Cognitive Multitasking: Inhibition in Task Switching Depends on Stimulus Complexity

Journal of Cognition, vol. 3, pp. 30

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, employing a standard experimental paradigm where participants switch between three different categorization tasks. The experiments differed with respect to the stimulus material. 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 costs in Experiment 2, where we used static pictures of faces, and in Experiment 3, where the 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. On a more general level, the results illustrate the difficulty of transferring laboratory tasks to settings that bear more similarity to everyday life situations.

Authors 4

1. Stefanie Schuch corresponding Aachen Institute of Psychology

   RWTH Aachen University

   Affiliation as printed

   Institute of Psychology, RWTH Aachen University, Aachen, DE

   Institute of Psychology, RWTH Aachen University, Aachen

2. Otmar Leo Bock

   German Sport University Cologne

   Affiliation as printed

   Institute of Exercise Training and Sport Informatics, German Sport University, Cologne, DE

   Institute of Exercise Training and Sport Informatics, German Sport University, Cologne

3. Klara Freitag Aachen Institute of Psychology

   RWTH Aachen University

   Affiliation as printed

   Institute of Psychology, RWTH Aachen University, Aachen, DE

   Institute of Psychology, RWTH Aachen University, Aachen

4. Luca Moretti Aachen Institute of Psychology

   RWTH Aachen University

   Affiliation as printed

   Institute of Psychology, RWTH Aachen University, Aachen, DE

   Institute of Psychology, RWTH Aachen University, Aachen