Abstract
People naturally dance to music, and it has been shown that auditory perception facilitates generation of precisely timed body movements. Here we investigated the converse: Does initiating action enhance auditory perception of timing? Participants performed a temporal bisection task; they heard a sequence of three sounds (13 ms each) spread over 550 ms. The timing of the middle sound was randomly varied, and participants responded as to whether the middle sound was temporally closer to the first or last sound. The slope of the resultant psychometric function indicated the precision of temporal bisection. In the active condition, participants initiated each sound sequence (via a key press), whereas in the passive condition each stimulus sequence was initiated by the computer. White noise was played over headphones throughout the experiment to mask key-press sounds. Auditory temporal bisection was more precise in the active than in the passive condition. To determine whether action similarly facilitated visual perception of timing, we repeated the same experiment except that we replaced the brief sounds with brief flashes. Interestingly, visual temporal bisection was more precise in the passive than in the active condition. These opposite results for auditory and visual modalities indicate that the benefit of action in auditory timing perception could not be attributable to increased alertness or reduced temporal uncertainty that could have been caused by voluntarily initiating each stimulus sequence. Thus, we have demonstrated a reciprocal relationship between action and auditory perception; as auditory stimuli facilitate precisely timed action, action enhances auditory perception of timing. In contrast, visual timing perception is enhanced when attention is fully focused in the visual modality and is distracted by action. These results suggest that auditory timing operates synergistically with motor mechanisms, whereas visual timing operates most effectively when neural resources are fully engaged to visual perception.
NSF BCS0643191, NIH R01EY018197-02S1.