Time in action contexts: learning when an action effect occurs

Participants who showed a bias for left or right responses were excluded as an unbalanced choice of left and right actions resulted in an unbalanced number of short and long delays. For example, the participant with the most extreme bias pressed the left key almost three times more often than the right key and as a result experienced the action-effect delay of 400 ms 280 times in the valid delay condition (296 times overall) and the delay of 1,200 ms 104 times in the valid delay condition (148 times overall). We assume that this bias may hamper the acquisition of the long delay and thus excluded participants with a significant bias toward one key. Nevertheless, we repeated the same within-subject analyses conducted in the results section including the six excluded participants. ANOVAs on RTs and anticipatory responses revealed that including the six participants did not change any main effects or interactions. That is, both analyses on RTs and anticipatory responses showed significant main effects of delay and validity of delay as well as an interaction of delay and validity of delay (all ps ≤ 0.002) and no other significant main effects or interactions.