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When humans are offered the choice between rewards available at different points in time, the relative values of the options are discounted according to their expected delays until delivery. Using functional magnetic resonance imaging, we examined the neural correlates of time discounting while subjects made a series of choices between monetary reward(More)
This paper considers how identity, a person’s sense of self, affects economic outcomes.We incorporate the psychology and sociology of identity into an economic model of behavior. In the utility function we propose, identity is associated with different social categories and how people in these categories should behave. We then construct a simple(More)
Zipf ’s law is a very tight constraint on the class of admissible models of local growth. It says that for most countries the size distribution of cities strikingly fits a power law: the number of cities with populations greater than S is proportional to 1/S. Suppose that, at least in the upper tail, all cities follow some proportional growth process (this(More)
The potential for rare economic disasters explains a lot of asset-pricing puzzles. I calibrate disaster probabilities from the twentieth century global history, especially the sharp contractions associated with World War I, the Great Depression, and World War II. The puzzles that can be explained include the high equity premium, low risk-free rate, and(More)
I quantitatively measure the interactions between the media and the stock market using daily content from a popular Wall Street Journal column. I find that high media pessimism predicts downward pressure on market prices followed by a reversion to fundamentals, and unusually high or low pessimism predicts high market trading volume. These and similar(More)
This paper solves a realistically calibrated life-cycle model of consumption and portfolio choice with uninsurable labor income risk and borrowing constraints. Since labor income substitutes for riskless asset holdings the optimal share invested in equities is roughly decreasing over life. We compute a measure of the importance of non-tradable human capital(More)
There are two sources of inconsistency in existing cross-country empirical work on growth: correlated individual effects and endogenous explanatory variables. We estimate a variety of crosscountry growth regressions using a generalized method of moments estimator that eliminates both problems. In one application, we find that per capita incomes converge to(More)
Previous research, involving monetary rewards, found that limbic reward-related areas show greater activity when an intertemporal choice includes an immediate reward than when the options include only delayed rewards. In contrast, the lateral prefrontal and parietal cortex (areas commonly associated with deliberative cognitive processes, including future(More)
This paper reports experiments designed to study strategic sophistication, the extent to which behavior in games reflects attempts to predict others’ decisions, taking their incentives into account. We study subjects’ initial responses to normal-form games with various patterns of iterated dominance and unique pure-strategy equilibria without dominance,(More)