RECONFIGURATION OF PROCESSING MODE PRIOR TO TASK-PERFORMANCE

Participants performed choice reaction time (RT) tasks on 2-dimensiona l stimuli such that each task was based on 1 stimulus dimension. A cue preceded the target stimulus and instructed the participant about whi ch (randomly selected) task to perform. Shifting between tasks was ass ociated with an RT cost, which was larger when the (randomly varying) cue-target interval was short as opposed to when it was long. Cue-targ et interval was not confounded with the remoteness from the previous t rial. Hence, it affected the task-shift cost through preparation rathe r than by allowing carryover effects to dissipate. Similar results wer e obtained for 2 location tasks and for the object-based tasks (color and shape discrimination). They indicate a time-effort consuming proce ss that operates after a task shift, precedes task execution, and pres umably reflects the advance reconfiguration of processing mode.