Abstract
Navigating successfully through our visual environment often requires the efficient co-ordination of multiple tasks, and understanding how we accomplish such multi-tasking behaviours is necessary for optimizing our performance in these situations. In the current work, we investigated dual-task performance using the backward compatibility effect (BCE) present in the Psychological Refractory Period (PRP) paradigm: When performing two tasks, Task1 reaction times (RTs) are faster if Task1 and Task2 responses are compatible. The BCE is believed to provide evidence that Task2 response information is automatically activated in parallel with Task1 response selection, however, the mechanisms through which this effect arises have been debated. Hommel & Eglau (2002) proposed a central role for episodic processes, whereas Ellenbogen & Meiran (2008) provided evidence that Task2 rules held in working memory facilitate parallel processing. Through two multipart experiments utilizing a visual PRP paradigm, we demonstrate a dissociation of these conflicting theories, and provide novel evidence in favour of an episodic model. In Experiment 1 we observed the selective development of BCEs following varying degrees of prior single-task practice. These results confirm the predictions of an episodic model, and contrast those of a working memory model: both BCEs and overall improvements in RT should occur, regardless of the context of prior practice. In Experiment 2 we further examined the time course of the development of BCEs through initial BCE development, followed by interference of initial learning on BCE development (through the introduction of novel, conflicting Task2 rules), and finally the re-establishment of BCEs through implementation of the original task. The presence of selective proactive interference effects from prior learning again provides evidence in favour of an episodic model. This work clarifies the role of episodic mechanisms in aiding efficient, parallel processing, while considering the role of working memory in contributing to additional aspects of dual-task performance.
Meeting abstract presented at VSS 2014