• This can come about partly because of a process known to psychologists as deindividuation: people begin to lose their self-awareness and sense of individual agency as they identify more strongly with the group, which often leads to antisocial behaviors they would never consider if they were acting alone. They can form a mob, cease to think for themselves, lose their moral compass, and adopt a classic us-versus-them stance that brooks no shared understanding.

• This fundamental claim about our common humanity has deep philosophical roots as well as empirical foundations. In his essay “The Culture of Liberty,” Peruvian novelist Mario Vargas Llosa notes that people who live in the same place, speak the same language, and practice the same religion obviously have much in common.

• Where does this cross-cultural similarity come from? How can people be so different from—even go to war with—one another and yet also be so similar? The fundamental reason is that we each carry within us an evolutionary blueprint for making a good society.

• Genes affect not only the structure and function of our bodies; not only the structure and function of our minds and, hence, our behaviors; but also the structure and function of our societies. This is what we recognize when we look at people around the world. This is the source of our common humanity.

• In short, at a very young age, humans appear pre-wired (in the sense of having a strong, innate proclivity) to interact in positive ways, with insight into the intentions of others and with a tendency to care about being fair. It is hardly surprising, therefore, that, although details vary from place to place, every society values kindness and cooperation, defines acts of cruelty, and categorizes people as either virtuous or nasty.

• Imagine studying two hills while standing on a ten-thousand-foot-high plateau. Seen from your perch, one hill appears to be three hundred feet high, the other nine hundred feet. This difference may seem large (after all, one hill is three times the size of the other), and you might focus your attention on what local forces, such as erosion, account for the difference in size. But this narrow perspective misses the opportunity to study the other, more substantial geological forces that created what are actually two very similar mountains, one 10,300 feet high and the other 10,900 feet.

• Most experiences that induce such a sense of awe prompt us to feel as if we are transcending our usual frame of reference. Some scientists believe (though it is hard to prove) that awe is an evolved emotion intended to cause a cognitive shift that reduces egocentricity and makes people feel more connected to others.

• For example, the fact that people are uniquely identified in every culture (almost always through the use of personal names) suggests that there is something fundamental about personal identity.

• The debate about universals also evokes broader tensions in the sciences. The most famous tension, to which we shall return, revolves around the relative contributions of nature and nurture as explanations for human experience. Those advocating for the existence of universals are generally seen as belonging to the nature camp. Another tension arises between “lumpers” and “splitters.” Lumpers seek to group similar things together; splitters identify fine distinctions in the natural world.16 Still another tension is between those focusing on the average tendency of a phenomenon (such as the average price of a house in a market) and those interested in its variation (for instance, the range of house prices and the forces that contribute to inequality in prices from place to place). But these different agendas—searching for consistency or studying variation—should be seen as complementary, rather than opposing, ways of studying natural phenomena, including our species, scientifically.

• In the cultural realm, human universals include myths, legends, daily routines, rules, concepts of luck and precedent, body adornment, and the use and production of tools; in the realm of language, universals include grammar, phonemes, polysemy, metonymy, antonyms, and an inverse ratio between the frequency of use and the length of words; in the social realm, universals include a division of labor, social groups, age grading, the family, kinship systems, ethnocentrism, play, exchange, cooperation, and reciprocity; in the behavioral realm, universals include aggression, gestures, gossip, and facial expressions; in the realm of the mind, universals include emotions, dichotomous thinking, wariness around or fear of snakes, empathy, and psychological defense mechanisms.

• These musical universals may be so fundamental that even other species manifest them; for instance, cockatoos make music by drumming with rhythms similar to our own.29 Moreover, music’s function—whether in birds, elephants, whales, or wolves—may be deliberately social. This observation regarding the appearance of human universals in other species is itself a very powerful idea. If a phenomenon (like friendship or cooperation, for example) is present in our species and also in others, then that phenomenon is an especially good candidate for a universal across groups within our own species. If we share a trait with animals, then we can surely share it widely with one another.

• At the core of all societies, I will show, is the social suite: (1) The 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 (that is, “in-group bias”) (7) Mild hierarchy (that is, relative egalitarianism) (8) Social learning and teaching

• The best way to ensure that health, age, and other factors are not confounding the scientists’ assessment of the efficacy of the drug is to randomly assign a pool of patients so that some get the drug and some do not and then compare the outcomes in both groups. This type of experiment—in which exposure to the drug is controlled by the scientists, thus minimizing the impact of extraneous factors—is the gold standard of scientific research.

• People declare their friendships to each other but are less likely to state that they are enemies.

• When the country had a common enemy, it fostered more informal solidarity and more civility in domestic politics. This is a general principle. The boundaries of the group and the attendant in-group bias can be broadened by a shared agenda, which facilitates cooperation on a larger scale.

• It is not a coincidence that the philosophers of the Enlightenment emphasized the special worth of each individual and, in parallel, highlighted the notion of universal human dignity

• In fact, findings from cross-cultural studies suggest that in-group bias and an emphasis on the distinction between us and them is higher in collectivist societies

• Anthropologist Claude Lévi-Strauss observed that binary opposition (male/female, good/evil, hot/cold, conservative/liberal, human/animal, body/soul, nature/nurture, and so forth) is one of the simplest and most widespread ways that humans come to terms with complexities

• Unsurprisingly, this tendency to categorize is also applied to social life, demarcating the difference between us and them, between friend and foe.

• In other words, once set on the path to being social, different animal species converged on a similar plan for social living. In a sense, the reason for this is that all social animals adapt to the exact same environment

• Ecologist Garrett Hardin famously called this the “tragedy of the commons.”76 Individuals act selfishly because the benefits of the acts accrue to them but the costs are divided across the whole group.

• The possibility of being alone reinforces the ability of a group to be together.

• Teaching can formally be defined as a behavior that (1) is primarily or exclusively performed in the presence of a naive individual; (2) costs the teacher or provides no immediate benefit; and (3) facilitates the ability of the learner to acquire information or skills more efficiently than would otherwise be the case.

• And this is another way of describing culture—knowledge that is transmitted between individuals and across time, that can be taught and learned, and that is distinctive to groups.

• To review, culture is a set of beliefs, behaviors, and artifacts that can be arbitrary or adaptive, that are shared by members of a group and are typical of it, and that are socially transmitted.

• In modern societies, where cultural traditions are generally not aimed at immediate survival, many of our practices may be arbitrary. The circumstances of modernity coupled with communication technology may have created runaway conditions for our cultural abilities. The rapid swings in clothing fashion and bodily adornment that we see in modern societies—at rates that far outstrip any analogous changes in attire and self-decoration in traditional societies—provide a good example of this.

• Since teaching is costly to teachers and does not necessarily benefit them, it is actually a kind of altruism.

• We are all beneficiaries of the collective knowledge that our species created over eons and transmitted from person to person across time and place and that now resides among us.

• Genes can have effects at a distance, beyond the bodies of animals in which they are found. These microscopic bits of code can shape the macroscopic world far above them.

• Since the mice are closely related enough that they could mate and reproduce, Hoekstra was able to crossbreed them, and she consequently showed that the making of such burrows is encoded genetically. Hoekstra found that a small set of genes, localized in just three regions of the genome, accounted for entrance-tunnel length, and that just one area of the genome, perhaps just a single gene, somehow coded for the presence of an escape tunnel! Leaving aside the mystery of how genes wind up coding for such complex behaviors resulting in artifacts at all, this experiment shows that genes can actually control the nature of the artifacts that animals make and that variations in specific genes correspond to variations in specific types of artifacts.

• The genes of other individuals now become yet another feature of the environment that every gene must face in the course of its own evolution.

• The capacity for speech is what is known as a network good, meaning that its value rises in relation to how many others have it too. An example of a network good is an e-mail account. If you are the first person on the planet to have one, it is useless to you. But as soon as one other person has one, its value becomes nonzero. And as more and more people get e-mail accounts, yours becomes more and more useful. It can be the same with genes that affect our social lives. They may require the presence of the same or other genes in other people to have their beneficial effects.

• Soviet doctrine at the time was heavily influenced by Trofim Lysenko, a Russian scientist who rejected the genetic and evolutionary theories of Mendel and Darwin in favor of a theory of “acquired characteristics” similar to that advanced by Jean-Baptiste Lamarck. This theory posited, for example, that if a parent learned to run faster to catch its prey, then its children would inherit this newfound ability to run fast. Natural selection had nothing to do with it.

• Given the patently political ways in which his theories were advanced, the term Lysenkoism has come to be used to describe the manipulation of science to reach predetermined, ideological conclusions. I believe that the rejection of the role of genetics in contemporary human social life is a type of Lysenkoism, a topic I explore in chapter 12.

• This is cumulative culture. People endlessly contribute to the accumulated wealth of knowledge that belongs to humanity, and each generation is generally born into greater such wealth.

• Technologies involve functional traits, which carry an adaptive value related to what they do, and stylistic traits, related to how they look (and which are adaptively neutral).33 The former traits tend to arise through convergence because they indicate people are addressing similar problems, while commonalities among stylistic traits tend to reflect shared cultural descent.

• Reductionism neglects the reality of emergence, which is the process by which wholes can have properties that are not present in the parts. An example of emergence we have seen is the differing properties of collections of carbon atoms depending on whether they are arranged as graphite or diamond.

• Physicist Philip Anderson, in his discussion of emergence, offered a piercing critique of reductionist thinking: “The ability to reduce everything to simple fundamental laws does not imply the ability to start from those laws and reconstruct the universe.

• As systems expand along these axes—as physical entities aggregate into chemical ones, as chemical entities aggregate into biological ones, as biological entities aggregate into social ones—they acquire new, emergent properties, and they require entirely new approaches, concepts, and laws to comprehend.

• When I asked whether he believed that genetics might have some role in criminality, he said, “Absolutely not.” And when I gently pointed out that 93 percent of incarcerated criminals were men and that scientists have a lot of evidence, for example, regarding the role of testosterone in aggression in nonhuman primates (for instance, among chimpanzees, 92 percent of attackers and 73 percent of victims are male), he seemed befuddled.

• How can we say that the blueprint is good? Many of the elements of the social suite—individuality, love, friendship, cooperation, learning, and so on—seem manifestly pleasing and, indeed, good. But philosopher G. E. Moore argued a hundred years ago that goodness cannot be equated with pleasingness. Furthermore, he went on to state—overly nihilistically, in my view—that goodness cannot be defined because it is not a natural property at all. He coined the term naturalistic fallacy to explore these ideas, a concept that, in its contemporary usage, refers to the claim that just because something is natural does not make it good. Maternal death during delivery is natural, in the sense that it is not uncommon without the “artificial” intervention of modern medicine, but no one would characterize it as good.

• The topic of the origin of morality is related to another famous dichotomy in moral philosophy, known as the is/ought problem; that is, the distinction between the state the world is in and the state we would want it to be in. Moral judgments implicitly contain commands. Ought invites us to do something in a way that is does not. This dichotomy also sets morality apart from nature, outside it, because it can prescribe a state of affairs that does not or could not exist—for instance, an impossibly utopian community. However, other philosophers argue that if humans are part of the natural world, then their morals must be too.