Upon introducing heterogeneity and dynamics into a model of the demand for children, a problem of optimal population is defined and analyzed. It is shown that from the perspective of social welfare, better-educated individuals produce too few children while less-educated individuals produce too...

Why are economists convinced that {\it homo economicus}\/ is selfish? No doubt we find considerable support for this hypothesis in the behavior of our colleagues. Beyond this, a plausible evolutionary argument for selfishness would assert that if natural selection favors those who receive high...

Replaced with revised version of paper 02/27/08.

We study the joint role of altruism and impatience, and the impact of evolution in the formation of long-term time preferences and in the determination of optimal consumption and optimal bequests. We show how the consumption paths of dynasties relate to altruism and to impatience, and we reason...

A framework that yields different possible patterns of migration as optimal solutions to a simple utility maximization problem is presented and explored. It is shown that seasonal migration arises as an optimal endogenous response to a comparison of costs (of living and of separation) and...

This paper synthesizes and extends recent research on "The New Economics of the Brain Drain." In a unified framework, the paper shows that while recently identified adverse repercussions of the brain drain exacerbate the long-recognized negative impacts of the brain drain, longer-term...