Why our ancestors were more gender equal than us

May 18, 2015 by Andrea Migliano And Lucio Vinicius, The Conversation

It is often believed that hierarchical and sometimes oppressive social structures like the patriarchy are somehow natural – a reflection of the law of the jungle. But the social structure of today's hunter gatherers suggests that our ancestors were in fact highly egalitarian, even when it came to gender. Their secret? Not living with many relatives.

These societies were not only strikingly different from most horticulturalist, farming and pastoralist societies today, but also from the hierarchical societies of apes, our closest evolutionary relatives. Chimpanzees and gorillas are known to have patterns of sex inequality similar to post-agriculture humans.

The history of hierarchy

About 10,000 years ago, humans started forming societies based on food production which also led to the development of wealth accumulation and inheritance. It was these factors that resulted in well-structured hierarchies based on social ranking – with more wealth leading to more power. This organisation was also expressed at the gender level. The sex that could monopolise resources could also take charge of territories, wedding decisions, family life and was ultimately able to control the opposite sex.

Specifically, sex inequality – which is seen in most food-producing societies that evolved relatively recently in human history – meant that the powerful sex (most often men) could dictate alliances between the relatives they lived with. This increased the power of clans and facilitated wealth transfer over generations. The weaker sex (most often the women) as a rule had no choice but to follow their husbands and move with their husband's family.

Well, we do not believe that this grim scenario is necessarily "natural". Before food production started, we were all hunter-gatherers. And if the few hunter-gatherer groups living today are representative of our adaptive past, then our findings suggest that our ancestors were much more egalitarian, and sex-egalitarian, than we are.

In our study of the BaYaka from Congo and the Agta from the Philippines, what is striking is how egalitarian these populations are in many social domains: there are no chiefs, no large households, no property of land or resources, and couples are welcome to come and go between camps as they please. Couples must constantly move around between camps in search of food or in search of people to share food with, and for this reason group composition keeps changing. As a result individuals in a camp can be highly unrelated to each other, which prevents the formation hierarchical structures.

This freedom of movement allows for both men and women to recruit help from their families when necessary. The main result from our computer simulations and co-residence data was that although both husbands and wives try to maximise the number of family members living close by, neither sex has the upper hand. This implies that neither one ends up living with their relatives but instead reside with a small proportion of relatives and in-laws and a large number of unrelated individuals. Rules of sharing are therefore extended to unrelated co-residents, and movement between camps is frequently used as a way to avoid the less cooperative individuals.

These populations could not have evolved in harsh environments without placing cooperation between the sexes and families at the heart of their lifestyle. In a nutshell, this means that egalitarianism, food sharing, large-scale cooperation and sex equality are all a matter of necessity in hunter-gatherers.

The evolution of fairness

Our simulations are a simple mechanistic answer for the puzzle of why modern hunter-gatherers live with so few kin, but they have huge implications for our understanding of , and also of human nature.

The fact that we are able to live, interact and cooperate with unrelated individuals and not only with kin has been recently identified as the most fundamental difference between and other .

Of course, humans have the capacity to be anything, from the most cruel and unequal species, with sex slavery and warfare, to the most cooperative and caring animal, with people donating blood to complete strangers. Good and evil are just the two extremes of our malleable nature. However, the few surviving groups show us that without the equality and cooperation between sexes that they share with our distant ancestors many of the characteristics that we like to call "uniquely human", such as caring for others and fairness, would probably not have evolved.

Explore further: Unique social structure of hunter-gatherers explained

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