Default processing of event sequences.

In a wide range of circumstances, it is important to perceive and represent the sequence of events. For example, sequence perception is necessary to learn statistical contingencies between events, and to generate predictions about events when segmenting actions. However, viewer's awareness of event sequence is rarely tested, and at least some means of encoding event sequence are likely to be resource-intensive. Therefore, previous research may have overestimated the degree to which viewers are aware of specific event sequences. In the experiments reported here, we tested viewers' ability to detect anomalies during visual event sequences. Participants viewed videos containing events that either did or did not contain an out-of-order action. Participants were unable to consistently detect the misordered events, and performance on the task decreased significantly to very low levels when performing a secondary task. In addition, participants almost never detected misorderings in an incidental version of the task, and performance increased when videos ended immediately after the misordering, We argue that these results demonstrate that viewers can effectively perceive the elements of events, but do not consistently test their expectations about the specific sequence of natural events unless bidden to do so by task-specific demands.