Baptist Liefooghe

Bio: Baptist Liefooghe is an academic researcher from Ghent University. The author has contributed to research in topics: Task switching & Task (project management). The author has an hindex of 25, co-authored 62 publications receiving 2349 citations. Previous affiliations of Baptist Liefooghe include Utrecht University.

Task switching: interplay of reconfiguration and interference control.

Abstract: The task-switching paradigm is being increasingly used as a tool for studying cognitive control and task coordination. Different procedural variations have been developed. They have in common that a comparison is made between transitions in which the previous task is repeated and transitions that involve a change toward another task. In general, a performance switch cost is observed such that switching to a new task results in a slower and more error-prone execution of the task. The present article reviews the theoretical explanations of the switch cost and the findings collected in support of those explanations. Resolution and protection from interference by previous events explain part of the switching cost, but processes related to task setting and task preparation also play a prominent role, as testified by faster execution and lower switch costs when the preparation time is longer. The authors discuss the evidence in favor of each of these sets of accounts and raise a number of questions that situate task switching in a broader context of cognitive control processes. The role of several aspects of the task set, including task variations, task-set overlap, and task-set structure, is addressed, as is the role of knowledge about probability of task changes and about the structure of task sequences.

Top-down and bottom-up sequential modulations of congruency effects.

Abstract: Several studies have demonstrated reduced congruency effects after incongruent trials. The conflict monitoring hypothesis (Botvinick, Braver, Barch, Carter, & Cohen, 2001) assumes that this sequential modulation is based on top-down cognitive control and suggests that more control is engaged after the detection of conflict. An alternative account is based on repetition effects of stimulus and response features and can be considered bottom up. This study investigates both modulatory sources. In a Stroop task with two response-stimulus intervals (RSIs), we demonstrate that top-down modulation does not occur with a very short RSI, suggesting that it takes some time before the system can be reconfigured. Bottom-up modulation is observed for both RSIs. This finding demonstrates that two different sources simultaneously reduce congruency effects after incongruent trials.

Stimulus-and response-conflict-induced cognitive control in the flanker task

Abstract: Recently, several studies have been conducted to investigate the top-down adjustments made after incongruent trials during conflict tasks In the present study, we investigated conflict monitoring with different types of conflict In a modified version of the flanker task, a distinction was made between stimulus—stimulus conflict and stimulus—response conflict Six colors were mapped to three responses in order to exclude all sequences in which a relevant or an irrelevant stimulus- or response-related feature was repeated from trialn−1 to trialn An analysis of the effect of the congruency of the previous trial demonstrated that conflict adaptation was present The stimulus congruency effect was reduced after both a stimulus-incongruent trial and a response-incongruent trial The response congruency effect did not vary as a function of previous congruency These findings are discussed in relation to the distinction between conflict detection and conflict regulation

Working Memory Costs of Task Switching.

Abstract: Although many accounts of task switching emphasize the importance of working memory as a substantial source of the switch cost, there is a lack of evidence demonstrating that task switching actually places additional demands on working memory. The present study addressed this issue by implementing task switching in continuous complex span tasks with strictly controlled time parameters. A series of 4 experiments demonstrate that recall performance decreased as a function of the number of task switches and that the concurrent load of item maintenance had no influence on task switching. These results indicate that task switching induces a cost on working memory functioning. Implications for theories of task switching, working memory, and resource sharing are addressed.

Control and interference in task switching--a review.

Abstract: The task-switching paradigm offers enormous possibilities to study cognitive control as well as task interference. The current review provides an overview of recent research on both topics. First, we review different experimental approaches to task switching, such as comparing mixed-task blocks with single-task blocks, predictable task-switching and task-cuing paradigms, intermittent instructions, and voluntary task selection. In the 2nd part, we discuss findings on preparatory control mechanisms in task switching and theoretical accounts of task preparation. We consider preparation processes in two-stage models, consider preparation as an all-or-none process, address the question of whether preparation is switch-specific, reflect on preparation as interaction of cue encoding and memory retrieval, and discuss the impact of verbal mediation on preparation. In the 3rd part, we turn to interference phenomena in task switching. We consider proactive interference of tasks and inhibition of recently performed tasks indicated by asymmetrical switch costs and n-2 task-repetition costs. We discuss stimulus-based interference as a result of stimulus-based response activation and stimulus-based task activation, and response-based interference because of applying bivalent rather than univalent responses, response repetition effects, and carryover of response selection and execution. In the 4th and final part, we mention possible future research fields.