The vast majority of decision making research has focused on examining monetary decisions. However, real-world decision making often requires that individuals weigh the costs and benefits across a variety of domains. Thus, my colleagues designed a set of discounting tasks to test how different types of costs and rewards influence choice behavior. In a study focused on decisions about monetary rewards, we discovered that while the tolerance of different costs is behaviorally dissociable, subjective value signals share a common representation in the brain across adulthood (Seaman, Brooks et al., 2018). Additionally, we found no consistent evidence for age differences in preferences or the neural representations of subjective value across adulthood. This suggests that the ability to represent value is preserved across the life span, and that age differences in choice behavior may be due to other, non-biological, factors. One potential factor is motivation: with age, goal priorities shift and some decisions become more motivationally salient than others. Consistent with an age-related shift in priorities, our results suggest that older adults may be more motivated than young adults to obtain social and health rewards immediately and with certainty (Seaman et al., 2016).Collectively, this line of work demonstrates the importance of considering motivation when examining choice behavior across adulthood – and focusing on abstract monetary rewards may limit our ability to quantify age differences in domain-general decision making. Understanding what matters to people is critical to understanding the decisions they make.
Conjunction of subjective value representation during effort and probability (green), probability and time (blue), and effort, probability, and time (purple). The conjunction of subjective value representation of effort and time is obscured by other conjunctions in the figure (Seaman, Brooks et al., 2018).