Process interference and code overlap in dual-task performance.

Perceptual encoding processes have recently been shown to interfere with response selection in dual tasks (P. Jolicoeur & R. Dell'Acqua, 1998). Spatial cross-task compatibility (CTC) was varied to additionally manipulate code overlap across tasks. A new response-cuing paradigm was devised, in which a stimulus movement was used for later report in a perceptual task and a finger movement was used as response in a logically independent reaction task. Three experiments were conducted showing dual-task process interference, but shorter reaction times with CTC than without were also observed. This CTC priming effect was largest with high temporal overlap between the perception and reaction stimuli. The CTC effect was interpreted as resulting from overlap of code activation across tasks, whereas process interference seems to occur to prevent temporal overlap on the level of perceptual encoding and response retrieval processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)