Search

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. Keywords: task switching, cognitive control, interference DOI: 10.1037/a0019842

Performance of task sequences is assumed to rely on activation and inhibition of tasks. Ah empirical marker of task inhibition is the so-called n--2 repetition cost, which is assessed by comparing performance in trial n--2 task repetitions (i.e., ABA) with that in n--2 task switches (i.e., CBA). Current theoretical accounts assume that inhibition acts on the level of task representations (i.e., task sets). However, another potential target of task inhibition could be the representation of the task cue. To decide between these two alternatives, the authors used a 2:1 cue-to-task mapping design. They found significant n--2 task repetition costs both with n--2 cue repetitions and n--2 cue switches. These costs were about equal (Experiment 1), and this data pattern was found for both short and long cuing intervals (Experiment 2). Together, the data suggest that task inhibition acts on task sets and not on cue representations. Keywords: cognitive control, task sequence performance, inhibition, cue-based processes On reconnait generalement que la performance lors de l'execution d'une sequence de taches repose sur l'activation et l'inhibition de la tache. Un indicateur empirique de l'inhibition de la tache, le << cout associe a la repetition de la tache >>, est evalue par la comparaison de la performance a des repetitions de taches n/2 lors de la phase d'essai (c.-a-d. aba) avec la performance a une permutation de taches n/2 (c.-a-d. CBA). Selon les theories actuelles, cette inhibition a une incidence sur le niveau de representation de la tache (c.-a-d. series de taches). Toutefois, une autre cible po tentielle de l'inhibition de la tache pourrait etre la representation de l'indice d'activation de la tache. Pour verifier la deuxieme hypothese, nous avons concu un modele de mappage indice-tache. Nous avons observe des couts de repetition n/2 significatifs, autant avec les repetitions n/2 qu'avec les pernmtations de l'indice n/2. Ces couts etaient pratiquement identiques (experience 1) et le meme schema de donnees produit par les intervalles d'amorce courts et les intervalles d'amorce longs a ete observe. Dans l'ensemble, ces donnees semblent indiquer que l'inhibition de la tache a une incidence sur la serie de taches et non sur la representation de l'amorce.

The hypothesis that planning music-like sequential actions involves anticipating their auditory effects was investigated in a series of experiments. Participants with varying levels of musical experience responded to each of four colour-patch stimuli by producing a unique sequence of three taps on three vertically aligned keys. Each tap triggered a tone in most experimental conditions. Responseeffect (key-to-tone) mapping was either compatible--taps on the top, middle, and bottom keys triggered high, medium, and low pitched tones, respectively--or incompatible--key-to-tone mapping was scrambled, reversed, or neutral (taps on different keys triggered the same tone). The results suggest that action planning was faster with compatible than with incompatible mappings (and faster than with no tones). Furthermore, the size of this compatibility effect grew with increasing musical experience, which suggests that improvements in auditory imagery ability that typically accompany musical training may augment the role of anticipatory auditory-effect representations during planning.

The present study used a go/no-go signal delay (GSD) to explore the role of response-related processes in task switching. A go/no-go signal was presented at either 100 ms or 1,500 ms after the stimulus. Participants were encouraged to use the GSD for response selection and preparation. The data indicate that the opportunity to select and prepare a response (i.e., long GSD) resulted in a substantial reduction of task-shift costs (Experiment 1) and n - 2 task-repetition costs (i.e., backward inhibition; Experiment 2) in the current trial. These results suggest that interference from the preceding trial can be resolved during response selection and preparation. Furthermore, the shift costs and the n - 2 repetition costs after no-go trials with long GSD (i.e., response selection but no execution) were markedly smaller than after go trials. These findings suggest that the interference that gives rise to shift costs and n - 2 repetition costs is related not solely to response selection but also to response execution. Thus, the present study demonstrates dissociable contributions of response selection and response execution to interference effects in task switching. Keywords: task switching, response selection, response execution, go/no-go, inhibition

Cognitive flexibility can be studied using the task-switching paradigm. This paradigm requires subjects to adapt behaviour to changing contexts as indicated by a cue. In our study, we addressed the question of how cue-based implementation of mental 'task sets' occurs. We assumed that cues build up associations to the tasks that they indicate. These associations lead to retrieval of the associated task set once the cue shows up again. In three experiments, we tested this assumption using a negative transfer paradigm. First participants were exposed to one cue-task mapping. After a training phase, the cue-task mapping changed in either of two ways. Whereas one group of participants got new cues, the other experienced a reversal of the learnt cue-task mapping. Our results show that participants build up cue-task associations and that these formerly learnt associations can hamper the implementation of new cue-task mappings (particular with mapping reversal). Prolonged preparation time decreased the cost of changing the cue-task mapping but did not change the overall pattern of results.