Body-shape adaptation cannot be explained by adaptation to narrow and wide rectangles.

Visual adaptation to certain body shapes alters visual perception of subsequently presented pictures of bodies. We investigated whether these effects can be explained by adaptation to low-level visual objects, ie narrow and wide rectangles. Participants (n = 29) adapted to manipulated photographs of their own bodies, depicting them either unrealistically thin or fat. The perceived shapes of their own bodies were subsequently assessed by an interleaved staircase paradigm. A second experiment (n = 29) used the same design to test for adaptation effects evoked by narrow and wide bars. After adapting to a thin picture of own body, participants also judged a thinner than actual body picture to be the most realistic and vice versa, resembling a typical aftereffect. Importantly, this effect could not be replicated by adaptation to narrow and wide bars, demonstrating that the body-shape aftereffect cannot be explained by adaptation to low-level properties. The results support the existence of a perceptual body-shape aftereffect, resulting from a specific adaptation to thin and fat body shapes.