Visual adaptation aftereffects for muscularity are body-part specific

Visual adaptation to extreme body types is known to produce contrastive adaptation aftereffects on the subsequent perception of human bodies. This approach has been exploited to probe the perceptual mechanisms underlying body perception by measuring the extent to which aftereffects occur when the adapting and test stimuli differ in specific characteristics (cross adaptation). The present study used this approach to investigate the body-part specificity of adaptation to body muscularity. Participants made judgments of the muscularity of torsos and arms both before and after adaptation to muscular torsos (Experiment 1) or muscular arms (Experiment 2). Across experiments, we report a double dissociation in the effects of adaptation. In Experiment 1, adaptation to muscular torsos produced aftereffects for torso judgments, but not arm judgments. In Experiment 2, adaptation to muscular arms produced aftereffects for arm judgments, but not torso judgments. These results demonstrate body-part specificity of the visual mechanisms underlying perception of body muscularity.