Processing resources in timing and sequencing tasks.

Subjects performed timing and sequencing tasks under separate (single-task) and concurrent (dual-task) conditions in two experiments. The timing task required the subjects to generate a series of 5-sec temporal productions. The sequencing task in Experiment 1 involved verifying reasoning statements that described the ordering of a pair of letters. The task in Experiment 2 involved monitoring a familiar event sequence and detecting omissions in that sequence. Comparisons of single-task and dual-task conditions showed a pattern of bidirectional interference. In each experiment, the concurrent sequencing task caused temporal productions to become more variable and longer. The concurrent timing task interfered with sequencing by lengthening response times to the reasoning statements (Experiment 1) and by lengthening response times to sequence omissions and reducing sensitivity at detecting the omissions (Experiment 2). The results suggest that time perception and sequence perception are related cognitive processes that rely on a common set of attentional resources.