For experienced drivers, talking on a cell phone while driving seems relatively easy. From a processing perspective, however, it requires the concurrent perception, analysis, decision making, and response selection of multiple stimuli from different sensory modalities. Research on the efficiency of such concurrent perceptual and cognitive processing of multiple stimuli or tasks comes under the heading of divided attention. The degree to which performance deteriorates under such conditions has been studied to characterize limitations on real-world human performance, as well as to inform theoretical models of the functional architecture of the human perceptual-cognitive system. Theories of divided attention have proposed that limitations on multitask performance can be attributed to competition for processing resources as well as to competition for processing mechanisms.

Laboratory research on divided attention ...