A Computational Theory of Executive Cognitive Processes and Multiple-Task Performance: Part 2. Accounts of Psychological Refractory-Period Phenomena

Further simulations of human multiple-task performance have been conducted with computational models that are based on the executive-process interactive control (EPIC) architecture introduced by D. E. Meyer and D. E. Kieras (1997a ). These models account well for patterns of reaction times and psychological refractory-period phenomena (delays of overt responses after short stimulus onset asynchronies) observed in a variety of laboratory paradigms and realistic situations. This supports the claim of the present theoretical framework that multiple-task performance relies on adaptive executive control, which enables substantial amounts of temporal overlap among stimulus identification, response selection, and movement-production processes for concurrent tasks. Such overlap is achieved through optimized task scheduling by flexible executive processes that satisfy prevailing instructions about task priorities and allocate limited-capacity perceptual-motor resources efficiently.