Science of Good and Evil

WHY WE ARE MORAL: THE EVOLUTIONARY ORIGINS OF MORALITY

Who are we? The answer to this question is not only one of the tasks but the task of science.

Erwin Schrödinger, Science and Humanism, 1951

In an episode of the classic television comedy series The Honeymooners, Jackie Gleason and Art Carney’s characters—the boisterously bellicose Ralph Kramden and the benignly bumbling Ed Norton—engage in one of their archetypal over-the-top arguments, this time over a universal problem found in all primate species: food sharing and its anticipated consequent reciprocity. The conflict arises when the two families decide they are going to save on rent by sharing an apartment, which then involves dining together. Alice has just served dinner.

RALPH: When she put two potatoes on the table, one big one and one small one, you immediately took the big one without asking what I wanted.

NORTON: What would you have done?

RALPH: I would have taken the small one, of course.

NORTON: You would?

RALPH: Yes, I would!

NORTON: So, what are you complaining about? You got the little one!

In its essence this comedic routine symbolizes an enormous source of tension in human relations that led to the evolution of what was almost certainly the first moral principle—the Golden Rule. In 1690 the English political philosopher John Locke, in his classic work Essay Concerning Human Understanding, inquired about whether this “unshaken rule of morality, and foundation of all social virtue, ‘that one should do as he would be done unto,’ be proposed to one who never heard of it before, but yet is of capacity to understand its meaning, might he not without any absurdity ask a reason why?” Certainly, but as I shall argue, no such individual would find the Golden Rule surprising in any way because at its base lies the foundation of most human interactions and exchanges and it can be found in countless texts throughout recorded history and from around the world—a testimony to its universality. Table 1 presents just a few of its manifestations in chronological order (B.C.E. and C.E. are Before Common Era and Common Era).

TABLE 1

The Historical and Universal Expression of the Golden Rule
Lev. 19:18, c. 1000 B.C.E.: “Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbor as thyself.”
Confucius, The Doctrine of the Mean, 13, c. 500 B.C.E.: “What you do not want others to do to you, do not do to others.”
Isocrates, c. 375 B.C.E.: “Do not do to others what would anger you if done to you by others.”
Tob. 4:15, c. 180 B.C.E.: “What thou thyself hatest, do to no man.”
Diogenes Laertius, Lives of the Philosophers, c. 150 B.C.E.: “The question was once put to Aristotle how we ought to behave to our friends; and his answer was, ‘As we should wish them to behave to us.’”
The Mahabharata, c. 150 B.C.E.: “This is the sum of all true righteousness: deal with others as thou wouldst thyself be dealt by. Do nothing to thy neighbor which thou wouldst not have him do to thee hereafter.”
Matt. 7:12, c. first century C.E.: “All things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.”
Luke 6:31, c. first century C.E.: “As ye would that men should do to you, do ye also to them likewise”
Epictetus, Encheiridion, c. 100: “What thou avoidest suffering thyself seek not to impose on others.”
The Didache, or Teaching of the Twelve Apostles, c. 135: “All things whatsoever that thou wouldst not wish to be done to thee, do thou also not to another.”
John Wycliffe, translation of Luke 7:31, 1389: “As ye will that men do to you, and do ye to them in like manner.”
David Fergusson, Scottish Proverbs, 1641: “Do as ye wald be done to.”
Thomas Hobbes, Leviathan, 1651: “Whatsoever you require that others should do to you, that do ye to them.”
The Book of Common Prayer (catechism), 1662: “My duty towards my neighbor is to love him as myself, and to do to all men as I would they should do unto me.”
Henry More, Enchiridion ethicum, 4, 1667: “The evil which you do not wish done to you, you ought to refrain from doing to another, so far as may be done without injury to some third person.”
Baruch Spinoza, Ethica, 4, 1677: “Desire nothing for yourself which you do not desire for others.”
John Wise, A Vindication of the Government of New England Churches, 1717: “If a man any ways doubt whether what he is going to do to another man be agreeable to the law of nature, then let him suppose himself to be in that other man’s room.”
John Stuart Mill, Utilitarianism, 1863: “To do, as one would be done by, and to love one’s neighbor as one’s self, constitute the ideal perfection of utilitarian morality.”
Henry Sidgwick, The Methods of Ethics, 1874: “Reason shows me that if my happiness is desirable and a good, the equal happiness of any other person must be equally desirable.”
Peter Kropotkin, La Morale Anarchiste, 1891: “Do unto others as you would have others do unto you in like case.”

Hillel Ha-Babli, in the thirty-first book of The Sabbath in 30 B.C.E., raised the Golden Rule to the ultimate moral principle: “Whatsoever thou wouldst that men should not do to thee, do not do that to them. This is the whole Law. The rest is only explanation.” That explanation, however, forms the basis of the evolutionary origins of morality, beginning with the evolution of the premoral sentiments.

The Evolution of Premorality

Our moral sentiments—the moral emotions contained within our mental armory—evolved out of premoral feelings of our hominid, primate, and mammalian ancestors, the remnants of which can be found in modern apes, monkeys, and other big-brained mammals. I consider these sentiments to be premoral because morality involves right and wrong thoughts and behaviors in the context of a social group. To date, it does not appear that nonhuman animals can consciously assess the rightness or wrongness of a thought, behavior, or choice in themselves or fellow members of their species. Thus, I hold that morality is the exclusive domain of Homo sapiens.

Of course, we are animals and so it is not surprising to discover premoral sentiments in other animals. And, equally unsurprising, the more like us a species is the more moral-like are their premoral sentiments, such as those observed in the great apes (e.g., chimpanzees, bonobos, and gorillas), monkeys (e.g., rhesus, baboons, and macaques), and other big-brained mammals (e.g., whales and dolphins). As we travel across the phylogenetic (evolutionary) scale away from humans we see that mammals exhibit more premoral behaviors than nonmammals (e.g., reptiles). In fact, when we examine the evolutionary sequence in detail we see that there is no distinct place to draw the line between moral and nonmoral, a problem created by the restrictive nature of binary logic. In binary logic one sees the world as black or white, up or down, in or out. In fuzzy logic one sees the world in shades of gray, between up and down, in and out. Instead of dividing the world into binary digits of 0 or 1, we can nuance it with shades in between (.1, .2, .3 … .9). Instead of simply saying that humans are moral and animals are not moral (1 and 0), we could describe humans as .9 or .8 moral, the great apes as .7 or .6 moral, monkeys as .5 or .4 moral, whales and dolphins as .3 or .2 moral, and so forth. This is why a scientific analysis of morality can be more fruitful than a philosophical one. An evolutionary perspective grants other animals degrees of morality (or premorality) that allows us to discover how we developed our moral sentiments; it also grants them greater dignity and status than does a nonevolutionary perspective.

Let us begin with household pets such as dogs and cats, since they are arguably the animals of which we are most intimately knowledgeable. Surely few outside of extreme animal rights’ activists would claim that dogs and cats are moral animals, yet anyone who has had one for a pet for very long recognizes that they quickly learn the difference between right and wrong, and that dogs, especially, feel some sense of shame or guilt when being scolded for bad behavior and openly express joy and pride when being praised for good behavior. That sense of shame and guilt, or joy and pride, is what I mean by moral sentiments. But it appears that dogs and cats are not self-aware and self-conscious of their and other dogs’ and cats’ good and bad behavior—at least to an extent that would allow them to assess a moral judgment upon another member of their species (even if they cannot articulate it due to lack of language and speech apparatus). It might be more appropriate to call these premoral sentiments. (Some would debate this point, noting that wolf parents appear to teach their offspring the difference between right and wrong behavior, at least in terms of survival.) ¹

The difference between dogs and cats in the expression of such premoral sentiments reveals the importance of another component in morality—the social group. Cats are notoriously individualistic and independent, not typically herd or hierarchical social animals, especially when compared to dogs, who in the wild travel in packs with pecking orders (particularly noted in wolves, from which all dogs evolved) and in domestic situations establish social bonds with members of the household. (It is well known among dog trainers that the first rule of obedience is to establish yourself as the alpha member of the home, thereby relegating your dog to a lower rung in the pecking order.)

Examples of premoral sentiments among animals abound. It has been well documented that vampire bats, for example, exhibit food-sharing behavior and the principle of reciprocity. They go out at night in hordes seeking large sleeping mammals from which they can suck blood. Not all are successful, yet all need to eat regularly because of their excessively high metabolism. On average, older experienced bats fail one night in ten, younger inexperienced bats fail one night in three. Their solution: successful individuals regurgitate blood and share it with their less fortunate comrades, fully expecting reciprocity the next time they come home sans bacon. Gerald Wilkinson, in his extensive study of cooperation in vampire bats, has even identified a “buddy system” among bats, in which two individuals share and reciprocate from night to night, depending on their successes or failures. He found that the degree of affiliation between two bats—that is, the number of times they were observed together—predicted how often they would share food. Since bats live for upwards of eighteen years among the same community, they know who the cooperators are and who the defectors are.² Of course, the bats are not aware they are being cooperative in any conscious goodwill sense. All animals, including human animals, are just trying to survive, and it turns out that cooperation is a good strategy. This is especially apparent in the primates.

Psychologist and primatologist Frans de Waal has documented hundreds of examples of premoral sentiments among apes and monkeys. At the Yerkes Field Station where he and his colleagues observe their primate charges from on high, de Waal reveals the high level of conflict among these social species, as well as how those conflicts are resolved: “These records show that once the dust has settled after a fight, combatants are often approached by uninvolved bystanders. Typically the bystanders hug and touch them, pat them on the back, or groom them for a while. These contacts are aimed at precisely those individuals expected to be most upset by the preceding event.” This is most apparent in the chimpanzees, our closest evolutionary relatives: “When upset, chimpanzees pout, whimper, yelp, beg with outstretched hand, or impatiently shake both hands so that the other will hurry and provide the calming contact so urgently needed. If all else fails, chimpanzees resort to their ultimate weapon, the temper tantrum. They lose control, roll around screaming pathetically, hitting their own head or beating the ground with their fists, regularly checking the effects on the other.”³

Aristotle described humans as political animals. De Waal has discovered that chimpanzees are political animals as well (figure 1). When he shifted his research from macaques to chimps, he writes, “I was totally unprepared for the finesse with which these apes con each other. I saw them wipe undesirable expressions off their face, hide compromising body parts behind their hands, and act totally blind and deaf when another tested their nerves with a noisy intimidation display.”⁴ Politics—human and chimp—depends on reciprocity, and this too has been cleverly studied by de Waal in experiments whereby in order to obtain a heavy bucket of food two chimps must work together to pull it up with ropes. Although both are needed to haul the bucket up to the cage (where they are separated by a barrier), only one gets the food. De Waal discovered that if the recipient of the food did not share it with his companion, the companion refused to cooperate in the rope pulling in subsequent trials. In the long run, however, “cooperative behavior between two primates leads to greater food sharing after the task in which the cooperation occurred.”⁵ Quid pro quo.

Figure 1. Food Sharing in Chimpanzees

As documented by psychologist Frans de Waal at the Yerkes Field Station, four chimpanzee adults and one infant (seen in the food pile) participate in a vital social exchange process of food sharing that encourages cooperation and reciprocal altruism. In this group, the exchange process is controlled by the possessor female in the upper right corner. The female in the lower left reaches for food; whether it will be granted or not depends on her relationship to the possessor female. (Photograph by Frans de Waal)

Other scientists have documented premoral sentiments in other higher mammals. Dolphins have been seen to push sick or wounded members of a pod to the surface so that they may catch their breath. Whale fishermen know—and capitalize on the fact—that whales will put themselves in harm’s way by coming to the defense of a wounded member of their group, circling them and striking the water with their flukes (thereby alerting the hunters to their whereabouts). One theory for why whales beach themselves in what often appears to be mass suicide is that, in fact, one member is disoriented and gets beached, and the others follow trying to help. In 1976 a pod of thirty false killer whales heaved themselves up on a Florida beach where they remained for three days; after one of their members died, the rest returned to the sea (able to do so because of a fortunate timing of the tides).⁶ Cynthia Moss recorded the responses of a community of elephants to one of their members being shot by a poacher. As the struck elephant’s knees buckled and she began to go down, her elephant comrades struggled to keep her upright. “They worked their tusks under her back and under her head. At one point they succeeded in lifting her into a sitting position but her body flopped back down. Her family tried everything to rouse her, kicking and tusking her, and Tallulah even went off and collected a trunkful of grass and tried to stuff it into her mouth.” After she died, her friends and family members covered the corpse in dirt and branches.⁷

Hundreds of such examples exist in the scientific literature, and thousands more in popular literature.⁸ The following characteristics appear to be shared by humans and other mammals, including and especially the apes, monkeys, dolphins, and whales: attachment and bonding, cooperation and mutual aid, sympathy and empathy, direct and indirect reciprocity, altruism and reciprocal altruism, conflict resolution and peacemaking, deception and deception detection, community concern and caring about what others think about you, and awareness of and response to the social rules of the group. Species differ in the degree to which they express these sentiments, and with our exceptionally large brains (especially the well-developed and highly convoluted cortex) we clearly express most of them in greater degrees than other species. Nevertheless, the fact that such premoral sentiments exist in our nearest evolutionary cousins may be a strong indication of their evolutionary origins. Still, something profound happened in the last 100,000 years that made us—and no other species—moral animals to a degree unprecedented in nature.

The Evolution of Morality

For the first 90,000 years of our existence as a species—that is, as anatomically modern humans distinct from other hominid species such as the Neanderthals—humans lived in small bands of tens to hundreds of individuals. In the last 10,000 years—only 10 percent of Homo sapiens’ existence—some bands evolved into tribes of thousands of individuals, some tribes developed into chiefdoms of tens of thousands of individuals, some chiefdoms coalesced into states of hundreds of thousands of individuals, and a handful of states conjoined together into empires of millions of individuals. Within a rough order of magnitude comparison, the evolution of our species proceeded as depicted in table 2. (Recent fossil finds in Ethiopia by paleoanthropologist Tim White and his team indicate that anatomically modern humans may date to 160,000 years. The DNA evidence also supports this claim, although such figures come equipped with some error, meaning that the rough estimates presented here are legitimate.)⁹

TABLE 2

The Social Evolution of Humans Over the Past 100,000 Years
100,000–10,000 years	Bands	10s–100s of individuals
10,000–5,000 years	Tribes	100s–1,000s of individuals
5,000–3,000 years	Chiefdoms	1,000s–10,000s of individuals
3,000–1,000 years	States	10,000s–100,000s of individuals
1,000–present	Empires	100,000s–1,000,000s of individuals

Somewhere along the way, moral sentiments evolved out of the premoral sentiments of our primate and hominid ancestors and moral codes were created. Generally speaking, moral sentiments as expressed in thoughts and behaviors evolved during those first 90,000 years when we lived in bands. In the last 10,000 years, these moral thoughts and behaviors were codified into moral rules and principles by religions that arose as a direct function of the shift from tribes to chiefdoms to states.¹⁰ How and why did this happen?

The human story begins roughly six to seven million years ago when a hominid primate branched off from the common ancestor shared by our primate contemporary, the chimpanzees. Two to three million years ago hominids in Olduvai Gorge in east Africa began chipping stones into tools and altering their environment. Around one million years ago Homo erectus added controlled fire to hominid technology, and between half a million and 100,000 years ago other hominids, such as Homo neanderthalensis and Homo heidelbergensis, lived in caves, had relatively elaborate tool kits, and developed throwing spears with finely crafted spear points. The evidence is now overwhelming that many hominid species lived simultaneously, and at present we can only speculate what speciation pressures these changing technologies put on natural selection.¹¹

Sometime around 35,000 years ago one hominid species improved its tool kit dramatically, making it noticeably (in the fossil record) more complex and varied. Suddenly clothing covered their bodies, art adorned their caves, bones and wood formed the structure of their living abodes, and, perhaps most significantly, language produced sophisticated symbolic communication. They even buried their dead in prepared grave sites with burial ceremonies (figure 2). By 13,000 years ago our species had spread to nearly every region of the globe and all people everywhere lived in a condition of hunting, fishing, and gathering (HFG). Most were nomadic, staying in one place for no longer than a few weeks at a time. Small bands grew into larger tribes, and with this shift, possessions became valuable, rules of conduct grew more complex, and population numbers climbed steadily upward. When population pressures in numerous places around the globe grew too intense for the HFG lifestyle to support, an agricultural revolution sprouted.¹² New food-production technologies allowed populations to increase dramatically. With those increased populations came new social technologies for governance and conflict resolution. The creation of tribes from bands began around 13,000 years ago. Archaeological evidence indicates that the coalition of tribes into chiefdoms occurred in the Fertile Crescent of western Asia around 7,500 years ago. Within 2,000 years—roughly 5,500 years ago—chiefdoms began to merge into states in the same general area.

Figure 2. The Evolutionary Origins of Morality 100,000 Years Ago

The moral sentiments evolved roughly 100,000 years ago among bands of hunter-gatherers who learned to cooperate with each other and compete with other hominid groups. Depicted here is the burial of a child at Qafzeh Cave in Israel, the oldest-known decorated grave site in the world, where paleoanthropologists discovered the skeleton of a child grasping the skull of a fallow deer. (Courtesy of W. W. Norton)

The concomitant leap in food production and population that accompanied the shift to chiefdoms and states allowed for a division of labor to develop in both economic and social spheres. Full-time artisans, craftsmen, and scribes worked within a social structure organized and run by full-time politicians, bureaucrats, and, to pay for it all, tax collectors. Organized religion came of age—along with these other social institutions—to fill many roles, not the least of which was the justification of power for the ruling elite. The “divine right of kings” is not the invention of early-modern European monarchs. In fact, every chiefdom and state society known to archaeologists from around the world, including those in the Middle East, Near East, Far East, North and South America, and the Polynesian Pacific islands, justified political power through divine sanction, in which the chief, pharaoh, king, queen, monarch, emperor, sovereign, or ruler of whatever title claimed a relationship to God or the gods, who allegedly anointed them with the power to act on behalf of the divinity. In a type of reciprocal exchange program, the masses would pay for this divine connection through taxes, loyalty, and service to the chiefdom or state (for example, through military inscription). As states evolved into bona fide civilizations and the centuries witnessed small cults evolve into world religions, behavior commitments evolved into standardized rituals, accompanied by the appropriate architectural displays of both political and religious power.¹³ Organized religion as we know it was born.

This historical development supports what is known as the rational choice theory of religion.¹⁴ Fundamental to this theory is that the beliefs, rituals, customs, emotions, commitments, and sacrifices associated with religion are best understood as a form of exchange relations between humans and God or gods. In this model, humans are assumed to be rational, making mental calculations to maximize resources and rewards. Where resources and rewards are available through secular avenues, religion is not needed. Where resources and rewards are scarce (for example, rain for crops) or nonexistent (for example, immortality) through secular sources, then religion becomes the accepted venue for the exchange of goods and services. Sociologists Rodney Stark and William Bainbridge present examples from various religions that reveal that the greater the number of gods in the religion the lower the price of exchange (the less that has to be given for the product or service received). They have also found that the more dependable and responsive the gods are in delivering goods and services the higher the price people are willing to pay. Finally, they found that religious rituals and the confidence of fellow believers serve to reinforce the confidence people have that their gods will deliver the goods and services, that such confidences are enhanced through miracles and mystical experiences associated with religions, and that religious organizations require commitment from believers in order to sustain their power as the primary source for such exchanges.

With the exception of the American experiment of separating church and state, politics and religion have always been tightly interdigitated. The reason has to do with the even more important role that religion has played in the development of morality. That is, in addition to the sanction of political power, religion has also served as an institution of social order and behavior control. The reinforcement of positive moral sentiments (and the punishment of negative ones) became a central role of religious leaders and organizations; they codified subjective social and moral norms and, with the invention of writing, literally canonized them in sacred scrolls and texts. From Moses proclaiming that God dictated to him the Ten Commandments, to Joseph Smith claiming that the angel Moroni delivered to him the golden plates, to L. Ron Hubbard’s pulp science fiction repackaged as sacred religious texts said to be inspired by advanced alien intelligences, most religions tend to decree divine inspiration in order to enhance social and political power.

Such elaborate behavior controls yoked to religious rituals are not needed in bands and tribes, whose numbers are small enough that other less formal methods are more effective. In his three decades of research in New Guinea, for example, Jared Diamond says he has “never heard any invocation of a god or spirit to justify how people should behave toward others.” Social obligations, he explains, depend on human relationships. “Because a band or tribe contains only a few dozen or a few hundred individuals respectively, everyone in the band or tribe knows everyone else and their relationships. One owes different obligations to different blood relatives, to relatives by marriage, to members of one’s own clan, and to fellow villagers belonging to a different clan.” Conflicts are directly resolved within these small bands because everyone is related to one another or knows one another. Members of the band are distinctly different from nonmembers on all levels. “Should you happen to meet an unfamiliar person in the forest, of course you try to kill him or else to run away; our modern custom of just saying hello and starting a friendly chat would be suicidal,” Diamond reflected.¹⁵ Populations in the many thousands of people, however, made such informal behavioral control mechanisms ineffectual. This led to the wedding of God and mammon.

This historical trajectory makes good sense in an evolutionary model. In bands and tribes the declaration of love for one’s neighbors means something rather different than it does in chiefdoms, states, and empires. In the Paleolithic social environment in which our moral sentiments evolved, one’s neighbors were family, extended family, and community members who were well known to all. To help others was to help oneself. In chiefdoms, states, and empires the biblical admonition “Love thy neighbor” meant only one’s immediate in-group. Out-groups were not included. In a group selection model of the evolution of religion and morality, those groups who were particularly adept at amity within the group and enmity between groups were likely to be more successful than those who haphazardly embraced total strangers. This evolutionary interpretation also explains the seemingly paradoxical nature of Old Testament morality, where on one page high moral principles of peace, justice, and respect for people and property are promulgated, and on the next page raping, killing, and pillaging people who are not one’s “neighbors” are endorsed. In terms of evolutionary group selection, religious violence, genocide, and war are adaptive because they serve to unite in-group members against enemy out-groups.

Figure 3. A Group of New Guinea Hunter-Gatherers Prepares for Battle

Before state societies, “love thy neighbor” meant one’s immediate family, extended family, and community of fellow in-group members. “Out-groupers” were to be dealt with cautiously. Trust was tentative. Conflict was frequent. Death by war was common. (Courtesy of Film Study Center)

Consider what Moses thought God meant by “neighbor” (in Lev. 19:18): “Thou shalt not avenge, nor bear any grudge against the children of thy people, but thou shalt love thy neighbour as thyself.” Here “the children of thy people” are the neighbors one is not to kill (King James Version). In other translations, neighbors are “the sons of your own people” (Revised Standard Version) and “your countrymen” (Tanakh), in other words, thy fellow in-group members. By contrast, where Deut. 5:17 admonishes readers “Thou shalt not kill,” fifteen chapters later, in Deut. 20:10—18, the Israelites are commanded to lay siege to an enemy city, steal their cattle, enslave all citizens who surrender, and kill the men and rape the women who do not surrender:

When you draw near to a city to fight against it, offer terms of peace to it. And if its answer to you is peace and it opens to you, then all the people who are found in it shall do forced labor for you and shall serve you. But if it makes no peace with you, but makes war against you, then you shall besiege it; and when the LORD your God gives it into your hand you shall put all its males to the sword, but the women and the little ones, the cattle, and everything else in the city, all its spoil, you shall take as booty for yourselves; and you shall enjoy the spoil of your enemies, which the LORD your God has given you. Thus you shall do to all the cities which are very far from you, which are not cities of the nations here.

But in the cities of these peoples that the LORD your God gives you for an inheritance you shall save alive nothing that breathes, but you shall utterly destroy them, the Hittites and the Amorites, the Canaanites and the Perizzites, the Hivites and the Jebusites, as the LORD your God has commanded; that they may not teach you to do according to all their abominable practices which they have done in the service of their Gods, and so to sin against the LORD your God.

As believers in sham gods and worshippers of false idols, heathens are to be extirpated by those who follow the One True God. The first of the Ten Commandments, in fact, states that one is to put no other gods before the One True God.

The rabbinical commentaries in the Talmud also support this in-group /out-group evolutionary model. The law (Mishnah) clarifies intentional and unintentional murder of an Israelite by an Israelite as such: “If he intended killing an animal but slew a man, or a heathen and he killed an Israelite … he is not liable” (Sanhedrin 79a). Further discussion of this law provides additional examples: “This excludes [from liability] the case of one who threw a stone into the midst of a company of Israelites and heathens. How is this? Shall we say that the company consisted of nine heathens and one Israelite? Then his non-liability can be inferred from the fact that the majority were heathens” (Gemara). So, thou shalt not kill a fellow Israelite, unless one is trying to kill a heathen, in which case the sacrifice was worth it. By contrast, the venerable rabbinical scholar Maimonides says that “if a resident alien slays an Israelite inadvertently, he must be put to death in spite of his inadvertence.” In other words, good intentions apply only to members of our in-group. The book of Judges (5:9) is even more extreme in its in-group inclusiveness and out-group exclusiveness: “A Noahide [non-Jew] who kills a person, even if he kills an embryo in the mother’s womb, is put to death. So too, if he kills one suffering from a fatal disease … he is put to death. In none of these cases is an Israelite put to death.” The notion of “God’s chosen people” resonates with evolutionary in-groupness.¹⁶

Because our deep moral sentiments evolved as part of our behavioral repertoire of responses for survival in a complex social environment (and not simply as infinitely plastic socially conditioned moral codes relative to one’s culture), we carry the seeds of such in-group inclusiveness today. Israeli psychologist Georges Tamarin tested this hypothesis in 1966 on 1,066 schoolchildren ages eight to fourteen, by presenting them with the story of the battle of Jericho in Josh. 6. Joshua told his people to rejoice because God granted them access to Jericho: “Then they utterly destroyed all in the city, both men and women, young and old, oxen, sheep, and asses, with the edge of the sword … . And they burned the city with fire, and all within it; only the silver and gold, and the vessels of bronze and or iron, they put into the treasury of the house of the LORD.” Tamarin wanted to test how biblical stories influenced children, particularly those stories that touted the superiority of monotheism, focused on the notion of the “chosen people,” and made acts of genocide heroic. After presenting the Joshua story, the children were asked: “Do you think Joshua and the Israelites acted rightly or not?” Tamarin offered them three answers from which to choose: A, approval; B, partial approval or disapproval; and C, total disapproval. The results were disturbing: 66 percent of the children completely approved of the Israelites’ murderous actions, while only 8 percent chose B and 26 percent chose C. One youngster wrote: “In my opinion Joshua and the Sons of Israel acted well, and here are the reasons: God promised them this land, and gave them permission to conquer. If they would not have acted in this manner or killed anyone, then there would be the danger that the Sons of Israel would have assimilated among the ‘Goyim.’”Change the in-group to an out-group, on the other hand, and approval ratings for genocide drop precipitously. Substituting “General Lin” for Joshua and a “Chinese Kingdom 3,000 years ago” for Israel, Tamarin found that only 7 percent of his Israeli subjects (a control group of 168 different children) approved of the genocide (with 18 percent in the middle and 75 percent disapproving totally).¹⁷

The evolution of in-group morality, of course, is not restricted to any one religion, nation, or people.¹⁸ It is a universal human trait common throughout history, from the earliest chiefdoms and states to modern nations and empires. As we shall see in the next chapter, the Y

nomamö people of the Amazon consider themselves to be the ultimate chosen people—in their language their name represents humanity, with all other peoples as something less than human. As the novelist and social commentator Aldous Huxley noted: “The propagandist’s purpose is to make one set of people forget that the other set is human. By robbing them of their personality, he puts them outside the pale of moral oligation.”¹⁹ As we shall also see in the next chapter, the Nazis did this in spades. As many science fiction authors have suggested, perhaps an extraterrestrial threat to the entire planet Earth is what is needed to unite all humans into one giant in-group.

Morality and the Magic Number 150

Humans are, by nature, pattern-seeking, storytelling animals that evolved in both a physical and a social environment. As we have seen, morality is inextricably bound to religion, the first social structure to codify moral behaviors into ethical systems. Given the amount of time spent in the environment of our evolutionary history, we need to look more closely at the nature of human relationships in these small bands and tribes. In order to survive, these small hunter-gatherer bands would have had to employ considerable skills in cooperation and communication. Anthropologist Robert Bettinger demonstrates how, compared with individuals, “groups may often be more efficient” not only “in finding and taking prey, particularly large prey,” but also in coordinating the activities of individuals, who might otherwise unduly interfere with each other. Foraging groups “that pool and share resources have the effect of ‘smoothing’ the variation in daily capture rates between individuals.”²⁰ That is, as the group grows larger, “lucky” individuals share their take with “unlucky” individuals, and everyone benefits. (Think again of those vampire bats who share regurgitated blood.) Cooperation would have been as powerful, if not more powerful, a drive in human evolution as competition. And communication is an essential tool of cooperation, so it makes sense that Paleolithic hunter-gatherers, as well as their modern counterparts, would have employed language to solve the problems of survival in both the physical and the social environments.

How large were these communities? Most modern hunter-gatherer bands and tribes range in size from 50 to 400 residents, with a medium range of 100 to 200 people. Anthropologist Napoleon Chagnon, in his extensive studies of the Yanomamö people in the Amazonian rain forest, found the typical group to be roughly 100 people in size, with 40 to 80 living together in the rugged mountain regions, and 300 to 400 members living together in the largest lowland villages. He has also noted that when groups get excessively large for the carrying capacity of their local environment and level of technology, they fission into smaller groups.²¹ Such bifurcations are the result of exceeding the carrying capacity of both the physical and social environments. Psychologist Robin Dunbar suggests that these limits on social group size are related to the carrying capacity of human memory and thus have a deep evolutionary basis.²² It turns out that 150 is roughly the number of living descendants (children, grandchildren, great-grandchildren) a Paleolithic couple would produce in four generations at the birthrate of hunter-gatherer peoples. In other words, this is how many people they knew in their immediate and extended family, which is corroborated by archaeological evidence from the Near East showing that agricultural communities typically numbered about 150 people. Even modern farming communities, like the Hutterites, average about 150 people.

When groups get large they split into smaller groups. Why? The answer is moral discipline and behavior control. According to the Hutterites, shunning as a primary means of social control does not work well in large groups. Sociologists know that once groups exceed 200 people, a hierarchical structure is needed to enforce the rules of cooperation and to deal with offenders, who in the smaller group could be dealt with through informal personal contracts and social pressure. Still larger groups need chiefs and a police force, and rule enforcement involves more violence or the threat of violence. Even in the modern world with a population exceeding six billion individuals, most of whom are crowded into dense cities, people find themselves divided into small groups. Studies on optimal group size (in terms of finding a balance between autonomy and control) by the military during the Second World War found that the average-size company in the British Army was 130 men, and in the U. S. Army it was 223 men. The 150 average also fits the size of most small businesses, departments in large corporations, and efficiently run factories. A Church of England study, conducted in an attempt to balance the financial resources provided by a large group with the social intimacy of a small group, concluded that the ideal size for congregations was 200 or less. The average number of people in any given person’s address book also turns out to be about 150 people.

It would appear that 150 is the number of people each of us knows fairly well. Dunbar claims that this figure fits a ratio of primate group size to their neocortex ratio (the volume of the neocortex—the most recently evolved region of the cerebral cortex—to the rest of the brain). Extremely social primates (like us) need big brains to handle living in big groups, because there is a minimum amount of brain power needed to keep track of the complex relationships required to live in relatively peaceful cooperation. Dunbar concludes that these groupings “are a consequence of the fact that the human brain cannot sustain more than a certain number of relationships of a given strength at any one time [figure 4]. The figure of 150 seems to represent the maximum number of individuals with whom we can have a genuine social relationship, the kind of relationship that goes with knowing who they are and how they relate to us. Putting it another way, it’s the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar.”²³

Gossip and the Enmityville Horror

Morality evolved in these tiny bands of 100 to 200 people as a form of conflict resolution, social control, and group cohesion. In this social mode of religion and morality, amity is promoted over enmity. Without a system to reinforce cooperation and altruism and to punish excessive competitiveness and selfishness, Amityville becomes Enmityville. One means of accomplishing this social control is through what is known as reciprocal altruism, or “I’ll scratch your back if you’ll scratch mine.” But, as Lincoln noted, men are not angels. There are cheaters. Individuals defect from informal agreements and social contracts. Reciprocal altruism, in the long run, only works when you know who will cooperate and who will defect. In small groups, cooperation is regulated through a complex feedback loop of communication between members of the community. (This also helps to explain why people in big cities can get away with being rude, inconsiderate, and uncooperative—they are anonymous and thus are not subject to the normal checks and balances that come with seeing the same people every day.)

Figure 4. The Relationship Between Group Size, Brain Size, and Evolutionary History

Humans evolved as hierarchical social primate species living in tiny bands of hunter-gatherers. These groups grew larger over the past three million years, as hominid brains grew larger (top). Psychologist Robin Dunbar has identified a powerful relationship between group size in primates as a function of the ratio of their neocortex (defined as neocortex volume divided by volume of the entire brain), which is the seat of higher learning and memory (bottom). Dunbar theorizes that in order to live in large, complex social groups, primates need more memory and mental power to keep track of various relationships and social hierarchies. (From Robin Dunbar, “Brain on Two Legs,” in Tree of Origin)

In order to play the game of reciprocation you need to know whose back needs scratching and who you will trust to scratch yours. This information is gathered through telling stories about other people, more commonly known as gossip. Gossip is a tool of social control through communicating cultural norms, as anthropologist Jerome Barkow observed: “Reputation is determined by gossip, and the casual conversations of others affect one’s relative standing and one’s acceptability as a mate or as a partner in social exchange. In Euro-American society, gossiping may at times be publicly disvalued and disowned, but it remains a favorite pastime, as it no doubt is in all human societies.”²⁴ This theory is well illustrated in figure 5, a 2003 Crock cartoon by Bill Rechin and Don Wilder, where the main character doesn’t gossip; he transmits “pertinent data via a verbal mode.” Well spoken.

Figure 5. Gossip as the Transmission of Data Via a Verbal Mode
(Courtesy of Bill Rechin and Don Wilder)

The etymology of the word gossip, in fact, is enlightening. The root stem is “godsib,” or “god” and “sib,” and means “akin or related.” Its early use, as traced through the Oxford English Dictionary, included “one who has contracted spiritual affinity with another,” “a godfather or godmother,” “a sponsor,” and “applied to a woman’s female friends invited to be present at a birth” (where they would gossip). (In one of its earliest uses in 1386, for example, Chaucer wrote: “A womman may in no lasse synne assemblen with hire godsib, than with hire owene flesshly brother.”) The word then mutated into talk surrounding those who are akin or related to us, and eventually to “one who delights in idle talk,” as we employ it today.

Not surprisingly, we are especially interested in gossiping about the activities of others that most affect our inclusive fitness, that is, our reproductive success, the reproductive success of our relatives, and the reciprocation of those around us. Normal gossip is about relatives, close friends, and those in our immediate sphere of influence in the community, plus members of the community or society that are high ranking or have high social status. It is here where we find our favorite subjects of gossip—sex, generosity, cheating, aggression, violence, social status and standings, births and deaths, political and religious commitments, physical and psychological health, and the various nuances of human relations, particularly friendships and alliances. Gossip is the stuff of which not only soap operas but also grand operas are made.

My colleague Kari Konkola, a scholar researching the psychology of religious reinforcement and punishment of moral and immoral behavior, upon reading my initial theoretical foray into the connection between religion and morality (in How We Believe), made these important observations:

The Protestants of early modern England knew very well the habit to gossip and regarded it as a personality trait that absolutely had to be eliminated. Indeed, the commandment “thou shalt not give false witness” was believed to be specifically a prohibition of gossiping. (In early modern religious terminology gossiping was called “backbiting.”) The early modern interest in the roots of sin produced quite a bit of “research” on what today would be called the psychology of backbiting. The desire to talk about others was believed to be produced by envy, because the destructive competitiveness of envious people made them eager to spread rumors that would damage the reputation of those whom they envied. The competitiveness of proud people mostly manifested itself in efforts to surpass their peers, which made them less destructive to people around them than the envious. The desire to get ahead of others, however, made the proud an eager audience for malicious gossip, because they loved to hear disparaging news about their competitors.

In early modern England, gossiping thus was a grave sin—a breach of one of the Ten Commandments. The strict religious prohibition against these behaviors is likely to have been quite effective, because a trained observer could easily notice them. Indeed, one commonly recommended method to detect hypocrisy was to observe people’s favorite subjects of discussion: if a person liked to talk and hear about the flaws of others, this signified envy, pride and hypocrisy. On the other hand, an eagerness to dwell on one’s own faults and to disparage one’s achievements was a sign of humility and true religiosity. Normative evidence from early modern England leaves no doubt that at least some religions have been very emphatic about—and possibly also quite effective in—rooting the habit to gossip out of human nature.²⁵

What is the relationship between gossip, morality, and ethics? Moral sentiments and behaviors were initially codified into ethical systems by religion. That is, long before there were such institutions as states and governments, or such concepts as laws and rights, religion emerged as the social structure to enforce the rules of human interactions. The history of the modern nation-state with constitutional rights and protection of basic human freedoms can be measured in mere centuries, whereas the history of organized religion can be measured in millennia, and the history of the evolution of moral sentiments can be measured in tens of millennia. When bands and tribes gave way to chiefdoms and states, religion developed as the principal social institution to facilitate cooperation and goodwill. It did so by encouraging altruism and selflessness, discouraging excessive greed and selfishness, promoting cooperation over competition, and revealing the level of commitment to the group through social events and religious rituals. If I see you every week in church, mosque, or synagogue, consistently participating in our religion’s activities and following the prescribed rituals and customs, it is a positive indication that you can be trusted and you are a reliable member of our group that I can count on. As an organization with codified moral rules, with a hierarchical structure so well suited for hierarchical social primates like humans, and with a higher power to enforce the rules and punish their transgressors, religion responded to a need. In this social and moral mode I define religion as a social institution that evolved as an integral mechanism of human culture to encourage altruism and reciprocal altruism, to discourage selfishness and greed, and to reveal the level of commitment to cooperate and reciprocate among members of the community.

The divinity evolved along a parallel track. As bands and tribes coalesced into chiefdoms and states, animistic spirits gave way to anthropomorphic and polytheistic gods, and in the eastern Mediterranean the anthropomorphic gods of the pastoral people there lost out to the monotheistic God of Abraham. In addition to serving as an explanation for the creation of our universe, our world, and ourselves, God became the ultimate enforcer of the rules, the final arbiter of moral dilemmas, and the pinnacle object of commitment. God, religion, and morality were inseparable. People believe in God because we are pattern-seeking, storytelling, mythmaking, religious, moral animals.²⁶

The Bio-Cultural Evolutionary Pyramid: A Model for the Origins of Morality

The Bio-Cultural Evolutionary (BCE) Pyramid in figure 6 depicts how morality evolved in small bands and tribes as individuals cooperated and competed with one another to meet their needs. Individuals belonged to families, families to extended families, extended families to communities, and, in the last several millennia (in parallel with the rise of chiefdoms and states), communities to societies. This natural progression is now in its latest evolutionary stages: perceiving societies as part of the species, and the species as part of the biosphere.

The BCE Pyramid is a hybrid of Abraham Maslow’s hierarchy of needs and Peter Singer’s expanding circle of ethical sentiments. It depicts the 1.5 million years over which moral sentiments evolved among social primates primarily under biogenetic control. Around 35,000 years ago a transition took place, and sociocultural factors increasingly assumed control in shaping our moral behavior and ethical systems. Keep in mind that this is a continuous process. There was no point at which an Upper Paleolithic Moses descended from a glacier-covered mountain and proclaimed to his fellow Cro-Magnons, “I’ve just invented culture. We no longer have to obey our genes like those stupid Neanderthals. From now on we obey THE LAW!”

The “bio-cultural transitional boundary” marks the shift from mostly biological control to mostly cultural control. It divides time and the dominant source of influence. In the early phases of our evolution, the individual, family, extended family, and Paleolithic communities were primarily molded by natural selection. In the later phases, Neolithic communities and modern societies were and are primarily shaped by cultural selection. Starting at the bottom of the BCE Pyramid, the individual’s need for survival and genetic propagation (through food, drink, safety, and sex) is met through the family, extended family, and the community. The nuclear family is the foundation. Despite recent claims that the traditional family is going the way of the Neanderthals, it remains the most common social unit around the world. Even within extremes of cultural deprivation—slavery, prison, communes—the structure of two-parents-with-children emerges: (1) African slave families that were broken up retained their structure for generations through the oral tradition; (2) in women’s prisons pseudofamilies self-organize, with a sexually active couple acting as “husband” and “wife” and others playing “brothers” and “sisters”; (3) even when communal collective parenting is the norm (for example, kibbutzim), many mothers switch to the two-parent arrangement and the raising of their own offspring. ²⁷ Our evolutionary history is too strong to overcome this foundational social structure. Conservatives need not bemoan the decline of families. They will be around as long as our species survives.

Figure 6. The Bio-Cultural Evolutionary Pyramid

The Bio-Cultural Evolutionary Pyramid models the origin and evolution of moral sentiments and ethical systems. The pyramid depicts the 1.5 million years over which moral sentiments evolved biogenetically among social primates and the transition about 35,000 years ago when sociocultural factors increasingly assumed control in shaping Homo sapiens’ moral behavior and ethical systems. The “transitional boundary” shows the time range during which social groups grew larger and cultural selection began to take precedence over natural selection. In early Homo sapiens (the bottom of the pyramid), the individual’s need for survival and genetic propagation is met through the family, extended family, and the community. Over time, basic psychological and social needs evolved that aided and reinforced cooperation, altruism, and, subsequently, genetic propagation through children. This inclusive fitness applies to anyone who is genetically related to us. In larger communities and societies, where there is no genetic relationship, reciprocal altruism and indirectlblind altruism supplement kin altruism. The natural progression leads to species altruism and bioaltruism . (Rendered by Pat Linse)

Moving up the BCE Pyramid, basic psychological and social needs such as security, bonding, socialization, affiliation, acceptance, and affection evolved to aid and reinforce cooperation and altruism, all of which facilitate genetic propagation through children. Kin altruism works indirectly—siblings and half siblings, grandchildren and great-grandchildren, cousins and half cousins, nieces and nephews, all carry portions of our genes.²⁸ This inclusive fitness applies to anyone who is genetically related to us. In larger communities and societies, where there is no genetic relationship, reciprocal altruism and indirectlblind altruism (if you scratch my back now, I may scratch yours much later) supplements kin altruism. Inclusive fitness gives way to what we might call exclusive fitness. The natural progression of exclusive fitness may be the adoption of species altruism and bioaltruism (we will prevent extinction and destruction now for a long-term payoff), which Ed Wilson argues in Biophilia, may even have a genetic basis.²⁹ But, Wilson confesses, this should probably still be grounded in self-interest arguments—my children will be better off in a future with abundant biodiversity and a healthy biosphere—since inclusive fitness is more powerful than exclusive fitness.

The width of the BCE Pyramid at any point indicates the strength of ethical sentiment and the degree to which it is under evolutionary control. The height of the BCE Pyramid at any point indicates the degree to which that ethical sentiment extends beyond our own genome (ourselves). But the pyramid also shows that these two sets of sentiments are inversely related. The more a sentiment reaches beyond ourselves, the further it goes in the direction of helping someone genetically less related, and the less support it receives from underlying evolutionary mechanisms. This relationship is grounded in the aphorism that blood is thicker than water, as visualized in figure 7.

Figure 7. The Expanding Circle of Inclusiveness

Blood is thicker than water. According to evolutionary psychology theory, the percentage of genes (on average) shared by various degrees of kinship should predict the amount of benefits received from a given individual. The right side of the diagram shows relatives resulting from monogamy; the left side, polygyny. The assumption behind the theory is that organisms (including humans) act to enhance their inclusive fitness, that is, to increase the frequency and distribution of their genes in future generations. (Rendered by Pat Linse, adapted from Richard D. Alexander, Darwinism and Human Affairs)

Group Selection and the Evolution of Morality

Since I first began work a decade ago on a theory to explain the origins of morality, new research has emerged that leads me to think that there might be an additional force at work in the evolution of morality, and that is group selection. Natural selection is believed by most evolutionary biologists to operate strictly on the organism level: the individual organism is the primary target of selection because it is the only thing that nature “sees.” Genotypes, or genes, are simply code for phenotypes, or bodies. Nature cannot see genes, but it can see bodies running around and can select for or against those individuals based on their characteristics. In group selection, a group of individuals is the target of selection as a group of individuals competes against another group of individuals. When one succeeds and the other fails, the successful group passes along the genes of the individuals more than the unsuccessful group.

Among evolutionary theorists this is a volatile subject because group selection has, for the past thirty years, been next to creationism as the doctrine strict Darwinians most love to hate. There is some irony in this because the first person to propose group selection was none other than Charles Darwin. In The Descent of Man Darwin began by making a case against applying his own theory of natural selection at the individual level, noting that in trying to explain the origins of morality, “It is extremely doubtful whether the offspring of the more sympathetic and benevolent parents, or of those who were the most faithful to their comrades, would be reared in greater number than the children of selfish and treacherous parents of the same tribe. He who was ready to sacrifice his life, as many a savage has been, rather than betray his comrades, would often leave no offspring to inherit his noble nature … .” Darwin concluded that “it seems scarcely possible (bearing in mind that we are not here speaking of one tribe being victorious over another) that the number of men gifted with such virtues, or that the standard of their excellence, would be increased through natural selection, that is, by survival of the fittest.”³⁰Within a group, Darwin argued, natural selection would not foster cooperation and virtue. From whence did it come? It came from competition between groups, Darwin concluded:

It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, yet that an increase in the number of well-endowed men and advancement in the standard of morality will certainly give an immense advantage to one tribe over another. There can be no doubt that a tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, the standard of morality and the number of well-endowed men will thus everywhere tend to rise and increase.³¹

Subsequent to Darwin, group selection was occasionally invoked until the mid-1960s, when the highly influential evolutionary biologist George C. Williams published his widely read book Adaptation and Natural Selection, in which he demonstrated that natural selection at the individual level was all that was needed to explain nature’s diversity, including human social and moral behavior. Since the 1960s, group selection was vilified as the pap of bleeding-heart liberals who couldn’t deal with the reality of “nature red in tooth and claw.” Evolutionary theorist Michael Ghiselin described the “economy of nature” as competitive exclusively at the individual level: “The impulses that lead one animal to sacrifice himself for another turn out to have their ultimate rationale in gaining advantage over a third … . Given a full chance to act in his own interest, nothing but expediency will restrain him from brutalizing, from maiming, from murdering—his brother, his mate, his parent, or his child. Scratch an ‘altruist,’ and watch a ‘hypocrite’ bleed.”³²

In the late 1990s, however, group selection made something of a comeback. In their 1998 book Unto Others, anthropologist David Sloan Wilson and his colleague, philosopher Elliott Sober, demonstrated through a sophisticated mathematical model and a series of logical arguments that group selection is viable. They began by defining a group as “a set of individuals that influence each other’s fitness with respect to a certain trait but not the fitness of those outside the group.” They then explained how “individual selection favors traits that maximize relative fitness within single groups,” and that “group selection favors traits that maximize the relative fitness of groups.” In this model, “altruism is maladaptive with respect to individual selection but adaptive with respect to group selection.” Therefore, they conclude, “altruism can evolve if the process of group selection is sufficiently strong.”³³ For example, they cite William Hamilton’s analysis of how consciousness might have provided a group selective advantage for certain human populations with regard to the ethical enforcement of rules: “The more consciences are lacking in a group as a whole, the more energy the group will need to divert to enforcing otherwise tacit rules or else face dissolution. Thus considering one step (individual vs. group) in a hierarchical population structure, having a conscience is an ‘altruistic’ character.”³⁴ The reason individual selection will not work becomes apparent in this thought experiment proposed by David Sloan Wilson:

Imagine a population that consists of solid citizens and shirkers. The solid citizens produce a public good that is available to everybody, including themselves. For purposes of the example, let’s say that the public good can be produced at no cost to the solid citizens. Not only do they share the bounty, but they lose nothing by creating it. Even so, the solid citizens will not be favored by natural selection in this example because the solid citizens and shirkers do not differ in their survival or reproduction. Natural selection requires differences in fitness so raising or lowering the fitness of everyone in the population has no effect. If, as seems likely, the public good is costly to produce, the solid citizens will go extinct, even if they share the benefits, because their private cost reduces their fitness relative to the shirkers. Behaviors that are “for the good of the group” are at best neutral (if the public good is cost-free) and at worst maladaptive (if there is any cost associated with producing the public good).

Wilson calls this “the fundamental problem of social life” and provides the following group selection solution:

Imagine not one but many populations that vary in their proportions of solid citizens and shirkers. Even if shirkers fare better than solid citizens within each population, populations with an excess of solid citizens fare better than populations with an excess of shirkers. In short, there is a process of natural selection at the group level that favors solid citizens, just as there is a process of natural selection at the individual level (within each group) favoring shirkers. Group-level adaptations will evolve whenever group-level selection is stronger than individual-level selection.³⁵

Part of the problem in this debate is the all-too-human tendency to dichotomize. Instead of viewing this as a forced choice between individual selection and group selection, we can readily adopt a hierarchical theory of evolution, where we recognize and acknowledge both forces at work. A second challenge is in how we define certain terms, such as altruism and cooperation, and the temptation to force these categories into either-or choices, where people are (generally/situationally /purely) altruistic or selfish, cooperative or competitive. As descriptive terms, altruistic and cooperative are not reified things; they are behaviors. And like all behaviors, there is a broad range of expression, from a little to a lot. Here again a fuzzy logic analysis helps clarify this complex human phenomenon. Depending on the circumstances, some people in some situations are .2 altruistic and .8 nonaltruistic (or selfish), or .6 cooperative and .4 noncooperative (or competitive). Fuzzy fractions apply to individual and group selection as well. Individuals and groups can be altruistic and nonaltruistic, cooperative and noncooperative in degrees of expression changing over varying circumstances. It all depends on the situation. In this context, it might be useful to settle the group selection debate, at least provisionally, by acknowledging that group selection might work in a limited set of circumstances for some species. Group selection is not in opposition to individual selection; it is complementary, giving whole populations a selective advantage over other whole populations.

In applying group selection to the origins of religion, Wilson argues that “Religions exist primarily for people to achieve together what they cannot achieve alone. The mechanisms that enable religious groups to function as adaptive units include the very beliefs and practices that make religion appear enigmatic to so many people who stand outside of them.” Going inside religion, Wilson argues, allows us to see what their practical function is—the group itself becomes a living organism, subject to the forces of natural selection. “Through countless generations of variation and selection, they acquire properties that enable them to survive and reproduce in their environments.”³⁶ He notes as support, for example, anthropological studies of meat sharing practiced by all modern hunter-gatherer communities around the world. It turns out that these small bands and tribes—which can cautiously be used as a model for our own Paleolithic ancestors—are remarkably egalitarian. Using portable scales to precisely measure how much meat each family within the group received after a successful hunt, anthropologists discovered that the immediate families of successful hunters got no more meat than the rest of the families in the group, even when this was averaged over several weeks of regular hunting excursions. “Hunter-gatherers are egalitarian, not because they lack selfish impulses but because selfish impulses are effectively controlled by other members of the group,” Wilson explains. “In human hunter-gatherer groups, an individual who attempts to dominate others is likely to encounter the combined resistance of the rest of the group. In most cases even the strongest individual is no match for the collective, so self-serving acts are effectively curtailed.”³⁷

How gossip, morality, and group selection link together can be seen in studies of a number of hunter-gatherer societies. Anthropologist Chris Boehm, for example, has demonstrated the use of gossip to ridicule, shun, and even ostracize individuals whose competitive drives and selfish motives interfere with the cooperative needs and altruistic tendencies of the group. In other words, people are competitive and selfish, and individual selection has created these important and powerful drives. But people are also cooperative and altruistic, and these drives are created and reinforced by the group in which the individual lives. Thus, an emotional sense of “right” and “wrong” action is ingrained into individuals back to the earliest days in human evolutionary history, through genetic transmission of such traits supplemented by culture transmission through modeling and learning. A moral “sense,” then, need not be culturally codified in some formal fashion (for example, in writing), or even be a conscious effort on the part of individuals. “Good” and “bad” behaviors are rewarded and punished by the group, individuals succeed or fail as members of the group depending on their moral or immoral behaviors, and groups with more moral individuals than immoral individuals gain a collective advantage over other groups who are less successful at fostering a healthy balance between cooperation and competition, altruism and selfishness.

An anthropological example of how this process works can be seen in the Malaysian rain forest tribe called the Chewong. Like other hunter-gatherer groups, the Chewong (who also employ limited agriculture) are egalitarian, a way of life that is governed by a system of superstitions called punen. In the words of anthropologist Signe Howell, who conducted an extensive ethnography of the Chewong, punen is “a calamity or misfortune, owing to not having satisfied an urgent desire.” In the Chewong world, for example, strong desires are connected with food, and powerful norms about food sharing are associated with the mythical being Yinlugen bud, who supposedly brought the Chewong out of a more primitive state by insisting that eating alone was improper human behavior. Myth, gods, religion, and morality are all integrated in the Chewong culture through the concept of punen and are linked to a very practical matter of individual and group survival: eating and sharing food. Thus, the Chewong avoid provoking punen at all costs. When game is caught away from the village, it is promptly returned, publicly displayed, and equitably distributed among all households and even among all individuals within each home. To reinforce the sanction against punen, someone from the hunter’s family touches the catch and then proceeds to touch everyone present, repeating the word punen. In this system, religious superstitions and gods oversee the exchange process, generating within the individuals an overall sense of right and wrong action as related to the success or failure of the group.³⁸

The Psychology of Morality: Emotions, Tipping, and the Prisoner’s Dilemma

At the foundation of the Bio-Cultural Evolutionary model is an evolved moral sense. By a moral sense, I mean a moral feeling or emotion generated by actions. For example, positive emotions such as righteousness and pride are experienced as the psychological feeling of doing “good.” These moral emotions likely evolved out of behaviors that were reinforced as being good either for the individual or for the group. Negative emotions such as guilt and shame are experienced as the psychological feeling of doing “bad.” These moral emotions probably evolved out of behaviors that were reinforced as being bad either for the individual or for the group. This is the psychology of morality—the feeling of being moral or immoral. These moral emotions represent something deeper than specific feelings about specific behaviors. While cultures may differ on what behaviors are defined as good or bad, the general moral emotion of feeling good or feeling bad about behavior X (whatever X may be) is an evolved emotion that is universal to all humans.

Consider some of the more basic emotions that represent something deeper than specific feelings. When we need to eat we do not compute caloric input/output ratios; we simply feel hungry. That feeling is an evolved hunger sentiment that triggers eating behavior. When we need to procreate to pass on our genes into the next generation we do not calculate the genetic potential of our sexual partner, we just feel horny and seek out a partner we find attractive. The sexual urge—the undeniably powerful feeling of wanting to have sex—is an evolved sexual sentiment that triggers sexual behavior. In other words, we are hungry and horny because, ultimately, the survival of the species depends on food and sex, and those organisms for whom healthy foods tasted good and for which sex was exquisitely delightful left behind more offspring. To be blunt, we are the descendants of hungry and horny hominids.

Theists often ask, “If there is no God why should we be moral?” In this evolutionary theory of morality, asking “Why should we be moral?” is like asking “Why should we be hungry?” or “Why should we be horny?” For that matter, we could ask, “Why should we be jealous?” or “Why should we fall in love?” The answer is that it is as much a part of human nature to be moral as it is to be hungry, horny, jealous, and in love.

Again, to punch home the important distinction between the how and the why in the search for the origins of morality, specific behaviors in a culture may be considered right or wrong and these vary over cultures and history. But the sense of being right or wrong in the emotions of righteousness and pride, guilt and shame, is a human universal that had an evolutionary origin. There is variation within human populations on this evolved trait, just as there is variation in any personality trait, where some people feel more or less guilt or more or less pride than others. This variation, like the variation in personality traits, is accounted for by roughly half genetics and half environment.

Consider tipping at a restaurant in a city where you have never been and will never return. Since I travel a fair amount for my work I am faced with this moral question nearly every trip: why should I bother to tip a restaurant server I will never see again? There is no anticipated reciprocity since the tip comes after the service. I often dine alone so there is no one to impress with my generosity. Since I do not believe in God my answer cannot be “because God will know.” (Even if you are a believer this seems like a rather shallow reason in any case.) Ethical egoism theory states that I will leave a tip because it makes me feel good. That is, tipping is not an altruistic act at all, but a purely selfish one. But what does it mean to feel good about an act, regardless of whether we consider it selfish or altruistic? In my theory this sense of feeling good about doing something good for someone else is an evolved moral sense that has a perfectly reasonable evolutionary explanation. Humans practice both deception and self-deception. Research shows that we are better at deception than at deception detection, but deceivers get caught often enough that it is risky to attempt to deceive others. Research also shows that the normal cues we give off when we are attempting to deceive others (particularly nonverbal cues like taking a deep breath, looking away from the person you are talking to, hesitating before answering, and so forth) are less likely to be expressed if you actually believe the deception yourself.³⁹ Liars are not liars if they believe the lie. This is the power of self-deception.

It is not enough to fake doing the right thing in order to fool our fellow group members, because although we are fairly good deceivers, we are also fairly good deception detectors. We cannot fool all of the people all of the time, and we do learn to assess (through gossip, in part) who is trustworthy and who is not trustworthy, so it is better to actually be a moral person because that way you actually believe it yourself and thus there is no need for deception. What I am saying is that the best way to convince others that you are a moral person is not to fake being a moral person but to actually be a moral person. Don’t just go through the motions of being moral (although this is a good start), actually be moral. Don’t just pretend to do the right thing, do the right thing. It is my contention that this is how moral sentiments evolved in our Paleolithic ancestors living in small communities.

Modern game theory grants us a deeper understanding of the tension between competitiveness and cooperation, the most common example of which is the “Prisoner’s Dilemma,” first developed in the 1950s by the Rand Corporation to model global nuclear strategy. The scenario is that each of two prisoners arrested for a crime is independently made an offer (and both know the other has been presented with the same deal). To make the game more real, pretend you are one of those charged with the crime. Here are the four possible options:

1. If you and your partner cooperate with each other and take the Fifth, then you each get one year in jail.

2. If you confess and admit that your partner was in on the crime with you, then you get off and your partner gets three years in the slammer.

3. If your partner confesses and you don’t, then you receive a three-year stay in the pokey while he walks.

4. If you both confess, then you each get a two-year stay in the gray-bar hotel.

What should you do? If you defect on your partner and confess, then you will get either zero or two years in the pen, depending on what he does. If you cooperate and stay quiet, you get either one or three years, again depending on his response. In this scenario the logical choice is to defect. Of course, your partner is likely going to make the same calculation as you, which means he too will defect, guaranteeing that you will receive a two-year stint in prison. Knowing that he is probably computing the same strategy as you, then surely he will realize that you should both cooperate. Of course, perhaps he’ll figure that this will be your conclusion as well, so he’ll defect in hopes that you will cooperate, getting him off the hook and sending you to wallow in the general population for three big ones. Herein lies the dilemma.

When the game is noniterated—that is, just one round is played—defection is the norm. When the game is iterated over a fixed number of trials, defection is also the norm because awareness of how many rounds there will be means that both players know that the other one will defect on the last round, which pushes another defection strategy to the second to the last round, and so forth back to the start of the game. But when the game is iterated over an unknown number of trials, and both players keep track of what the other has been doing throughout the history of the game—that is, it more closely resembles real life—cooperation prevails.

Still more realistic simulations include the “Many Person Dilemma,” in which one player interacts with multiple other players. Of particular interest to the study of ethical theory is the “Tit-for-Tat” strategy in which you start off cooperating and then do whatever the other player does. Although Tit-for-Tat resembles the Golden Rule, it more closely models the Old Testament “Eye for an Eye” morality than it does the idealistic New Testament strategy of turning the other cheek. Jesus, Gandhi, and Martin Luther King heroically employed an unalloyed New Testament ethic and all paid with their lives (receiving what is called the “sucker’s payoff” in game theory). Turning the other cheek only works if the opposition is inherently benevolent or has chosen a purely cooperative game strategy. In most cases, defections creep in often enough to make a purely Gandhian morality ineffective, even dangerous. On the optimistic side, the more experience the players have with one another—that is, the better they know each other—the more cooperation dominates as the preferred strategy. This is why the scenario of informal and noncodified rules of conduct developed within small communities so accurately describes how morality evolved—knowing all the other players in the game leads to the evolution of cooperation.⁴⁰

The Prisoner’s Dilemma model has been applied to everything from cold war strategies to marital conflict. It turns out that in both computer simulations and real-world experiments, not only is being a cooperator better than being a defector, but being a real cooperator is better than being a fake cooperator because being genuine about cooperating more readily convinces others of the genuineness of the action. And action backed by good intentions pays off in bigger dividends for all individuals in the group (and for the group as a whole in relation to other groups). So, tipping a stranger makes you feel good because it really is a good thing to do, for the recipient, for yourself, and for the group.

Human Moral Universals: The Transcendency of Morality and Universality of Moral Sentiments

In his great philosophical work An Enquiry Concerning the Principles of Morals, David Hume speculated on the universal nature of human morality: “The notion of morals implies some sentiment common to all mankind, which recommends the same object to general approbation, and makes every man, or most men, agree in the same opinion or decision concerning it.”⁴¹ Is there a moral sentiment common to all humans? Are there moral universals?

In anthropology, human universals “comprise those features of culture, society, language, behavior, and psyche for which there are no known exceptions to their existence in all ethnographically or historically recorded human societies.”⁴² Common and well-known universals include tools, myths and legends, sex roles, social groups, aggression, gestures, grammar, and emotions. There are general universals, such as social status and emotional expressions, and specific universals within broader universals, such as kinship statuses and facial expressions like the smile, frown, or eyebrow flash. Since cultures vary dramatically, the supposition made about “universals” is that there is an evolutionary and biological basis behind them (or, at the very least, that they are not strictly culturally determined). As such, we can presume that there is a genetic predisposition for these traits to be expressed within their respective cultures, and that these cultures, despite their considerable diversity, nurture these genetically predisposed natures in a consistent fashion.

For an analysis of universals we turn to anthropology, because it is this science that documents the diversity of ways that humans live and illuminates so clearly which traits are universal and which traits are not. “Universals exist, they are numerous, and they engage matters unquestionably of anthropological concern,” explains anthropologist Donald E. Brown, who has arguably done more work on human universals than anyone in his field. “Universals can be explained, and their ramified effects on human affairs can be traced. But universals comprise a heterogenous set—cultural, social, linguistic, individual, unrestricted, implicational, etc.—a set that may defy any single overarching explanation. If, however, a single source for universals had to be sought, human nature would be the place to look.”⁴³ Culture matters, of course, but not in some token fashion tossed off by sociobiologists and evolutionary psychologists to display proper political correctness, rather as wholly integrated and fully interdigitated with nature such that you cannot speak of one without the other. This interactionism is the only reasonable position to take on the so-called (and artificial) nature-nurture debate, despite the limitations most anthropologists have set on understanding this interaction. As Brown notes in castigating his fellow anthropologists: “these interactions can only be properly explored if there are ways to distinguish nature from culture, and I submit that there is little if anything in the way of an established and valid method in anthropology for doing this. Typically, anthropologists simply do not concern themselves with this problem, because they assume (in accordance with other propositions) that what humans do, unless it is ‘obviously’ natural, is essentially cultural.”⁴⁴

In his comprehensive study of human universals, Brown compiled a list of 373. From these I count 202 (54 percent) moral and religious universals, which I list in appendix 2 along with parenthetical notes explaining what I think the relationship is between the universal trait and morality or religion. (I include religious universals because in my theory on the origins of morality, religion and morality were inseparable in their coevolution.) Although some traits are more obviously related to morality and religion than others, in general it is strikingly clear just how much of what we do has some bearing on our state of being as social organisms in interaction with others of our kind. We are moral animals, and these moral universals belong to the species and are thus transcendent of the individual members of that species.

The expression of human moral behavior is a product of internal psychological traits related to morality, and external social states related to moral behavioral control. Going through the list of moral and religious universals in appendix 2, the sheer number is indicative of their undeniable role in human biological and cultural evolution. Some moral psychological traits (or sentiments) include: affection expressed and felt (necessary for altruism and cooperation to be reinforced); attachment (necessary for bonding, friendship, pro-social behavior); coyness display (courtship, moral manipulation); crying (sometimes expression of grief, moral pain); emotions (necessary for moral sense); empathy (necessary for moral sense); envy (moral trait); fears (generate much religious and moral behavior); generosity admired (reward for cooperative and altruistic behavior); incest between mother and son unthinkable or tabooed (obvious evolutionary moral trait); judging others (foundation of moral approval/disapproval); mourning (expression of grief, part of symbolic moral reasoning); pride (a moral sense); self-control (moral assessment and judgment); sexual jealousy (foundation of major moral relations and tensions); sexual modesty (foundation of major moral relations and tensions); and shame (moral sense), to name just a few.

Going through the list again, this time picking out moral behavioral control mechanisms universal to human cultures, we are again awed by their numbers and importance. Some moral behavioral control mechanisms include: age statuses (vital element in social hierarchy, dominance, respect for elder’s wisdom); coalitions (foundation of social and group morality); collective identities (basis of xenophobia, group selection); conflict, consultation to deal with (resolution of moral problems); conflict, means of dealing with (resolution of moral problems); conflict, mediation of (foundation of much of moral behavior); corporate (perpetual) statuses (moral ranking of groups); customary greetings (part of conflict prevention and resolution); dominancelsubmission (foundation of hierarchical social primate species); etiquette (enhances social relations); family (or household) (the most basic social and moral unit); food sharing (form of cooperation and altruism); gift giving (reward for cooperative and altruistic behavior); government (social morality); group living (social morality); groups that are not based on family (necessary for higher moral reasoning and blind altruism); inheritance rules (reduces conflict within families and communities); institutions (organized coactivities) (religion); kin groups (foundation of kin selection/altruism and basic social group); law (rights and obligations) (foundation of social harmony); law (rules of membership) (foundation of social harmony); males engage in more coalitional violence (gender differences in moral behavior); marriage (moral rules of foundational relationship); murder proscribed (moral judgment necessary in communities); oligarchy (de facto) (group social control); property (foundation of moral reasoning and judgment); reciprocal exchanges (of labor, goods, or services) (reciprocal altruism); redress of wrongs (moral conflict resolution); sanctions (social moral control); sanctions for crimes against the collectivity (social moral control); sanctions include removal from the social unit (social moral control); taboos (moral and social control); tabooed foods (element in moral and social control); tabooed utterances (communication of moral and social control); and violence, some forms of proscribed (moral and social control), to name just a few.

Finally, we began this chapter with the Golden Rule, a moral guideline found in all cultures that represents the very foundation of universal morality. Of the list of human moral universals, here are the traits that contribute to a behavioral expression of the Golden Rule: cooperation (part of altruism); cooperative labor (part of kin, reciprocal, and blind altruism); customary greetings (part of conflict prevention and resolution); empathy (necessary for moral sense); fairness (equity); food sharing (form of cooperation and altruism); generosity admired (reward for cooperative and altruistic behavior); gestures (signs of recognition of others, conciliatory behavior); gift giving (reward for cooperative and altruistic behavior); good and bad distinguished (necessary for moral judgment); hospitality (enhances social relations); inheritance rules (reduces conflict within families and communities); insulting (communication of moral approval/disapproval); intention (part of moral reasoning and judgment); interpolation (part of moral reasoning and judgment); interpreting behavior (necessary for moral judgment); judging others (foundation of moral approval/disapproval); making comparisons (necessary for moral judgments); moral sentiments (the foundation of all morality); moral sentiments, limited effective range of (parameters of moral foundation); planning for future (foundation for moral judgment); pride (a moral sense); promise (moral relations); reciprocal exchanges (of labor, goods, or services) (reciprocal altruism); reciprocity, negative (revenge, retaliation) (reduces reciprocal altruism); reciprocity, positive (enhances reciprocal altruism); redress of wrongs (moral conflict resolution); shame (moral sense); turn taking (conflict prevention).

The Nature of Human Moral Nature

Humans are, by nature, moral and immoral, good and evil, altruistic and selfish, cooperative and competitive, peaceful and bellicose, virtuous and nonvirtuous. Such moral traits vary between individuals and within and between groups. Some people and populations are more or less moral and immoral than other people and populations, but all people have the potential for all the moral traits. (Whether the evolution of such moral and immoral traits was inevitable is an important and interesting question, but it is an ancillary one to my analysis here.) Most people most of the time in most circumstances are good and do the right thing for themselves and for others. But some people some of the time in some circumstances are bad and do the wrong thing for themselves and for others.

The codification of moral principles out of the psychology of moral traits evolved as a form of social control to ensure the survival of individuals within groups and the survival of human groups themselves. Religion was the first social institution to canonize moral principles, but morality need not be the exclusive domain of religion. Religions succeeded in identifying the human universal moral and immoral thoughts and behaviors most appropriate for accentuating amity and attenuating enmity. But we can improve on the ethical systems developed thousands of years ago by people of agricultural societies whose moral codes are surely open to change. As we transition from kin and reciprocal altruism to species altruism and bioaltruism, and as religion continues to give ground to science, we need a new ethic for an Age of Science, a new morality that not only incorporates the findings of science, but applies scientific thinking and the methods of science to tackling moral problems and resolving moral dilemmas. We have done well thus far, but we can do better.