How we get along (1)

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It’s hard to believe, with daily news of fevered disagreement and of actual fighting, but human beings excel at cooperation. We mostly trust each other to do our part. Thomas Hobbes wrote, in Leviathan, that the state of nature was a war of all against all, exited only when our ancestors signed a social contract, waived their rights to take what they could, and authorized a King’s enforcement of their pledge. But “we have been obligate co-operators for hundreds of thousands of years; perhaps millions of years” (Kim Sterelny). Back then, no one could read a contract, or sign their name. No one could even think the thoughts the agreement contained. How then did they find a way to get along?

In social contract theory the stroke of a pen changes total war into civil society, ordered and secure. In reality this change took generations, step by gradual step, in “evolutionary time.” The Pleistocene Social Contract is Kim Sterelny’s account of those steps (he draws on the work of many others). I’m not qualified to validate or dispute his account, with archaeological evidence or expertise in evolutionary theory. But the account is interesting, and I can sketch its outline.

1. Collective action with immediate returns.

Many forms of cooperation are beneficial to all. Division of labor is familiar: I make the bread, you make the wine, and together we have a full meal. Sterelny says that the first form of cooperation was simpler: collective action with immediate returns.

The paradigm is group hunting. If we hunt together, and split the kill equally, we will each have more: we can take down bigger game, or more efficiently capture the small stuff.

But any form of cooperation, including this one, may be undermined by cheating. Free-riders enjoy the benefits while avoiding the costs. I drive the roads but don’t pay my taxes. Or someone may be greedy: participating, but taking too much of the profit—say, half the kill, when there are five hunters. Cheating in either form erodes cooperation's benefits. If it spreads too far there comes a “tipping-point where co-operators do best to cease cooperating and go it alone.”

Free-riding and greed are still with us today (you may have noticed). But we keep them well-enough under control for cooperation to remain beneficial. Techniques for controlling cheating have become more complicated, as cooperation has become more complex. In group hunting, free-riding is easily handled: since returns are immediate, they go only to those who participate. But greed is a problem, if bullying is possible. A bully is able and willing to beat up others, and take what they have. Bullies will take for themselves a too-large share of the proceeds of the hunt. It was a crucial moment in human history when

the great ape pattern was broken; the dominance hierarchy [organized around bullying] was suppressed.

What broke the pattern? The bad news is that “we do not know how or when bullies were stripped of their coercive power in the hominin lineage.” But there’s some good news: a speculative but plausible model of the process, which Sterelny sketches. Central to it is the evolution of the use of weapons. Weapons make bullying harder. Hand to hand, you might pack a harder punch, and be more willing to risk a fight. Knowing this, I’ll submit. But once projectile weapons are available, your advantage diminishes. Even with my flabbier arms, I could kill you with one shot from a safe distance. If everyone is armed, fewer will risk acting on their greed.

While the new weapons technology was a “difference-maker,” it was not by itself enough to end bullying: also needed was

enduring motivation [to retaliate against bullies] and an ability to act together....Over evolutionary time the motivation to suppress bullying shifted from flares of hot but brief reactive attitudes to become more sustained and persisting. Erectines or Heidelbergensians learned to treasure and sustain their resentments, a psychology not wholly unknown in [anatomically modern humans].

2. Reciprocation.

If I forage for food and share it around, counting on others to share with me later, we’ve moved past collective action with immediate returns, to reciprocation. Reciprocation is more beneficial than collective action: “foragers who share through indirect reciprocation gather resources more efficiently, and manage risk more effectively.” The flip-side is that cheating is harder to control.

Cheaters get more than they are due. Free-riders, because they get a “standard share” but put in less, or no effort; the greedy, because they take too much. (The line between these is blurry.) In group hunting, cheating is easy to spot; it’s less easy in reciprocation. “Commensurability” is a central problem. Suppose you return to camp with a bag of mussels; tomorrow I will hunt duck. If you take too much duck, you’re cheating. But “how much of a duck tomorrow is your contribution of mussels worth?”: