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From alpha bullies to Bernard machines: The evolution of prosocial behaviour

Published on 03 May 2013
Updated on 14 February 2024

About 6 million years ago, the chimpanzees, the bonobos, and hominids divided up the realm of ‘pan’, their common ancestor. Looking at the apish offspring today, we see a shared tendency for alpha males and females1 to appear at the top of pecking orders. There is a predisposition for hierarchical structures. There is also strong competition for high ranks. Subordinates, however, soon balk at the top male’s behaviour and create counter-dominant coalitions in an attempt to defeat him (see Hierarchy in the Forest: The Evolution of Egalitarian Behaviour by Christopher Boehm).

The divergence of humans and great apes from a common ancestor, into hominins, chimpanzees and bonobos, and gorillas.
The divergence of humans and great apes from a common ancestor (Britannica).

This tension seems to have been particularly present in humans (see Moral Origins: The Evolution of Virtue, Altruism, and Shame by Christopher Boehm and The Bonobo and the Atheist: In Search of Humanism Among the Primates by Frans de Waal). What we know for sure is that, at the end of humanity’s evolutionary process, homo habilis was resolutely egalitarian (see The Creation of Inequality: How Our Prehistoric Ancestors Set the Stage for Monarchy, Slavery, and Empire Kent Flannery and Joyce Marcus). How did we get to be that way?

The rise of prosocial behaviour

It probably was a ‘just so’ or contingent story. 400,000 or so years ago, we invented tools that could kill at a distance – spears. The scavenger ape became a big-game hunter, but in a group only. This created a group management problem. How to divide the carcass within the group? An alpha male grabbing too much meat for himself would leave the rest of the band with insufficient energy for the next hunt. All members needed feeding for the system to work. It looks as if hunting efficiency drove the group toward egalitarianism.

What did this entail? The group ‘declared’ overbearing alpha males (‘alpha bullies’, in fact) ‘unfit’ for reproduction and took them out of reproduction by ostracism, and even capital punishment. Among the first images from the distant past, there is one of a man pierced by arrows like a porcupine. It may have represented a warning to prospective alpha bullies.

Fear-based control (as in other apes) was too crude an instrument to work all by itself. Nor did it work terribly well with free-riders (the other scourge of any collective effort) who disguised themselves while being antisocial, or were slick and charming characters. Also, the process was mainly genetic in origin, hence slow to evolve.

Student bullying on a school bus.

Active policing of alpha-male social predators by their own band-level communities emerged as a social tool. Prosocial behaviour transformed us into altruists, but also terrible gossips and moralists. An ‘ethical project’ emerged (see The Ethical Project by Philip Kitcher). Building on biological preadaptations (see Braintrust: What Neuroscience Tells Us About Morality by Patricia S. Churchland), hominids internalised social, i.e. cultural, rules and linked them to emotions. Since then, an inner ‘voice’ tells us what is right and wrong. When we say something we know to be morally wrong, we blush uncontrollably; this is a tell-tale sign of a link between biology and culture. Not only do we feel the voice, but we gossip about moral behaviour all the time, validating and reinforcing a prosocial stance. Most likely, sexual selection (‘reputation’ as the basis for reproductive success) was also involved.

Such culturally based purposeful inputs are both part of natural selection and a product thereof. ‘Their effects have gone beyond shaping everyday group life prosocially, for they have helped to shape our gene pools in prosocial directions that are similar’. Some archaeologists conjecture that we became egalitarian 250,000 years ago. Boehm sums it up: we had developed a mechanism for ‘self-domestication’.

Characteristically, the moral sense is not absolute, but highly flexible. The inner voice urges prosociality. The individual may override this instinct—depending on material and social context—and be egoistic. Christopher Boehm regrets this ‘weakness’ of mankind’s moral compass as compared to innate egoism.

Bernard machines and moral homeostasis

He need not worry. The ‘ethical project’ may just be the first instance of a social ‘Bernard machine’. The Bernard machine is named for the great French physiologist Claude Bernard, who first pointed to homeostasis as a central feature of living systems. Bernard machines are agents of homeostasis, and I discuss how design emerges from the action of Bernard machines that create new environments and impose homeostasis on them. Generation of design by Bernard machines contrasts in some fundamental ways from the Darwinist explanation for design, in which good design arises from a selection for ‘good function genes’

Once the ‘self-domestication’ system got going, it shaped human evolution (see Niche Construction: The Neglected Process in Evolution (MPB-37)). It was a balancing act aimed at moral homeostasis. Too little morality, and the alpha bullies have it. Too much morality, and self-domestication leads to effete ineffectiveness. In order for the social system to survive, it needed to curb excesses either way in a flexible way. Rigid rules would destroy homeostasis. Only homeostasis ensures survival, including its own. Dialectic tinkering will ever so subtly yield this. The aim is ‘good enough’, keeping the social system from seizing up. To put it another way, social Bernard machines are dialectic: their dynamics are not based on action or reaction, but just the opposite: contradiction. Bernard machines are adaptive, not directive.

The image shows homeostatic regulation of temperature in humans. When body temperature falls, blood vessels constrict so that heat is conserved. Sweat glands do not secrete fluid. Shivering (involuntary contraction of muscles) generates heat, which warms the body. Heat is retained, which leads to normal body temperature. When body temperature rises, blood vessels dilate, resulting in heat loss to the environment. Sweat glands secrete fluid. As the fluid evaporates, heat is lost from the body. Heat is thus lost to the environment, leading to normal body temperature.
Homeostatic regulation of temperature in humans (Khan Academy).

Bernard machines are demanding. Once in place, they ‘impose’ their will on the living structure, be it biological or social. Of course, no intentionality is involved. But the effect is to yield stable design – necessary path-dependent outcomes. This is probably why moral systems around the world are similar.

Having learned the usefulness of social Bernard machines, humans applied them everywhere unthinkingly. The ‘checks-and-balances’ system for a well-functioning democracy is such a Bernard machine. Most likely, society is a social ‘meta-Bernard machine’ composed of many topical ‘sub-machines’ and sporting many inconsistencies, poor interfaces, or contradictions that cancel each other out.

Bernard machines are not ‘beautiful’ in a mechanical sense. They are not ‘well-structured’. In fact, they may look downright ugly to our geometrically trained eye. A termite mound would not please Leonardo’s eye. On the other hand, discovering its inner workings of homeostasis—so different from that of the mechanical contraptions he imagined—might have pleased Leonardo’s mind.

Funnily enough, we rely on analogies from mechanics and the inanimate world to describe such living structures. Our favourite metaphor is the ‘infinite complications’ of a clock, even though Bernard machines are just the opposite of clockwork. We prize order and structure over functioning. With Bernard machines, function yields structure, not the other way around. This gives rise to no end of trouble. Fortunately, an ability to ‘suspend disbelief’ and ignore contradictions allows papering over such disconnects.

We may not be able to do so for much longer, however. Drawing on analogies from the physical world, we clamour for consistency and direction deduced from first principles. We yearn for the certainties of mechanical linearity rather than the endless surprise of dialectics. In this view, everything is reduced to structure. Are we unwittingly destroying social Bernard machines in an iconoclastic drive for reductionist order? As Tacitus said about the Romans: ‘Where they make a desert, they call it peace.’

1. Among the bonobos, we have matriarchs. Adult females migrate, while boys stay under the wing of their moms. Such is the diversity of life.

The post was first published on DeepDip.

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