Fleeting Effects of Incentives: Adult Age Differences in ERP Measures of Motivated Attention

Reward-based motivation is associated with transient and sustained dopaminergic activity and with modulatory effects on attention and cognitive control. Age-related changes in the dopamine system are well documented, but little is known about age differences in the temporal dynamics of motivational influences on cognitive functions. The current study examined the effects of financial incentives on visual attention using event-related potentials (ERPs). Participants (26 younger, aged 18-33; 24 older, aged 65-95) completed an incentivized flanker task in which trial-level incentive cues signaled the availability of performance-contingent reward, and subsequent alerting cues signaled the onset of the flanker target. ERP components of interest included incentive-cue P2 and CNV, alerting-cue N1, target N1, and target P3. Transient effects of incentives were assessed by comparing ERP amplitudes across incentive and non-incentive trials from mixed-incentive blocks. Younger adults showed transient effects of incentives on all components, whereas older adults showed effects for incentive-cue P2 and alerting-cue N1 only. Sustained effects of incentives were assessed by comparing ERP amplitudes across non-incentive trials from mixed-incentive blocks and non-incentive trials from pure non-incentive blocks. Both age groups showed sustained effects of incentives on cue-locked ERPs, but only younger adults showed sustained effects on target-locked ERPs. Reaction-time patterns mirrored the ERP findings, in that younger adults showed greater incentive-based modulation than older adults. Overall, these findings suggest that both transient and sustained effects of incentives on visual attention are more fleeting for older than younger adults, consistent with widespread alterations in dopaminergic neuromodulation in aging.