The effect of divided attention on probe reaction time in multiple-task performance.

Examined information processing demands in 5 experiments in which a total of 72 candidates who were being processed for aircrew selection and pilot training performed a serial addition, pursuit tracking, or probe reaction time (PRT) task separately and in dual- and triple-task combinations. The experiments manipulated the assigned priority and the capacity requirements of the serial addition and tracking tasks. PRT is usually assumed to reflect spare processing capacity in dual-task studies and to increase with greater processing demands. Since PRT did not increase between dual- and triple-task conditions, results of the present studies suggest that PRT could be measuring spare capacity, which remained relatively constant as processing demands increased. Analogous data were reported by C. D. Wickens (see record 1976-09005-001) for a triple-task situation. These observations would not have been predicted by available models of divided-attention performance. (French summary) (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)