Perception of speed-accuracy trade-offs in action

The way speed and accuracy trade off in human movement is well  described by Fitts' law. The aim of the study I will discuss was to  determine whether this law also holds for the perception of movement.  Participants were shown displays of a person moving at various speeds  between two targets that could vary in amplitude and width, and were  asked to judge whether the person could perform such movements  without missing the targets. Perceived movement times, defined in  terms of the speeds at which participants provided an equal  proportion of .possible. and .impossible. judgments, were successfully predicted by the index of difficulty of the movements,  as stated by Fitts. law. Two subsequent experiments showed that this  law also holds for the perception of non-human objects that resemble  the human body, but it does not affect the perceived speed of human  movement. These findings are consistent with an action-simulation  account of action perception.