The discounted future: Relationship between temporal discounting and future thinking in Alzheimer’s disease

Abstract

Temporal discounting refers to the tendency to prefer smaller sooner rewards over larger later rewards. Prior research has reported temporal discounting in Alzheimer’s disease (AD). We thus investigated, in this study, the relationship between temporal discounting and future thinking in AD. The study included 40 patients with AD and 42 control participants. We invited participants, on a temporal discounting task, to choose between an immediate but smaller or a delayed but larger amount of money (e.g. “would you prefer 10 dollars today or 50 dollars after one month?”). We also invited the participants to imagine events that may happen in the future, a task known as future thinking. Analysis demonstrated a bias toward immediate rewards (i.e. temporal discounting) as well as difficulties to imagine specific future events in patients with AD. Critically, temporal discounting and future thinking in AD were significantly correlated. Generally speaking, a lack of thinking about the future may lead to impulsive behavior. More specifically, decline in future thinking in AD may limit the ability of patients to project themselves in time to consider outcomes of their decisions, resulting in a tendency to devaluate future rewards in favor of more imminent ones (i.e. temporal discounting).