Adapting temporal preference to scarcity: A role for emotion?

A critical optimization problem is how to distribute resource consumption over time. Humans tend to value immediate rewards over equivalent future rewards—a phenomenon called temporal discounting. Such imbalance can lead to poor health, education, and financial decisions. It is also a hurdle for implementing sustainability policies. A major research goal is to identify factors that influence temporal discounting, so that policymakers could develop interventions to correct for this imbalance. One such factor is available resources; scarcity may increase in temporal discounting. Another potential factor is emotion; negative emotions may lead to high temporal discounting. However, emotion and resources are not independent. For example, losing a large sum of money will lead to negative affect. Here, we take advantage of one of the largest global ‘income shocks’ in history, to tease apart the role of emotion and income on temporal discounting. We tested 1,145 individuals as the market was crashing in late March 2020 and unemployment rising and then retested 200 of those individuals as the market was recovering in June 2020. We found that income shock was strongly related to an increase in delay discounting using cross-sectional and longitudinal data. Importantly, this relationship was independent of the negative impact on affect. These findings suggest that, contrary to wide held assumptions, people directly adapt delay discounting to environmental constraints, without the need for input from the affective system. This independence may be adaptive, as affect is a noisy reflection of environmental constraints, which may lead to suboptimal choice.