WITHIN‐SUBJECT COMPARISON OF REAL AND HYPOTHETICAL MONEY REWARDS IN DELAY DISCOUNTING

TLDR

The study used a within‑subject design with human participants to compare delay‑discounting functions for real and hypothetical monetary rewards ranging from $10 to $250. Results showed no systematic difference in discount rates between real and hypothetical rewards for 5 of 6 participants, confirmed that discount rates decline with reward magnitude, and that a hyperbolic decay model better fits the data.

Abstract

A within-subject design, using human participants, compared delay discounting functions for real and hypothetical money rewards. Both real and hypothetical rewards were studied across a range that included $10 to $250. For 5 of the 6 participants, no systematic difference in discount rate was observed in response to real and hypothetical choices, suggesting that hypothetical rewards may often serve as a valid proxy for real rewards in delay discounting research. By measuring discounting at an unprecedented range of real rewards, this study has also systematically replicated the robust finding in human delay discounting research that discount rates decrease with increasing magnitude of reward. A hyperbolic decay model described the data better than an exponential model.