Tuning in to another person's action capabilities: perceiving maximal jumping-reach height from walking kinematics

Three experiments investigated the ability to perceive the maximum height to which another actor could jump to reach an object. Experiment 1 determined the accuracy of estimates for another actor's maximal reach-with-jump height and compared these estimates to estimates of the actor's standing maximal reaching height and to estimates of the perceiver's own maximal reaching and reach-with-jump height. Perception of another actor's maximum reach-with-jump height was less accurate than the other estimates, but still accurate to within 8% error. The actor's reach-with-jump height was modified in Experiment 2 by attaching weights around the actor's ankles. Perceivers, who were explicitly aware of the manipulation, adjusted their maximum reach-with-jump estimates for the actor accordingly. In Experiment 3, perceivers were not explicitly aware of the weight manipulation, but provided significantly lower maximum reach-with-jump estimates after watching the actor walk while wearing the weights compared to estimates obtained after watching the actor walk while not wearing the weights. The results suggest that the actor's walking pattern was informative about the actor's capacity to produce a different action, jumping to reach an object.