Previous studies have shown that the experience of negative emotions is rarer, while experience of positive emotions is more frequent in the elderly, suggesting an overall improvement in emotional well-being as people age. However, most research did not account for the dynamic characteristics of emotions (e.g. peak intensity, latency, duration) and the levels of emotional challenges. In addition, since most previous studies have focused on studying the experience, expression, and psychophysiological response of emotion, it is still not fully understood how performance in cognitive or behavioral tasks (e.g., automobile driving) can be affected by emotions in older age. To address this gap, the current study examined the effect of normal aging on the dynamic processes of emotion during different levels of emotional challenge (aim 1), and the effect of emotion on driving in older adults as compared to middle-aged adults (aim 2). Parkinson’s disease (PD) is an age-related neurodegenerative disease that shares similar pathological characteristics with the process of normal aging (i.e., reduced dopamine), but to a much higher degree. In addition to investigating the effect of normal aging, the current study also examined the effect of “abnormal aging” on emotion and driving using PD as a model (aim 3).
Participants included 16 older (65 - 79 years old), 16 middle-aged (38 - 55 years old) neurologically normal adults, and 16 patients with mild PD (56 - 80 years old). This study focused on fear and anger, the two negative emotions that are most likely to be elicited by driving experiences and to disrupt driving behaviors. Low-level and high-level fear and anger challenges were created using simulated driving scenarios: 1) Low fear task, participants drove in fog and frequently encountered static obstacles on the road; 2) High fear task, participants drove at nighttime and frequently encountered deer running across the road; 3) Low anger task, participants drove following a slow-moving vehicle; 4) High anger task, participants followed a slow vehicle and were honked at by a tailgating vehicle. Participants rated the intensity of fear and anger experiences at 1- minute intervals when they were driving.
Comparing older adults against middle-aged adults, it was found that 1) fear intensity was lower in older adults in the low fear task. In contrast, latency and duration of fear were similar between groups in both fear tasks. 2) Anger intensity was lower in older adults in both anger tasks. Anger latency and duration were similar between groups in the high anger task, but anger took longer to develop and was of shorter duration in older adults in the low anger task. 3) In the low fear task, older adults exhibited more cautious driving behaviors (e.g., more frequent uses of brake). In the high anger task older adults were less able to control the acceleration and brake pedals smoothly (e.g., higher forces for brake and acceleration). These results suggest that age differences in the dynamic processes of emotion and the effect of emotion on driving may depend on the type of emotion and level of emotional challenge.
When comparing PD patients against age- and education-matched neurologically normal participants (n = 18), it was found that the PD patients reported experiencing similar degrees of fear and anger as the normal comparisons. However, in the high fear task PD patients were less responsive to deer running across the road (e.g., mean and variation of force for brake was lower in PD patients). This finding suggests an impaired ability in PD patients to respond to the sudden appearance of driving hazards.
Collectively, the findings of this study provide a window into how the moment-to-moment experience of negative emotions in response to environmental challenges may contribute to the overall emotional well-being of older adults. They also suggest that both the type of emotion and the level of challenge may be important factors in determining the experience of emotion and the effect of emotion on driving during “normal” and “abnormal” aging.