Effects of Cognitive and Perceptual Loads on Driver Behavior

Abstract

The objective of the study was to examine how cognitive and perceptual loads affect driving strategies and the guidance of attention. A cue–target search task was implemented, and two experiments manipulated prioritization of a primary task and working memory load (Experiment 1) and congruence and salience of targets (Experiment 2). The cues and non-target distracters in the environment were designed to influence discriminability and predictability of target locations (e.g., target pedestrians or target squares). Driving-related variables along with reaction times and accuracy scores were collected. The load theory of attention was used as a framework for the design of the experiments. The study was designed to expand the findings of load theory research to a more realistic driving environment and identify how drivers strategized in conditions of cognitive and perceptual loads. In line with previous studies, both experiments found better lane control during the dual-task period when compared with single-task performance. The other driving results showed detrimental effects of performing secondary tasks while driving. In Experiment 1, prioritization increased target accuracy while decreasing reaction times. In Experiment 2, high salience of targets increased accuracy, but curiously increased reaction times for target detection. Although some results were not as expected, the perceptual load manipulation had an overall negative effect on visual search. In-vehicle interfaces could benefit by incorporating designs that do not exhaust drivers’ working memory or distract them with complex displays.