Sex differences and action scaling in overhead reaching

Specifications of affordances is independent of the anthropometric scale of the perceiver. It is therefore predicted that sex differences disappear wh en perceptual performance is scaled relative to the relevant physical prope rties of the system formed by performer and environment in a particular act ion. 24 women and 30 men mere compared for their ability to perceive the bo undaries for overhead reaching for a ball suspended above them. Perceived a nd actual maximum action boundaries were measured in two height conditions, with and without wearing 15-cm high blocks under their feet. On average th e men reached higher than the women; however, when perceived maximum reacha ble height was expressed as a ratio of actual maximum reachable height, the difference between the groups disappeared. The participants showed an iden tical fit between environment and performer in both height conditions. The results indicate that the specification of affordances for overhead reachin g is independent of the height and the sex of the performer.