Evidence of task-triggered retrieval of the previous response: a binding perspective on response-repetition benefits in task switching.

In task switching, response repetitions (RRs) usually yield performance benefits as compared to response switches, but only when the task also repeats. When the task switches, RR benefits vanish or even turn into costs, yielding an interaction between repeating versus switching the task and the response (the RR effect). Different theoretical accounts for this RR effect exist, but, in the present study, we specifically tested a prediction derived from binding and retrieval accounts. These maintain that repeating the task retrieves the previous-trial response, thus causing RR benefits. Retrieval is possible due to the task-response binding formed in the previous trial. We employed a task-switching paradigm with three response options that allowed us to differentiate error types. Across two experiments (N = 46 and N = 107) we showed that response-repetition errors in response-switch trials were more likely in task repetitions than in task switches, supporting the notion that the previous response is retrieved by the repeating task, despite being wrong. Such a finding is in line with binding and retrieval accounts but cannot be easily accommodated by the competing theoretical accounts. Thus, the present study indicates task-response binding as an important mechanism underlying RR benefits in task repetitions.

Reconfiguration of response-set in task switching: Event-related potential evidence.

In task switching, an interaction between task and response is often observed, with response repetition (RR) benefits in task-repeat trials and RR costs in task-switch trials. The theoretical accounts of the RR effect remain controversial, and neuroscience evidence is scarce. The present study utilized the event-related potentials (ERPs) method to explore the neural mechanism underlying the RR effect by adopting a cued task-switching paradigm. The ERP results revealed the interaction between task and response in the P3b time window, with a response switch positivity under task-repetition conditions and an RR positivity under task-switching conditions. In addition, there were RR positivity in the N2 irrespective of task transition and in the late component (LC, 550-600 ms) that only under the task repetition condition. On the individual level, the RR benefit positively correlated with the RR positivity in the LC, while the RR costs negatively correlated with RR positivity in the N2/P3 component. These results suggest that both response reconfiguration and episodic-retrieval make contributions to the RR effects, which were also discussed in terms of predictive model for a domain-general inference and learning of perceptual categories.

Contextual Features of the Cue Enter Episodic Bindings in Task Switching.

Evidence suggests that the features of a stimulus and the actions performed on it are bound together into a coherent mental representation of the episode, which is retrieved from memory upon reencountering at least one of these features. Effects of such binding and retrieval processes emerge in action control, such as in multitasking situations like task switching. In the task-switching paradigm, response-repetition benefits are observed in task repetitions, but response-repetition costs in task switches. This interaction of task repetition (vs. switch) with response repetition (vs. switch) may be explained in terms of task-response binding. In two experiments, we included a task-irrelevant contextual feature in a cued task-switching paradigm using word identification tasks. In Experiment 1, the cue modality could vary between visual and auditory; in Experiment 2, the cue language could vary between English and Spanish, while the target stimulus was always presented visually and in German. We predicted that repeating the contextual feature in the subsequent trial would retrieve the features of the previous trial, even though cue modality or cue language did not afford any response and were not associated with either task. The results showed that response repetition-benefits in task repetitions were observable when the context (i.e., the modality or the language of the cue) repeated but disappeared when the context switched from the previous trial. These results are consistent with context-specific binding and retrieval processes in task switching.

Neural correlates of the mechanism underlying negative response repetition effects in task-switching.

In a task-switching paradigm, usual response-repetition benefits are replaced by response-repetition costs when the task switches. Inhibition of a previous response and mismatch interference induced by response-repetition have been proposed as sources of negative response-repetition effects by the response inhibition account and episodic binding and retrieval model, respectively. The present study utilized electroencephalograph (EEG) to investigate the mechanism underlying negative response-repetition effects. Lateralized enhancements in the upper-alpha and beta bands served as indexes of response inhibition, and significant lateralized beta enhancements appeared after the previous response execution. About 500-600 ms after the onset of current stimuli, event-related potentials presented significant response-repeat negativity in the task-switch sequence, indicating the occurrence of mismatch interference induced by response repetition. Moreover, lateralized beta enhancements and response-repeat negativity were each positively related to behavioral negative response-repetition effects. These results suggest that both response inhibition and mismatch interference induced by response repetition make contributions to negative response-repetition effects.

Response inhibition in the task-switching paradigm.

In a task-switching paradigm, response repetition (RR) often produces costs in task-switch trials but smaller costs or even benefits in task-repeat trials. Response inhibition accounts consistently attribute negative RR effects to the inhibition of the previous response, but they have different views on this inhibition process. According to the task-specific inhibition hypothesis, the previous response is inhibited when the task-switch is called for; whereas according to the general inhibition hypothesis, the response was generally inhibited after the execution. The present study utilized the electroencephalographs (EEGs) to investigate the response inhibition in the task-switching paradigm, with lateralized upper-alpha and beta enhancements serving as indexes of response inhibition. In blocks with task preparation, a task cue during the response-stimulus interval (RSI) was used to indicate which task was required, and the blocks without task preparation served as the control condition. The result indicated that, during the cue-stimulus interval (CSI), lateralized upper-alpha enhancements appeared only in trials with task-switch preparation, supporting the task-specific inhibition hypothesis. By contrast, regardless of whether there was task preparation and which task to prepare, lateralized beta enhancements appeared during the RSI, which provided evidence for the general inhibition hypothesis. These results suggest the existence of two different response inhibition processes in the task-switching paradigm.