Knowledge that Transforms

We develop a theory of prosocial behavior that combines heterogeneity in individual altruism and greed with concerns for social reputation or self-respect. Rewards or punishments (whether material or image-related) create doubt about the true motive for which good deeds are performed, and this “overjustification effect” can induce a partial or even net crowding out of prosocial behavior by extrinsic incentives. We also identify the settings that are conducive to multiple social norms and, more generally, those that make individual actions complements or substitutes, which we show depends on whether stigma or honor is (endogenously) the dominant reputational concern. Finally, we analyze the socially optimal level of incentives and how monopolistic or competitive sponsors depart from it. Sponsor competition is shown to potentially reduce social welfare.

Many developed countries have a market for private health insurance that supplements publicly funded, universal coverage. Government regulation of the supplemental market, including the extent to which insurers are permitted to adjust premiums based on individual characteristics such as age, sex, and health status, varies across countries (OECD, 2004). Proponents of rate regulation argue that the resulting crosssubsidization from low to high risks is necessary to maintain the affordability of coverage for high risks. Economic theory, however, raises the concern that the inability to adjust premiums to reflect individual risk could create adverse selection by driving low risks from the market (Michael Rothschild and Joseph Stiglitz, 1976). Little empirical evidence exists to determine the optimal role of rate regulation in private, supplemental insurance markets. Existing studies of the consequences of rating restrictions focus on markets for primary health insurance and find that these laws have had surprisingly little effect on overall rates of coverage (Simon, 2004). In this paper, we study the effects of rate regulation in supplemental health insurance markets by examining the market for individually purchased coverage that supplements Medicare among the elderly in the United States. While the publicly financed Medicare program provides nearly universal coverage of a standard set of benefits for those 65 and over, beneficiaries are exposed to significant financial risk due to the cost sharing associated with covered services and a lack of coverage for some important services. The vast majority of Medicare beneficiaries obtain supplemental coverage through a complex system of publicly and privately funded sources. State Medicaid programs provide publicly financed supplemental coverage for low-income and disabled beneficiaries, and employers provide highly subsidized retiree supplemental health insurance for other beneficiaries, but the remainder rely on highly regulated, private insurance markets. Medicare’s Part C managed care plans are a voluntary, private replacement for traditional Medicare, while “Medigap” coverage is a private policy, bought by about 30 percent of Medicare beneficiaries, that provides only supplemental benefits (Franklin J. Eppig and George S. Chulis, 1997). Our study examines the effects of regulations limiting the information on individual characteristics insurers can use in setting premiums for Medigap coverage.

For more than a decade, an MIT-trained economist has meticulously recorded the results of nearly 75,000 deliveries of bagels and donuts to corporate offices. These bagels and donuts are left in workplaces in the morning, along with a list of prices and a lockbox. Office workers purchase the products on the honor system. Later that day, the uneaten goods and the lock box are collected and the relevant data for each office are recorded in a spreadsheet. These data provide a unique opportunity for understanding the extent to which individuals behave honestly in this setting and the factors that influence the level of honesty. An analysis of the discrepancy between the prices of the goods consumed and the actual payments deposited in the lock box yields a number of insights. First, the base payment rate is quite high. On average, payments represent almost 90 percent of the posted price. In a model of pure self-interest, one would expect very low payment rates, because there would seem to be many opportunities for individuals to take the products with almost no chance of their nonpayment being detected. Moderating the tendency to take the products without paying is the fact that low payment rates will increase the probability the delivery company stops serving the company. Paying for one’s bagels and donuts, viewed in this light, is a public good for other office workers. Thus, one might expect a strong negative relationship between office size and payment rates, which is not present in the data. Rather, the data appear more consistent with a model in which there are internal, nonpecuniary costs associated with stealing the bagels and donuts, i.e., people overwhelmingly pay for the products because it would be wrong not to do so. The observed payment rates are systematically related to a variety of observable factors. For instance, payment rates fall in response to increases in the posted price. This is consistent with the increase in financial costs pushing some marginal consumers to be willing to sustain the moral cost associated with not stealing the goods or paying less than full price. Payment rates are higher when many of the bagels and donuts go uneaten, suggesting that the marginal consumer pays a lower share of the posted price than the inframarginal consumer. Purchasers of donuts appear to be more likely to pay less than the full price. There is a sharp and persistent increase in the payment rate following the September 11 terrorist attacks.

This paper studies an overlapping generations model with stochastic production and incomplete markets to assess whether the introduction of an unfunded social security system leads to a Pareto improvement. When returns to capital and wages are imperfectly correlated, a system that endows retired households with claims to labor income enhances the sharing of aggregate risk between generations. Our quantitative analysis shows that, abstracting from the capital crowding-out effect, the introduction of social security represents a Pareto-improving reform, even when the economy is dynamically efficient. However, the severity of the crowding-out effect in general equilibrium tends to overturn these gains.

We analyze the consequences of control on motivation in an experimental principal-agent game, where the principal can control the agent by implementing a minimum performance requirement before the agent chooses a productive activity. Our results show that control entails hidden costs since most agents reduce their performance as a response to the principal's controlling decision. Overall, the effect of control on the principal's payoff is nonmonotonic. When asked for their emotional perception of control, most agents who react negatively say that they perceive the controlling decision as a signal of distrust and a limitation of their choice autonomy.

In an experiment, players' ability to learn to cooperate in the repeated prisoner's dilemma was substantially diminished when the payoffs were noisy, even though players could monitor one another's past actions perfectly. In contrast, in one-time play against a succession of opponents, noisy payoffs increased cooperation, by slowing the rate at which cooperation decays. These observations are consistent with the robust observation from the psychology literature that partial reinforcement (adding randomness to the link between an action and its consequences while holding expected payoffs constant) slows learning. This effect is magnified in the repeated game: when others are slow to learn to cooperate, the benefits of cooperation are reduced, which further hampers cooperation. These results show that a small change in the payoff environment, which changes the speed of individual learning, can have a large effect on collective behavior. And they show that there may be interesting comparative dynamics that can be derived from careful attention to the fact that at least some economic behavior is learned from experience.

In recent decades, U.S. foreign trade grew much faster than GDP, but there is no consensus why. Notably lacking is an understanding of the role of multinational corporations (MNCs), which mediate over half of world trade. We use Bureau of Economic Analysis data on U.S. MNCs to study the rapid growth of MNC-based trade from 1983 to 1996. Using a model of U.S. MNCs and Canadian affiliates, we decompose this growth by source. Tariff reductions can largely explain increases in arms-length MNC-based trade. But intra-firm trade growth is attributed mostly to “technical change.” We present additional evidence suggesting just-in-time production facilitated intra-firm trade.

Researchers in a variety of important economic literatures have assumed that current income variables as proxies for lifetime income variables follow the textbook errors-in-variables model. In our analysis of Social Security records containing nearly career-long earnings histories for the Health and Retirement Study sample, we find that the relationship between current and lifetime earnings departs substantially from the textbook model in ways that vary systematically over the life cycle. Our results can enable more appropriate analysis of, and correction for, errors-in-variables bias in any research that uses current earnings to proxy for lifetime earnings.

Countries? ” If there exist aggregate production functions representing approximately the same technology across countries, then the vastly higher output per worker in richer countries implies that capital per worker must be much higher in these countries, and diminishing returns implies a much lower rate of return to capital in rich than in poor countries. The details of the calculation depend, of course, on specific assumptions. However, the magnitudes are sufficiently large that the absence of massive capital flows to the poorest countries is properly seen as a fundamental puzzle. Lucas considers the possibility that capital market imperfections permit the existence of a gap in the returns to capital across countries, but argues that this cannot account for most of the difference implied by his calculation. He, therefore, raises the possibility that there are huge differences in human capital across countries, and externalities associated with these differences imply that returns to physical capital are not so different across countries with even large differences in physical capital per worker. Accordingly, there is no mystery about the lack of physical capital flows. In contrast, Abhijit V. Banerjee and Esther C. Duflo (2005) review a good deal of evidence, mostly from India, showing widely varying and often very high real interest rates. In addition, ∗We are grateful to Marcus Noland for the initial conversation that led to this paper, to Erica Field, Barbara O’Brien and Yuichi Kitamura for valuable comments, and to Hyungi Woo, Tavneet Suri, and Patrick Amihere

We study cross-country differences in the aggregate production function when skilled and unskilled labor are imperfect substitutes. We find that there is a skill bias in cross-country technology differences. Higher-income countries use skilled labor more efficiently than lower-income countries, while they use unskilled labor relatively and, possibly, absolutely less efficiently. We also propose a simple explanation for our findings: rich countries, which are skilled-labor abundant, choose technologies that are best suited to skilled workers; poor countries, which are unskilled-labor abundant, choose technologies more appropriate to unskilled workers. We discuss alternative explanations, such as capital-skill complementarity and differences in schooling quality.