The Future is Less Concrete than the Present: A Neural Signature of the Concreteness of Prospective Thought Is Modulated by Temporal Proximity during Intertemporal Decision-Making

Abstract

Why do people discount future rewards? Multiple theories in psychology argue that future events are imagined less concretely than immediate events, thereby diminishing their perceived value. Here we provide neuroscientific evidence for this proposal. First, we construct a neural signature of the concreteness of prospective thought, using an fMRI dataset where the concreteness of imagined future events is orthogonal to their valence by design. Then, we apply this neural signature in two additional fMRI datasets, each using a different delay discounting task, to show that neural measures of concreteness decline as rewards are delayed farther into the future. Significance StatementPeople tend to devalue, or discount, outcomes in the future relative to those that are more immediate. This tendency is evident in peoples difficulty in making healthy food choices or saving money for retirement. Several psychological theories propose that discounting occurs because delayed outcomes are perceived less concretely that more immediate ones. Here we build a brain decoder for the concreteness of future thought and use this unobtrusive measure to show that outcomes are processed less concretely as they occur farther into the future.