title: Response-repetition effects in task switching - dissociating effects of anatomical and spatial response discriminability.
abstract: In task switching, response repetitions typically lead to performance benefits for task repetitions but costs for task switches. We examined whether this cost-benefit pattern is affected by response discriminability (RD), varying (a) the anatomical response separation (within-hand vs. between-hand responses) and (b) the spatial separation (close vs. far response keys). We assumed that anatomical RD increases response competition generally, whereas spatial RD increases the salience of left-right coding and thus facilitates response selection. In two experiments, we found that spatial RD increased the response-repetition costs in task switches but similarly decreased the response-repetition benefit in task repetitions. The effect of spatial RD was response-specific but did not interact with task switching. This data pattern is consistent with a recent account that proposed that facilitated response selection increases response "self-inhibition" after response execution. In contrast, the influence of anatomical RD primarily consisted of an overall increase of reaction-time level in all conditions, whereas error rates decreased, suggesting a general shift in response criterion. Taken together, the data suggest that a self-inhibition mechanism on the level of motor response codes contributes to response-repetition effects in task switching, which is possibly independent of task-specific mechanisms of strengthening of associations.
authors.affiliation: Institute of Psychology, RWTH Aachen University, Aachen, Germany. koch@psych.rwth-aachen.de
authors.forename: Iring
authors.initials: I
authors.lastname: Koch
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schuch
authors.forename: Kim-Phuong L
authors.initials: KP
authors.lastname: Vu
authors.forename: Robert W
authors.initials: RW
authors.lastname: Proctor
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*