Perceptualand Motor Skilh, 1990, 71, 1003-1010. O Perceptual and Motor Skills 1990

BODY-IMAGE DISTORTION A M O N G MALE A N D FEMALE COLLEGE A N D HIGH SCHOOL STUDENTS, A N D EATING-DISORDERED PATIENTS ' CARL R. GUSTAVSON A N D JOAN C. GUSTAVSON

Center for Environmental Studies Arizona State University ANDRES J. PUMARIEGA AND DIANE E . REINARZ

Department of Psychiatry and Behavioral Sciences Universiry of h s Medical Branch RACHEL DAMERON

ANDREW R. GUSTAVSON

Galveston

School of Medicine University of Texas Medical Branch Galveston

TODD PAPPAS

KEVIN McCAUL

Department of Anatomy and Neuroscience University of Texas Medical Branch Galveston

Department of Psychology North Dakota State University

Szlmmary.-For 179 male and female college and high school students, and 26 female eating-disordered patients body-image distortion was measured using a computer-based image-analysis of redrawn images of standardized human figures. Statistical analysis indicated that body-image distortion was the same for all groups. Body-image distortion was significantly and negatively related to weight:height ratio as a function of a simple polynomial. These results suggest this evaluation of distortion of body-image yields a quantitative measure reliably related to weight status but also suggests the technique, and possibly measurement of body-image distortion in general, may not be a valid &scriminator between eating-disordered and normal persons.

The diagnosis and treatment of individuals with eating disorders has emphasized the role of distorted perception of body-image in the pathogenesis of anorexia nervosa and bulimia. Bruch (1973), in her early work on anorexia nervosa, found that patients with this eating disorder overestimated the sizes of others' bodies. She felt that this was part of the patient's general tendency towards perceptual disturbance, including distortion of internal bodily sensations. Anorexic patients who overestimate their body sizes score high on measures of faulty internal sensitivity (Garner, Olmstead, Polivy, & Garfinkel, 1984). Garner and Garfinkel (1981) reviewed a number of other

'Address correspondence to Carl R. Gustavson, Ph.D., Center for Environmental Smdies, Arizona State University, Tempe, AZ 85287-1201.

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factors they thought might contribute to faulty body-size estimation by anorexics. These factors included avoidance of biological maturity and denial of their dness. Indeed, distortion of body size as a specific component of body-image distortion is included in the diagnostic criteria specified in DSM-III-R (American Psychiatric Association, 1988) for anorexia nervosa and bulimia. Little evidence exists, however, to suggest body-size distortion is a unique characteristic of individuals with eating disorders. Rather, evidence suggests such misperceptions are common among- normal individuals. For example, using silhouettes ranging from very thin to very fat, Fallon and Rozin (1985) showed that "normal" college women overestimated their own sizes. Halmi, Goldberg, and Cunningham (1977) on a visual size-estimation task found a related overestimation by normal female adolescents of their own body sizes. Greater overestimation was common among younger subjects. Halmi, et al. concluded maturation in cognitive development contributed to more accurate perception of body size. The present study compared the body-image distortion measured with a computer-based body-image-distortion technique found among women diagnosed as suffering from eating disorders to distortion measured in male and female high school and .college students.

Subjects One hundred ninety-five subjects participated. Twenty-six of these were recruited from a university-affiliated eating-disorders program, ranged in age from 14 to 37 yr. old, and were classified into several diagnostic groups: anorexia nervosa (n = 2), bulimia (n = l o ) , atypical eating disorder, with food restriction or binge eating (n = 6), compulsive overeating (n = 5), and other ~ s ~ c h i a t r idiagnosis c with eating problems present (n = 3). The diagnoses were established using DSM-III-R criteria (American Psychiatric Association, 1988), using either the Diagnostic Interview Schedule (Robins, Helzere, & Grougham, 1981) or the Diagnostic Interview Schedule for Children and Adolescents (Herjanic & Reich, 1982) as structured interviews. The nonclinical samples included 85 females, ages 14 to 24 yr., and 84 males, ages 14 to 26 yr., recruited from high school and college campuses in two middle-sized cities in the southwest and midwest United States. All nonclinical subjects reporting psychiatric diagnoses, recent serious illness, major surgery, or accident were excluded from our evaluation.

Materials and Procedures Body-image distortion was operationalized using a technique we have titled the Body-image Distortion Evaluation. The subjects were given a stapled card packet consisting of two 3-in. x 5-in. cards, each with a sex-

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B.I.D.E. Body Image Distortion Evaluation INSTRUCTIONS: Imagine that the two drawings in this booklet are you, at your current height. Using sharp solid clear lines, fedtaw the figure to make it look like you. When you are finished fill out the information on the back page. COWRIGHT

Carl R. Gustavson Psychiatric Ethology Laboratory T h e University o f Texas M e d i c a l Branch

I.D. # Today's Dale

-1-1 -

or

Your Initials

Inches What is your currenl h e i g h t ? Feet What is yourcurrenl w e i g h t ? Pounds

Age?-

Whal is the most you have weighed al lhis h e i g h t ? Pounds Whal is the least you have weighed at lhis h e i g h t ? Pounds Have you ever had a serious medical or psychialric illness?

Was this illness associated with any of the above weights? Which weight?

m

Copy Image Reduced:

Smaller than Actual Size

FIG. 1. Female fi re developed as a computer-based scaled reduction of mean measurements reported by ~ i f E e n t ,T i e y , and Bardagiy (19741, and presented to female subjects on 3- x 5-in. cards with tinted test instructions. Similar male figures were presented to male subjects. Reproduced witE permission of Carl R. Gustavson.

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appropriate line drawing of a person. One human figure is a frontal view, while the other is a side view. The human figures (see Fig. 1) were developed as computer-based scaled reductions of mean measurements of US men and women reported by Diffrient, Tdey, and Bardagjy (1974). Subjects were told to read the instructions on the front of the card packet (see Fig. 1) or told to imagine the figures represented them at their current height. They were instructed to alter the drawings using clear solid lines so the figures looked like themselves. Each subject was instructed to fill out the information requested on the back of the card packet (see Fig. l ) .

Scoring Quantification of body-image distortion was accomplished by digitizing each altered card image as a PCX (ZSoft Corporation, Marietta, GA) format graphics file at a resolution of 300 x 300 pixels per square inch (2.54 crn2), using a Canon IX-12 scanner (Canon, Lake Success, NY) interfaced to a ~andy@ (Tandy is a registered trademark of Radio Shack, Fort Worth, TX) 3000-HD computer. Publisher's Paintbrush (ZSoft Corporation, Marietta, GA) graphics software was used to erase the original figure lines, leaving only the subjects' alterations. General body areas were colored to code for head, upper torso (waist to neck), lower torso, arm(s), upper leg(s), and lower leg(s). We used a custom computer program to count the number of pixels corresponding to each colored area in the graphics file and to store these numbers as an ASCII text file. The ASCII text file information was then imported into sex-specific spreadsheets (Symphony, Lotus Development Co., Cambridge, MA). The spreadsheet formula structure we developed calculated the expected number of pixels for the whole body figure and for each body region (color). The number of pixels for the standard whole body figure and body regions were scaled on each subject's height and weight to produce expected whole-body and body-region values for each subject. The total number of pixels in the frontal view of the female Body-image Distortion Evaluation figure equaled 527,682. If a female subject of the same actual height as the figure represented on the card weighed 10% less than the figure represented on the card, that subject would be expected to produce a figure with 474,914 pixels. Similarly, if a female subject of the same actual height as the figure represented on the card weighed 10% more than the figure represented on the card, that subject would be expected to a figure with 580,914 pixels. Finally, if a female subject 10% shorter than the figure represented on the card weighed 10% less than the figure represented on the card, that subject would be expected to produce a figure with 527,682 pixels. Body-image distortion scores, as presented, are a percent deviation from expected score, calculated as the percent of pixels by individual color, or for the whole figure, divided by the expected number of pixels for each color, or

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for the whole figure, multiplied by 100, minus 100. A score of zero bodyimage distortion indicates that the person accurately altered the drawn figures to match the expected figure for his own weight and height; a score of a minus 10 (-10) indicates that the altered figure was 10% smaller than the expected figure, and a score of 10 indicates that the altered figure was 10% larger than expected. To make comparisons of body-image-distortion scores across persons of varying body statures, a percent deviation score for each subject was calculated by subtracting the individual's weight:height ratio (pounds [0.454 kg1:inches [2.54 cml) from the weight:height ratio of the Body-image Distortion Evaluation figure (Females = 145 1b:63.6 in.; Males = 172 lb:68.8 in.) divided by the Body-image Distortion Evaluation figure weight:height ratio multiplied by 100. Thus, a female with a weight:height percent deviation score of zero might weigh 155 Ib and be 68 in. tall or weigh 137 Ib and be 60 in. tall, while a male with a weight:height percent deviation score of zero might weigh 170 lb and be 68 in taU or weigh 150 lb and be 60 in. tall. A female with a weight:height percent deviation score of a minus 20 (-20) might weigh 124 Ib and be 68 in. tall or weigh 109 Ib and be 60 in. tall, while a male with a weight:height percent deviation score of a minus 20 (-20) might weigh 136 Ib and be 68 in. tall or weigh 120 lb and be 60 in. tall.

A response surface analysis (Hintze, 1989) was used to calculate the correlation between weight:height ratio scores and whole body-image-distortion scores for male, female, and eating disordered subjects to judge the best mathematical formula to describe the relationship between stature and distortion. Our analysis indicated no reliable differences among the distortion scores of these three groups when weight:height ratios were used as a covariate in a sequential analysis of covariance. The analysis did indicate that the relationship between body-image-distortion scores and weight:height ratio deviation scores was negative and reliable ( r = -.937, F,,,,, = 688.99, p < .0001). Fig. 2 shows the X and Y coordinate plots of individual subject's percent weight:height ratio deviation scores and percent body-image-distortion scores, and the X and Y coordinate plots of the significant regression curve of predicted body-irnage-distortion scores calculated from our analysis (probability of lack of fit, F,,,,,,, = .55, p = .97) at weight:height ratio deviations w i t h n the weight:height ratio deviations represented by our research samples (Hintze, 1989). Independent analyses using individual body-area-distortion scores also did not indicate reliable differences among the groups of subjects.

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Weight: Height Ratio Deviation Scores (Percent) FIG. 2. X and Y coordinate plots of individual subjects' percent weight:height ratio deviation scores and percent body-image distortion scores, and the X and Y coordinate plot of the regression curve of predicted body-image scores

Our results indicate that the Body-image Distortion Evaluation technique we developed and used for this study yields a quantitative measure of distortion reliably related to the weight status of the subjects we tested. Overweight subjects draw images smaller than expected even though the human figure on the test card is altered by increasing the size of the figure. Underweight subjects draw images larger than expected even though the human figure on the test card is altered by decreasing the size of the figure. Average weight subjects draw images which quite accurately reflect their own body proportions. The findings of our study: which are limited by the small number of patient subjects, and especially the small number of subjects in each diagnostic category, suggest our technique, or possibly body-image-distortion measurement in general, is less than promising as a clinical device. We observed no reliable body-image distortion differences between any two of the study groups. We had few difficulties associated with the subjects misunderstanding how to complete the test. The materials needed for each subject are inexpensive (25 cents per card set) and the test can be administered in group (classroom) or individual settings. While the technique requires sophisticated and moderately expensive equipment to score, learning how to operate the scoring programs has been reasonably simple for our laboratory staff. Scoring

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time ranges between 25 and 35 rnin. per test, but use of a computer with a faster clock speed than the one used for scoring in this study could reduce the time to 15 to 20 min. The person scoring the test requires about 10 min. to change the image once the altered drawing is digitized. From a technical viewpoint, the Body-image Distortion Evaluation yields a quantitative score of a subjective process which varies reliably with small changes in body stature and differentiates the direction of variations in body stature from average. The technique does not rely upon verbal communication so that demand characteristics of the test setting, and secondary motives of the subjects may influence the outcome of the final score less than when questions concerning perception of body stature are asked directly or indirectly in questionnaire or interview approaches. The technique may be the relationship between bodyuseful as a research tool for invest~ga~ing image and a variety of factors which may be associated with the perceptual processes of how persons view their physical stature. Cross-cultural and cross-subcultural comparisons may yield interesting estimates of how lifelong exposure to social ideas of desirability and resource availability influences the ways we see ourselves. A n n u d y repeated evaluations might yield estimates of the effects produced by fad, fashion, and resource change. Other computer-based image-analysis systems could be used to produce quantitative scores for magazine, newspaper, and video images presented to the public as comparison material for measuring fad and fashion changes. Investigation of age- and maturation-related variables would require development of new stimulus cards to retain the seeming advantages of the measurement approach we have taken in developing this technique. However, the availability of a reliable quantitative measure of subjective body-image during t h s period of rapid physical change may prove especially useful in understanding the processes of accommodation to growth as it differs from weight gain characteristic of later life. The results of our study call into question the use of body-image distortion as a criterion for the diagnosis of anorexia nervosa, bulimia, or atypical eating disorders, and the proposed etiological role that body-image distortion might play in the development of these disorders. Other researchers have suggested that dissatisfaction or distress about body-image distortion, not image distortion per se, sets aside individuals with eating disorders (Polivy, Herman, & Pliner, in press). Further research examining emotional elements of body-image distortion and their relationships to actual body stature and cognitive distortion of body-image for either psychiatric or normal subjects is indicated. However, like the subjective experience of body-image and body-image distortion, dissatisfaction may be better measured using an imagebased comparison than a verbal approach. Body dissatisfaction could possibly be quantified by malung a comparison between the score on the Body-image -

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Distortion Evaluation, and an image produced by asking the subject to alter the human figure on the cards to "look like themselves as they would like to look." REFERENCES AMERICANPSYCHIATRIC ASSOCIATION. (1988) Diagnostic and statistical manual of mental disorders. (3rd ed., rev.) Washington, DC: Author. BRUCH,H. (1973) Eating disorders: obesity, anorexia, and the person within. New York: Basic Books. DIFFRIENT,N., TILLEY,A. R., & BARDAGJY, J. C. (1974) Humanscale 1/2/3. Boston, MA: MIT Press. FALLON,A. E., & ROZIN,l? (1985) Sex differences in perceptions of desirable body shape. Journal of Abnormal Psychology, 94, 102-104. l? E. (1981) Body-image in anorexia nervosa: measurement, GARNER,D. M., & GILRRNKEL, theory, and clinical implications. International Journal of Psychiatric Medicine, 11, 263-234. GARNER,D. M., OLMSTEAD, M. P., POLIVY,J., & GARFINKEL, I? E. (1984) Comparison between weight-preoccupied women and anorexia nervosa. Psychosomatic Medicine, 46, 255-266. HALMI,K., GOLDBERG, S. C., & CUNNINGHAM, S. (1977) Perceptual distortion of body-image in adolescent girls: distortion of body-image in adolescence. Psychological Medicine, 7, 253-257. HERJANIC, B., & REICH,W. (1982) Development of a structural psychiatry interview for children. Jorrrnal of Abnormal Clinical Psychology, 10, 307-324. HINTZE,J. L. (1989) Number Cruncher Statistical System, Version 5.02. [Computer program] Kaysville, UT Author. POLIVY, J., HERMAN,C. P., & PLMER,l? (in press) Perception and evaluation of body-image: the meaning of body shape and size. In J. M. Olson & M. l? Zanna (Eds.), Self-inferenceprocesses: The Ontnrio Symposium. Vol. 6 . Hillsdale, NJ: Erlbaum. ROBINS,L. N., HELZERE,J. E., & GROUGHAM, J. (1981) The NIMH Diagnostic Interview Schedule: its history, characteristics and validity. Archives of General Psychiatry, 38, 381-389.

Accepted October 30, 1990.

Body-image distortion among male and female college and high school students, and eating-disordered patients.

For 179 male and female college and high school students, and 26 female eating-disordered patients body-image distortion was measured using a computer...
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