EPIC Computational Models of Psychological Refractory-Period Effects in Human Multiple-Task Performance,

Perceptual-motor and cognitive processes whereby people perform multiple concurrent tasks have been studied through an overlapping-tasks procedure. During this procedure, two successive choice-region tasks are performed with a variable interval stimulus onset asynchrony, or SOA between the beginning of the first and second tasks. Subjects reaction times RTs for Task 2 are typically greater after very short SOAs. The RT increase, called the psychological refractory-period PRP effect, reveals basic characteristics of multiple-task performance. In the present report, quantitative computational models are formulated to explain and predict the PRP effect together with other related phenomena on the basis of the EPIC information-processing architecture, a theoretical framework for precisely modeling human performance under representative single-task and multiple-task conditions Kieras Meyer, 1994, Tech. Report TR-94ONR-EPIC-1. Computer simulations with these models suggest that the PRP effect may stem from subjects task strategies and limitations on their peripheral perceptual-motor resources, rather than from a cognitive decision or response-selection bottleneck. The goodness-of-fit between simulated and empirical data documents the EPIC architectures utility for understanding and characterizing human multiple-task performance.