Prehistoric shuttle dispersals in a Malthusian economy

Early humans undertook multiple waves of migration out of Africa and back to the continent. We explore prehistoric human migration in a two‐region Malthusian growth model. Whether migration occurs depends on the migration cost, relative population size, relative land supply, and relative hunting‐gathering productivity between regions. Suppose one region is initially uninhabited. Then, a lower migration cost leads to migration and a larger human population. Back migration occurs when hunting‐gathering productivity and supply of natural resources in the foreign region decrease relative to the home region, which provides an economic rationale for the multi‐directional “shuttle dispersal model” of prehistoric human migration out of and back to Africa.