Psychological Medicine, 1990, 20, 973-975 Printed in Great Britain
PRELIMINARY COMMUNICATION
An electrophysiological correlate of Eating Attitudes Test scores in female college students JOSEPHINE F. WILSON1 AND JOY C. MERCER From the Department of Psychology, Wittenberg University, Springfield, Ohio, USA
Eating Attitudes Test (EAT) scores of forty female college students were compared to their electrodermal activity (EDA) responses when offered a plate of chocolate chip cookies. A significant positive correlation was detected between the EAT scores and the skin conductivity measures associated with the presentation of food. Women with the highest EAT scores also exhibited the greatest sympathetic nervous system responses to a plate of cookies. This finding supports the conclusion that the EAT is capable of identifying individuals who are preoccupied with food or anxious about eating. SYNOPSIS
INTRODUCTION Eating disorders are common on college campuses, especially among female students (Golden, 1986). Since both anorexia nervosa and bulimia are increasing in prevalence in the college population (Halmi et al. 1981), it is necessary to have diagnostic instruments that identify women with eating disorders and those at risk to become anorexic or bulimic. A number of instruments have been developed to measure bulimic and anorexic symptoms. Garner & Garfinkel (1979) constructed and validated the first objective measure, the Eating Attitudes Test (EAT), which identifies behaviour patterns associated with anorexia nervosa. The Compulsive Eating Scale or CES (Dunn & Ondercin, 1981) measures behavioural, attitudinal and affective traits associated with bulimia. The Eating Disorder Inventory (EDI) was developed later (Garner et al. 1983; Garner & Olmstead, 1986 a, b) to assess attitudinal and affective, as well as behavioural, characteristics associated with anorexia nervosa and bulimia. Two behavioural symptoms of anorexia nervosa included on the EAT scale are (1) avoiding food when hungry and (2) feeling anxious prior to eating. These symptoms suggest that the body's arousal system, or sympathetic 1 Address for correspondence: Dr Josephine F. Wilson, Department of Psychology, Wittenberg University, PO Box 720, Springfield, Ohio 45501, USA.
nervous system, is activated in anorexics when they confront food. The purpose of the present study was to determine whether women with anorexic symptoms, as identified by high EAT scores, experience autonomic arousal when offered a sugary, appetizing snack (a plate of chocolate chip cookies). In this study, an electrodermal activity (EDA) measure of skin conductance was used to indicate activation of the sympathetic nervous system. METHOD Subjects The subjects were 40 female college students who were enrolled in an introductory psychology class and who volunteered to participate in a study called 'Personality Profile'. Subjects ranged in age from 18 to 21 years. Of these subjects, three were college juniors, three were sophomores and 34 were freshmen. Materials and apparatus The EAT scale (Garner & Garfinkel 1979) was imbedded in a battery of published scales that included: Rotter's Internality/Externality Scale (Rotter, 1966), the Bern Sex Role Inventory (BSRI) (Bern, 1974), and the Women's Issues Attitudes Test (Burns, 1974). A personal history questionnaire was developed by the authors to obtain background information (e.g. age, grade point average, year in college, marital status,
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dating history) and was administered with the battery of scales. EDA measures were recorded using Human Relations Media's 'Biofeedback Microlab' (HRM Software, Pleasantville, NY) interfaced with an Apple He computer. Silver chloride electrodes (10cm in diameter) for measuring skin conductivity and computer hardware and software were provided with the 'Biofeedback Microlab'. To measure EDA, the 'Biofeedback Microlab' utilizes a constant-current circuit with a system current of 10 /tamps. The EDA measure was calibrated each day prior to the start of the experiment. Procedure
Subjects were scheduled individually for one 30minute session. When each subject arrived for her appointment, she was greeted by one of the experimenters (J.M.) and asked to complete a battery of'Personality Tests'. Each subject was initially given the personal history questionnaire, Rotter's Internality/Externality Scale, the EAT scale, and the Women's Issues Attitudes Test. These scales were always administered in the order listed above and subjects were assured that their responses would remain anonymous. When each subject had completed the first battery of questionnaires, electrodes were attached to the middle and ringfingersof her nondominant hand. The subject was then given the Bern Sex Role Inventory (BSRI) and a baseline measure of EDA was recorded in /tohm (or /isiemen) units forfiveminutes. While the subject was still answering the BSRI, the experimenter thanked the subject for her participation in the experiment and offered her a plate containing four chocolate chip cookies. The subject was instructed not to eat any cookies until after the experimental session. The plate of cookies was placed in front of the subject and her EDA level continued to be recorded until she finished the BSRI. When the subject indicated that she was finished, the electrodes were removed and the subject was urged to eat some cookies before she departed. RESULTS AND DISCUSSION Five out of the 40 subjects (12-5%) had a total score of 30 or above on the EAT, indicating that they may have an eating disorder or a strong
potential for one. A score of 30 was proposed by the EAT's authors (Garner & Garfinkel, 1979) as the standard criterion for identifying women with disordered eating or preoccupation with their weight. In agreement with this finding, Raciti & Norcross (1987) reported that 12% of their sample of college women scored 30 or higher on the EAT. For each subject, EDA measures were recorded every thirty seconds and then averaged to obtain pre- and post-cookie EDA levels. Each subject's averaged baseline, or pre-cookie, EDA measure was subtracted from her averaged EDA response to the plate of cookies in order to obtain an EDA difference score for each subject. Pre-cookie EDA averages ranged from 21 to 15-5/ 005) in cookie consumption was detected between subjects with high and low EAT scores. The major finding of this study, that subjects with high EAT scores react with high levels of sympathetic arousal when offered snack food, provides evidence that the EAT is a useful
Electrophysiological correlate of EA T scores
diagnostic tool capable of identifying college students who are preoccupied with food and/or anxious about eating. The college students who served as subjects in this study were not and had never been in treatment for an eating disorder. Unfortunately, because height and weight measures for the subjects were not obtained, it was impossible to calculate each subject's deviation from average weight and, hence, verify that they were or were not showing physical symptoms of anorexia nervosa. However, the electrophysiological measures obtained in this study do indicate that high EAT scores are related to activation of the sympathetic nervous system in the presence of food. It would be extremely informative to obtain EDA measures (or comparable measures of sympathetic nervous system activity) from anorexic patients in clinical treatment, as well as those who are in recovery, when they are presented with food. Additionally, because the EAT was not designed to identify individuals with bulimic disorders, generalizations cannot be made about the autonomic response of bulimics to food. Bulimics' EDA, or other electrophysiologial, responses to food should be compared to those of anorexics. These comparisons might suggest a psychophysiological method of diagnosing anorexia nervosa and bulimia, although EDA responses by themselves would probably not be specific enough to constitute a diagnostic test.
975
REFERENCES Bern, S. L. (1974). The measurement of psychological androgyny. Journal of Consulting and Clinical Psychology 42, 155-162. Burns, M. S. A. (1974). Life styles for women, an attitude scale. Psychological Reports 35, 227-230. Dunn, P. & Ondercin, P. (1981). Personality variables related to compulsive eating in college women. Journal of Clinical Psychology 37, 43-49. Garner, D. M. & Garfinkel, P. E. (1979). The Eating Attitudes Test: an index of the symptoms of anorexia nervosa. Psychological Medicine 9, 273-279. Garner, D. M. & Olmstead, M. P. (1986a). Scoring the Eating Disorders Inventory. American Journal of Psychiatry 143, 680. Garner, D. M. & Olmstead, M. P. (I986A). More on the Eating Disorders Inventory. American Journal of Psychiatry 143,805 806. Garner, D. M., Olmstead, M. P. & Polivy, J. (1983). Development and validation of a multidimensional eating disorder inventory for anorexia nervosa and bulimia. International Journal of Eating Disorders!, 15-34. Golden, B. R., Buzcek, T. & Robbins, S. B. (1986). Parameters of bulimia: Examining the Compulsive Eating Scale. Measurement and Evaluation in Counseling and Development 42, 85-91. Halmi, K. A., Falk, J. R. & Schwartz, E. (1981). Binge-eating and vomiting: a survey of a college population. Psychological Medicine 11,697-706. Raciti, M. C. & Norcross, J. C. (1987). The EAT and EDI: screening, interrelationships, and psychmetrics. International Journal of Eating Disorders 6, 579-586. Rotter, J. B. (1966). Generalized expectancies for internal versus external control of reinforcement. Psychological Monographs 80 (Whole No. 609, 1).
PRELIMINARY COMMUNICATION
An electrophysiological correlate of Eating Attitudes Test scores in female college students JOSEPHINE F. WILSON1 AND JOY C. MERCER From the Department of Psychology, Wittenberg University, Springfield, Ohio, USA
Eating Attitudes Test (EAT) scores of forty female college students were compared to their electrodermal activity (EDA) responses when offered a plate of chocolate chip cookies. A significant positive correlation was detected between the EAT scores and the skin conductivity measures associated with the presentation of food. Women with the highest EAT scores also exhibited the greatest sympathetic nervous system responses to a plate of cookies. This finding supports the conclusion that the EAT is capable of identifying individuals who are preoccupied with food or anxious about eating. SYNOPSIS
INTRODUCTION Eating disorders are common on college campuses, especially among female students (Golden, 1986). Since both anorexia nervosa and bulimia are increasing in prevalence in the college population (Halmi et al. 1981), it is necessary to have diagnostic instruments that identify women with eating disorders and those at risk to become anorexic or bulimic. A number of instruments have been developed to measure bulimic and anorexic symptoms. Garner & Garfinkel (1979) constructed and validated the first objective measure, the Eating Attitudes Test (EAT), which identifies behaviour patterns associated with anorexia nervosa. The Compulsive Eating Scale or CES (Dunn & Ondercin, 1981) measures behavioural, attitudinal and affective traits associated with bulimia. The Eating Disorder Inventory (EDI) was developed later (Garner et al. 1983; Garner & Olmstead, 1986 a, b) to assess attitudinal and affective, as well as behavioural, characteristics associated with anorexia nervosa and bulimia. Two behavioural symptoms of anorexia nervosa included on the EAT scale are (1) avoiding food when hungry and (2) feeling anxious prior to eating. These symptoms suggest that the body's arousal system, or sympathetic 1 Address for correspondence: Dr Josephine F. Wilson, Department of Psychology, Wittenberg University, PO Box 720, Springfield, Ohio 45501, USA.
nervous system, is activated in anorexics when they confront food. The purpose of the present study was to determine whether women with anorexic symptoms, as identified by high EAT scores, experience autonomic arousal when offered a sugary, appetizing snack (a plate of chocolate chip cookies). In this study, an electrodermal activity (EDA) measure of skin conductance was used to indicate activation of the sympathetic nervous system. METHOD Subjects The subjects were 40 female college students who were enrolled in an introductory psychology class and who volunteered to participate in a study called 'Personality Profile'. Subjects ranged in age from 18 to 21 years. Of these subjects, three were college juniors, three were sophomores and 34 were freshmen. Materials and apparatus The EAT scale (Garner & Garfinkel 1979) was imbedded in a battery of published scales that included: Rotter's Internality/Externality Scale (Rotter, 1966), the Bern Sex Role Inventory (BSRI) (Bern, 1974), and the Women's Issues Attitudes Test (Burns, 1974). A personal history questionnaire was developed by the authors to obtain background information (e.g. age, grade point average, year in college, marital status,
973
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J. F. Wilson and J. C. Mercer
dating history) and was administered with the battery of scales. EDA measures were recorded using Human Relations Media's 'Biofeedback Microlab' (HRM Software, Pleasantville, NY) interfaced with an Apple He computer. Silver chloride electrodes (10cm in diameter) for measuring skin conductivity and computer hardware and software were provided with the 'Biofeedback Microlab'. To measure EDA, the 'Biofeedback Microlab' utilizes a constant-current circuit with a system current of 10 /tamps. The EDA measure was calibrated each day prior to the start of the experiment. Procedure
Subjects were scheduled individually for one 30minute session. When each subject arrived for her appointment, she was greeted by one of the experimenters (J.M.) and asked to complete a battery of'Personality Tests'. Each subject was initially given the personal history questionnaire, Rotter's Internality/Externality Scale, the EAT scale, and the Women's Issues Attitudes Test. These scales were always administered in the order listed above and subjects were assured that their responses would remain anonymous. When each subject had completed the first battery of questionnaires, electrodes were attached to the middle and ringfingersof her nondominant hand. The subject was then given the Bern Sex Role Inventory (BSRI) and a baseline measure of EDA was recorded in /tohm (or /isiemen) units forfiveminutes. While the subject was still answering the BSRI, the experimenter thanked the subject for her participation in the experiment and offered her a plate containing four chocolate chip cookies. The subject was instructed not to eat any cookies until after the experimental session. The plate of cookies was placed in front of the subject and her EDA level continued to be recorded until she finished the BSRI. When the subject indicated that she was finished, the electrodes were removed and the subject was urged to eat some cookies before she departed. RESULTS AND DISCUSSION Five out of the 40 subjects (12-5%) had a total score of 30 or above on the EAT, indicating that they may have an eating disorder or a strong
potential for one. A score of 30 was proposed by the EAT's authors (Garner & Garfinkel, 1979) as the standard criterion for identifying women with disordered eating or preoccupation with their weight. In agreement with this finding, Raciti & Norcross (1987) reported that 12% of their sample of college women scored 30 or higher on the EAT. For each subject, EDA measures were recorded every thirty seconds and then averaged to obtain pre- and post-cookie EDA levels. Each subject's averaged baseline, or pre-cookie, EDA measure was subtracted from her averaged EDA response to the plate of cookies in order to obtain an EDA difference score for each subject. Pre-cookie EDA averages ranged from 21 to 15-5/ 005) in cookie consumption was detected between subjects with high and low EAT scores. The major finding of this study, that subjects with high EAT scores react with high levels of sympathetic arousal when offered snack food, provides evidence that the EAT is a useful
Electrophysiological correlate of EA T scores
diagnostic tool capable of identifying college students who are preoccupied with food and/or anxious about eating. The college students who served as subjects in this study were not and had never been in treatment for an eating disorder. Unfortunately, because height and weight measures for the subjects were not obtained, it was impossible to calculate each subject's deviation from average weight and, hence, verify that they were or were not showing physical symptoms of anorexia nervosa. However, the electrophysiological measures obtained in this study do indicate that high EAT scores are related to activation of the sympathetic nervous system in the presence of food. It would be extremely informative to obtain EDA measures (or comparable measures of sympathetic nervous system activity) from anorexic patients in clinical treatment, as well as those who are in recovery, when they are presented with food. Additionally, because the EAT was not designed to identify individuals with bulimic disorders, generalizations cannot be made about the autonomic response of bulimics to food. Bulimics' EDA, or other electrophysiologial, responses to food should be compared to those of anorexics. These comparisons might suggest a psychophysiological method of diagnosing anorexia nervosa and bulimia, although EDA responses by themselves would probably not be specific enough to constitute a diagnostic test.
975
REFERENCES Bern, S. L. (1974). The measurement of psychological androgyny. Journal of Consulting and Clinical Psychology 42, 155-162. Burns, M. S. A. (1974). Life styles for women, an attitude scale. Psychological Reports 35, 227-230. Dunn, P. & Ondercin, P. (1981). Personality variables related to compulsive eating in college women. Journal of Clinical Psychology 37, 43-49. Garner, D. M. & Garfinkel, P. E. (1979). The Eating Attitudes Test: an index of the symptoms of anorexia nervosa. Psychological Medicine 9, 273-279. Garner, D. M. & Olmstead, M. P. (1986a). Scoring the Eating Disorders Inventory. American Journal of Psychiatry 143, 680. Garner, D. M. & Olmstead, M. P. (I986A). More on the Eating Disorders Inventory. American Journal of Psychiatry 143,805 806. Garner, D. M., Olmstead, M. P. & Polivy, J. (1983). Development and validation of a multidimensional eating disorder inventory for anorexia nervosa and bulimia. International Journal of Eating Disorders!, 15-34. Golden, B. R., Buzcek, T. & Robbins, S. B. (1986). Parameters of bulimia: Examining the Compulsive Eating Scale. Measurement and Evaluation in Counseling and Development 42, 85-91. Halmi, K. A., Falk, J. R. & Schwartz, E. (1981). Binge-eating and vomiting: a survey of a college population. Psychological Medicine 11,697-706. Raciti, M. C. & Norcross, J. C. (1987). The EAT and EDI: screening, interrelationships, and psychmetrics. International Journal of Eating Disorders 6, 579-586. Rotter, J. B. (1966). Generalized expectancies for internal versus external control of reinforcement. Psychological Monographs 80 (Whole No. 609, 1).
