Visuospatial working memory and distracted driving : deciphering gaze behavior, cognitive workload and driving errors

Abstract

This research examines issues concerning visuospatial working memory (VSWM) related to distracted driving. Analyses of gaze behavior, driving errors, and cognitive workload (CWL) are emphasized. This dissertation is comprised of three experiments conducted on a two-lane test-track. The role of VSWM processes are investigated in terms of suppression of Articulatory Rehearsal Mechanism (ARM), in-vehicle object and spatial distractions, and in-vehicle spatial – simultaneous and – sequential distractions. This dissertation reports development of three variants of an experimental paradigm named as ‘Direction Following in Distracted Driving (D3)’ that were employed in three separate experiments.Experiment-1 investigates the effect of suppressed ARM on gaze behavior and driving performance. In this experiment, 45 drivers voluntarily participated and drove an instrumented vehicle on a two-lane track. The results demonstrate that there are significantly lesser fixation durations and fixation counts under Complex Suppression (CS) of ARM as compared to the other two levels of suppression, i.e., Simple Suppression (SS) and Non-Suppression (NS) of ARM. Overall driving error analysis revealed that there are more significant errors under CS as compared to SS and NS. Moreover, drivers committed more slips than lapses irrespective of the levels of suppression.Experiment-2 investigates how in-vehicle distractions (object and spatial distractions) affect drivers’ gaze behavior and driving performance (N = 47). The results demonstrate that compared to spatial distraction, during object distraction fixation durations on AOI are significantly reduced and driving errors (i.e., both slips and lapses) are significantly increased. The frequency of committing slips and lapses is significantly higher in novices than expert drivers. The results of the study also demonstrate that the drivers experienced more CWL during object distraction as comparedto spatial distraction. Furthermore, an increased CWL is associated with an increase in the occurrence of slips and lapses. Experiment-3 focuses on investigating the role of in-vehicle spatial distractions (spatial-simultaneous and spatial-sequential) in driving errors and gaze behavior by engaging 27 participants. The results demonstrate that in comparison to spatial-sequential in-vehicle distractions, fixation durations and fixation counts on AOI (i.e., direction signboards) are significantly reduced and overall driving errors (i.e., both slips and lapses) are significantly increased during in-vehicle spatial-simultaneous distractions. Moreover, the results of the study also reveal that the drivers have committed more number of slips than lapses. The results of the study indicate that spatial-simultaneous distraction has more detrimental effect on driving performance as compared to spatial-sequential distraction.