<p>Research on backward response compatibility effects (Task 2-to-Task 1 response priming) in the Psychological Refractory Period (PRP) paradigm has suggested that compatibility effects arise from episodic representations of Stimulus-Response (S-R) pairings (Hommel & Eglau, 2002). However, more recent work suggests that these effects are mediated by S-R rules held online in working memory during dual task performance (Ellenbogen & Meiran, 2008). We sought to dissociate these accounts. In Experiment 1, we observed the development of backward response compatibility effects over time in a common PRP task, following varying degrees of prior single task practice of the PRP component tasks. In Experiment 2, we trained participants on a PRP dual task, and then switched Task 2 to one of three different tasks with variable response mapping overlap with the original Task 2, before finally reverting back to the original PRP tasks. Backward response compatibility effects appeared initially, were abolished during the subsequent interference phase, and then reappeared with the original PRP task. Despite equivalent overall performance across conditions suggesting successful task rule instantiation in working memory to guide task performance, backward response compatibility effects were selectively absent in conditions where current S-R rules were mapped in conflict with prior S-R experiences within the experiment. Both experiments provide evidence in favour of an episodic account of backward response compatibility effects, in which prior learning influences subsequent performance in contextually relevant situations. Implications for the understanding of backward response compatibility mechanisms and parallel processing in the PRP paradigm are discussed.</p> / Master of Science (MSc)