Robin Dunbar, Free Will? What’s complicated about social life?, Have societies evolved?, in his Evolution: What Everyone Needs to Know
Evolution of Behavior
80. Doesn’t the theory of evolution imply that there is no such thing as free will?
Ah, the question that always comes up eventually and the one that reveals the bugbear that underlies most concerns about evolution. The short answer to this question is simply: no. As we saw in the previous question, the point of paying the enormous cost of having a big brain is to be able to make your own decisions about what to do in light of the particular circumstances you happen to encounter. It is worth having everything determined by your genes only if your circumstances and the decisions you need to make never change. That is probably ever true only for bacteria and viruses. For the rest, it helps if the organism has some control over its own destiny so that it can fine-tune its behavior to the circumstances of the moment.
Natural selection simply sets the ground rules that determine the costs and benefits of alternative courses of action. It usually does that by establishing some goal states in the organism (“always keep your energy levels up”) with some kind of signal to let the body monitor its state (hunger pangs when energy levels are low) and a motivational system that allows you to fulfill that goal (find something to eat when the hunger pangs kick in). It is important that the organism has control over how to fulfill the goal, because its circumstances won’t always be the same. It is then up to the individual to do the best it can. If you choose well, you will leave many descendants; if you choose badly, you won’t.
Of course, we all have innate predispositions, or prepotent actions, that, all else equal, make us prefer one course of action rather than another. But for large-brained species, learning becomes an increasingly important part of that mix as a way of moderating those prepotent actions—allowing us to see both the short- and long-term consequences of our actions, and providing us with the basis for deciding which strategy is the best among our available options. If we grab the whole cake, that may satisfy our short-term craving for sweet food, but it may cause us to pay a longer-term cost because we upset everyone else when they get none—or we overdose on sugar and make ourselves ill. If we destabilize our friendships with everyone else, we risk leaving ourselves without an ally on some future occasion just when we need their support. We have to learn to recognize those consequences and be able to adapt our behavior accordingly. Without that ability, we will be dead in the evolutionary water. And extinct.
There is an important reason for being able to do this: the kinds of societies that we and other primates (monkeys and apes) live in are implicit social contracts—we club together to gain some greater benefit—but for that to work we have to be able to inhibit our natural tendency to satisfy all our desires irrespective of the consequences for everyone else. If we can’t, our social systems will break down (as they demonstrably do when things get out of hand during civil wars and there is a loss of civic control). This is mainly why we have to teach children how to behave morally and courteously toward others. They do not do it naturally, despite some well-meaning attempts to claim that they do.
Of course, this is not to say that everyone is a perfect citizen. Some people never learn to behave in this way, either because of the circumstances in which they grew up or because they lack the ability to inhibit their own behavior—the two often go together, the one reinforcing the other. Long-term studies of individuals from childhood to adulthood suggest that individuals who fail to learn these skills as children continue to behave antisocially as adults, with boys being more prone to this than girls.
Ultimately, however, it is we who choose to behave the way we do. We are not driven to do so by our genes, even though these may predispose us to behave in certain ways. As most religions have recognized, we always have the final say in deciding whether or not to give way to the “temptations of the flesh”.
Evolution of Sociality
84. What’s so complicated about social life?
While it is true that many of the same rules about the costs and benefits of joining and leaving groups will be common to both casual herds and bonded groups, there are some important differences between aggregations (casual groups that form for some immediate benefit and disperse again as soon as the benefit ceases) and congregations (stable social groups that maintain a level of social cohesion over time even when there is no immediate benefit).
Aggregations (or fission-fusion social systems) have the advantage of minimal cognitive cost, and the benefit of considerable flexibility that allows the ecological and physiological costs of group-living to be dissipated. But they suffer from a lack of certainty: the risk is that you might find yourself with no one nearby when the one predator for miles around happens to turn up. Worse still, even if you do happen to have companions, there is no guarantee that they will stay with you when the predator appears. Most of these herding species follow an everyone-for-themselves strategy rather than an all-hands-to-the-pump one. Living in a stable group incurs significant costs (being tolerant of others, having a sense of commitment to others, coping with disrupted time budgets) that require the evolution of a large, very costly brain to manage. But their advantage is certainty that others will always be nearby because they won’t let you drift away without noticing, as is so often the case with casual aggregations. The issue is that these kinds of relationships have to be set up way ahead of the time when you need them.
If predation risk increases and a larger group is needed, then some solution also has to be found to mitigate the fertility costs that living in groups incurs. Group size can then increase, but only up to the next glass ceiling, because there will always be one. Indeed, the distribution of group sizes in primates turns out to consist of a series of very specific values that seem to correspond to a set of natural optima or glass ceilings. The way primates, and perhaps a small number of other mammals (including the horse family and the elephants), have solved the fertility problem is by females forming protective coalitions, either with each other or, in a small number of cases, with males who in effect act as “hired guns” or bodyguards (examples of the latter include the gorilla and the gelada baboons).
These coalitions, built around grooming bonds, are essentially a balancing act: they work mainly by keeping everyone else at a distance so that they don’t impose stresses by coming too close, but at the same time without driving them away so completely that they leave the group (which would mean losing the benefits provided by the group altogether). These kinds of relationships are complex to manage. In effect, they require the capacity both to forecast the future consequences of one’s actions (and evaluate any alternatives) and to inhibit actions that would produce a short-term gain at the expense of a much larger long-term cost.
In larger social groups, the formation of coalitions creates a layered structure to the social network of the group: instead of everyone interacting with everyone else, each individual confines its interactions to its core coalition partners. Its remaining relationships with other group members are virtual and can be dealt with third-hand (e.g., by observation of third-party interactions, by reputation management, or by inferences about who is related to whom). Maintaining virtual relationships requires us to model their intentions in a virtual world because this is something we know about only indirectly by inference from observed behavior. In humans, this form of modeling the relationships behind the behavior in the mind has been shown in neuroimaging studies to be cognitively much more demanding than manipulating factual information about the physical world: it requires the recruitment of many more neurons.
Evolution of Sociality
90. Have human societies evolved?
Over the past 10 millennia, human societies have progressively moved from the classic hunter-gatherer form of fission-fusion sociality (in which a community of 100–200 individuals is distributed in three or four small camp groups, with individual families able to move between camp groups when it suits them) to settled villages, city-states, kingdoms, and eventually the kinds of nation-states in which most of us now live. The Victorians certainly thought this was a natural evolutionary sequence. Evolution, however, is almost never progressive in the way implied by this sequence, so we probably should be suspicious of any such claims.
A better way of thinking about this is in terms of the function (or adaptive value) of social groups. In almost all birds and mammals, animals live in groups as a defense against predators. The size of the group reflects the risk of predation. Historical sociologists have argued that the push toward settlement in the Neolithic, and the progressive growth in settlement size that followed, was a consequence of raiding by neighbors. In other words, other humans increasingly became the predators, replacing conventional predators in importance as we became more successful as a species and our population density increased. This forced the scattered camp groups to come together in villages where they could defend themselves against raiders more effectively. That this continued to be a problem through the following millennia is indicated by the large number of Iron Age forts in Europe: these were invariably built in defensive positions, many with ditches full of arrowheads and evidence of having been destroyed by conflagration.
As with all biological processes, any change in how something works has inevitable consequences elsewhere in the system. The growth in settlement size incurs at least three major problems. One is ecological: how to feed a large, spatially concentrated population. Foraging out from a central roost inevitably denudes the environment nearest to the center, so that, with time, individuals have to forage farther and farther away, thereby exposing themselves once more to risk of attack by raiders as well as conventional predators—the very problem that settlement was designed to avoid. The solution was agriculture, or at least an intensification of the kinds of casual agriculture that hunter-gatherers were already doing at the time.
The second cost is the stress of living in close proximity. Living on top of each other inevitably results in an increase in petty squabbles, and even outright violence, as people become increasingly frustrated with each other. The third is a simple coordination problem: how to keep everyone on the same page, and especially how to prevent people from leaving as a result of these stresses, thereby losing the defensive benefits of having a large group. One solution was the evolution of hierarchical social systems in which a strong chief imposes both his will and a degree of political stability on the community. With this inevitably come laws and police forces. Associated with these have been the evolution of doctrinal religions.
Detailed statistical analysis of the historical development of the Austronesian and Polynesian societies of the Pacific indicates that these evolved step by step along the same trajectory in different locations, moving progressively from simple village societies with no formal structure and no chiefs to simple chiefdoms, then complex chiefdoms with rituals and hierarchies of officials, and eventually fully fledged states with the equivalent of kings. These structural changes are a simple consequence of the need to manage increasing numbers of relationships as communities get larger. This much is evidenced by the fact that when states later fail and go into decline, they typically go through the same sequence in reverse as their populations decrease in size.
Some communities, like the Hutterites of North America, deliberately sidestep this problem by splitting their communities whenever they exceed about 150 individuals. They do this precisely because they want to avoid having hierarchies and laws in order to manage their affairs and relationships. By keeping community size small, they can manage their relationships by peer pressure alone. It seems that you don’t necessarily have to embark on a trajectory toward the nation-state, but to avoid doing so you have to keep your community size very small. If for any reason you need to increase community size, then the evolutionary treadmill seems to be unavoidable because we do not have the social and psychological mechanisms to mitigate the stresses of living in large communities in any other way. [End]
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Robin Dunbar, Evolution: What Everyone Needs to Know, Oxford University Press 2020
Robin Dunbar has been a Social Science Files subscriber since March 2023.
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