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Many researchers have employed secondary tasks, which have to be performed in parallel with a primary task requirement, to examine how successful task selection is accomplished in the context of task switching. The influence of such a secondary task on the observed switch cost (i.e., the cost arising when the currently relevant task differs from the task performed most recently) is seen as indicative that cognitive processes such as self-instruction are involved. Most secondary tasks chosen so far have required the repeated utterance of a word or syllable or a rhythmic movement of the foot. In the present study, we manipulated the dynamics of the to-be-performed secondary task (i.e., a repeated utterance or movement, or a static task that involved similar muscles—holding a spattle in the mouth or pressing keys). Additionally, we tested for modality-specific influences by asking participants to perform a dynamic or nondynamic (i.e., static) secondary task with two effector systems, namely oral and manual. Overall, our secondary tasks led to a reduced (rather than an increased) switch cost, as compared to a control condition without any secondary task. This reduction in switch cost was dependent on the secondary-task dynamics but independent of the effectors involved, showing larger switch-cost reductions for dynamic secondary tasks. To explain this finding, we suggest that performing secondary tasks interferes with the formation of episodic-memory traces that would lead to retrieval benefits in the case of a task repetition, so that our reduced task-switch costs actually represent reduced repetition benefits. [ABSTRACT FROM AUTHOR]

Working memory (WM) holds and manipulates representations for ongoing cognition. Oberauer ( Psychology of Learning and Motivation, 51, 45-100, 2009) distinguishes between two analogous WM sub-systems: a declarative WM which handles the objects of thought, and a procedural WM which handles the representations of (cognitive) actions. Here, we assessed whether analogous effects are observed when participants switch between memory sets (declarative representations) and when they switch between task sets (procedural representations). One mechanism assumed to facilitate switching in procedural WM is the inhibition of previously used, but currently irrelevant task sets, as indexed by n-2 task-repetition costs (Mayr & Keele, Journal of Experimental Psychology: General, 129(1), 4-26, 2000). In this study we tested for an analogous effect in declarative WM. We assessed the evidence for n-2 list-repetition costs across eight experiments in which participants switched between memory lists to perform speeded classifications, mental arithmetic, or a local recognition test. N-2 list-repetition costs were obtained consistently in conditions assumed to increase interference between memory lists, and when lists formed chunks in long-term memory. Further analyses across experiments revealed a substantial contribution of episodic memory to n-2 list-repetition costs, thereby questioning the interpretation of n-2 repetition costs as reflecting inhibition. We reanalyzed the data of eight task-switching experiments, and observed that episodic memory also contributes to n-2 task-repetition costs. Taken together, these results show analogous processing principles in declarative and procedural WM, and question the relevance of inhibitory processes for efficient switching between mental sets. [ABSTRACT FROM AUTHOR]

The aim of the present study was to examine the contribution of overlapping response sets to the occurrence of task inhibition, measured as n-2 task repetition cost. We had subjects switch among four tasks. Three tasks overlapped on both stimulus set and response set. A fourth, neutral, univalent task never overlapped on the stimulus set but, across three experiments, varied in terms of the degree of overlap in the response set. We found that overlap in response set affects task inhibition. We suggest that response set overlap increases the competition among tasks and, thus, triggers task inhibition to resolve this competition. [ABSTRACT FROM AUTHOR]