Perceiving the affordance of interceptability for multiple others

Previous research has demonstrated that people can perceive the affordance of interceptability not only for themselves but also for another person. In the present study we explored whether they could do so for multiple others. To this end, we asked one group of 12 participants (the "actors") to attempt to intercept balls moving along various trajectories downwards across a large screen by moving an on-screen paddle along a horizontal interception axis. By manipulating the paddle's maximum reachable distance, we introduced an action boundary beyond which balls could not be intercepted. A selection of each actor's recorded interception attempts, sampled around this action boundary, was subsequently played back to another group of 12 participants (the "observers"), half of which had previously participated in an actor-type session themselves. On each trial, observers thus viewed the temporal unfolding of some actor's ball-and-paddle kinematics, with the last 25% of the trial being occluded to make the trial outcome unavailable to them. At the end of each trial, observers judged whether an actor would have been able to intercept the ball or not using the 2AFC method. Observers demonstrated an overall 72% accuracy in their judgments, indicating that they could reliably perceive the affordance of interceptability for the twelve actors. We conclude that in our task information about the interceptability for another individual resides in the unfolding ball-and-paddle kinematics. This information appears to be quite salient, as observer accuracy was not affected by whether they had previously performed the constrained interception task themselves or not.