title: Dual-task backward compatibility effects are episodically mediated.
abstract: In dual-task performance, the backward compatibility effect (BCE; faster Task 1 reaction time when Task 1 and Task 2 responses are compatible) is thought to represent automatic activation of Task 2 response information in parallel with attended Task 1 performance. Work by Hommel and Eglau (Psychological Research, 66, 260-273, 2002) has suggested the BCE relies on stimulus-response learning in long-term memory. Subsequent work by Ellenbogen and Meiran (Memory and Cognition, 36, 968-978, 2008), however, proposed that the BCE is mediated by Task 2 rules held in working memory (WM) during Task 1 performance. The present study aimed to dissociate these two theoretical claims. In Experiment 1, we assessed the effects of prior single-task practice with Task 1 or Task 2 of a subsequent dual-task paradigm. Where the WM-mediated model predicts both BCE and overall reaction time improvement relative to prior task practice, an episodic learning model makes divergent predictions for BCE based on the context specificity of prior Task 2 learning. Results showed a close fit with episodic predictions and contradicted WM model predictions. Experiment 2 examined the finer grained timecourse of BCE over initial development, subsequent interference of this initial learning on BCE development with new conflicting Task 2 response mappings, and finally reestablishment of BCE in the original dual task. Data again showed close agreement with long-term learning predictions. We argue in favor of an episodic account of the BCE, and consider implications of WM and episodic mechanisms of automatic response activation on other aspects of dual-task performance.
authors.affiliation: Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada. mgiammarco13@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Giammarco
authors.affiliation: Department of Psychology, St. Thomas University, 51 Dineen Drive, Fredericton, New Brunswick, E3B 5G3, Canada. sthomson@stu.ca.
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Thomson
authors.affiliation: Department of Psychology, Neuroscience & Behaviour, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada. watter@mcmaster.ca.
authors.forename: Scott
authors.initials: S
authors.lastname: Watter
mesh_terms: D000293:Adolescent; D003071:Cognition / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D061212:Memory, Episodic; D057567:Memory, Long-Term / Q000502:physiology; D008570:Memory, Short-Term / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D055815:Young Adult
keywords: Backward response compatibility; Divided attention; Dual-task processing; Episodic memory; Practice effects; Psychological refractory period; Working memory