How pleasantly surprising to see an official link which is the fulltext as well. I&#x27;ll just quote the abstract to entice people into reading it:<p>&quot;The anthropological record indicates that approximately 85 per cent of human societies have permitted
men to have more than one wife (polygynous marriage), and both empirical and
evolutionary considerations suggest that large absolute differences in wealth should favour more polygynous
marriages. Yet, monogamous marriage has spread across Europe, and more recently across the
globe, even as absolute wealth differences have expanded. Here, we develop and explore the hypothesis
that the norms and institutions that compose the modern package of monogamous marriage have been
favoured by cultural evolution because of their group-beneficial effects—promoting success in
inter-group competition. In suppressing intrasexual competition and reducing the size of the pool of
unmarried men, normative monogamy reduces crime rates, including rape, murder, assault, robbery
and fraud, as well as decreasing personal abuses. By assuaging the competition for younger brides, normative
monogamy decreases (i) the spousal age gap, (ii) fertility, and (iii) gender inequality. By shifting
male efforts from seeking wives to paternal investment, normative monogamy increases savings, child
investment and economic productivity. By increasing the relatedness within households, normative
monogamy reduces intra-household conflict, leading to lower rates of child neglect, abuse, accidental
death and homicide. These predictions are tested using converging lines of evidence from across the
human sciences.&quot;