The ancestral logic of politics: Upper body strength regulates men’s assertion of self-interest over economic redistribution

Abstract

Over human evolutionary history, upper body strength has been a major component of fighting ability. Evolutionary models of animal conflict predict that actors with greater fighting ability will more actively attempt to acquire or defend resources than less formidable contestants. Here, we apply these models to political decision-making about redistribution of income and wealth among modern humans. In studies conducted in Argentina, Denmark and the U.S., men with greater upper body strength more strongly endorsed the self-beneficial position: Among men of lower socioeconomic status (SES), strength predicted increased support for redistribution; among men of higher SES, strength predicted increased opposition to redistribution. As personal upper body strength is irrelevant to payoffs from economic policies in modern mass democracies, the continuing role of strength suggests that modern political decision-making is shaped by an evolved psychology designed for small-scale groups.