Personal ideal, cultural ideal and optimal attractiveness: Are these constructs for body size and shape the same or different?

There has been an assumption in the literature that the three concepts of ideal body shape (personal ideal, cultural ideal, and the most attractive body shape) are effectively the same percept. To test this presumption, 554 participants completed either a between- or within-subjects condition using a matrix of 32 bodies varying in two dimensions: muscle and adiposity. Three separate groups of participants were recruited to the between-subjects design and made only one of these judgements, whilst participants in the within-subjects version completed all three of these judgments. These bodies are based on 3D scans of 221 women’s bodies and so accurately represent the change in size and shape caused by changing body composition. The participants also completed a set of psychometric questionnaires to index the degree to which external concepts of body image have been internalised. The results show that in both conditions, all three judgements collapse onto the same average preferred body shape, with low adiposity and relatively high muscularity. However, this masked systematic differences in responses between personal ideals and the other body judgements, which may be explained by a difference in how information directly related to oneself is processed relative to more abstract third person judgements.