Strategic Learning and the Topology of Social Networks

We consider a group of strategic agents who must each repeatedly take one of two possible actions. They learn which of the two actions is preferable from initial private signals and by observing the actions of their neighbors in a social network. We show that the question of whether or not the agents learn efficiently depends on the topology of the social network. In particular, we identify a geometric “egalitarianism” condition on the social network that guarantees learning in infinite networks, or learning with high probability in large finite networks, in any equilibrium. We also give examples of nonegalitarian networks with equilibria in which learning fails.     

Migration decision making and migration behavior in rural Kenya

Micro theories of migration have generally been tested with data which do not allow one to distinguish between the decision to move and the act of moving. The latter is usually treated as a proxy for the former. Using data from a two round survey of youth in rural Kenya we classify respondents as decision processors/nondecision processors from round one data, and determine who migrates over a nine month interval from round two data. Thirty-four percent of the sample are classified as decision processors and 25% as migrants, but decision processors were only slightly more likely to migrate than nondecision processors and more migrants actually came from the latter group.A simple model is developed to determine the extent to which the same factors that influence decision-processing influence who migrates. The model is tested using regression procedures by first treating decision-processing as the dependent variable then migration. The model explains 26% of the variance in who decides, but only 10% of the variance in who actually moved. Finally, separate analyses are done of the determinants of migration for decision processors and nondecision processors.     

The component structure of elderly population growth in the Netherlands: 1950–1980

While there is no doubt about the magnitude of the growth of older age groups in industrialized nations, its structural components are less well understood. This paper examines the roles played by cohort succession and mortality in the process for the Netherlands during the period 1950 to 1980. While the size of population aged 65 and over has increased for both males and females, increases in the size of succeeding cohorts explain all of the growth in the older male population. Reductions in mortality at the older old ages play a much greater role than do reductions at younger old ages; the latter reductions occur among females only.     

The consequences of metropolitan decentralization for personal gasoline consumption

It is often argued that more decentralized and spatially dispersed metropolitan areas require their residents to consume more gasoline than more centralized metropolitan areas. This notion is deduced from the assumption that, (1) populations decentralize, and (2) as this happens, people locate at distances farther removed from metropolitan centers which house most of the services, shops and jobs which suburban residents must travel to. In this article, it is argued that, at advanced stages of metropolitanization, the places to which people travel also decentralize and as this happens the gasoline consumption of metropolitan residents in more decentralized areas actually becomes lower than that of residents in more centralized areas. The latter argument is tested using multiple indicators of decentralization, and a number of control variables. All of the indicators of expansion relate to gasoline consumption in the predicted direction; the implications of this for energy and location policy are discussed.This research was supported in part by grants from the National Science Foundation (SOC 7826121 and SOC 77-07579), and the Program of University Research, U.S. Department of Transportation (80-193).