Measuring risk preference: temporal stability, convergent validity, and age differences

Across various domains in life we need to make choices where the outcomes are not guaranteed and there is the potential for a loss. Individuals differ in their willingness to partake in risky activities or make choices under risk. Risk preference, is a psychological construct that reflects individual’s appetite for risk. Various disciplines, in particular, psychology and economics, have developed risk preference measures and used these to investigate inter and intra-individual differences. Despite the popularity of risk preference in the behavioural sciences, we lack a clear understanding of how stable this construct is and how coherently it is captured. This lack of clarity can have consequences on how well we understand and quantify individual differences in risk preference, in particular age differences. This dissertation aims to address these open questions by using meta-analytic methods, where we synthesised and analysed data from various sources. In three studies we: (1) compare the temporal stability and convergent validity of risk preference measures; (2) assess to what extent published evidence on age differences in task-based risk-taking aligns with theoretical predictions; and (3) how self-reported risk-taking propensity changes across adulthood. Overall, (1) we observe substantial differences in the temporal stability of risk preference measures and an overall lack of convergence; (2) whilst most theories predict an age-related decline in risk taking, this is not in line with the evidence observed from behavioural tasks; in contrast (3) we note across several domains, that self-reported risk-taking propensity declines with age. Through these three studies, we show that not all measures of risk preference are comparable, and that we need to establish a clearer definition and operationalisation of the construct. This has implications for the understanding of individual differences, as well as the development and evaluation of theories

Reconciling psychological and neuroscientific accounts of reduced motivation in aging

Motivation is a hallmark of healthy aging, but the motivation to engage in effortful behavior diminishes with increasing age. Most neurobiological accounts of altered motivation in older adults assume that these deficits are caused by a gradual decline in brain tissue, while some psychological theories posit a switch from gain orientation to loss avoidance in motivational goals. Here, we contribute to reconcile the psychological and neural perspectives by providing evidence that the frontopolar cortex (FPC), a brain region involved in cost–benefit weighting, increasingly underpins effort avoidance rather than engagement with age. Using anodal transcranial direct current stimulation together with effort–reward trade-offs, we find that the FPC’s function in effort-based decisions remains focused on cost–benefit calculations but appears to switch from reward-seeking to cost avoidance with increasing age. This is further evidenced by the exploratory, independent analysis of structural brain changes, showing that the relationship between the density of the frontopolar neural tissue and the willingness to exert effort differs in young vs older adults. Our results inform aging-related models of decision-making by providing preliminary evidence that, in addition to cortical thinning, changes in goal orientation need to be considered in order to understand alterations in decision-making over the life span

Reconciling psychological and neuroscientific accounts of reduced motivation in aging

Motivation is a hallmark of healthy aging, but the motivation to engage in effortful behavior diminishes with increasing age. Most neurobiological accounts of altered motivation in older adults assume that these deficits are caused by a gradual decline in brain tissue, while some psychological theories posit a switch from gain orientation to loss avoidance in motivational goals. Here, we contribute to reconcile the psychological and neural perspectives by providing evidence that the frontopolar cortex (FPC), a brain region involved in cost–benefit weighting, increasingly underpins effort avoidance rather than engagement with age. Using anodal transcranial direct current stimulation together with effort–reward trade-offs, we find that the FPC’s function in effort-based decisions remains focused on cost–benefit calculations but appears to switch from reward-seeking to cost avoidance with increasing age. This is further evidenced by the exploratory, independent analysis of structural brain changes, showing that the relationship between the density of the frontopolar neural tissue and the willingness to exert effort differs in young vs older adults. Our results inform aging-related models of decision-making by providing preliminary evidence that, in addition to cortical thinning, changes in goal orientation need to be considered in order to understand alterations in decision-making over the life span