Body size aftereffects are adult-like from 7 years onward.

There is considerable evidence that adults' perception of body weight in others can be manipulated via visual exposure to multiple bodies at one or another weight extreme. No study has yet examined how early in childhood such visual adaptation aftereffects exist. We ran experimental adaptation tests with predominantly White British 11- and 12-year-olds, 14- and 15-year-olds, and adult men and women (Study 1; N = 181) and with 7- and 11-year-olds and adults (Study 2; N = 110).