A Cooperative Species

“In the pages that follow we advance two propositions.
First, people cooperate not only for self-interested reasons but also because they are genuinely concerned about the well-being of others, try to uphold social norms, and value behaving ethically for its own sake. People punish those who exploit the cooperative behavior of others for the same reasons. Contributing to the success of a joint project for the benefit of one’s group, even at a personal cost, evokes feelings of satisfaction, pride, even elation. Failing to do so is often a source of shame or guilt.
Second, we came to have these “moral sentiments” because our ancestors lived in environments, both natural and socially constructed, in which groups of individuals who were predisposed to cooperate and uphold ethical norms tended to survive and expand relative to other groups, thereby allowing these prosocial motivations to proliferate. The first proposition concerns proximate motivations for prosocial behavior, the second addresses the distant evolutionary origins and ongoing perpetuation of these cooperative dispositions.”

Here’s my goodreads review of the book – I gave the book five stars on goodreads. In the post I have included some illustrative quotes below, but really you should read all of it if you find this sort of stuff interesting and you’re not mathematically illiterate (and as the authors note early on, they have given the way they present their ideas some thought: “We have presented technical material in verbal as well as mathematical form wherever possible, and avoided mathematical formulations entirely where that was possible without sacrificing clarity.” Even so, the book is somewhat dense and it takes some work to get through).

…

“In short, humans became the cooperative species that we are because cooperation was highly beneficial to the members of groups that practiced it, and we were able to construct social institutions that minimized the disadvantages of those with social preferences in competition with fellow group members, while heightening the group-level advantages associated with the high levels of cooperation that these social preferences allowed. These institutions proliferated because the groups that adopted them secured high levels of within-group cooperation, which in turn favored the groups’ survival as a biological and cultural entity in the face of environmental, military and other challenges.”

“The regulation of social interactions by group-level institutions plays no less a role than altruistic individual motives in understanding how this cooperative species came to be. Institutions affect the rewards and penalties associated with particular behaviors, often favoring the adoption of cooperative actions over others, so that even the self-regarding are often induced to act in the interest of the group. […] the individual motives and group-level institutions that account for cooperation among humans include not only the most elevated, including a concern for others, fair-mindedness, and democratic accountability of leaders, but also the most wicked, such as vengeance, racism, religious bigotry, and hostility toward outsiders.”

“Optimizing models are commonly used to describe behavior not because they mimic the cognitive processes of the actors, which they rarely do, but because they capture important influences on individual behavior in a succinct and analytically tractable way.”

“Culture is an evolutionary force in its own right, not simply an effect of the interaction of genes and natural environments. […] human preferences and beliefs are the product of a dynamic whereby genes affect cultural evolution and culture affects genetic evolution, the two being tightly intertwined in the evolution of our species. [I have of course talked about gene-culture coevolution before here on the blog and I don’t like to repeat myself, but this idea/notion really is unknown to many people who should know better, and so is perhaps worth repeating here even so – US] […] The idea of treating culture as a form of epigenetic transmission was pioneered by Cavalli-Sforza and Feldman (1973), Karl Popper (1979), and Richard Dawkins, who coined the term “meme” […] to represent an integral unit of information that could be transmitted phenotypically. There quickly followed several major contributions to a biological approach to culture, all based on the notion that culture, like genes, could evolve through replication (intergenerational transmission), mutation, and selection […] Richard Dawkins added a second fundamental mechanism of epigenetic information transmission in The Extended Phenotype (1982), noting that organisms can directly transmit environmental artifacts to the next generation […] Creating a fitness-relevant aspect of an environment and stably transmitting this environment across generations, known as niche construction, is a widespread form of epigenetic transmission […] niche construction gives rise to what might be called a gene-environment coevolutionary process, since a genetically induced environmental regularity becomes the basis for genetic selection, and genetic mutations that give rise to mutant niches will tend to survive if they are fitness enhancing for their constructors. […] Human cultures, along with the institutional structures they support, are instances of niche construction”.

“while genetic transmission of information plays a central role in our account, the genetics of non-pathological social behavior is for the most part unknown. […] No “gene for cooperation” has been discovered. Nor is it likely that one will ever be found, for the idea of a one-to-one mapping between genes and behavior is unlikely given what is now known about gene expression, and is implausible in light of the complexity and cultural variation of cooperative behaviors. […] an explanation of the evolution of human cooperation must hinge on the empirical evidence. The question is not “Which model works?” They all work, if mathematical coherence is the bar. The question we are asking is about something that actually happened in the human past. Thus we measure the empirical plausibility of alternative explanations against the conditions under which early humans lived during the Pleistocene, roughly 1.6 million years before the present, until the advent of agriculture beginning about 12,000 years ago, and especially the last 100 or so millennia of this period.”

“in small-scale societies punishment can be highly effective even when it takes the form of ridicule or gossip and it inflicts no material costs on its targets. […] People are sensitive to others’ evaluation of their moral worth or intentions and will cooperate in social dilemmas when the punishment for free-riding takes the form of criticism by peers rather than a reduction in material payoffs. […] People punish not only those who have hurt them, but also those who hurt others. […] even self-regarding individuals may engage in third-party punishment if they believe that this will induce other-regarding individuals to behave favorably toward them. […] recent experimental results are consistent with the view that the social preferences that become salient in a population depend critically on the manner in which a people’s institutions and livelihood frame social interactions and shape the process of social learning. An expected result, confirmed by a growing body of international comparative evidence, is substantial cross-cultural differences in the nature and extent of social preferences.”

“In experimental and natural settings, people often behave differently toward others, depending on the organizational, linguistic, ethnic, and religious groups to which they belong. People choose to associate with others who are similar to themselves in some salient respect […] Among the salient characteristics on which this choice operates are racial and ethnic identification, and religion […] Conversely, people often seek to avoid interactions with those who are different from themselves. […] Those who condition their behavior on the group membership of the other may do this because group membership is thought to provide information about the other’s likely behavior. Or group membership may matter because people would like to help or to interact with members of some groups more than others. In the first case the actor’s beliefs are involved. In the second case, group-sensitive preferences are at work. […] a series of experiments by Toshio Yamagishi and his associates […] show that experimental subjects’ allocations favor in-group members not because of altruistic sentiments toward those who are similar to themselves, but because they expected reciprocation from in-groupers and not from out-groupers. […] taking account of ethnic, racial and other characteristics of those with whom one interacts appears to be a quite common human trait. We seem quite attuned to noticing and treating as salient the ascriptive markers of group difference. For example, Americans of European and African origin are better at recognizing faces of their own ancestral group, and faces of their own group induce greater activation in the part of the brain associated with face recognition.” (my bold)

“The most parsimonious and compelling proximate explanation of behavior in the ultimatum game, public goods game, and other social dilemma experiments is that people think that cooperating is the right thing to do and enjoy doing it, and that they dislike unfair treatment and enjoy punishing those who violate norms of fairness. […] Recent studies of brain functioning provide some support for this hedonic view of cooperative behavior.“

“Differential group success […] plays a central role in the evolution of human behaviors and institutions, members of less successful groups copying the more successful or being eliminated by them. […] the speed of an evolutionary process is proportional to the differences on which it works […] reduction in within-group differences slows down the selection against altruistic individuals. Insider biases and individual preferences to interact with like individuals lead to large between-group differences in behavior and, to a lesser but not negligible extent, in genotypes too […] insider biases result in frequent between-group conflicts as well as high levels of positive assortment in interactions both within and between groups. […] All of these aspects of human social life enhance the force of between-group selection relative to within-group selection.” (my bold)

“The fact that helping behaviors are […] motivated by [a] wide range of proximate motives, from maternal love, to enlightened self-interest, to solidarity with one’s coethnics or conationals, is consistent with our view that in all likelihood each of the mechanisms […] has played a significant role in human evolution, the importance of each depending on the forms of cooperation under consideration and the ecological and social conditions under which ancestral humans interacted. […] what can be known or reasonably conjectured from genetic, archaeological and other data about [the] ancestral human conditions suggests that neither helping close family members nor reciprocal altruism provides an adequate account of the emergence of [our] cooperative species. […] multi-level selection models based on gene culture coevolution [however] contribute substantially to a convincing explanation.”

…

As mentioned, if you find this kind of stuff interesting you should strongly consider reading the book.