A human tendency to value expertise, not just sheer power, explains how some social hierarchies form

Born on the same day, Bill and Ben both grew up to have high status. But in every other way they were polar opposites.

As children, Bill was well-liked, with many friends, while Ben was a bully, picking on smaller kids. During adolescence, Bill earned a reputation for athleticism and intelligence. Ben, flanked by his henchmen, was seen as formidable and dangerous. In adulthood, Bill was admired for his decision-making and diplomacy, but Ben was feared for his aggression and intransigence.

People sought out Bill’s company and listened to his advice. Ben was avoided, but he got his way through force.

How did Ben get away with this? Well, there’s one more difference: Bill is a human, and Ben is a chimp.

This hypothetical story of Bill and Ben highlights a deep difference between human and animal social life. Many mammals exhibit dominance hierarchies; forms of inequality in which stronger individuals use strength, aggression and allies to get better access to food or mating opportunities.

Human societies are more peaceable but not necessarily more equal. We have hierarchies, too – leaders, captains and bosses. Does this mean we are no more than clothed apes, our domineering tendencies cloaked under superficial civility?

I’m an evolutionary anthropologist, part of a team of researchers who set out to come to grips with the evolutionary history of human social life and inequality.

Building on decades of discoveries, our work supports the idea that human societies are fundamentally different from those of other species. People can be coercive, but unlike other species, we also create hierarchies of prestige – voluntary arrangements that allocate labor and decision-making power according to expertise.

This tendency matters because it can inform how we, as a society, think about the kinds of social hierarchies that emerge in a workplace, on a sports team or across society more broadly. Prestige hierarchies can be steep, with clear differences between high and low status. But when they work well, they can form part of a healthy group life from which everyone benefits.

Equal by nature?

Primate-style dominance hierarchies, along with the aggressive displays and fights that build them, are so alien to most humans that some researchers have concluded our species simply doesn’t “do” hierarchy. Add to this the limited archaeological evidence for wealth differences prior to farming, and a picture emerges of humans as a peaceful and egalitarian species, at least until agriculture upended things 12,000 years ago.

But new evidence tells a more interesting story. Even the most egalitarian groups, such as the Ju/‘hoansi and Hadza in Africa or Tsimané in South America, still show subtle inequalities in status, influence and power. And these differences matter: High-ranking men get their pick of partners, sometimes multiple partners, and go on to have more children. Archaeologists have also uncovered sites that display wealth differences even without agriculture.

So, are we more like other species than we might care to imagine, or is there still something different about human societies?

Dominance and prestige

One oddity is in how human hierarchies form. In other animals, fighting translates physical strength into dominance. In humans, however, people often happily defer to leaders, even seeking them out. This deference creates hierarchies of prestige, not dominance.

Why do people do this? One current hypothesis is that we, uniquely, live in a world that relies on complex technologies, teaching and cooperation. In this world, expertise matters. Some people know how to build a kayak; others don’t. Some people can organize a team to build a house; others need someone else to organize them. Some people are great hunters; others couldn’t catch a cold.

In a world like this, everyone keeps an eye out for who has the skills and knowledge they need. Adept individuals can translate their ability into power and status. But, crucially, this status benefits everyone, not just the person on top.

That’s the theory, but where’s the evidence?

There are plenty of anthropological accounts of skillful people earning social status and bullies being quickly cut down. Lab studies have also found that people do keep an eye on how well others are doing, what they’re good at, and even whom others are paying attention to, and they use this to guide their own information-seeking.

What my colleagues and I wanted to do was investigate how these everyday decisions might lead to larger-scale hierarchies of status and influence.

From theory to practice

In a perfect world, we’d monitor whole societies for decades, mapping individual decisions to social consequences. In reality, this kind of study is impossible, so my team turned to a classic tool in evolutionary research: computer models. In place of real-world populations, we can build digital ones and watch their history play out in milliseconds instead of years.

In these simulated worlds, virtual people copied each other, watched whom others were learning from and accrued prestige. The setup was simple, but a clear pattern emerged: The stronger the tendency to seek out prestigious people, the steeper social influence hierarchies became.

Below a threshold, societies stayed mostly egalitarian; above it, they were led by a powerful few. In other words, “prestige psychology” – the mental machinery that guides whom people learn from – creates a societal tipping point.

The next step was to bring real humans into the lab and measure their tendency to follow prestigious leaders. This can tell us whether we, as a species, fall above or below the tipping point – that is, whether our psychology favors egalitarian or hierarchical groups.

To do this, my colleagues and I put participants into small groups and gave them problems to solve. We recorded whom participants listened to, and let them know whom their group mates were learning from, and we used this information to find the value of the human “hierarchy-forming” tendency. It was high – well above the tipping point for hierarchies to emerge, and our experimental groups ended up with clear leaders.

One doubt lingered: Our volunteers were from the modern United States. Can they really tell us about the whole human species?

Rather than repeat the study across dozens of cultures, we returned to modeling. This time, we let prestige psychology evolve. Each simulated person had their own tendency for how much they deferred to prestige. It guided their actions, affected their fitness and was passed on to their children with minor mutations.

Over thousands of generations, natural selection identified the most successful psychology: a sensitivity to prestige nearly identical to that we measured in real humans – and strong enough to produce the same sharp hierarchies.

Inequality for everyone?

In other primates, being at the bottom of the social ladder can be brutal, with routine harassment and bullying by group mates. Thankfully, human prestige hierarchies look nothing like this. Even without any coercion, people often choose to follow skilled or respected individuals because good leadership makes life easier for everyone. Natural selection, it seems, has favored the psychology that makes this possible.

Of course, reality is messier than any model or lab experiment. Our simulations and experiment didn’t allow for coercion or bullying, and so they give an optimistic view of how human societies might work – not how they do.

In the real world, leaders can selfishly abuse their authority or simply fail to deliver collective benefits. Even in our experiment, some groups rallied around below-average teammates, the snowballing tendency of prestige swamping signs of their poor ability. Leaders should always be held to account for the outcomes of their choices, and an evolutionary basis to prestige does not justify the oppression of the powerless by the powerful.

So hierarchies remain a double-edged sword. Human societies are unique in the benefits that hierarchies can bring to followers, but the old forces of dominance and exploitation have not disappeared. Still, the fact that natural selection favored a psychology that drives voluntary deference and powerful leaders suggests that, most of the time, prestige hierarchies are worth the risks. When they work well, we all reap the rewards.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: Thomas Morgan, Arizona State University

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Thomas Morgan has received research funding from DARPA, the NSF and the Templeton World Charity Foundation.