Comparing Effects of Reward Anticipation on Working Memory in Younger and Older Adults

Abstract

Goal-directed behavior requires sufficient resource allocation of cognitive control processes, such as the ability to prioritize relevant over less relevant information in working memory. Findings from neural recordings in animals and human multimodal imaging studies suggest that reward incentive mechanisms could facilitate the encoding and updating of context representations, which can have beneficial effects on working memory performance in young adults. In order to investigate whether these performance enhancing effects of reward on working memory processes are still preserved in old age, the current study aimed to investigate whether aging alters the effects of reward anticipation on the encoding and updating mechanisms in working memory processing. Therefore, a reward modulated verbal n-back task with age-adjusted memory load manipulation was developed to investigate reward modulation of working memory in younger (age 20–27) and older (age 65–78) adults. Our results suggest that the mechanism of reward anticipation in enhancing the encoding and updating of stimulus representations in working memory is still preserved in old age. EZ-diffusion modeling showed age distinct patterns of reward modulation of model parameters that correspond to different processes of memory-dependent decision making. Whereas processes of memory evidence accumulation and sensorimotor speed benefited from reward modulation, responses did not become more cautious with incentive motivation for older adults as it was observed in younger adults. Furthermore, individual differences in reward-related enhancement of decision speed correlated with cognitive processing fluctuation and memory storage capacity in younger adults, but no such relations were observed in older adults. These findings indicate that although beneficial effects of reward modulation on working memory can still be observed in old age, not all performance aspects are facilitated. Whereas reward facilitation of content representations in working memory seems to be relatively preserved, aging seems to affect the updating of reward contexts. Future research is needed to elucidate potential mechanisms for motivational regulation of the plasticity of working memory in old age.

Losing Money and Motivation: Effects of Loss Incentives on Motivation and Metacognition in Younger and Older Adults

“…To our knowledge, only one study has examined the effects of incentive on working memory in both younger and older adults (Thurm et al, 2018). The lack of studies on how incentives might affect working memory performance in younger and older adults stands in contrast to the training and neurostimulation literatures, where working memory is a frequent target because of its large age differences and importance in everyday life (Basak et al, 2008;Buschkuehl et al, 2008;Li et al, 2008;Stephens and Berryhill, 2016;Rhodes and Katz, 2017;Di Rosa et al, 2019).…”

“…Third, many studies have focused on reward ("gain") incentives (e.g., Castel et al, 2002;Spaniol et al, 2014;Cohen et al, 2016;Thurm et al, 2018;Di Rosa et al, 2019;Yee et al, 2019;Bowen et al, 2020). However, loss is thought to play an increasingly important part in older adults' experience, and real-world attempts to motivate their behavior often focus on the opportunity to avoid such losses (e.g., of health, of employment or financial stability, of driving privileges).…”

Opposite reactions to loss incentive by young and older adults: Insights from diffusion modeling

“…Therefore, when older adults show smaller performance changes in response to changing incentive than do young adults, it may be difficult to disentangle whether this represents reduced sensitivity to the incentive per se versus a more general age-related impairment in dynamically modulating control. Thurm et al, (2018) noted that older adults' failure to adjust response bias in accordance with trialwise changes in reward in their study might reflect difficulties in adapting to changing reward context. Even young adults can show large carryover effects: The response to a non-incentivized trial is quite different depending on whether it occurs intermixed with incentivized trials or in a block of non-incentivized trials (e.g., Jimura et al, 2010;see Schmitt et al, 2017 for differential effects in older adutls).…”

Decision experience in hyperchoice: the role of numeracy and age differences

“…Similarly, in a study examining the relationship of age differences and attitude toward risk, the ages for the younger and older participant groups were 16–23 and 63–87, respectively (Rolison et al 2012 ). In the field of working memory, a study on effect of aging and reward anticipation employed two age groups with 20–27 for the younger adults and 65–78 for the older adults (Thurm et al 2018 ). One goal of the current work was to test older adults’ decision experience in the scenarios with different choice set sizes.…”