Dual-Task Performance: Theoretical Analysis and an Event-Coding Account

Bernhard Hommel

doi:10.5334/joc.114

Abstract

Theorizing on dual- and multi-tasking has not made much progress since the early insight of Telford (1931) and Welford (1952) that response selection may represent a bottleneck in human information processing. A closer look reveals that the questions being asked in dual-task research are not particularly interesting or realistic, and the answers being given lack mechanistic detail. In fact, present theorizing can be considered mere empirical generalization, which has led to merely labeling processing bottlenecks rather than describing how they operate and how they actually produce the bottleneck. As a template for how to overcome this theoretical gap, the Theory of Event Coding (TEC) is applied to dual-task performance. It is shown that TEC, which has not been developed to account for, and has not yet been applied to dual-task performance and its deficits, can nevertheless easily account for the key findings guiding resource and stage theories, while making the underlying mechanisms explicit and transparent. It is thus suggested to consider multitasking costs a mere byproduct of the typical functioning of the cognitive system that needs no dedicated niche theorizing. Rather, what is needed is more mechanistic detail and a more integrative account that can deal with findings related to both resource theory and stage theory.

Highlights

In stark contrast to many topics studied by cognitive psychologists, the question whether people can perform more than one task at one time has always enjoyed widespread interest
This means that it is the completion of response selection that counts in Theory of Event Coding (TEC), which provides a natural account of the fact that response selection is assumed to be the bottleneck
As I have tried to explain, this is because of the widespread acceptance of more or less descriptive models that go hardly beyond empirical generalization and provide no insight into the actual mechanisms, that is, into the representations involved, the processes that operate on these representations, and the particular way that these interactions generate the phenomenon under investigation

Summary

Introduction

In stark contrast to many topics studied by cognitive psychologists, the question whether people can perform more than one task at one time has always enjoyed widespread interest. This part of the prediction directly follows from the implementation of the instruction: given that participants are requested to begin with Task 2 not before the completion of Task 1, the foot code that the model assumes to initiate the actual selection process receives the necessary boost of activation only after the selection controlled by the hand code has been finished This means that it is the completion of response selection that counts in TEC, which provides a natural account of the fact that response selection is assumed to be the bottleneck (for a very similar reasoning, see Logan & Gordon, 2001). Taken altogether, TEC cannot only fully compete with the classical stagetheoretical accounts of dual-task costs, but it provides natural explanations for observations that stage accounts have difficulties with, such as the BCE

Conclusions

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