The effects of route-familiarity and mind wandering on driving behaviour: examining driving performance using a high fidelity driving simulator

Many traffic accidents occur because the driver is in an inattentive state of mind (mind wandering). I hypothesize that as a route becomes more familiar, less effort is required for the driving task, thus increasing the occurrence of mind wandering. On this hypothesis, a driver’s response to unexpected emergencies should be impaired along familiar relative to unfamiliar routes. Over the course of three chapters I present a series of experiments designed to test this hypothesis. In Chapter 1, participants followed a vehicle along a route with which they were either familiar or unfamiliar. During the experimental session, participants had to respond when the lead-vehicle braked (central emergency) and when they noticed pedestrians heading towards the road from a sidewalk (peripheral emergency). I found that drivers familiar with the route follow the lead vehicle more closely and, with following distance held constant, are slower to respond to both central and peripheral emergencies. In Chapter 2, I explored the notion that if the route-familiarity effect is mediated by mind-wandering, similar effects should be in evidence when mind-wandering is studied independently. I found that mind wandering impairs driving behaviour in much the same way as route familiarity, supporting the hypothesis that the route familiarity effect is mediated by mind wandering. Finally, in Chapter 3 I investigated whether increasing the explicitness of monitoring would lead to improved performance (Hawthorne effect) and possibly reverse the negative effects of route familiarity. The idea being that, when monitored, drivers are unlikely to mind wander, thus freeing resources for focusing on the driving task. Drivers familiar with the route should have more free resources and should, therefore, show more improved performance compared to drivers unfamiliar with the route. The results support the mind-wandering hypothesis.