Coordinating information from perception and working memory.

Individuals must often coordinate information in working memory with information from perception. The demands of coordination have been analyzed in terms of the cost to switch attention. Coordination is considered in terms of the organization of control processes. Ss in 4 experiments performed list-processing tasks that sometimes required alternation between sets of items that were held in working memory or were currently displayed. Experiment 1 demonstrated that performance was slower and more error-prone when alternating between sets than when reporting a single set. On alternation tasks, latency varied with serial position, indicating that Ss paused between pairs of responses. In Experiment 2, this serial position function was observed for tasks requiring alternation between sets of information in the same modality (memory or perception). Experiments 3 and 4 demonstrate that this effect depends on the requirement to generate a new sequence of responses. A model of control processes for coordination is developed and tested.