On Attentional Control and the Aging Driver

Introduction

The term attentional control has been used to refer to cognitive processes that support one’s ability to actively maintain task goals in the face of distraction (Kane & Engle, 2002) and are thought to be primarily mediated by Prefrontal Cortex (PFC). Further, evidence from neuropsychological studies implies the PFC is particularly susceptible to age-related decline (Chan & McDermott, 2007; West, 1996). As shown in Figure 1, the cognitive neuroscience literature reveals a striking symmetry between the biological development of frontal cortex across the life span and the corresponding rise and fall of goal-directed behavior (see Watson, Lambert, Miller, & Strayer, 2011, for a recent review). Hence, with advanced age, activities that require PFC-mediated attentional control and managing task goals to resist interference in information processing may become increasingly difficult to complete. Consistent with this argument, decades of laboratory research have reported age-related impairments on cognitive tasks thought to require attentional control such as Stroop color naming, where individuals are instructed to respond to the color of a stimulus like the word “RED” printed in green ink and to ignore conflicting words (Spieler, Balota, & Faust, 1996). While these findings contribute to a vast empirical literature on age-related deficits in controlled processing, an applied cognitive neuroscience perspective may provide a useful complement to traditional methods, enabling researchers to move beyond the examination of mental processes in lab tasks like Stroop to consider the implications of diminished PFC function and reduced attentional control in more naturalistic settings like driving a motor vehicle.

Figure 1.

The curvilinear development of frontal cortex across the life span. Developmental changes have been observed in a variety of dependent measures including myelination, dendritic branching, synaptogenesis, glucose metabolism, blood flow, dopamine neurotransmitter function, and brain volume. Adapted from Watson, Lambert, Miller, and Strayer (2011).

Though many aspects of driving become automated with practice, situations requiring drivers to exert attentional control often occur. Consider that turning left at a green light requires maintaining the goal of safe gap detection in the face of ongoing processing of the visual environment, where optimal functioning of attentional control may be the difference between a normal commute and a tragic accident. Older adults are six times more likely to be involved in an accident while attempting to turn left at a green light (National Highway and Traffic Safety Administration, 2009a). Moreover, when involvement in at-fault accidents are considered, there is a U-shaped function such that accidents decrease from teenage years, remain steady through middle age, and then increase for older adults (Allianz, 2006), particularly from age 75 onward. Factors such as lack of experience and increased risk-taking may account for the driving profile of teenagers (National Highway Traffic Safety Administration, 2009b). However, something else is necessary to explain the profile of older adults because they generally have more experience and are less likely to take risks (National Highway Traffic Safety Administration, 2009a). Again, diminished attentional control stemming from the declines in frontal cortex as shown in Figure 1 could partly explain these age-related changes in driving.