Experimentally elicited discount rates are frequently higher than what seems reasonable for economic decision-making. Such high rates are often attributed to present-biased discounting. A well-known bias of standard measurements is the assumption of linear consumption utility. Attempting to correct this bias using measures of risk aversion to identify concavity, researchers find reasonable discounting but at the cost of exceptionally high utility function curvature. We present a new methodology for identifying time preferences, both discounting and curvature, from simple allocation decisions. We find reasonable levels of both discounting and curvature and, surprisingly, dynamically consistent time preferences.

Risk and time are intertwined. The present is known while the future is inherently risky. This is problematic when studying time preferences since uncontrolled risk can generate apparently present-biased behavior. We systematically manipulate risk in an intertemporal choice experiment. Discounted expected utility performs well with risk, but when certainty is added common ratio predictions fail sharply. The data cannot be explained by prospect theory, hyperbolic discounting, or preferences for resolution of uncertainty, but seem consistent with a direct preference for certainty. The data suggest strongly a difference between risk and time preferences.

If people enjoy giving, then why do they avoid fund-raisers? Partnering with the Salvation Army at Christmastime, we conducted a randomized field experiment placing bell ringers at one or both main entrances to a supermarket, making it easy or difficult to avoid the ask. Additionally, bell ringers either were silent or said “please give.” Making avoidance difficult increased both the rate of giving and donations. Paradoxically, the verbal ask dramatically increased giving but also led to dramatic avoidance. We argue that this illustrates sophisticated awareness of the empathy-altruism link: people avoid empathic stimulation to regulate their giving and guilt.

A norm of 50–50 division appears to have considerable force in a wide range of economic environments, both in the real world and in the laboratory. Even in settings where one party unilaterally determines the allocation of a prize (the dictator game), many subjects voluntarily cede exactly half to another individual. The hypothesis that people care about fairness does not by itself account for key experimental patterns. We consider an alternative explanation, which adds the hypothesis that people like to be perceived as fair. The properties of equilibria for the resulting signaling game correspond closely to laboratory observations. The theory has additional testable implications, the validity of which we confirm through new experiments.

Economists have long observed that crowding out of government grants to private charities is incomplete. The accepted belief is that givers treat the grants as imperfect substitutes for private giving. We theoretically and empirically investigate a second reason: the strategic response of a charity will be to reduce fund-raising efforts after receiving a grant. Employing panel data from arts and social service organizations, we find that government grants cause significant reductions in fund-raising. This adds a new dimension to the policy discussions—analysts should account for the behavioral responses of the charity, as well as the donors, to government grants.

The Carrot or the Stick: Rewards, Punishments, and Cooperation by James Andreoni, William Harbaugh and Lise Vesterlund. Published in volume 93, issue 3, pages 893-902 of American Economic Review, June 2003

The ultimatum game, by its all-or-nothing nature, makes it difficult to discern what kind of preferences may be generating choices. We explore a game that convexifies the decisions, allowing us a better look at the indifference curves of bargainers while maintaining the subgame-perfect equilibrium. We conclude that bargainers' preferences are convex and regular but not always monotonic. Money-maximization is the sole concern for about half of the subjects, while the other half reveal a preference for fairness. We also found, unexpectedly, the importance of risk aversion among money-maximizing proposers, which in turn generates significant bargaining power for fair-minded responders.

In settings with uncertainty, tension exists between ex ante and ex post notions of fairness. Subjects in an experiment most commonly select the ex ante fair alternative ex ante and switch to the ex post fair alternative ex post. One potential explanation embraces consequentialism and construes reversals as time inconsistent. Another abandons consequentialism in favor of deontological (rule-based) ethics and thereby avoids the implication that revisions imply inconsistency. We test these explanations by examining contingent planning and the demand for commitment. Our findings suggest that the most common attitude toward fairness involves a time-consistent preference for applying a naive deontological heuristic.