Cognitive Multitasking: Inhibition in Task Switching Depends on Stimulus Complexity

Abstract

We report a series of three experiments investigating inhibition in task switching, using N-2 repetition costs as an empirical marker. The experiments were structurally identical, employingastandardexperimentalparadigmwhereparticipantsswitchbetweenthree different categorizationtasks.Theexperimentsdifferedwithrespecttothestimulusmaterial. According to prominent theories of cognitive control, N-2 repetition costs should be observed in all three experiments. To our surprise, this is not what we observed: N-2 repetition costs did not occur in Experiment 1, where we used static pictures from a driving simulator environment showing an oncoming car, embedded in a car-driving scene. In contrast, we observed robust N-2 repetition costsinExperiment2,whereweusedstaticpicturesoffaces,andinExperiment 3,wherethe identical car stimuli from Experiment 1 were used, but without the surrounding visual scene. These results suggest that N-2 repetition costs depend on the complexity of the stimulus material. We discuss two aspects of complexity: 1) When the relevant stimulus feature is embedded in a complex visual scene, task-irrelevant features in that scene might trigger additional task sets, and thus induce additional task switches, attenuating N-2 repetition costs among the instructed task sets. 2) The presence of distractors might lead to additional covert or overt shifts of spatial attention, which in turn might reduce the size of N-2 repetition costs. Onamoregenerallevel,theresultsillustratethedifficultyoftransferringlaboratorytasksto settings that bear more similarity to everyday life situations.

The State-of-the-art of Research into Human Multitasking: An Editorial

“…Based on this latter finding, the authors argue that competing modality mappings based on ''backward'' linkages between anticipated response effects and stimuli lead to modality compatibility-dependent switching costs. By focusing on n-2 taskrepetition costs and in order to translate traditional experimental paradigms into contexts and settings that more closely resemble everyday life situations, Schuch et al (2020) investigated the importance of inhibitory processes in task switching in the situational context of complex visual scenes depicting the perspective of a car driver. They observed n-2 task repetition costs only when Journal of Cognition DOI: 10.5334/joc.185 target stimuli were not surrounded by a complex visual scene as in traditional experiments.…”