Associations between phasic arousal and decisions under risk in younger and older adults

Higher arousal is linked to simple decision strategies and an increased preference for immediate rewards in younger adults, but little is known about the influence of arousal on decision making in older adults. In light of age-related locus coeruleus-norepinephrine system declines, we predicted a reduced association between arousal and decision behavior in older adults. Younger and older participants made a series of choices between smaller, higher-probability and larger, lower-probability financial gains. Each choice was preceded by the presentation of a high-arousal or low-arousal sound. Pupil dilation was continuously recorded as an index of task-evoked arousal. Both age groups showed significant modulation of pupil dilation as a function of arousal condition. Higher-arousal sounds were associated with shorter response times, particularly in younger adults. Furthermore, higher-arousal sounds were associated with greater risk aversion in younger adults and greater risk seeking in older adults, in line with an arousal-related amplification of baseline preferences in both age groups. Jointly, these findings help inform current theories of the effects of arousal on information processing in younger and older adults.