Can you see me in the snow? Action simulation aids the detection of visually degraded human motion

Using a novel paradigm, we demonstrate that action simulation can directly facilitate ongoing perception of people's movements. Point-light actors (PLAs) representing common human motions were shown embedded in a visual noise reminiscent of "TV snow". At first, the PLAs were perceived clearly, then occluded from view for a short duration, during which it was hypothesized that a real-time action simulation was generated tracking the motion's course. The PLA then reappeared in motion at variable visibility against the noise, whilst detection thresholds for the reappearance were measured. In the crucial manipulation, the test motion was either temporally congruent with the motion as it would have continued during occlusion, and thus temporally matching the simulation, or temporally incongruent. Detection thresholds were lower for congruent than for incongruent reappearing motions, suggesting that reappearing motion that temporally matched the internal action simulation was more likely to be detected.