Novel methods of measuring and modifying perception of and satisfaction with body size: a clinical translational approach

Body dissatisfaction is a risk factor for subsequent eating disorders, weight gain and low mood. It is resistant to treatment and, untreated, predicts relapse to eating disorders. Measurement of its perceptual and cognitive components currently relies predominantly on self-report questionnaires. This thesis describes the development and testing of a novel brief intervention designed to change perception of and satisfaction with own body size. Three studies demonstrate and replicate the finding that whether one-off, or repeated over the course of a week, exposure to over- or normal- weight images leads to participants subsequently perceiving othersâ bodies as smaller, in comparison to those shown underweight bodies. One-off exposure to images of overweight, compared to normal or underweight, women also leads to participants viewing their own bodies as smaller, and being more satisfied with their body size; however, repeated exposure over the course of a week does not have this effect, and in fact leads to women perceiving their own bodies as larger. Such repeated exposure to over- rather than underweight bodies does however increase womenâs ideal body size. The thesis also describes two studies concerning the development and testing of novel measures of body size and satisfaction with body size in healthy women and those with an eating disorder. Using an Avatar to demonstrate real and ideal body size, and a novel behavioural measure of body satisfaction using outfits, both correlated well with existing measures of body size and satisfaction, and there were differences on these measures between individuals with and without eating disorders. The novel implicit tasks (Implicit Association Tasks and a Lexical Decision Task) also correlated with existing measures of body size and satisfaction, however, there were no differences on these measures between individuals with and without eating disorders. The findings suggest that exposure to images of women of different sizes is effective in changing perception of what constitutes a normal weight, but has less predictable effects in relation to perception of and satisfaction with own size. Implicit measures of body size and satisfaction do not appear to be useful in distinguishing between women with and without eating disorders, but a novel behavioural measure using outfits, and using Avatars to demonstrate perceived own size, does show promise.