Abstract
This study explores the evolution of family systems in non-industrial agricultural societies based on environmental conditions. First, the authors conduct a multi-evolutionary simulation for each family system: absolute nuclear families (nuclear with unequal inheritance), egalitarian nuclear families (nuclear with equal inheritance), stem families (extended families with unequal inheritance), and community families (extended families with equal inheritance). Second, they use Spearman's rank correlation analyses to assess the relation between the 186 non-industrial societies and the types of inheritance relationships, either parent-child (nuclear or extended) or inter-sibling (strongly biased or equal). The results show that the four core family systems are related to wealth and land resources. Other relevant findings are that low polygyny is related to agricultural societies, higher poverty levels to extended families, and accelerated wealth accumulation to strongly biased inheritance.