Cognitive resource limitations shift effort trade-offs across the lifespan

Abstract

Previous work suggests that lifespan developmental differences in cognitive control abilitiesmight be due to maturational and aging-related changes in prefrontal cortex functioning.However, there are other explanations: For example, it could be that children and older adults differ from younger adults in how they balance the effort of engaging in control against its potential benefits. In this work, we assume that the degree of engagement in cognitive effort depends on the opportunity cost of time (average reward rate per unit time). If the average reward rate is high, participants should speed up responding whereas if it is low, they should respond more slowly. Developmental changes in opportunity cost assessments may lead to differences in the sensitivity to changes in reward rate. To examine this hypothesis in children, adolescents, younger, and older adults, we applied a reward rate manipulation in two well-established cognitive control tasks: a modified Erikson Flanker and a task-switching paradigm. We found a significant interaction between age group and average reward rate, such that older adults were more sensitive to the average reward rate than the other age groups. However, as task complexity increased (from the Flanker task to the task-switching paradigm), children also became sensitive to changes in reward rate. This may suggest that when demands on cognitive load reach capacity limitations, participants engage in strategic behaviour to optimize performance: a view we present as the “sweet sport” argument of effort allocation.

Resource‐rational approach to meta‐control problems across the lifespan

“…Instead, children and older adults, recognizing their limitations, may prefer to invest resources when it yields maximum rewards, without considering the future depletion of resources. Extrapolating from these findings, we suggest that children and older adults may have a sweet spot at which the incentivization structure and the cognitive demands of the task are tailored to the needs of the different age groups (see Devine et al, 2019;Devine, Neumann, Otto, Bolenz, Reiter & Eppinger, 2020). That is, based on a combination of age-related and individual cognitive limitations, we suggest that each participant will have a "sweet spot" at which they will demonstrate optimal engagement in meta-control.…”

“…To incentivize maximal engagement in such control, variants of the Flanker task provide a small monetary incentive for each correct response participants make (see Hsieh, Li & Tsai, 2010). In other variants, rewards fluctuate across trials (Devine, Otto, Bolenz, Reiter & Eppinger, 2019; see Figure 1A). In these cases, participants are presented with a meta-control decision: either to invest resources into sustained control to maximize performance and reward, or to reduce control and risk foregoing potential gains.…”

Influences of dopaminergic system dysfunction on late-life depression

“…For instance, the ventromedial prefrontal cortex (vmPFC) shows a reduced subjective value signal in older adults displaying suboptimal decision-making even though there is no overall decline in vmPFC subjective reward signaling across the lifespan in healthy adults [ 144 , 145 ]. A greater perceived cost of cognitive effort [ 146 ] is observed in older adults, which may be linked to declines in cognitive resources with aging [ 147 ]. There may be similar parallels for physical effort in relation to co-existing motoric difficulties that contribute to increased fatigability, a common complaint of many elders that predicts disability [ 148 , 149 ].…”