title: Is it harder to switch among a larger set of tasks?
abstract: When stimuli afford multiple tasks, switching among them involves promoting one of several task-sets in play into a most-active state. This process, often conceptualized as retrieving task parameters and stimulus-response (S-R) rules into procedural working memory, is a likely source of the reaction time (RT) cost of a task-switch, especially when no time is available for task preparation before the stimulus. We report 2 task-cuing experiments that asked whether the time consumed by task-set retrieval increases with the number of task-sets in play, while unconfounding the number of tasks with their frequency and recency of use. Participants were required to switch among 3 or 5 orthogonal classifications of perceptual attributes of an object (Experiment 1) or of phonological/semantic attributes of a word (Experiment 2), with a 100 or 1,300 ms cue-stimulus interval. For 2 tasks for which recency and frequency were matched in the 3- and 5-task conditions, there was no effect of number of tasks on the switch cost. For the other tasks, there was a greater switch cost in the 5-task condition with little time for preparation, attributable to effects of frequency/recency. Thus, retrieval time for active task-sets is not influenced by the number of alternatives per se (unlike several other kinds of memory retrieval) but is influenced by recency or frequency of use.
authors.affiliation: School of Psychology, University of Exeter.
authors.forename: Félice
authors.initials: F
authors.lastname: van 't Wout
authors.affiliation: School of Psychology, University of Exeter.
authors.forename: Aureliu
authors.initials: A
authors.lastname: Lavric
authors.affiliation: School of Psychology, University of Exeter.
authors.forename: Stephen
authors.initials: S
authors.lastname: Monsell
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D003463:Cues; D004193:Discrimination Learning; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012660:Semantics; D055815:Young Adult