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In many task-switch studies, task sequence and response sequence interact: Response repetitions produce benefits when the task repeats but produce costs when the task switches. Four different theoretical frameworks have been proposed to explain these effects: a reconfiguration-based account, association-learning models, an episodic-retrieval account, and a priming and inhibition account. The main goal in the present study was to test the unique prediction of the priming and inhibition account that stimulus categories remain active from one trial to the next, thus counteracting the negative effects of response inhibition in task-repetition trials. As testing this prediction required a somewhat untypical task-switch design, a second aim in the present study consisted in evaluating the generality of the alternative models. In the present experiments the task-switch paradigm was modified to include trials in which pure stimulus-category repetitions could occur. Across 3 experiments, benefits were observed for stimulus-category repetitions in task-switch trials, a prediction that conforms only to the priming and inhibition account and the reconfiguration account. However, the benefits in task-repetition trials were consistently smaller than the benefits in task-switch trials. This effect is in line only with the predictions from the priming and inhibition account. Thus, the current results support the notion of stimulus-category priming and response inhibition as the 2 mechanisms causing the opposite response-repetition effects in task-repetition and task-switch trials.

The article investigates the relation between declarative and procedural working memory (WM; Oberauer, 2009). Two experiments test the assumption that representations in the two subsystems are selected for processing in analogous ways. Participants carried out a series of decisions on memorized lists of digits. For each decision, they had to select declarative and procedural representations. Regarding declarative representations, participants selected a memory set and a digit within this set as the input to each decision. With respect to the procedural representations, they selected a task set to be applied to the selected digit and a response within that task set. We independently manipulated the number of lists and the number of tasks to be switched among (one, two, or three; Experiment 1) and preparation time for a list switch (Experiment 2). For three effects commonly observed in task-switch studies, analogues in declarative WM were found: list-switch costs, mixing costs, and residual switch costs. List- and task-switch costs were underadditive, suggesting that declarative and procedural representations are selected separately and in parallel. The findings support the hypothesis of two analogous WM subsystems. [ABSTRACT FROM PUBLISHER]

Under task switch conditions, response repetitions usually produce benefits if the task also repeats, but costs if the task switches. So far, it is largely undecided how to account for these effects. In the present study, we provide additional evidence in favor of the account that each response is inhibited in order to prevent its accidental re-execution. To test this hypothesis, the risk of an accidental re-execution of a given response was manipulated by modulating the activation of the response in the previous task. In Experiment 1, this was done by means of congruent and incongruent stimuli. As expected, on task switch trials, the repetition costs were larger if a congruent rather than an incongruent stimulus occurred in the previous task. In Experiment 2, the same effect occurred for stimulus-response compatible versus incompatible stimuli in the previous task. In Experiment 3, both manipulations were applied together, which produced almost additive effects. Altogether, the results support the inhibition account for the response repetition effects under task switch conditions. [ABSTRACT FROM AUTHOR]

Abstract: The article investigates the mechanisms of selecting and updating representations in declarative and procedural working memory (WM). Declarative WM holds the objects of thought available, whereas procedural WM holds representations of what to do with these objects. Both systems consist of three embedded components: activated long-term memory, a central capacity-limited component for building structures through temporary bindings, and a single-element focus of attention. Five experiments test the hypothesis of analogous mechanisms in declarative and procedural WM, investigating repetition effects across trials for individual representations (objects and responses) and for sets (memory sets and task sets), as well as set-congruency effects. Evidence for analogous processes was obtained from three phenomena: (1) Costs of task switching and of list switching are reduced with longer preparation interval. (2) The effects of task congruency and of list congruency are undiminished with longer preparation interval. (3) Response repetition interacts with task repetition in procedural WM; here we show an analogous interaction of list repetition with item repetition in declarative WM. All three patterns were reproduced by a connectionist model implementing the assumed selection and updating mechanisms. The model consists of two modules, an item-selection module selecting individual items from a memory set, or responses from a task set, and a set-selection module for selecting memory sets or task sets. The model codes the matrix of binding weights in the item-selection module as a pattern of activation in the set-selection module, thereby providing a mechanism for building chunks in LTM, and for unpacking them as structures into working memory. [Copyright &y& Elsevier]