title: Dual-task performance with ideomotor-compatible tasks: is the central processing bottleneck intact, bypassed, or shifted in locus?
abstract: The present study examined whether the central bottleneck, assumed to be primarily responsible for the psychological refractory period (PRP) effect, is intact, bypassed, or shifted in locus with ideomotor (IM)-compatible tasks. In 4 experiments, factorial combinations of IM- and non-IM-compatible tasks were used for Task 1 and Task 2. All experiments showed substantial PRP effects, with a strong dependency between Task 1 and Task 2 response times. These findings, along with model-based simulations, indicate that the processing bottleneck was not bypassed, even with two IM-compatible tasks. Nevertheless, systematic changes in the PRP and correspondence effects across experiments suggest that IM compatibility shifted the locus of the bottleneck. The findings favor an engage-bottleneck-later hypothesis, whereby parallelism between tasks occurs deeper into the processing stream for IM- than for non-IM-compatible tasks, without the bottleneck being actually eliminated.
authors.affiliation: National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA, USA. mei.lien@oregonstate.edu
authors.forename: Mei-Ching
authors.initials: MC
authors.lastname: Lien
authors.forename: Robert S
authors.initials: RS
authors.lastname: McCann
authors.forename: Eric
authors.initials: E
authors.lastname: Ruthruff
authors.forename: Robert W
authors.initials: RW
authors.lastname: Proctor
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008960:Models, Psychological; D011597:Psychomotor Performance; D011930:Reaction Time; D012033:Refractory Period, Psychological