Preserved effects of monetary and social rewards on processing speed and episodic memory in aging: Evidence from task performance and skin conductance responses.

Improving processing speed and episodic memory in older adults is important for supporting their daily functioning. Although rewards can increase sympathetic activity and improve cognitive performance in younger adults, and aging may be associated with changes in arousal-related neurotransmitter systems, it remains unclear whether reward effects are altered in older adults. This study investigated the age-related effects of monetary and social rewards on processing speed, episodic memory, and sympathetic arousal. Twenty-nine adults aged 18-35 and 30 adults aged 56-73 completed an incentive delay task and a visual recognition task in which they could receive no reward, a monetary reward, or a social reward on a trial. Skin conductance responses during target preparation and stimulus encoding were measured across reward conditions. We found that younger and older adults similarly showed increased arousal and improved speed when either monetary or social reward was available, with monetary rewards producing stronger effects. Notably, the skin conductance response elicited during anticipation of monetary reward mediated the improvement in speed in older adults. Regarding memory, both age groups showed improved visual recognition and a greater ability to mentally re-experience past events when monetary reward was available. However, reward did not modulate skin conductance responses during encoding. Overall, these findings suggest that reward enhances older adults' processing speed and episodic memory similarly to those of younger adults, despite potentially different contributions of sympathetic arousal. They deepen our understanding of the three-way relationship among reward, psychophysiological functioning, and aging.