Seminar Series

Task set and attention: Facilitation and suppression of competing tasks

Switching between mutually incompatible S-R tasks (e.g., add-3 vs. subtract-2; object-naming in English vs. French; colour-naming vs. word-reading in response to a 'Stroop' stimulus, etc) results in large time-costs in RT. It seems natural to interpret these RT 'switch costs' as reflecting the time taken to get 'set' - i.e., to reconfigure the processing system for one task vs another. I will describe four new experiments (and a couple of old ones) that show this interpretation cannot be correct. I will argue that the performance-costs of task-switching are involuntary PRIMING effects ('task set inertia') from preceding S-R mappings: persisting facilitation of the prior task and persisting suppression of the upcoming ('intended') task. Task suppression can be very long-lasting. These task-priming effects include both higher-order priming (of task processing pathways) and stimulus- or item-specific cuing of task operations. (authors: Alan Allport and Glenn Wylie)