Demographic dynamics and kinship in anthropological populations.

Changes in fertility and mortality affect the size of surviving sibling sets and thus numbers of surviving kin. Because the genealogical generations specifying kinship relations are not temporal cohorts and most plausible demographic changes in anthropological populations are period shocks, the effect of such shocks on kin counts are complex. Shocks increasing fertility or decreasing mortality produce larger numbers of kin per ego and decrease the inequality of the distribution of kin and vice versa. Effects are more diffuse at more distant collateral ranges. Effects are stronger the more intense the shock and the longer its duration. Kinship distributions return to their initial state after the shock and as the original age structure of the population is ergodically reattained. Alternating shocks produce more complex patterns. Implications of these outcomes are that opportunities for political networking and consolidation by means of kinship are altered by demographic instabilities, as are the dynamics of kin selection. This analysis is limited for simplicity to unilineal agnatic reckoning of kin.