The evolutionary origins of a good society

By: Nicholas A. Christakis.

Published: 2019

Read: 2019


Natural selection has equipped us with the capacity and desire to form and join groups.

It is argued that humans universally evolved a set of features called the “social suite”: a collection of innate proclivities that drive our capacity for love, friendship, cooperation, learning and that ultimately bring about the creation of specific types of social order, groups and societies, the types that we live and thrive in and that are universally regarded as “good”.

This social suite of traits evolved because they were highly useful for human survival in an uncertain world, because they allowed for the acquisition and transmission of knowledge and the pooling of risks, thereby enhancing our fitness and because they allowed us to adapt to one of the most consistent features in our environment, the presence of other humans.

Having evolved universally, these social traits feedback into and shape our social environment, and in some cases create a positive feedback loop of further enhancing the fitness of these social traits (example, if being extroverted primed us to form and operate in human communes, subsequently, being an extrovert operating in such a group at times may have enhanced your usefulness and fitness).

Arising in individuals and characterizing the groups formed by individuals, the universal elements of the social suite work together to create functioning, enduring and morally good societies:

  1. Capacity to have and recognize individual identity.
  2. Love for partners and offspring.
  3. Friendship
  4. Social networks.
  5. Cooperation
  6. Preference for one’s own group.
  7. Mild hierarchy.
  8. Social learning and teaching.

Worth Reading:

Wide ranging, well researched and convincingly argued. The speculations and evolutionary explanations around the evolutionary basis of pair bonding, friendship and cooperation are especially interesting and build on territory earlier explored in books like the Moral Animal (Robert Wright).

Some of the concepts overlap and at times it is hard to tease apart meaningful differences between the impact of concepts like friendship and cooperation, social networks and in-group bias, but this rarely diminishes the strength of the arguments or the quality of the story telling.

Much of the praise for this book centers on its optimism and its emphasis on human commonalities. The book indeed is a convincing exploration of the evolutionary origins of common human tendencies and social behaviors and how these combine to constrain the universe of possible social orders.

However, the book is less convincing (and arguably doesn’t really try) in delivering on its title: the origins of a good social order.

What is moral and “good” is more or less defined as “that what we are compelled to do under the constraints of our human nature”. In the context of the social suite, this means that we are compelled to live socially and cooperate in groups, and the societies we end up forming are good because we were designed by evolution to do so.

Beyond the fact that this is somewhat of a circular argument, we were designed by evolution to be capable of a lot more than only “the good stuff” (as the author acknowledges). We are also quite capable of violent, selfish and competitive behavior. Following the author’s logic and definitions of moral behavior, this type of (as designed) “bad” behavior would also be moral, rational and therefore good…

These subtleties are not necessarily overlooked in the book, but very much so in many of the commentaries on this book. Perhaps the author is partly guilty because of the title he chose for the book.

Practical Takeaways:

  • Pro- and anti-social behaviors:
    • Evolving and interacting genetic and cultural forces prime human social behaviors.
    • Certain pro-social tendencies and capabilities shape the emergence of certain types of human social order.
    • We are capable of both pro- and anti-social behavior.
    • Various types of human behavior (cheating, punishing, cooperating, loners, etc.) co-exist and co-evolve, ensuring that no particular type will disappear or dominate the population.
  • Friendship:
    • Non-conditional exchanges …
      • Temporary relaxing of expectations of an even exchange.
    • … that are tracked over time …
      • Helping others when they need it and when the cost of helping is low and tracking such individual connections.
    • … and build relationships … 
      • Characterized by closeness, affection, trust, feelings of individual recognition and value.
    • …  that provide insurance against setbacks … :
      • In the absence of institutions.
    • … and lay the foundation for many other pro-social traits: 
      • Sets the stage for cooperation, in-group bias, social learning, culture and morality.
  • Cultural evolution and growth:
    • If the environment changes so frequently that genetic evolution can’t provide the appropriate adaptation fast enough, cultural evolution through (brains capable of) social learning becomes more adaptive.
    • The ever-increasing amount of culture (knowledge; cumulative, complex ideas) is the biggest source of economic growth.

Key Concepts

  1. Individuality
  • The ability to express and recognize individuality evolves when that ability is beneficial. Generally, animals recognize each other based on cues or signals: phenotypic traits that facilitate individual recognition. In order for these traits to work, there needs to be a lot of variation in them and they need to be noticeably distinctive and memorable. For humans, facial recognition is a key part of social and sexual interactions.
  1. Love
  • The human capacity to form a loving relationship (not just a sexual one, which is easily explained by evolution) with another person arose from an ancient tendency to form pair-bonds: the biologically guided impulse to form an intense, stable, mutually dependent social attachment to a partner. Pair-bonding means that one is not indifferent to the identity of one’s partner.
  • Over the course of evolution, parents initially felt a special bond for their offspring, which was then repurposed for pair-bonding with mates (and ultimately further extended to include biological kin, friends, strangers, etc. – see also Peter Singer’s expanding circles of interest).
  • In most mammals, exclusive pair bonding reproductive strategies may have evolved in response to conditions of larger female foraging territories (and corresponding low female population density) and resource competition, making it more logical for males and females to stick together once they find each other.
  • In human, pair bonding may have evolved when males secured mates by providing for them and females evolved high fidelity to elicit this provisioning. The result is a group-living species with mostly faithful females pair-bonded to mostly good-provider males (minimizing the need for the “crazy bastard” (excessive risk taking to secure a mate) or “sneaky fucker” (self-explanatory) reproductive strategies). The evolutionary psychology of both men and women is to exchange love for support (provisioning, child rearing).
  • Sorting out precise anatomical, physiological and genetic bases for pair bonding is difficult. Neural pathways are activated in partner recognition, resulting in the release of hormones such as oxytocin (for instance, mother-offspring bonding) and vasopressin (erection, ejaculation, etc.) and many others. This leads to an association between various stimuli and the development of partner preference. This shows that (the expression of) a few genes can strongly influence the pair-bonding behavior of a species.
  • The neurological functions of oxytocin may have been co-opted by evolution for purposes beyond the recognition and care of offspring. Females came to feel about their partners the same as they did about their babies. In male brains, attachment to females may have become an extension of the concept of territory (which needed to be identified, marked and defended).
  • Pair-bonding (sustained attachment) allowed for mutual parent-offspring recognition (uncommon in many other animals), paving the way for the development of larger, multi-family social groups and laying the foundation for other aspects of the social suite (such as cooperation).
  • Social monogamy then offered advantages in competition among groups, as there are fewer conflicts – everyone has the same number of partners. There are fewer men “missing out on” spouses and there are fewer women in households with multiple women.
  1. Friendship
  • Kin recognition (or recognition of the place where kin is) served dual needs: avoid inbreeding and helping kin (altruistic behavior increases if the benefit to relatives is sufficiently high). Avoiding inbreeding led to larger social groups and larger groups in turn led to adaptations to be better at living socially (ie, friendships).
  • In many species friendship, unrelated males and females having meaningful enduring ties devoid of sexual implications (see When Harry Met Sally on how realistic that is…), is rare. In some, such as humans, the requirement for group cooperation and mutual aid (the current needs hypothesis) as well as the benefits of social learning drove the development of friendship ties, especially in situations of high uncertainty.
  • When one is safe, healthy and fed, tit-for-tat social exchange relationships suffice (the conditions for most in the modern developed world). It is more problematic to attract assistance during (temporary) threatening reversals in one’s welfare (the banker’s paradox: people that need resources the most are those that bankers are least interested in lending money to.) The social adaptation to this problem is a fluid system of social accounting: helping others when they need it and when the cost of helping is low and tracking such individual connections – in other words, friendship. As such, friendship is the (temporary) relaxing of expectations of an even exchange [I would argue it only stretches expectations out over a longer time frame…]. Such non-conditional exchanges help to bring about feelings of individual recognition and value. In contrast, the prevalence of frequent conditional exchanges in modern market economies may be read (from an evolutionary perspective) as markers of superficial and meaningless interactions, leading to alienation and vulnerability.
  • In the absence of institutions, friendships provide insurance against sudden setbacks. Conversely, an increasing reliance on formal institutions in the modern world may weaken communal relations and lessen natural inclinations to make friends.
  • People choose friends (and enemies) from within the groups that they have contact with. Friendship selection may be based on a wide variety of traits that produce different degrees of synergy and specialization, but typically there is a slight preference for (genetically) similar people that would react to adverse situations in mutually beneficial and similar ways.
  • Relationships among friends are characterized by closeness (inclusion of the other in one’s self-identification: what is good for them, is good for you), affection (time-intensive, exclusive behavior) and trust (expressions of emotion and vulnerability).
  • Friendship sets the stage for culture (transmitting information across time and space): connections with non-kin provide access to new ideas and resources.
  • Friendship also provides a foundation for morality and the emergence of moral sentiments: how to interact with others (especially non-kin).
  1. Social Networks
  • People’s broader social connections are of two general types: personal interactions within a community (“Gemeinschaft”) and indirect interactions within formal a broader and impersonal society (“Gesellschaft”).
  • Being part of groups allows for the recognition of common and shared characteristics and perspectives, a common humanity. The social suite helps to explain many similarities in human cultures and societies. It seems that our evolutionary past compels us universally to make a certain type of society. Social organization converges on remarkable similar structures. The same core patterns repeat themselves. Even in the most extreme cases (shipwreck, etc.), human societies tend to have stable and predictable outcomes. At the same time this also implies that certain other types of society are highly unlikely or even impossible.
  • In some cases, environmental barriers may stand in the way of the formation of productive social groups: the human propensity for animosity and violence, environmental conditions or constraints, or dysfunctional individuals or cultural elements.
  • People joining communes often aim to break out of impersonal society and seek out more personal relationships within smaller communities. Communes tend to flourish during periods of major social or cultural disruption, typically attracting people that have a greater awareness of or sensitivity to alienation. People who join communes seek authenticity through a reduction of scale, deep contact and personal interactions. Communes typically struggle with the concept of individuality and their success depends primarily on shared ideology, a unified set of beliefs and a common sense of purpose, and on structure of its social network.
  • Social networks and the connections within it are not static, change over time and starting conditions matter (for instance, a collection of strangers in a new shared environment is typically more open to making new connections). Changing network characteristics can affect individual behavior. For instance, the tendency to be kind or altruistic can be strongly influenced by how the surrounding social world is organized and the rules that govern it. In other words, certain social tendencies are not just the properties of individuals, but also of the groups they are a part of. There are optimum social network configurations (for instance for the stability of network connections, a spectrum of fluid to rigid) that drive preferred social outcomes.

 5. Cooperation

  • Friendship sets the stage for cooperation. Formally defined as a contribution to an outcome that benefits all members of a group, regardless of whether the other people themselves contributed to the outcome, cooperation is a central organizing principle of human life.
  • As contributors pay a cost, while free-riders do not, it is perhaps puzzling how cooperation evolved. One of the reasons it may have evolved is repeated interactions in non-zero sum situations: the promise of cooperation tomorrow can incentivize cooperation today, reinforcing trust and positive expectations. In this tit-for-tat scenario, rounds of cooperation can be spaced out in time and the nature of cooperation can vary. However, this can’t explain cooperation in one-off situations (leaving a tip in a restaurant you will never go back to).
  • The other explanation is that status and reputation matter for people living in groups. Cooperation now may lead to someone else cooperating with you later, because of group members sharing stories (even, sometimes, about strangers – gossip).
  • Reciprocity generally works because it keeps people from taking advantage of one another. But, reciprocity mechanisms become less effective when group size increases: cheaters can move on to new victims and can hide more easily. Evolution tends to favor these free-riders more in larger groups. This can be addressed by shrinking group size (or creating sub-groups, communities with stronger ties) or introducing punishment – the organized desire for retribution (mostly in the form of compensating the wronged party). Institutionalized punishment therefore strengthens cooperation.
  • These various types of behavior (cheating, punishing, cooperating, loners) co-exist and co-evolve, ensuring that no particular type will disappear or dominate the population.
  1. In-group Bias
  • Friendship also sets the stage for in-group bias. The ability to form and recognize alliances is essential to social animals. This ability leans on the ability to categorize individuals as friends or foes, as inside or outside of one’s group. This categorization of “us” versus “them” drives the urge to discriminate against out-group members and to make one’s own group distinct from others. Treating others in one’s own group better helps that group seem better and increases one’s self-worth as a member of such group. It also increases the likelihood of mutual aid among group members. The boundaries of the group and the attendant in-group bias can be broadened by a shared agenda (for instance, the emergence of a new, larger common enemy that unites previously divided groups), facilitating cooperation on a larger scale. Altruism (within groups) may have evolved because of competition between groups for scarce resources (ie, peace within required war without – or vice versa).
  1. Hierarchy
  • As group size increases, patterns of connection density and strength determine the shape of the social network, with some members more connected than others. Social mammals are status seeking, in that they are interested in strengthening their connections with powerful individuals or individuals useful in accessing resources, resulting in a status-based society in which individuals associate with others who have similar status and characteristics. This type of network organization has has the side benefit of minimizing the (quick) spread of disease and allows for the emergence of network leaders. Stable leadership facilitates further social order.
  • The variability of our environment may have contributed to the preference for a mild hierarchy, reflecting a balance of prestige and dominance (in a more violent environment, a hierarchy ruled by dominance may be more preferred).
  1. Social learning
  • Identity, friendship and cooperation support the capacity for social teaching and learning and eventually, the emergence of culture.
  • Our connection and cooperation with others allows us to learn from them. Social learning means acquiring knowledge without paying the experiential costs. In the presence of social learning, cooperative behavior in the form of teaching may evolve as well. Teaching makes learning more efficient.
  • From this, culture can emerge: the (cumulative) knowledge transmitted between individuals across time, that can be taught and learnt and that is distinctive to groups. Culture is a property of groups, not individuals. It is an emergent property of human groups, a new property of the whole not manifested in the parts themselves. The structure of a social network affects how culture (complex ideas, behavior) emerges and spreads.
  • The ever-increasing amount of culture (cumulative, complex ideas) is the biggest source of economic growth (see “Why Information Grows). The cultural environment that humans construct for themselves has become a major force of natural selection. In certain environments, a species’ capacity for survival may depend on its ability to fashion culture. If the environment changes so frequently that genetic evolution can’t provide the appropriate adaptation fast enough, (brains capable of) social learning becomes more adaptive.

The Role of Genes

  • Genes are associated with patterns inside as well as outside the organisms that conserve their existence. Outside, genes are closely associated with complex types of behavior, as well as the structure and function of social groups. Because of the external effects of genes, the entire living world could be viewed as a network of interacting genes.
  • In some case, the fitness of certain genes is dependent on the presence of similar genes in other individuals, creating a type of network effect (for instance: the capacity to speak is not very useful in the absence of other individuals being capable to speak). This co-dependence could explain the emergence and evolution of pro-social genes in human, predisposing them to make beneficial social arrangements, potentially a way of natural self-domestication.
  • In this sense, the social environment that human create is partially under the control of our genes.

Genes Affect Culture and Culture Affects Genes

  • Our capacity to create culture (certain cognitive and psychological features) was shaped by genetic natural selection. The capacity for culture may have evolved in order to cope with the variability of our environment. In a more consistent environment, there may be less need for learning and more room for instinctive behavior. Humans have a constellation of psychological traits built for the development and transmission culture, such as a tendency to imitate, to obey local norms and to value status (in the form of prestige, where prestige, the ability to offer culturally derived benefits to others, can lead to greater reproductive fitness.)
  • Culture itself further evolves over time as ideas compete and outperform each other. The way in which cultures evolve may be quite similar to the evolution of species or genes: both are fundamentally driven by the need to adapt to the (variability of the) environment and in both cases, population size matters (bigger is better) and the structure of the social network ties among individuals matters (in the case of cultural evolution, determining how easily information is transferred).
  • The cultural environment itself becomes a force of natural selection. The social environment created partially under the influence of genes in turn feeds back and affects the fitness of certain genes. As an example, culture and genes may co-evolve when certain forms of cultural organization or cultural norms then put pressure on the kinds of genes that promote or accommodate such culturally driven behavior (for instance, religion, forming non-kin communities, institutionalized punishment – each of these cultural constructs may become a force of natural selection, increasing or decreasing the fitness of certain types of genes). Or, cultural adaptations (such as clothes or glasses) may actually decrease genetic selection pressures, perhaps allowing certain genetic problems that would otherwise disappear to persist.
  • We pass on both genes and culture to the next generation: we inherit both genetic and cultural information from our ancestors.


  • The social suite is a universal feature. It is founded on human evolutionary biology. In other words, there are scientific underpinnings to our social lives. These underpinning prime the flow of certain human behaviors, triggering genetic and cultural adaptations to our human environment. The social suite reflects genetic similarities and shared evolutionary heritage that can’t easily be swept aside.
  • While accepting the evolutionary basis of the social suite may be seen as reductionist, it helps to explain how emergent properties such as social networks and cooperation arise. As systems increase in complexity and scale, they acquire new, emergent properties and require entirely new approaches, concepts and laws in order to be observed and understood. Putting the parts into a whole in order to understand what is happening (holisms, as opposed to reductionism) is difficult.
  • These universal features and emergent properties, the nature of our species as shaped under evolutionary pressures, provide the underpinnings and constraints for human morality.
  • When morality is narrowly defined as doing what you are compelled to do by your nature, a moral and “good” action is a rational action, one that we are compelled to make due to the design of our species.
  • In that sense, it is good to live socially, because we are naturally compelled to do so. The social suite is “good” in the sense that it enhances our ability to function as “designed”.
  • [I think all of this is circular and problematic; the definition of what is good and moral (actions are good when they take full advantage of the way we were designed by natural selection) may work to describe how morality plays out on a population level, but provides little practical guidance to morality on an individual level; as the author admits, we are primed by natural selection not just for good, but also for bad, for conflict and hatred, as well as love, friendship and cooperation.].
  • As a species, we have evolved higher order needs to allow us to more efficiently satisfy the basic needs of life.

Other Quotes

  • People go mad in herds, while they only recover their senses one by one.
  • Scientific method: a way of studying the natural world by systematic observation, measurement, and experimentation, formulating, testing and revising hypotheses.
  • State: an entity in a given area that claims a monopoly on the legitimate use of force.
  • Public goods: items that people work cooperatively to fashion and that are of mutual benefit.
  • Emergence: wholes having properties not present in the separate parts.
  • Inequality experiment: inequality itself is not corrosive to group cooperation. Visibility of inequality however reduces group cohesion and cooperative behavior.
  • While humans have both a desire to possess one partner and to have multiple partners, over time, attachment and commitment have proven to be the more evolutionarily successful drivers.
  • From birth, humans have a rudimentary moral sense (see also moral foundations theory by Jonathan Haidt) and manifest consistent, socially relevant behaviors (for instance, voluntarily child’s play), including in-group favoritism, a sense of fairness and reciprocity. Over time, these moral intuitions are shaped further by experience and education.
  • Cultural universals are traits shared by all peoples around the world, suggesting that they are shaped by evolution.

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