Network Ecology of Marriage

TL;DR

This paper models marriage as a social technology that enhances family network interconnectedness, promoting cooperation and larger groups, explaining its unique role in human evolution.

Contribution

It introduces a network ecology model showing how marriage increases social interconnectedness and cooperation among human kin.

Findings

Marriage increases family network interconnectedness.

Enhanced interconnectedness promotes cooperation and larger social groups.

Marriage reduces free-riding in collaborative groups.

Abstract

The practice of marriage is an understudied phenomenon in behavioural sciences despite being ubiquitous across human cultures. This modelling paper shows that replacing distant direct kin with in-laws increases the interconnectedness of the family social network graph, which allows more cooperative and larger groups. In this framing, marriage can be seen as a social technology that reduces free-riding within collaborative group. This approach offers a solution to the puzzle of why our species has this particular form of regulating mating behaviour, uniquely among pair-bonded animals.