Age Effects in Sequence-Construction for a Continuous Cognitive Task: Similar Sequence-Trends but Fewer Switch-Points

Reconceptualizing mind wandering from a switching perspective

Mind wandering is a universal phenomenon in which our attention shifts away from the task at hand toward task-unrelated thoughts. Despite it inherently involving a shift in mental set, little is known about the role of cognitive flexibility in mind wandering. In this article we consider the potential of cognitive flexibility as a mechanism for mediating and/or regulating the occurrence of mind wandering. Our review begins with a brief introduction to the prominent theories of mind wandering-the executive failure hypothesis, the decoupling hypothesis, the process-occurrence framework, and the resource-control account of sustained attention. Then, after discussing their respective merits and weaknesses, we put forward a new perspective of mind wandering focused on cognitive flexibility, which provides an account more in line with the data to date, including why older populations experience a reduction in mind wandering. After summarizing initial evidence prompting this new perspective, drawn from several mind-wandering and task-switching studies, we recommend avenues for future research aimed at further understanding the importance of cognitive flexibility in mind wandering.

Temporal discounting across adulthood: A systematic review and meta-analysis

A number of developmental theories have been proposed that make differential predictions about the links between age and temporal discounting, or the devaluation of future rewards. Most empirical studies examining adult age differences in temporal discounting have relied on economic intertemporal choice tasks, which pit choosing a smaller, sooner monetary reward against choosing a larger, later one. Although initial studies using these tasks suggested older adults discount less than younger adults, follow-up studies provided heterogeneous, and thus inconclusive, results. Using an open science approach, we test the replicability of adult age differences in temporal discounting by conducting a preregistered systematic literature search and meta-analysis of adult age differences in intertemporal choice tasks. Across 37 cross-sectional studies (Total N = 104,737), a planned meta-analysis found no sizeable relation between age and temporal discounting, r = -0.068, 95% CI [-0.170, 0.035]. We also found little evidence of publication bias or p-hacking. Exploratory analyses of moderators found no effect of research design (e.g., extreme-group vs. continuous age), incentives (hypothetical vs. real rewards), duration of delay (e.g., days, weeks, months, or years), or quantification of discounting behavior (e.g., proportion of immediate choices vs. parameters from computational modeling). Additional analyses of 12 participant-level data sets found little support for a nonlinear relation between age and temporal discounting across adulthood. Overall, the results suggest that younger, middle-aged, and older adults show similar preferences for smaller, sooner over larger, later rewards. We provide recommendations for future empirical work on temporal discounting across the adult life span. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Age-related cognitive decline in rats is sex and context dependent

Previously, we had observed age-related cognitive decline in male rats compared to adolescent and adult rats. This was shown in both a multi-branched maze test (MBM), as well as in the Morris water maze test (MWM). In the present study, we compared the behavior of similar age groups in both male and female rats using the same paradigms. The results confirmed the increase in errors and time spent in MBM in aged male rats compared to other age groups. However, no such differences were observed in female rats. In the acquisition phase of MWM, aged male rats did not differ significantly from the other two groups in terms of time spent in quadrants, whereas aged female rats spent significantly more time in quadrants compared to the other 2 age groups. Aged male rats also travelled significantly more than the other 2 age groups during the acquisition phase, whereas no such differences were observed in female rats. In both short term (30 min post acquisition) and long term (24 h after acquisition) retrieval phases of MWM, significant gender-related differences were also observed in all age groups. These findings suggest gender- and context-dependent alterations in cognitive functions during aging.

Aging affects cognition and hippocampal ultrastructure in male Wistar rats

It is now well established that aging is associated with emotional and cognitive changes. Although the basis of such changes is not fully understood, ultrastructural alterations in key brain areas are likely contributing factors. Recently, we reported that aging-related anxiety in male Wistar rats is associated with ultrastructural changes in the central nucleus of amygdala, an area that plays important role in emotional regulation. In this study, we evaluated the cognitive performance of adolescent, adult, and aged male Wistar rats in multi-branch maze (MBM) as well as in Morris water maze (MWM). We also performed ultrastructural analysis of the CA1 region of the hippocampus, an area intimately involved in cognitive function. The behavioral data indicate significant impairments in few indices of cognitive functions in both tests in aged rats compared to the other two age groups. Concomitantly, a total number of presynaptic vesicles as well as vesicles in the resting pool were significantly lower, whereas postsynaptic mitochondrial area was significantly higher in aged rats compared to the other age groups. No significant differences in presynaptic terminal area or postsynaptic mitochondrial number were detected between the three age groups. These results indicate that selective ultrastructural changes in specific hippocampal region may accompany cognitive decline in aging rats.

Age Differences in Intertemporal Choice: The Role of Task Type, Outcome Characteristics, and Covariates

OBJECTIVES

Prior research has revealed age differences in the preferred timing of monetary outcomes, but results are inconsistent across studies. The present study examined the role of task type, outcome characteristics, and a range of theoretically implicated covariates that may contribute to variations in age effects.

METHOD

Two types of intertemporal choice paradigms (temporal discounting and sequence construction) were administered to a diverse life-span sample (n = 287, aged 18-87). The design experimentally manipulated outcome delay (months vs years), amount (hundreds vs thousands), and valence (gain vs loss) while statistically controlling for a range of potential covariates including demographics, affect, personality, time perspective, subjective health, and numeracy.

RESULTS

In the temporal discounting task, no significant age differences were observed and this pattern did not differ by outcome delay, amount, or valence. In the sequence-construction task, age was associated with a preference for sequences of decreasing impact in the gain condition but not in the loss condition, whereas outcome delay and amount did not moderate age effects. Age patterns in discounting and sequences preferences remained unchanged after controlling for covariates.

DISCUSSION

These findings converge with prior studies reporting weak or null effects of age in temporal discounting tasks and suggest that inconsistent results are not due to variations in outcome valence, delay, or amount across studies. Findings also add to the scarce evidence for age differences sequence-preferences. After discussing methodological limitations, we consider implications for future research and practice.