects. It was, unfortunately, impossible to conduct recursive regressions to clarify this finding because of the sample size. Results for normal weight subjects showed that only the nonmanipulated variable of hunger level was related to eating \R2 = 0.116, F (1,38) = 4.98,p < 0.03]; normals ate more when hungry than when full, and were unaffected by both experimental manipulations and by percent overweight. While the results for obese subjects support our hypotheses, the finding that normal subjects' eating was not affected by their arousal level contradicts the experimental predictions, as well as earlier research [cf. (12)]. To further investigate this relationship, a more precise measure of individual subject's reactions to arousal manipulations was obtained by correlating self-ratings of arousal with eating for those subjects receiving the manipulation check (N = 20). A significant correlation was revealed (r = -0.51, p < 0.05); normals ate less the more aroused they reported themselves to be. There was no correlation between self-reported arousal and eating for obese subjects (r = -0.03). A secondary hypothesis concerned the notion that for obese subjects, eating 136
would be followed by arousal reduction, while no such relationship was posited for normal weight subjects. To test this, subjects who received both pre- and posteating arousal checks were examined as two separate weight groups. An index of arousal reduction was obtained by subtracting post- from preeating scores. Correlated t tests indicated that obese subjects showed significant affect reduction following eating \M change score = 2.35, t (19) = 4.32, p < 0.001). For normals, the same comparison was nonsignificant [M change score = 0.85, t (19) = 1.89]. A more precise way to examine this relationship is to test the correlation between the amount eaten and degree of affect reduction for each weight group. For obese subjects r = 0.45, p < 0.05, while for normals r = -0.04. When this correlation is examined for aroused and calm subjects separately, the results show that for aroused obese subjects, r = 0.63,p < 0.005. For low arousal obese subjects, r = 0.19 (NS). Thus, not surprisingly, it was only when the obese subject was aroused that his posteating affect level was related to the amount he ate. For both aroused and calm normals, there was no correlation between eating and arousal reduction (for high arousal normals, r = 0.09; for low arousal normals, r = 0.06). Manipulation Checks Half the subjects in each condition rated their arousal level on three 9-point bipolar scales following the arousal manipulation. Separate analyses of variance indicated that high arousal subjects, as compared with low arousal subjects, reported themselves to be considerably more anxious \F (1,32) = 9.57, p < 0.005], more upset [F (1,32) = 7.01,p< 0.02],andbelieved their heart was beating faster (F (1,32) = 10.39,
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p < 0.005 ]. There were no other significant self-ratings on arousal scales. For obese effects, however. Obese and normal sub- subjects, r = 0.89, p < 0.001; for normals, r jects did not differ in self-reported arousal = 0.50, p < 0.02. While both correlations level, and the presence or absence of a are quite high, further confirming the suclabel did not alter arousal level.1 cess of the manipulation, the significantly Those subjects in label conditions also stronger correlation for obese subjects, z = answered the open-ended question, "What 3.21, p < 0.002, suggests a greater tenddo you think produced your present heart ency for the obese to respond systematirate level?" Nineteen of these 20 subjects cally to this manipulation. said that the earphones had altered their Finally, the effects of receiving or not heart rate. No label subjects were not asked receiving manipulation checks on the dethis question, because it was expected to pendent variable were examined in a increase the likelihood that they would four-way analysis of variance. These data search for an arousal label. revealed no significant effects (allF < 1.0), Following the eating measure, all sub- and "check" and "no check" subjects were jects were asked why they thought they therefore pooled in all analyses. reacted as they did during the base-line measure. Perhaps because of the rather DISCUSSION ambiguous wording of the question, few subjects in label conditions (N = 6) attribTo recapitulate the major hypotheses for uted their arousal to the earphones. Instead, subjects gave reasons like "being in obese subjects, it was suggested that overa test" and "this strange room." Responses weight people respond to the experience were therefore coded as either "label" or of unlabeled, diffuse arousal by overeat"no label "responses. A label response was ing, while no such response was predicted considered any reason at all, while no label for labeled arousal states. A major function responses were answers of "don't know" of overeating was believed to be arousal or "no idea," etc. These data indicated that reduction. These hypotheses were 35 of the 40 subjects in label conditions confirmed: aroused obese subjects ate gave label answers, while only 8 of the 40 more than three times as much food in the no label subjects gave label responses [x2 unlabeled as in the labeled condition. = 33.99, p < 0.001). Obese and normal Furthermore, aroused obese subjects subjects did not differ in these response showed significant affect reduction following eating. On the other hand, normals patterns (x2 = 0.05). A different way to consider subjects' re- were not responsive to manipulations of sponsiveness to the experimental manipu- label. Instead, unlike the obese, they ate lations is to test the correlation between most when their stomachs were empty. In addition, normal subjects were sensitive to self-reported arousal level, al'The possibility that any obtained differences in sub- though their eating was not significantly jects' eating might be due to higher arousal in the no label condition was considered by comparing self- affected by the experimental manipulation reported arousal on all arousal scales in the high of arousal. This finding, coupled with the arousal label and no label conditions. These tests significantly higher correlations between revealed no significant effects (all F < 0.85), indicating that manipulations of arousal and label were not arousal measures for obese subjects, indiconfounded. cates that normals were less systematically Psychosomatic Medicine Vol. 38, No. 2 (March-April 1976)
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responsive to experimental manipulations than were the obese. This result, also reported by Rodin and Slochower (9), is consistent with the notion of increased external responsiveness in the obese group. The major hypothesis for this study concerned the eating of obese subjects, and the obtained data suggest that the conclusions of earlier investigators (12,1,7) should be modified. These authors found, at best, a weak tendency for the obese to eat more when anxious. In fact, the former two studies conclude that the obese do not overeat when aroused. It now appears that this conclusion is appropriate only when the obese subject's response to labeled arousal is considered, for the newly introduced condition of unlabeled arousal produced a significant increase in their eating. Thus, the eating behavior of the overweight person is affected by factors other than the salience of food cues. The potency of the food was not varied in this design, yet obese subjects ate different amounts in different conditions. It seems that the obese subject's relative insensitivity to his gastric state (which was again confirmed by these data) does not reflect a complete disregard for internal cues. Instead, it may be precisely his inability to identify hunger pangs as a discrete sensation that permits his "inappropriate" eating response to other internal states. These data suggest a model for the development of this eating pattern. It has been proposed by Bruch (3) that the potentially obese child was fed when he cried for reasons other than hunger, eventually producing the tendency to overeat when anxious. If the parental inclination to overfeed in response to stress is accompanied by a disinclination to explore the source of the distress, emotional insensitivity might result. This would suggest that the obese person is as incapable of correctly identify138
ing his emotional state as he is of labeling hunger pangs (15). It further seems plausible that the obese individual not only cannot identify discrete emotional states, but that he actually misinterprets these sensations as hunger pangs. In this sense, his eating response to unlabeled arousal may follow the intervention of a cognitive (mis)labeling mechanism. If this is correct, the tendency to overeat when diffusely anxious might be reduced by helping the obese patient to identify the specific emotional or nonemotional label for his internal state. Alternatively, some obese people may be perfectly aware of the fact that they eat when diffusely aroused, but may continue to do so because they "know" that eating will relieve their distress. For at least these individuals, alternative modes of stress reduction must be acquired before they will stop overeating in response to stress. Obesity is a state that varies widely in many respects, including degree of overweight, time of onset of obesity, stability of weight over time, the presence or absence of a clear medical cause (e.g., endocrine dysfunction) for the overweight, and the degree of neuroticism exhibited by the obese person. These data are not available for the sample tested here. One possibility that should be considered in future research studies is that the model developed here may be most relevant to only one of these subgroups (e.g., the unstable, somewhat neurotic, moderately obese group), while other subgroups may overeat in response to entirely different internal and external stimuli. In summary, an experiment was conducted to test the hypothesis that obese individuals respond to unlabeled or free-floating arousal by overeating, while no such response accompanies labeled arousal states. The results confirmed this
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EMOTIONAL LABELING AND OVEREATING hypothesis, and further indicated that eating serves a stress-reducing function for the aroused obese person. Thus, some new evidence was offered supporting a modified version of the psychosomatic theory of obesity. The manipulation of arousal used here (heart rate feedback) was designed to elicit arousal from as many participants as possible, and was therefore nonspecific in nature. Different obese people may be more likely to overeat in response to different emotional states (e.g., generalized anxiety, depression, or elation), however. Future research should explore the precise nature of the arousal state that produces eating in the obese sub-
ject. Nevertheless, these results point to a new weight-related line of research that may have practical implications. This article is based on a dissertation submitted to the Department of Psychology, Columbia University, in partial fulfilment 0/ the degree of Doctor of Philosophy, and was supported by National Science Foundation Grant GS-2317X to Morton Deutsch, thesis advisor. The author wishes to thank Professors Morton Deutsch and Harvey Hornstein for their help and encouragement, and Gary Bridge for his assistance in the data analysis.
REFERENCES 1. Abramson EE, Wunderlich RA: Anxiety, fear, and eating: A test of the psychosomatic concept of obesity. J Abnorm Psychol 79:317-321, 1972 2. Behnke AR, Osserman EF, Welham WC: Lean body mass. Arch Intern Med 91:585, 1953 3. Bruch H: Eating Disorders. New York, Basic Books, 1973 4. Frankenhaeuser M: Some aspects of research in physiological psychology, in Emotional Stress (edited by L Lennard). New York, American Elsevier, 1967 5. Goldstein D, Fink D, Mettee DR: Cognition of arousal and actual arousal as determinants of emotion. JPers Soc Psychol 21:41-51, 1972 6. Kaplan HI, Kaplan HS: The psychosomatic concept of obesity. J Nerv Ment Dis 125:181-201, 1957 7. McKenna RJ: Some effects of anxiety level and food cues on the eating behavior of obese and normal subjects. JPers Soc Psychol 22:311-319, 1972 8. Metropolitan Life Insurance Company: New weight standards for men and women. Stat Bull 40:1—4,1959 9. Rodin J, Slochower J: Fat chance for a favor: Obese-normal differences in compliance and incidental learning. J Pers Soc Psychol 29:557-565, 1974 10. Ross LD: Effects of manipulating the salience of food upon consumption by obese and normal eaters, in Obese Humans and Animals [edited by S Schachter, J Rodin). Washington D.C., Erlbaum Associates, 1974 11. Schachter S: Some extraordinary facts about obese humans and rats. Am Psychol 26:129-144, 1971 12. Schachter S, Goldman R, Gordon A: Effects of fear, food deprivation, and obesity on eating. J Pers Soc Psychol 10:91-97, 1968 13. Schachter S, Rodin J (eds.]: Obese Humans and Animals. Washington D. C., Erlbaum Associates, 1974 14. Schachter S, Singer JE: Cognitive, social and physiological determinants of emotional state. Psychol Rev 69:379-399, 1962 15. Stunkard AJ, Koch C: The interpretation of gastric motility: I. Apparent bias in the reports of hunger by obese persons. Arch Gen Psychiatry 11:74-82, 1964 16. Valins S: Cognitive effects of false heart rate feedback. J Pers Soc Psychol 4:400-408, 1966
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It was hypothesized that obese individuals respond to unlabeled high arousal by overeating, while no such response was predicted for labeled high arousal states. Obese and normal weight subjects were led to believe that they were hearing their own heart beat, and that it was either fast or slow. A label for this heart rate either was or was not provided, and subjects' eating behavior was measured unobtrusively. The results supported these hypotheses: aroused obese subjects ate more when they could not identify the cause of their arousal than when a label was known. When obese subjects were calm, the presence or absence of a label did not affect their eating. Furthermore, obese subjects showed significant affect reduction following eating. Normal weight subjects were not affected by the presence or absence of an arousal label. Instead, they ate more when they called themselves calm than when anxious, and more when hungry than when full.
INTRODUCTION
Recent investigations of the psychological factors producing overeating and obesity fall into two theoretical frameworks which stand in apparent conflict. One, initiated by Schachter, posits that overweight individuals are essentially unable to withstand the pressure of external, food-related cues, while their eating is believed to be relatively unaffected by both internal hunger and emotional states. In contrast to this emphasis on the external food environment in determining eating, psychosomatic theorists, most notably Bruch (3), point to the influence of early emotional experiences on the development of overeating as an anxiety-reducing mechanism [see Kaplan and Kaplan (6) for a review of this literature]. The psychosomatic position From the Department of Psychology, Hunter College, City University of New York, New York 10021. Received for publication July 28, 1975; revision received November 7, 1975.
focuses on precisely those internal, emotional factors that are disregarded in the theory of external responsiveness. There is substantial evidence concerning both the role of external cues in obesity (11,13) and the obese person's insensitivity to his internal gastric state (15). However, little experimental support is available for the notion that the obese individual eats when anxious. In one study, Schachter, Goldman, and Gordon (12) hypothesized that normal subjects would reduce their eating when aroused, because arousal inhibits the physiological correlates of hunger. Obese subjects, on the other hand, were thought to be unresponsive to their internal gastric state, and thus would not be affected by manipulations of arousal level. Subjects were threatened with severe or mild shock (high and low fear), and their eating was measured during a cracker "taste test." The results indicated that normal subjects ate more when calm than when frightened, while obese subjects ate the same amount in high and low fear conditions. Since obese subjects
Psychosomatic Medicine Vol. 38, No. 2 (March-April 1976) Copyright ° 1976 by the American Psychosomatic Society, Inc. Published by American Elsevier Publishing Company, Inc.
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did not report fear reduction following eating, it was also concluded that eating did not serve a stress reducing function for them. To clarify these findings, McKenna (7) either threatened subjects with direct physiological measurements or reassured them about the study, and measured their eating using either good or bland tasting food. Normal subjects ate significantly less when aroused than when calm. However, the obese group ate slightly more good food in high than in low arousal conditions (p < 0.10), while they ate nearly identical amounts of bland food independent of arousal state. Obese subjects also did not show arousal reduction following eating. Thus, only marginal support was offered for the psychosomatic position. In a different approach, Abramson and Wunderlich (1) argued that the psychosomatic hypothesis attributes overeating to a variety of neurotic rather than objective emotional reactions, and noted that the former studies had really manipulated objective fear rather than neurotic anxiety. Subjects were therefore either threatened with shock (fear condition) or were told that they would have difficulty forming deep personal relationships (anxiety condition). Eating was measured in a taste test. The results indicated that obese subjects ate about the same amount in all conditions. (Normal subjects did not respond to the anxiety manipulation appropriately, and their data were not discussed.) However, one implication of the psychosomatic notion that obesity is a manifestation of internal (and perhaps unconscious) conflicts is that the experiential anxiety state that triggers eating may be diffuse, and its source frequently not understood by the obese person. It seems
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plausible that it is precisely the "grossness" of the emotional reaction that results in overeating for the obese individual. However, tests of the psychosomatic hypothesis have thus far employed manipulations of the external environment that could allow subjects to label and to interpret their emotional state as, for example, fear of shock (14). Since obese subjects are highly responsive to external cues, they should be even more likely than normals to label their internal state according to the available external information. However, if the obese person experienced a diffuse, or free-floating anxiety state, his idiosyncratic eating response to high arousal might emerge. Furthermore, a likely consequence of overeating may be a reduction in emotional stress. These notions stand in contrast to both the theories discussed above. According to the Schachter position, the externally responsive obese subject should not be affected by either his arousal level or the presence or absence of a label for it; only variations in food salience should alter his eating. The psychosomatic position would predict an increase in eating when obese subjects are aroused; however, there is no direct support for our distinction between labeled and unlabeled arousal states. It is hypothesized that obese subjects will respond to both their arousal level and to the presence or absence of a label for it. Specifically, the aroused obese subject is expected to eat more when he lacks a label for this arousal state than when a label is known. When calm, the presence or absence of a label should not affect his eating, which should be at an intermediate level. Normal subjects' eating should parallel earlier findings; normals should eat more when calm than when aroused, and should not be affected by the label manipulation.
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EMOTIONAL LABELING AND OVEREATING cesses and were offered $2 to do so, 94% of those requested agreed to participate. Each potential subject completed a short form containing questions about height, weight, participation Overview of the Procedure in athletics, and experience with psychology courses Subjects were tested in a 2X2X2 factorial design: or experiments. Initial selection of subjects was based obese and normal weight subjects were either upon self-report of height and weight. Subjects were aroused or not aroused, and a label for their arousal eliminated if they participated in any sports (N = 6), either was or was not provided. The main dependent because their higher body weight is caused by inmeasure was the amount eaten during a task in which creased muscle rather than fat content (2). Students subjects could eat, doodle, or play with several toys with experience in psychology courses or studies [after Ross (10)]. This situation offered alternative were also eliminated (N = 8). (noneating) response choices to subjects, making eatAt the end of the study, subjects were weighed and ing simply one of several appropriate activities. A measured, and percent overweight was calculated second dependent measure was an index of arousal according to Metropolitan Life Insurance (8) weight reduction following eating. Checks on all manipula- norms. Forty moderately obese subjects, ranging betions were also obtained. However, since it seemed tween + 16% and +40% overweight (M = +25%), possible that asking subjects to introspect about their and 40 normal weight subjects, ranging between emotional state might alter the state itself, only half - 9 % and +9% overweight (M = +1.3%), were the subjects in each condition received these checks. selected. Following procedures outlined by SchachThe effects of receiving manipulation checks were ter, Goldman, and Gordon (12), subjects weighing later examined as a possible experimental effect. between +10% and +15% overweight (N = 5) were To manipulate arousal, subjects received false (fast eliminated, to more clearly differentiate obese from or slow) aural feedback of heart rate, which made it nonobese subjects. appear that they were actually hearing their own heart beat. There is evidence supporting the thesis that this feedback will cause subjects (1) to behave as Procedure if they are appropriately aroused and (2) to actually show physiological responses corresponding to apSubjects were randomly scheduled between 1:00 parent heart rate. In two studies, subjects who heard and 2:30 p.m. in order to minimize the effects of apparently increased heart rates to certain pictures of differential hunger on eating. When the subject arnude females rated those pictures as most desirable rived , he waited for 5 min before the study began (the IValins (16)1, and actually "tracked" the heart rate waiting period was necessary to reduce betweenfeedback, i.e., showed significantly greater deviation subject differences in initial heart rate). Each room from base-line heart rate during presentation of contained a pair of earphones and a complex piece of falsely elevated heart rates [Goldstein, Fink, and Met- electrical equipment (to enhance the believability of tee (5)]. In another study, Frankenhaeuser (4) found the forthcoming manipulations). that subjects who were injected with a placebo they Taped instructions introduced subjects to the exbelieved was a stimulant showed increased perimental concerns, the physiological correlates of physiological arousal, while subjects who thought thinking. The subject learned that his heart rate the placebo was a depressant showed decreased ar- would be measured as an index of physiological arousal. ousal. The experimenter then entered and attached The label manipulation employed a neutral label two electrodes to his arm andfinger,remarking, "By (noise level) to reduce the possibility that subjects the way, our machine doesn't have a sound interwould self-arouse further upon learning the source of mediate, so you'll be able to hear the sound of the their arousal. beats corresponding to your heart rate over the earphones. Just ignore them."
METHOD
Arousal Manipulation. This manipulation was Subjects disguised in a "base-line heart rate measurement." Male undergraduates were recruited from dor- The "heart beats" were actually prerecorded low fremitories at Columbia University. When students were quency tones generated on a moog synthesizer. In requested to participate in a study of cognitive pro- high arousal conditions, subjects heard beats varying
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JOYCE SLOCHOWER between 84 and 92 per minute for 2 min. Low arousal subjects heard beats varying between 66 and 74 per minute for 2 min. [These heart rates were established as high and low arousal by Goldstein, Fink, and Mettee (5)]. At the end of the measurement, subjects received feedback about their heart rate level on a five-item checklist, varying from "very slow heart rate" to "very fast heart rate." High arousal subjects learned their heart rates were "very fast" and low arousal subjects learned their heart rates were "slightly slow." Label Manipulation. Subjects in the label high arousal condition were then told, "We have found that the unusual noise level which is produced by wearing earphones in the laboratory tends to increase heart rate level. That is, your heart rate was probably affected by the sound conditions in your room." Low arousal subjects received identical instructions, except that they believed the noise would decrease rather than increase heart rate. No label subjects received no instructions at this point.
The thinking task lasted for 3 min. Subjects then completed a questionnaire containing checks on posteating arousal as well as secondary measures. After a suspicion probe (which revealed that no subject suspected the validity of the experimental manipulations or measures), subjects were debriefed. However, no references were made to obesity, to avoid upsetting overweight participants.
RESULTS Dependent Measures
The amount eaten by obese and normal subjects is presented in Table 1 and Fig. 1. An analysis of variance (Table 2) indicated first that obese and normal subjects did not differ in the amount of cashews Manipulation Checks. Half the subjects in each eaten overall. Furthermore, no main efcondition then completed a questionnaire containing fects emerged for manipulations of label or of arousal. Instead, a significant Subject x checks on both manipulations. Label interaction and a significant Subject Dependent Measures. The eating measure was x Label x Arousal interaction were redisguised in a "thinking task." The experimenter entered and placed several objects before the subject. vealed. In order to test the relative conThese included a tin containing 800 g of large tributions of obese and normal subjects to cashews. The taped instructions continued: these overall interactions, tests for simple For the next few minutes we would like you to main effects were conducted. The results think about the objects on the table. In this con- indicated that the Subject x Label interacdition, we will not specify which objects you tion was largely accounted for by the reshould think about. . . think about the toy, the sponsiveness of obese subjects, who ate marbles, the ball, the nuts, the paper and pencil, significantly more when they lacked a or think about only one or two of these . . . feel free to touch the objects, to doodle, or to eat the label for their arousal state than when a label was known (for obese subjects, F = nuts. 4.63, p < 0.05; for normals, F = 1.07). TABLE 1. Mean Grams of Cashews Eaten by Obese Furthermore tests for simple interaction and Normal Subjects effects indicated that the obese subject's responsiveness to the presence or absence High arousal Low arousal of a label occurred primarily when he felt Subjects No label Label No label Label aroused (for obese subjects,F = 3.03, p < 6.05 16.38 16.90 16.40 Normal 0.09; for normals,F = 1.3). Taken together, (8) a (9) (9) (8) the data indicate that, as predicted, Obese 26.10 7.60 15.80 13.85 aroused obese subjects ate significantly (10) (8) (9) (9) more when the arousal they experienced N = 10 in each experimental condition. was "free-floating" than when its source 3 Numbers in parentheses, represent the number of subwas known. In low arousal conditions, the jects w h o ate at least 1 g of cashews.
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CASHEWS EATEN
Fig. 1. Mean grams of cashews eaten by obese and normal subjects.
TABLE 2. Analysis of Variance for Grams of Cashews Eaten Source Subjects Arousal Label Subjects x arousa Subjects x label Arousal x label Ss x A x L
F 0.32 0.26 0.62 1.23 5.08" 0.18 4.15*
*p < 0.05. **p < 0.03. For all f tests, df = 1,72.
obese did not respond to the presence or absence of a label for arousal. Normal weight subjects were not significantly affected by either experimental manipulation. Another way to examine subjects' eating behavior is to consider what other, non-
manipulated variables might affect it, in order to gain a more precise picture of those factors that influence this behavior. To do this, stepwise multiple regression analyses were performed for obese and normal subjects separately. Entered into the regressions as additional variables were (1) a measure of hunger, to assess the responsiveness of subjects to their gastric state and (2) a measure of body weight, to provide information about the linearity of the overweight-eating relationship. The index of hunger was the number of hours since the last meal eaten by each subject (a comparison of the amount eaten by subjects in each condition indicated that subjects did not differ in the quantity eaten that day). Percent overweight was entered as the weight measure. In addition, the two experimentally manipulated variables of arousal and label were entered.
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The results indicated that, for both obese and normal subjects, the only variable significantly related to eating was pulled out in the first step. For obese subjects, neither hunger nor percent overweight was significantly related to eating. Only label was significant P 2 = 0.102,F (1,38) = 4.33, p < 0.04], indicating again that obese subjects ate most in unlabeled arousal conditions (R2 represents the multiple correlation squared, and indicates the proportion of variance in the dependent variable "explained" by association with the independent variable). This significant effect clearly masks the interaction of arousal and label for obese subjects. It was, unfortunately, impossible to conduct recursive regressions to clarify this finding because of the sample size. Results for normal weight subjects showed that only the nonmanipulated variable of hunger level was related to eating \R2 = 0.116, F (1,38) = 4.98,p < 0.03]; normals ate more when hungry than when full, and were unaffected by both experimental manipulations and by percent overweight. While the results for obese subjects support our hypotheses, the finding that normal subjects' eating was not affected by their arousal level contradicts the experimental predictions, as well as earlier research [cf. (12)]. To further investigate this relationship, a more precise measure of individual subject's reactions to arousal manipulations was obtained by correlating self-ratings of arousal with eating for those subjects receiving the manipulation check (N = 20). A significant correlation was revealed (r = -0.51, p < 0.05); normals ate less the more aroused they reported themselves to be. There was no correlation between self-reported arousal and eating for obese subjects (r = -0.03). A secondary hypothesis concerned the notion that for obese subjects, eating 136
would be followed by arousal reduction, while no such relationship was posited for normal weight subjects. To test this, subjects who received both pre- and posteating arousal checks were examined as two separate weight groups. An index of arousal reduction was obtained by subtracting post- from preeating scores. Correlated t tests indicated that obese subjects showed significant affect reduction following eating \M change score = 2.35, t (19) = 4.32, p < 0.001). For normals, the same comparison was nonsignificant [M change score = 0.85, t (19) = 1.89]. A more precise way to examine this relationship is to test the correlation between the amount eaten and degree of affect reduction for each weight group. For obese subjects r = 0.45, p < 0.05, while for normals r = -0.04. When this correlation is examined for aroused and calm subjects separately, the results show that for aroused obese subjects, r = 0.63,p < 0.005. For low arousal obese subjects, r = 0.19 (NS). Thus, not surprisingly, it was only when the obese subject was aroused that his posteating affect level was related to the amount he ate. For both aroused and calm normals, there was no correlation between eating and arousal reduction (for high arousal normals, r = 0.09; for low arousal normals, r = 0.06). Manipulation Checks Half the subjects in each condition rated their arousal level on three 9-point bipolar scales following the arousal manipulation. Separate analyses of variance indicated that high arousal subjects, as compared with low arousal subjects, reported themselves to be considerably more anxious \F (1,32) = 9.57, p < 0.005], more upset [F (1,32) = 7.01,p< 0.02],andbelieved their heart was beating faster (F (1,32) = 10.39,
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p < 0.005 ]. There were no other significant self-ratings on arousal scales. For obese effects, however. Obese and normal sub- subjects, r = 0.89, p < 0.001; for normals, r jects did not differ in self-reported arousal = 0.50, p < 0.02. While both correlations level, and the presence or absence of a are quite high, further confirming the suclabel did not alter arousal level.1 cess of the manipulation, the significantly Those subjects in label conditions also stronger correlation for obese subjects, z = answered the open-ended question, "What 3.21, p < 0.002, suggests a greater tenddo you think produced your present heart ency for the obese to respond systematirate level?" Nineteen of these 20 subjects cally to this manipulation. said that the earphones had altered their Finally, the effects of receiving or not heart rate. No label subjects were not asked receiving manipulation checks on the dethis question, because it was expected to pendent variable were examined in a increase the likelihood that they would four-way analysis of variance. These data search for an arousal label. revealed no significant effects (allF < 1.0), Following the eating measure, all sub- and "check" and "no check" subjects were jects were asked why they thought they therefore pooled in all analyses. reacted as they did during the base-line measure. Perhaps because of the rather DISCUSSION ambiguous wording of the question, few subjects in label conditions (N = 6) attribTo recapitulate the major hypotheses for uted their arousal to the earphones. Instead, subjects gave reasons like "being in obese subjects, it was suggested that overa test" and "this strange room." Responses weight people respond to the experience were therefore coded as either "label" or of unlabeled, diffuse arousal by overeat"no label "responses. A label response was ing, while no such response was predicted considered any reason at all, while no label for labeled arousal states. A major function responses were answers of "don't know" of overeating was believed to be arousal or "no idea," etc. These data indicated that reduction. These hypotheses were 35 of the 40 subjects in label conditions confirmed: aroused obese subjects ate gave label answers, while only 8 of the 40 more than three times as much food in the no label subjects gave label responses [x2 unlabeled as in the labeled condition. = 33.99, p < 0.001). Obese and normal Furthermore, aroused obese subjects subjects did not differ in these response showed significant affect reduction following eating. On the other hand, normals patterns (x2 = 0.05). A different way to consider subjects' re- were not responsive to manipulations of sponsiveness to the experimental manipu- label. Instead, unlike the obese, they ate lations is to test the correlation between most when their stomachs were empty. In addition, normal subjects were sensitive to self-reported arousal level, al'The possibility that any obtained differences in sub- though their eating was not significantly jects' eating might be due to higher arousal in the no label condition was considered by comparing self- affected by the experimental manipulation reported arousal on all arousal scales in the high of arousal. This finding, coupled with the arousal label and no label conditions. These tests significantly higher correlations between revealed no significant effects (all F < 0.85), indicating that manipulations of arousal and label were not arousal measures for obese subjects, indiconfounded. cates that normals were less systematically Psychosomatic Medicine Vol. 38, No. 2 (March-April 1976)
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responsive to experimental manipulations than were the obese. This result, also reported by Rodin and Slochower (9), is consistent with the notion of increased external responsiveness in the obese group. The major hypothesis for this study concerned the eating of obese subjects, and the obtained data suggest that the conclusions of earlier investigators (12,1,7) should be modified. These authors found, at best, a weak tendency for the obese to eat more when anxious. In fact, the former two studies conclude that the obese do not overeat when aroused. It now appears that this conclusion is appropriate only when the obese subject's response to labeled arousal is considered, for the newly introduced condition of unlabeled arousal produced a significant increase in their eating. Thus, the eating behavior of the overweight person is affected by factors other than the salience of food cues. The potency of the food was not varied in this design, yet obese subjects ate different amounts in different conditions. It seems that the obese subject's relative insensitivity to his gastric state (which was again confirmed by these data) does not reflect a complete disregard for internal cues. Instead, it may be precisely his inability to identify hunger pangs as a discrete sensation that permits his "inappropriate" eating response to other internal states. These data suggest a model for the development of this eating pattern. It has been proposed by Bruch (3) that the potentially obese child was fed when he cried for reasons other than hunger, eventually producing the tendency to overeat when anxious. If the parental inclination to overfeed in response to stress is accompanied by a disinclination to explore the source of the distress, emotional insensitivity might result. This would suggest that the obese person is as incapable of correctly identify138
ing his emotional state as he is of labeling hunger pangs (15). It further seems plausible that the obese individual not only cannot identify discrete emotional states, but that he actually misinterprets these sensations as hunger pangs. In this sense, his eating response to unlabeled arousal may follow the intervention of a cognitive (mis)labeling mechanism. If this is correct, the tendency to overeat when diffusely anxious might be reduced by helping the obese patient to identify the specific emotional or nonemotional label for his internal state. Alternatively, some obese people may be perfectly aware of the fact that they eat when diffusely aroused, but may continue to do so because they "know" that eating will relieve their distress. For at least these individuals, alternative modes of stress reduction must be acquired before they will stop overeating in response to stress. Obesity is a state that varies widely in many respects, including degree of overweight, time of onset of obesity, stability of weight over time, the presence or absence of a clear medical cause (e.g., endocrine dysfunction) for the overweight, and the degree of neuroticism exhibited by the obese person. These data are not available for the sample tested here. One possibility that should be considered in future research studies is that the model developed here may be most relevant to only one of these subgroups (e.g., the unstable, somewhat neurotic, moderately obese group), while other subgroups may overeat in response to entirely different internal and external stimuli. In summary, an experiment was conducted to test the hypothesis that obese individuals respond to unlabeled or free-floating arousal by overeating, while no such response accompanies labeled arousal states. The results confirmed this
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EMOTIONAL LABELING AND OVEREATING hypothesis, and further indicated that eating serves a stress-reducing function for the aroused obese person. Thus, some new evidence was offered supporting a modified version of the psychosomatic theory of obesity. The manipulation of arousal used here (heart rate feedback) was designed to elicit arousal from as many participants as possible, and was therefore nonspecific in nature. Different obese people may be more likely to overeat in response to different emotional states (e.g., generalized anxiety, depression, or elation), however. Future research should explore the precise nature of the arousal state that produces eating in the obese sub-
ject. Nevertheless, these results point to a new weight-related line of research that may have practical implications. This article is based on a dissertation submitted to the Department of Psychology, Columbia University, in partial fulfilment 0/ the degree of Doctor of Philosophy, and was supported by National Science Foundation Grant GS-2317X to Morton Deutsch, thesis advisor. The author wishes to thank Professors Morton Deutsch and Harvey Hornstein for their help and encouragement, and Gary Bridge for his assistance in the data analysis.
REFERENCES 1. Abramson EE, Wunderlich RA: Anxiety, fear, and eating: A test of the psychosomatic concept of obesity. J Abnorm Psychol 79:317-321, 1972 2. Behnke AR, Osserman EF, Welham WC: Lean body mass. Arch Intern Med 91:585, 1953 3. Bruch H: Eating Disorders. New York, Basic Books, 1973 4. Frankenhaeuser M: Some aspects of research in physiological psychology, in Emotional Stress (edited by L Lennard). New York, American Elsevier, 1967 5. Goldstein D, Fink D, Mettee DR: Cognition of arousal and actual arousal as determinants of emotion. JPers Soc Psychol 21:41-51, 1972 6. Kaplan HI, Kaplan HS: The psychosomatic concept of obesity. J Nerv Ment Dis 125:181-201, 1957 7. McKenna RJ: Some effects of anxiety level and food cues on the eating behavior of obese and normal subjects. JPers Soc Psychol 22:311-319, 1972 8. Metropolitan Life Insurance Company: New weight standards for men and women. Stat Bull 40:1—4,1959 9. Rodin J, Slochower J: Fat chance for a favor: Obese-normal differences in compliance and incidental learning. J Pers Soc Psychol 29:557-565, 1974 10. Ross LD: Effects of manipulating the salience of food upon consumption by obese and normal eaters, in Obese Humans and Animals [edited by S Schachter, J Rodin). Washington D.C., Erlbaum Associates, 1974 11. Schachter S: Some extraordinary facts about obese humans and rats. Am Psychol 26:129-144, 1971 12. Schachter S, Goldman R, Gordon A: Effects of fear, food deprivation, and obesity on eating. J Pers Soc Psychol 10:91-97, 1968 13. Schachter S, Rodin J (eds.]: Obese Humans and Animals. Washington D. C., Erlbaum Associates, 1974 14. Schachter S, Singer JE: Cognitive, social and physiological determinants of emotional state. Psychol Rev 69:379-399, 1962 15. Stunkard AJ, Koch C: The interpretation of gastric motility: I. Apparent bias in the reports of hunger by obese persons. Arch Gen Psychiatry 11:74-82, 1964 16. Valins S: Cognitive effects of false heart rate feedback. J Pers Soc Psychol 4:400-408, 1966
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