Knowledge that Transforms

We study risk attitudes, ambiguity attitudes, and time preferences of 661 children and adolescents, aged ten to eighteen years, in an incentivized experiment and relate experimental choices to field behavior. Experimental measures of impatience are found to be significant predictors of health-related field behavior, saving decisions, and conduct at school. In particular, more impatient children and adolescents are more likely to spend money on alcohol and cigarettes, have a higher body mass index, are less likely to save money, and show worse conduct at school. Experimental measures for risk and ambiguity attitudes are only weak predictors of field behavior.

We measure the change in household spending caused by receipt of the economic stimulus payments of 2008, using questions added to the Consumer Expenditure Survey and variation from the randomized timing of disbursement. Households spent 12–30 percent (depending on specification) of their payments on nondurable goods during the three-month period of payment receipt, and a significant amount more on durable goods, primarily vehicles, bringing the total response to 50–90 percent of the payments. The responses are substantial and significant for older, lower-income, and home-owning households. Spending does not vary significantly with the method of disbursement (check versus electronic transfer).

We investigate whether car buyers are myopic about future fuel costs. We estimate the effect of gasoline prices on short-run equilibrium prices of cars of different fuel economies. We then compare the implied changes in willingness-to-pay to the associated changes in expected future gasoline costs for cars of different fuel economies in order to calculate implicit discount rates. Using different assumptions about annual mileage, survival rates, and demand elasticities, we calculate a range of implicit discount rates similar to the range of interest rates paid by car buyers who borrow. We interpret this as showing little evidence of consumer myopia.

Using data from a field experiment in Kenya, we document that providing individuals with simple informal savings technologies can substantially increase investment in preventative health and reduce vulnerability to health shocks. Simply providing a safe place to keep money was sufficient to increase health savings by 66 percent. Adding an earmarking feature was only helpful when funds were put toward emergencies, or for individuals that are frequently taxed by friends and relatives. Group-based savings and credit schemes had very large effects.

We offer a theory of polarization as an optimal response to ambiguity. Suppose individual A's beliefs first-order stochastically dominate individual B's. They observe a common signal. They exhibit polarization if A's posterior dominates her prior and B's prior dominates her posterior. Given agreement on conditional signal likelihoods, we show that polarization is impossible under Bayesian updating or after observing extreme signals. However, we also show that polarization can arise after intermediate signals as ambiguity averse individuals implement their optimal prediction strategies. We explore when this polarization will occur and the logic underlying it.

This paper develops a learning model of cultural change to investigate why women's labor force participation (LFP) and attitudes toward women's work both changed dramatically. In the model, women's beliefs about the long-run payoff from working evolve endogenously via an intergenerational learning process. This process generically generates the data's S-shaped LFP curve and introduces a novel role for wage changes via their effect on the speed of intergenerational learning. The calibrated model does a good job of replicating the evolution of female LFP in the United States over the last 120 years and finds that the new role for wages was quantitatively significant.

We study the mobile phone-based money transfer system in Kenya. Based on aggregate data, we estimate that the velocity with which units of e-money are transferred among users is approximately four times per month, and that the average number of transfers undergone by a unit of e-money between its creation and destruction is approximately one. Most M-Pesa transactions are made by frequent users. Examination of data on withdrawals shows a high frequency of small withdrawals and no response to “notches” in the price schedule, indicating that many users seem to have high implicit discount rates.

Dynamic matching and bargaining games are models of decentralized markets with trading frictions. A central objective is to investigate how equilibrium outcomes depend on the level of frictions. In particular, does the trading outcome become Walrasian when frictions become small? Existing specifications of such games provide divergent answers. This paper presents a new characterization result for competitive allocations in quasilinear economies. The characterization result is used to investigate what causes these differences and to generalize insights from the analysis of specific matching and bargaining games.

This article introduces a new approach to modeling the expanding universe of decision makers in the wake of growing awareness, and invokes the axiomatic approach to model the evolution of decision makers' beliefs as awareness grows. The expanding universe is accompanied by extension of the set of acts, the preference relations over which are linked by a new axiom, invariant risk preferences, asserting that the ranking of lotteries is independent of the set of acts under consideration. The main results are representation theorems and rules for updating beliefs over expanding state spaces and events that have the flavor of “reverse Bayesianism.”

Authority and power permeate political, social, and economic life, but empirical knowledge about the motivational origins and consequences of authority is limited. We study the motivation and incentive effects of authority experimentally in an authority-delegation game. Individuals often retain authority even when its delegation is in their material interest—suggesting that authority has nonpecuniary consequences for utility. Authority also leads to overprovision of effort by the controlling parties, while a large percentage of subordinates underprovide effort despite pecuniary incentives to the contrary. Authority thus has important motivational consequences that exacerbate the inefficiencies arising from suboptimal delegation choices.