Abstract
We designed a two-person competitive reaching task in a naturalistic setting to compare the action reading ability of 6–8-year-old children and adults. Two participants faced each other separated by a Plexiglass screen. One (a confederate adult Attacker) was instructed to touch one of two targets on the screen, and the other (a child or an adult Blocker) was told to touch the same target as quickly as possible. In both children and adults, Blocker reaction times were fast, much faster than the reaction times to a dot projected on the screen moving in the same manner. These results suggest that Blockers use subtle preparatory movements of Attackers to predict their goal. Next, we occluded body parts of the Attacker to determine the location of the bodily cues used by adults and children to achieve fast reactions. Both children and adults reacted fast when only the torso and arms were visible. Adults also reacted fast when only the head and shoulders were visible, indicating that they were able to read the goal of the Attacker from the cues in the head and shoulders, but children did not. These results suggest that adult humans have knowledge of the biomechanical constraints of the bodily movements of others and use it to accurately predict actions. This ability is present but still developing in 6–8- year-old children.