Adult Age Differences in the Temporal Dynamics of Motivated Attention.

Abstract

Reward-based motivation modulates attention and cognitive control across the life span, but little is known about age differences in the temporal dynamics of motivated attention. The current study examined the effects of financial incentives on visual attention using ERPs. Participants (26 younger, aged 18-33 years; 24 older, aged 65-95 years) 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 cue-related components (incentive-cue P2 and contingent negative variation, and alerting-cue N1) as well as target-related components (target N1 and P3). Transient effects of incentives were assessed by comparing ERP amplitudes across incentive and non-incentive trials from mixed-incentive blocks. 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. Younger adults showed transient effects of incentives on all components, whereas older adults showed these effects for incentive-cue P2 and alerting-cue N1 only. Both age groups showed sustained effects of incentives on cue-locked ERPs, but only younger adults showed sustained effects on target-locked ERPs. RT patterns mirrored the ERP findings, in that younger adults showed greater incentive-based modulation than older adults, but at a greater cost to accuracy. Overall, these findings reveal widespread age differences in the dynamics of incentive-motivated attention and cognitive control, particularly at longer timescales.