Virtually perfect time sharing in dual-task performance: Uncorking the central cognitive bottleneck

A fundamental issue foe psychological science concerns the extent to which people can simultaneously perform two perceptual-motor tasks. Some theorist s have hypothesized that skilled procedural decision making and response se lection for two or more tasks can proceed at the same time under adaptive e xecutive control. The three experiments reported here support this latter h ypothesis. Their results show that after relatively modest amounts of pract ice, at least some participants achieve perfect time sharing in the dual-ta sk performance of basic choice reaction tasks. The results also show that o bserved interference between tasks can be modulated by instructions about d ifferential task priorities and personnel preferences for darting (concurre nt) or cautious (successive) scheduling tasks. Given this outcome, future r esearch should investigate exactly when and how such sophisticated skills i n dual-task performance are acquired.