Willingness to wait covaries with endogenous variation in cortisol

Stress is a normal part of our everyday lives, alerting us to changes in our environment and working as an early warning system. However, when stress is prolonged, it can become harmful. The deleterious effects of stress on brain function are well established: chronic stress significantly impairs cognitive function, reducing our ability to solve problems and regulate behavior. Therefore, it may lead to more challenges that can further exacerbate stress. An important class of decisions made under stress includes those between rewards delivered immediately and those delivered in the future. Not considering or devaluing future outcomes (delay discounting) can result in adverse outcomes, such as not buying health insurance, gambling, or drug use. To date, however, little is known about how chronic stress influences economic decisions that differ in the timing of outcome delivery. A handful of studies suggest that increased stress may lead to more impulsive choices in subjects of average socioeconomic status and stress levels. In this study, we addressed this gap by using a multi-session design to determine whether chronic stress measures (via questionnaires, saliva, and hair samples) are associated with economic choices across different time scales within subject (N = 34). We found that the degree to which people think it is worth waiting, i.e., an individual's discount factor, varied reliably over seconds but not over days in response to endogenous stress. These results are crucial for understanding the impact of stress in various contexts. For instance, fluctuations in individual stress responses to the environment may help explain variations in consumer behaviors, such as impulse purchases, even among healthy adults.