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In one task-switching experiment, we compared bilinguals and monolinguals to explore the reliability of the bilingualism effect on the n-2 repetition cost. In a second task-switching experiment, we tested another group of bilinguals and monolinguals and measured both the n-1 shift cost and the n-2 repetition cost to test the hypothesis that bilingualism should confer a general greater efficiency of the executive control functioning. According to this hypothesis, we expected a reduced n-1 shift cost and an enhanced n-2 repetition cost for bilinguals compared to monolinguals. However, we did not observe such results. Our findings suggest that previous results cannot be replicated and that the n-2 repetition cost is another index that shows no reliable bilingualism effect. Finally, we observed a negative correlation between the two switch costs among bilinguals only. This finding may suggest that the two groups employ different strategies to cope with interference in task-switching paradigms. [ABSTRACT FROM AUTHOR]

When participants rapidly switch between tasks that share the same stimuli and responses, task confusions (i.e., the accidental application of the wrong task) can occur. The present study investigated whether these task confusions result from failures of endogenous control (i.e., from ineffective task preparation) or from failures of exogenous control (i.e., from stimulus-induced task conflicts). The frequency of task confusions was estimated by considering the relative proportion of distractor errors, that is, errors that result when participants erroneously respond to the distractor associated with the alternative task. In Experiment 1, the efficiency of exogenous control was manipulated by varying the temporal order of target and distractor presentation. In Experiment 2, the efficiency of endogenous control was manipulated by varying the time available for preparing the task in advance. It turned out that only the efficiency of exogenous control but not the efficiency of endogenous control influenced the proportion of distractor errors. Accordingly, task confusions are more related to failures in exogenous control. [ABSTRACT FROM AUTHOR]

Abstract: The present study investigates the influence of preparation on inhibitory effects in cued task switching. In three experiments, we assessed n−2 repetition costs as marker of inhibition of the just executed and now irrelevant task by comparing performance in task sequences such as ABA (i.e., n−2 repetitions, with A, B and C standing for different tasks) to task sequences such as CBA (i.e., n−2 switches). Specifically, we varied the cue–target interval (CTI) to examine cue-based preparation effects. In addition, we manipulated cue type (i.e., abstract, verbal, and direct cues) across the three experiments. We obtained significant reductions of n−2 repetition costs with prolonged CTI when using abstract cues (i.e., coloured frames) and task names (i.e., digit), but not when using the task-specific stimulus–response mapping as cue for the upcoming task. These data suggest that cue-based preparation is not a uniform process but depends on the information provided by the cue. [Copyright &y& Elsevier]

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]

In three task-switching experiments, we investigated the relationship of n-1 switch cost and n-2 repetition cost. N-1 switch cost is observed when participants are asked to switch from one classification task to another, e.g., from judging a digit as odd or even to judging a digit as smaller or larger than five. N-2 repetition cost is observed when participants are asked to switch among three tasks (thereafter called A, B, and C). This cost is observed when the task on trial n-2 is repeated in trial n (i.e., in task sequences like ABA) compared to when it is switched (i.e., in task sequences like CBA). So far, the n-1 switch cost is assumed to be caused either by reconfiguration processes or by episodic-memory inertia from the previously activated task-set. N-2 repetition cost is thought to reflect lingering inhibitory processes for resolving conflict among tasks. Whereas both views are integrated in some models, it is up to date unclear whether n-2 repetition cost is related to n-1 switch cost. To examine this relationship, we decomposed the processes underlying n-1 switch cost and n-2 repetition cost using a diffusion model analysis as well as a linear ballistic accumulator model. The results showed that n-1 switch cost reflects interference caused by the residual activation of the previous task set as indicated by slower evidence accumulation processes. In contrast, there were no consistent parameter modulations underlying n-2 repetition cost. These findings emphasize that different cognitive processes are involved in n-1 switch cost and n-2 repetition cost. • Task switching was modeled with diffusion and linear ballistic accumulator model. • N-1 switch cost reflects interference caused by residual activation. • N-2 repetition cost reflects different processes depending on experimental context. [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]