Perceiving action boundaries: learning effects in perceiving maximum jumping-reach affordances.

Coordinating with another person requires that one can perceive what the other is capable of doing. This ability often benefits from opportunities to practice and learn. Two experiments were conducted in which we investigated perceptual learning in the context of perceiving the maximum height to which an actor could jump to reach an object. Those estimates were compared with estimates that perceivers made for themselves. In Experiment 1, participants initially underestimated the maximum jumping-reach height both for themselves and for the actor. Over time, without explicit feedback, the participants were able to improve estimates of their own maximum jumping-reach height, but estimates for the actor did not improve. In Experiment 2, participants observed the actor perform either an action related but nonidentical to jumping (lifting a weight by squatting) or a nonrelated activity (rotating the torso). The participants who observed the actor perform the related action were able to improve the accuracy of their perceptual reports for the actor's maximum jumping-reach height, but the participants who watched the actor perform the nonrelated task were unable to do so. The results indicate some degree of independence between perceived affordances for the self and others, suggesting that affordance judgments are not entirely dependent on or determined by characteristics of the perceiver.