Evidence for feedback dependent conscious awareness of action.

To investigate the sources of conscious awareness of action, participants made judgments about the initiation times of active and passive key press movements that were either forceful or soft. After each trial, participants made judgments about when they moved by reporting the position of a rotating clock hand at the time they pressed the key. Judgment error was calculated as the difference between the actual and judged time of movement. Results showed that awareness of action for both active and passive movements was anticipatory and identical and that judgments of forceful movements were less anticipatory than judgments of soft movements. This suggests that the signal underlying conscious awareness of movement initiation in this experiment was not premotor, but instead related to sensory feedback arising from the movement. This work, in conjunction with other studies, suggests that the brain can use various sources of information to make conscious decisions about the timing of actions and that the source(s) used depend on prevailing task and operator constraints.