The Survival of the Friendliest?

Have we evolved to love our ingroup? Did our ancestors go through an evolutionary process of self-domestication? Is the occasional genocide just an unfortunate by-product of how friendly we are?

I. The survival of the friendliest

Books about the evolutionary origins of our species often begin in the following way.

First, they bemoan the fact that many people think evolutionary theory implies a cynical view of human nature. On this cynical interpretation, natural selection is a ruthlessly competitive process, favouring traits that help organisms outcompete other organisms in the merciless Darwinian battle for survival and reproduction.

Second, the book then contains something like the following passage: “But that cynical interpretation of evolution is all wrong! As this book will show, our best theories of human evolution reveal that human beings are naturally cuddly, prosocial, and friendly. In fact, cooperation is our species’ superpower!”

The Survival of the Friendliest by Brian Hare and Vanessa Woods roughly fits this template. They begin the book by arguing that “no folk theory of human nature has done more harm—or is more mistaken—than ‘the survival of the fittest’.” For many people, the phrase invokes a picture of the living world as competitive, conflictual, and brutal. And this picture, they argue, has given rise to such things as “corporate restructuring”, “extreme views of the free market”, “abolition of government”, and judgements of “groups of people as inferior.”

Next, they argue that this picture is based on a profound misunderstanding of evolutionary theory. The “ideal way to win at the evolutionary game”, they write, “is to maximise friendliness so that cooperation flourishes.” And that’s exactly what happened in our lineage: “Cooperation is the key to our survival as a species because it increases our evolutionary fitness.”

In defence of this claim, the book argues for the “human self-domestication hypothesis.” According to this hypothesis, changes in our ancestors’ material and social environment created new selection pressures in which aggressive individuals were outcompeted by friendly, prosocial ones - more specifically, by those who were friendly towards fellow “ingroup” members.

This process had two important consequences. First, it allowed for immensely powerful forms of communication, coordination, and culture that constitute the secret of our species’ evolutionary success. Second, it produced a set of physical, psychological, and behavioural traits - a “domestication syndrome” - characteristic of domesticated species selected for social tolerance and low aggression.

If this story is right, how can we understand anti-social behaviour? Genocides, slavery, and war don’t seem very friendly, for example. In response, Hare and Woods advance the surprising argument that such behaviours are an unfortunate by-product of how damn friendly we are. It’s precisely because we experience “love for our own groups”, they argue, that we feel “fear and aggression toward strangers with a different identity.” Specifically, this fear and aggression emerges when people feel that their group is being threatened by another one:

“With this new concern for others came a willingness to violently defend unrelated group members or even intragroup strangers. Humans became more violent when those we evolved to love more intensely were threatened” (my emphasis).

Given this, the self-domestication of our species helps to illuminate “the paradox of human nature: our kindness to the ingroup and cruelty to those outside it.”

II. What the book gets right

There are many things to like and admire in this book. It’s very engaging and thought-provoking. It also contains interesting ideas and facts I hadn’t come across before. Nevertheless, I think its account of human nature and evolution is almost completely mistaken.

Almost completely. Before I explain what I think the book gets wrong, then, I’ll first highlight three important things it gets right.

First, there are popular ways of understanding evolution by natural selection that are overly cynical. As I return to shortly, natural selection really is a competitive process, but cooperation often provides a powerful way of getting ahead, which is why it’s ubiquitous in nature.

Second, our species in particular is spectacularly cooperative. As individuals, we’re utterly dependent on extensive social support, mutual aid, and the collective provision of public goods. Moreover, this cooperation typically occurs in complex social networks featuring many people beyond close genetic relatives. In these respects, the scale and sophistication of human cooperation is an important and unusual feature of our species.

Third, as our ancestors became increasingly dependent on cooperation, they evolved social motives and capacities for cooperating and attracting cooperation partners (mates, friends, allies, etc.), which includes “friendliness” in the broadest sense of that term.

All of this is correct and important. However, on just about everything else I think Hare and Woods are mistaken.

III. Evolution is competitive

To begin with, a Darwinian understanding of human beings really does vindicate a kind of cynicism. It’s not a cartoonish cynicism. As noted, cooperation is ubiquitous in nature. Moreover, although evolution favours traits that maximise an organism’s fitness, organisms don’t make decisions by calculating the fitness consequences of behaviours. Instead, they act on adaptive drives, motives, emotions, and so on. In other words, the ultimate Darwinian causes of behaviours are different from their immediate (“proximate”) psychological causes.

If you put these two things together - that cooperation is often favoured by evolution, and that ultimate Darwinian causes are different from psychological ones - you get organisms with genuinely cooperative motives and feelings (i.e., “friendliness”). Given the importance of cooperation in human evolution, this explains a lot of our psychology. At least in some contexts, most of us feel genuine empathy for the suffering of others; we have a strong sense of fairness; we feel guilty when we violate moral rules; we love our romantic partners; we value loyalty to our friends and communities; and so on.

It’s true, then, that evolutionary theory doesn’t imply people will behave as psychopaths consciously striving to promote their self-interest. Nevertheless, it does support a milder and more nuanced form of cynicism. This reason is simple: Contrary to many heroic attempts to depict natural selection as an uplifting and heart-warming process, it really is a ruthlessly competitive one.

Roughly, natural selection favours traits that maximise an organism’s inclusive fitness. This includes its own reproductive success, but also the reproductive success of kin (i.e., those who share the organism’s genes) as weighted by their degree of genetic relatedness. Inclusive fitness is relative, however. There’s no absolute fitness target, as if any organism that reaches that target will start spawning infinitely. Evolution favours organisms that are the most successful at hoovering up energy to propagate their genes.

This fact has two important implications for understanding human cooperation. First, cooperation isn’t an alternative to competition. It’s a form of competition. As Nichola Raihani puts it,

“Viewing cooperation solely as a force for good betrays a fundamental misunderstanding of how evolution works. For a gene associated with any behavioural trait to come under positive selection, it must yield some advantage to its bearer. Cooperation is favoured, therefore, when it offers a way to get ahead.”

Second, because cooperation is a strategy designed to help organisms get ahead - to maximise their fitness - we should expect that people will deploy this strategy only when it helps them achieve their fitness-relevant goals.

As I will now show, these basic observations are strongly in tension with the hypotheses (i) that we’ve evolved indiscriminate friendliness towards our ingroup and (ii) that antisocial behaviour only emerges when people feel their ingroup is threatened.

IV. Understanding Human Cooperation

Insofar as the concept of “self-domestication” is just a cute way of capturing the fact that intense cooperation among our ancestors selected for prosociality and against certain forms of aggression, I don’t have a problem with it. However, interpreted as a serious scientific theory of human evolution, it’s highly misleading.

To begin with, the very idea of a clear “domestication syndrome” characterised by a consistent set of traits among domesticated animals doesn’t seem to be well-supported by research. The traits associated with the syndrome vary widely and are frequently absent in domesticated species. Moreover, the classic experiment alleged to vindicate it, in which Dimitry Belyaev selected for tameness in a population of foxes, is riddled with methodological problems. To take just one, most traits commonly attributed to domestication predated the experiment.

However, there’s a much deeper problem. Once you grasp that cooperation can only be understood in terms of Darwinian organisms competing to maximise fitness, it becomes clear that human cooperation must involve much more complexity and strategy than indiscriminate friendliness towards an ingroup.

Interdependence, Reciprocity, Social Selection, and Status

There’s a subtle evolutionary game theory of cooperation which grapples with when and why competitive Darwinian organisms will help each other. The following processes - and complex interactions between them - all seem to have played an important role in shaping the evolution of human psychology.

First, there’s interdependence. In such cases, one organism, A, has a stake in the fitness of another, B, in the sense that A can promote its own fitness by helping B. There are many sources of interdependence in human social life, including kinship; collaborative partnerships in things like resource acquisition, childcare, and the division of labour; the “strength in numbers” often associated with social groups; people’s possession of useful information; and much more.

Some theorists speculate that ecological changes forced our ancestors into situations of greater interdependence, which initiated a set of positive feedback loops that gave rise to increasingly complex cooperation.

Second, there’s reciprocity (i.e., “you scratch my back, I scratch yours”). Humans trade favours, often in the context of relationships in which mutual trust and sympathy are built up over long periods. Such reciprocity depends on sophisticated cognitive capacities, including the ability to track individuals through time, remember their past behaviours, and delay gratification, which might explain why it’s rare in non-human animals.

In some cases, reciprocity exists entirely between two individuals. However, human social life also involves indirect reciprocity, in which actions are rewarded or punished by members of a community not directly affected by the act (“you scratch my back, someone else will scratch yours”). In this latter case, cooperation is typically scaffolded by social norms (that determine what constitutes cooperation), reputations (shared beliefs about how cooperative group members are), and gossip (socially transmitted information about people’s cooperative behaviour).

Third, there’s reputation-based partner choice. In environments in which individual success depends on cooperation, individuals will shop around for the best partners (e.g., mates, friends, and allies). Given this, it becomes crucial to cultivate a reputation as an attractive cooperator: that is, as someone capable of benefiting others (i.e., competent) and motivated to do so (i.e., trustworthy and benevolent).

This involves a kind of social selection in which individuals strive to out-compete rivals by attracting cooperation partners, and it likely played a powerful role in human evolution. Just as sexual selection (a form of social selection) gives rise to evolutionarily surprising traits like the peacock’s tail, the dynamics of partner choice can explain surprising features of our psychology, including intense desires to win social approval and an intuitive sense of fairness, which plausibly functions to secure a good reputation.

Finally, there’s competitive altruism.¹ Human social worlds involve a distinctive kind of social status: prestige. Unlike dominance, the most common form of status in social animals, prestige is rooted in the ability to confer benefits on others rather than impose costs, and it elicits respect and admiration, not fear and avoidance. Once prestige hierarchies emerge, individuals can compete to win status through acts of altruism and generosity. This drive for prestige likely explains the most spectacular forms of self-sacrifice and heroism in our species.

Human cooperation is complex and strategic

There are good reasons to believe that all these forms of cooperation played important roles in shaping the evolution of human psychology, although it remains unclear at what points in our ancestral past they became both adaptive and possible. Nevertheless, once one lays out these processes, two things become apparent.

First, the hypothesis that humans underwent a process of self-domestication favouring the survival of the friendliest contains a grain of truth. In social worlds organised around interdependence, reciprocity, partner choice, and prestige competition, it’s often important to acquire prosocial motivations and a reputation as nice, conformist, and fair-minded. This has no doubt shaped our psychology in powerful ways.

Second, the hypothesis is nevertheless highly misleading. When it comes to each of the forms of cooperation just listed, they all demand a complex and strategic psychology which is not usefully understood in terms of indiscriminate friendliness towards an ingroup.

Consider interdependence. Although often depicted in heartwarming terms, it has a harsh logic. For example, people constantly (albeit often unconsciously) estimate the degree to which they have a stake in the interests of others, and emotions such as empathy closely track such estimations. For this reason, when you don’t depend on others or they threaten your interests, your empathy tends to disappear.

A similar lesson applies to reciprocity. By its very nature, reciprocity is selective. It involves helping others because helping - or the reputation for being helpful - will be repaid. In the absence of likely repayment, the motivation to cooperate therefore collapses.

For this reason, people are highly discriminating in which relationships they form and how much they help others. Of course, in social worlds organised around partner choice, it’s important not to appear too strategic and calculating. (Who wants to be friends with a stingy social climber?). The result is the evolution of a complex psychology with which people navigate these conflicting pressures, striving to avoid a reputation for being calculating and miserly whilst remaining sensitive to the costs of being indiscriminately friendly.

This choosiness extends to broader groups, which people join and leave in response to the benefits and costs they provide. In this sense, human communities function as coalitions that cooperate and coordinate in ways designed to promote shared interests. For this reason, an individual’s “ingroup” and the identity of their collaborators are constantly renegotiated, and communities often contain shifting sub-groups and alliances. To quote Raihani again,

“The unromantic truth is that coalitions, friendships and alliances function as social tools that help us to achieve our goals (even if we don’t consciously think of them in this way).”

Finally, because much of human cooperation is rooted in reputation management and status competition, people are highly attentive to whether their behaviours and habits are socially rewarded, even when they vehemently deny this.

In fact, the very tendency to favour the “ingroup”, which Hare and Woods depict as a basic human motivation, seems to be rooted in reputation management. People treat their ingroup as a market of potential cooperation partners within which it’s important to make a good impression. Take away this reputational motive and ingroup favouritism mostly disappears.

The bottom line

The bottom line is that human cooperation is extremely complex in ways that aren’t illuminated by analogy with the process of domestication. Because humans evolved to reap the benefits of cooperation whilst minimising its costs, the social psychology we’ve evolved to navigate such complexity is highly strategic and selective. What might superficially look like indiscriminate friendliness is rooted in subtle psychological processes that track whom one depends on, the benefits of different relationships and alliances, and the degree to which traits and behaviours are socially rewarded.

Once again, most of this isn’t conscious. In fact, people are instinctive press secretaries. We frame our traits and behaviours in the most socially attractive light we can get away with - which often means depicting ourselves as highly prosocial, friendly, and altruistic - and then sincerely believe our propaganda. The result is a complex, paradoxical, and strategic species, one that’s infinitely more interesting than the version of humanity presented in “The Survival of the Friendliest”.

V. Understanding Human Conflict

Now consider the other big claim that Hare and Woods advance: that antisocial behaviours - violence, aggression, exploitation, and so on - are an unfortunate byproduct of our friendliness. As they put it,

“Our friendliness has a dark side. When we feel that the group we love is threatened by a different social group, we are capable of unplugging the threatening group from our mental network – which allows us to dehumanize them. Where empathy and compassion would have been, there is nothing.”

The idea, then, is that our competitive, exploitative, and aggressive motives are (a) invariably directed towards “outgroup” members (i.e., individuals who belong to different groups) and (b) defensive, in the sense that people only bully, attack, victimize, or eliminate members of other groups because they view them as a threat to their own group.

Both claims are wrong.

Antisocial behaviour within the ingroup

First, there’s a vast amount of hostility, manipulation, bullying, and so on that occurs within human communities. In fact, there’s a surprising amount of conflict, aggression, and manipulation within human families, even of the most extreme forms. For example, one study of high-income countries suggests that between 4-16% of children suffer physical abuse within their families, with approximately 5% of boys and 5-10% of girls experiencing sexual abuse. Estimates of such abuse vary substantially, however, with some studies suggesting much higher rates in some populations.

Of course, these are just the extreme cases. Families and broader kinship networks also contain many milder forms of conflict and aggression.

Exploitative and aggressive behaviour are also widespread within romantic relationships. Domestic abuse and violence is extremely common worldwide, for example. A report by the World Health Organization documents that globally about 27% of women aged between 15-49 have been subjected to some form of physical (including sexual) violence by their intimate partner. And again, that’s just the most extreme case. Intimate relationships are hardly exclusive domains of friendliness and prosociality. They frequently involve conflict, betrayal, resentment, bitterness, and more.

Outside of the family and close relationships but still within recognisable communities, competitive, conflictual, and exploitative behaviours remain extremely common. Even setting aside intergroup conflict, human social life is riddled with strife, antipathy, bullying, bad blood, and friction. Considering just the most extreme case again, within-group physical violence - including murder - is very common throughout human history, including among hunter-gatherers.

More generally, societies and their institutions are often highly extractive, organised to benefit some individuals by exploiting others, even when the hierarchy doesn’t straightforwardly split along group lines. For example, much anthropological research suggests a common pattern in many small-scale societies involving coalitions of high-status men, who generate extremely oppressive rules and rituals, which they use to coerce others (e.g., women, children, and lower-status men) within their communities.

Such examples barely scratch the surface of within-group conflict. And don’t misunderstand me: I’m not denying there’s also an enormous amount of trust, sympathy, affection, generosity, and so on within communities. But the point is that the story here is complex, and it’s not true that exploitative or aggressive behaviours are primarily targeted at individuals outside of the perpetrator’s own “ingroup”.

Dehumanising the outgroup

Nevertheless, it is true that most large-scale forms of aggression and exploitation are inflicted by one group (the “ingroup”) on another (the “outgroup”). This is the case in war, genocides, slavery, pogroms, ethnic riots, and so on. However, the idea that these cases of extreme violence, brutality, and domination are invariably defensive, and hence arise only when people feel their ingroup is threatened, is highly implausible.

Consider slavery, which existed throughout most of human history since the agricultural revolution. People don’t take others as slaves out of self-defence but out of self-interest. The same is true of other systems of group-based domination. Feudalism didn’t start because lords were fearful of their serfs. It began and was maintained because it benefited lords and other elites, who used their power to enforce it.

Admittedly, the drivers of wars and genocides are more complex. Nevertheless, the idea that they invariably arise out of self-defence is false. When people - or, more commonly, elites and rulers - decide to launch raids, wars, and genocides, it’s often because they think it will promote their interests in some way. Although perpetrators in such cases will often depict their rivals and enemies as highly threatening, that’s often just propaganda that functions to coordinate group behaviour and justify atrocities.

Of course, I’m not denying that believing one’s group is under threat can trigger pre-emptive violence. That often happens in wars. Nevertheless, the reason why people are so ready to perceive rival groups as threats is because rival groups often are a threat. In fact, far from only attacking other groups out of self-defence, one of the main reasons people are so motivated to start and join groups throughout history is precisely to dominate or eliminate their rivals.

None of this should be surprising

Once you understand that natural selection is a competitive process and that organisms cooperate not because cooperation is inherently valuable but because it promotes their fitness-relevant goals, none of this should be surprising.

“It is good,” wrote Machiavelli, “to appear clement, trustworthy, humane, religious, and honest, and also to be so, but always with the mind so disposed that, when the occasion arises not to be so, you can become the opposite.” As with much of Machiavelli, the quote contains a deep insight into how self-interested individuals balance the demands of cooperation with the demands of egoism.

Yes, human beings are highly cooperative, but cooperation involves a complex set of strategies we’ve evolved to deploy in circumstances in which it promotes our basic evolutionary goals. This has many important implications that help to explain the complex mix of collaboration and conflict that characterises human social life.

First, people are highly discriminating cooperators, who cultivate those traits that are socially rewarded among those it’s beneficial to impress and attract. This is why slave owners throughout history are often friendly and fair-minded towards their social equals and psychopathic towards their slaves. It’s why people can happily eat burgers made from tortured, factory-farmed animals and yet experience explosive moral outrage at their boss’s petty selfishness. And it’s why people in rich countries are often more eager to spend money on gingerbread lattes than on helping those in poor countries dying from starvation and preventable diseases.

Second, when friendliness stands in the way of more important evolutionary goals, a very different psychology emerges. Even when it comes to close genetic relatives, powerful and innate altruistic tendencies get overridden if they hinder people’s interests. As Paul Turke points out, successions in ancient Rome and other empires often involved ruthless battles between siblings. Why? Because the allure of extreme status and power dominated people’s natural sympathy for family members.

The lesson generalises. When the benefits of friendliness and a reputation for friendliness are outweighed by the benefits of achieving other goals, those goals often win out. The result is a social life familiar to most people - a mix of conflict and collaboration, friendliness and fighting, prosociality and pugnacity - that emerges as strategic individuals with distinct interests compete and collaborate in complex ways.

Finally, people often cooperate in the service of competition, which includes brutal forms of oppression, exploitation, and aggression. There is an important truth in the idea that cooperation is our species’ superpower, but it doesn’t deserve its heartwarming reputation. As our ancestors became increasingly dependent on cooperation, the desire to dominate others didn’t disappear; it just changed form. Cooperation became the means of dominating rivals and enemies, and - as Paul Seabright points out - created “the massive resource gains that provoke our competitiveness and manipulativeness.” The result is a human history littered with persecution, subjugation, and violence.

Of course, such characteristics vary substantially across time and place. For most people living within Western democracies today, life tends to be pretty pleasant, and free from the more extreme forms of violence and domination that characterise much of human history. That brings me to the final topic I will consider: why any of this matters.

VI. The Importance of a Tragic View of Human Nature

Many disagreements about society and politics are rooted in different understandings of human nature. As Thomas Sowell points out in A Conflict of Visions, one fundamental difference concerns those who embrace a utopian (“unconstrained”) vision and those who embrace a tragic (“constrained”) vision.

Roughly, those who embrace the utopian vision view human nature as fundamentally good. From this perspective, any unfortunate features of human social life - domination, oppression, violence, conflict, and so on - don’t result from anything in the basic nature of human motives and psychology. They’re the product of contingent institutions and social systems (e.g., religion, capitalism, etc.), perhaps coupled with the actions of a few bad apples who aren’t representative of humankind generally.

“The Survival of the Friendliest” provides a clear example of this vision. As Brian Hare puts it in presenting its core idea, “Our psychology evolved in large part due to selection for prosociality.” On this view, humans are fundamentally friendly, and the really unfriendly things we do are ultimately rooted in our basic love for our ingroup and desire to defend it.

According to Hare and Woods, this perspective should shape how we understand society and social progress. “The principles of a kinder society and more successful democracy”, they write, “are informed by everything from dogs to bonobos” [i.e. friendly animals]. Because we experience unconditional love and affection for our “ingroup”, the solution to many of our political problems is to include more people within that group - to “expand our definition of who belongs” - which can be achieved by bringing those with different identities into contact with each other.

In other words, the solution to problems of conflict in society is to unleash our inner friendliness. For this reason, when it comes to understanding historical developments such as reduced violence and the expanding circle of moral concern within many Western countries, Hare and Woods frame this as a situation in which “our capacity for friendliness towards strangers has continued to increase.”

I think this perspective is not just mistaken. It’s dangerous.

Once you appreciate that human beings are Darwinian organisms and that cooperation is a complex set of strategies deployed to achieve more fundamental evolutionary goals, it becomes clear that this heartwarming story is a gross distortion of human social life.

Achieving mutually beneficial cooperation and peace isn’t a matter of unleashing people’s inner friendliness. It’s a matter of complex systems of norms, surveillance, incentives, institutions, and balances of power, which either constrain competition or channel it into desirable collective outcomes.

In countries such as Norway and Sweden, more than 60% of people report that “most people can be trusted.” In countries like Colombia, Brazil, Ecuador and Peru, it's less than 10%. In Zimbabwe, it’s 2%. Such differences don’t reflect innate differences in the degree of “friendliness” of people in these countries. They reflect the degree to which complex institutions, laws, regulations, and so on change society’s incentive structure in ways that make being trustworthy the smart, self-interested move.

By nature, humans are extremely morally limited. We’re strategic and selective cooperators, adjusting both the strength of our friendliness and its beneficiaries in ways that promote our interests. And yet we vehemently deny such tendencies, including to ourselves, because acknowledging them would make us seem less friendly, which would hurt our interests. As a consequence, we remain in collective denial about the true nature of our species, which leaves us without an accurate understanding of what makes human societies succeed.

This is a tragic vision of human nature. It’s not uplifting, and it wouldn’t make for a good Ted Talk. But if we’re to understand ourselves and our societies, we must face up to it.

Further Reading

I’ll be developing these and many more thoughts in my forthcoming book “Why it’s OK to be cynical”. Some articles and books that have really influenced how I think about this topic (which is not to say I agree with them or that the authors would endorse this essay):

• Nichola Raihani: The Social Instinct.

• Richard Alexander: The Biology of Moral Systems.

• Nicolas Baumard, Jean-Baptiste André and Dan Sperber: A Mutualistic Approach to Morality

• Will Storr, The Status Game

• Moshe Hoffman and Erez Yoeli, Hidden Games.

• David Pinsof, a rare example of a writer even more cynical than I am, has an excellent newsletter

1. Some people also include group selection (or so-called “multi-level section”) but it’s very implausible this played a role in human evolution.