You are walking along a railroad line when you come upon a fork in the track and a switch. There are five workers on one track and one worker on the other track. Suddenly, you realize that a trolley car is hurtling along and is about to hit and kill the five workers unless you throw the switch and divert the car down the other branch, killing the one worker instead. Kill one to save five. Would you throw the switch? Most people say that they would. In a second scenario, instead of coming upon a switch, you happen across a bridge where there is a large man standing next to you. The trolley is once again speeding down the track and is about to hit and kill the five workers, unless you push the large man onto the track, killing him but stopping the car. Kill one to save five. Would you throw the man? Most people say that they would not.1 Since the moral calculation is the same, logically it should not matter. But emotionally it does. Why?
The reason is that switches and people are categorically different, and evolutionary theory explains why. Evolution designed us to value humans over nonhumans, kin over nonkin, friends over strangers, in-group members over out-group members, and direct action over indirect action, because these differences impacted survival and reproduction. These intuitively felt differences and moral intuitions reflect a rational calculation conducted over the evolutionary eons. What may seem like irrational behavior today may actually have been rational deep in our Paleolithic past. Without an evolutionary perspective, the assumptions of “economic man” as selfish, rational, and free make no sense. The reason has to do with the evolution of our moral emotions.
In 2000, my mother fell and hit her head on the corner of a television cabinet and went into an irreversible coma. As she was already dying from inoperable meningioma brain tumors—after enduring a decade of craniometry brain surgeries, Gamma Knife radiation treatments, and chemotherapy—in the course of a few weeks my father and I decided to pull her feeding tube and start death’s clock, which wound down ten days later. As we were with her most of that time, I could see and sense her discomfort. Ten days without any nutrition must surely have been an unpleasant experience. Her mouth was so dry that I periodically gave her water to slake her thirst. Her nurse gave her sponge baths so that she would feel clean. Her docs had her on painkillers just in case there was any undetected internal distress—who knows what goes on inside a comatose mind? She was supposedly unconscious, but I could communicate with her by holding her hand and asking her questions, to which I would occasionally receive a squeeze in response. She was in some state of altered consciousness, so I repeated over and over, “I love you, Mama. You are a great mother and a heroic person. Wise owl, brave soul. A life well lived. It’s okay to say good-bye.”
Someone was still in there, and given her obvious discomfort—however fleeting it might have been in her state of mind—I wondered if it might not have been more humane to bring about my mom’s death sooner. But if so, how? Lethal injection or some other Kevorkianesque technique? That would be illegal. What about smothering her with a pillow? That would be swift and less likely to leave legally convicting evidence. Yikes! The very thought is repulsive. I could barely even write those words. Why is there an intuitively visceral difference between allowing someone to die and bringing about her death, or between passive and active euthanasia?2
These feelings we have about right and wrong, moral and immoral, good and evil, are telling us something important about how we should behave, even if the moral calculation seems irrational on the surface. In my previous book, The Science of Good and Evil, I argued that we have an evolved moral sense, by which I mean moral feelings or moral emotions. 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. The moral sentiments 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 is an evolved emotion that is universal to everyone.3
What I am after here is not why someone would feel guilty about some specific violation of a social norm—such as lying or stealing—but why anyone should feel guilty about anything. The feeling of guilt must have some deeper purpose that goes beyond immediate cultural norm violations. Emotions require brain power, and brains are expensive to run, so for evolution to have created a powerful emotion, there must have been a reason for it. Two of our more basic emotions serve as examples: hunger and sexual arousal.
When we need energy we do not consciously compute caloric input/output ratios; we simply feel hungry, and that emotion triggers eating behavior. When we need to procreate we do not consciously calculate the genetically based health indicators of potential sexual partners; we simply feel attracted toward someone, and that emotion triggers sexual arousal and behavior. For example, we are attracted to people whose bodies and faces are bilaterally symmetrical—where the left and right sides match each other fairly closely. Women are attracted to men with an inverted-pyramid-shaped upper body (narrow waist and broad shoulders), and men are attracted to women with a waist-to-hip ratio of 0.7:1. It turns out that these characteristics—along with full lips, strong cheek bones, thick and silky hair, and an overall hourglass shape in women, height, hair, and a strong jaw in men, and clear complexion in both men and women—are indicators of good genetic health.4 Now, no one walks into a room and starts computing bilateral symmetry and waist-to-hip ratios. Evolution has done the computation for us, and in its stead produced emotions that are proxies for these computations. In other words, we are hungry and aroused because, ultimately, the survival of the species depends on food and sex, and those organisms for which healthful foods tasted delicious and for which sex was exquisitely delightful, left behind more offspring. What we inherit are emotions that guide our behaviors.5
The economics of sexual emotions also has a deeper evolutionary basis, as discovered in such cross-cultural studies as the International Mate Selection Project, which examined thirty-seven cultures from six continents and five islands, in which people were asked to rate members of the opposite sex on eighteen different characteristics of mate desirability. Men from all over the world preferred younger attractive women of prime reproductive age with the physical characteristics noted above, whereas in 36 of the 37 samples, women valued men’s “good financial prospects” over “good looks.” Further, the study found that women tend to marry older men who have more resources, more attractive women were more likely to be married to men of higher occupational status, and that those who follow this pattern tend to have more children than those who follow a different mating strategy.6
An additional source of evidence for the evolution of the moral emotions comes from the cross-cultural study of human universals, or those features of human thought, behavior, language, social relations, and culture, for which there are no known exceptions in any human societies past or present.7 The most common examples of universals include tools, myths and legends, sex roles, social groups, aggression, gestures, grammar, and emotions. The anthropologist Donald Brown has compiled a comprehensive list of 373 human universals, from which I count 202 (54 percent) directly related to morality and religion. From this list 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.
Some universal moral emotions include affection expressed and felt (necessary for altruism and cooperation), attachment (necessary for bonding, friendship, mutual aid), coyness display (courtship, moral manipulation), crying (expression of grief, moral pain), empathy (necessary for moral sense), envy (moral trait), fears (basis of guilt), generosity admired (reward for cooperative and altruistic behavior), incest taboo (moral prohibition with genetic implications), judging others (foundation of moral approval/disapproval), mourning (expression of grief), pride (a moral sense), self-control (moral behavior), sexual jealousy (foundation of moral mate guarding), and shame (moral sense).
Some universal moral behaviors include age statuses (social hierarchy, dominance, respect for elder wisdom), coalitions (foundation of social and group morality), collective identities (basis of xenophobia, group selection), conflict mediation (foundation of much of moral behavior), customary greetings (part of conflict prevention and resolution), dominance/submission (foundation of social hierarchy), 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 indirect reciprocity), inheritance rules (reduces conflict within families and communities), institutions (rule enforcement), kin groups (foundation of kin selection/altruism and basic social group), law (rights and obligations) (foundation of social harmony), marriage (moral rules of foundational relationship), reciprocal exchanges (reciprocal altruism), redress of wrongs (moral conflict resolution), sanctions (social moral control), sanctions for crimes against the collectivity (social moral control), and sanctions that include removal from the social unit (social moral control).
Finally, some universal economic emotions and behaviors, based on the fundamental principle of reciprocity universally expressed as the golden rule of “do unto others as you would have them do unto you,” include cooperative labor (part of kin, reciprocal, and indirect altruism), 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), hospitality (enhances social relations), insulting (communication of moral disapproval), judging others (foundation of moral approval/disapproval), planning for future (foundation for moral judgment), pride (a moral sense), promise (moral relations), negative reciprocity (revenge, retaliation; reduces reciprocal altruism), positive reciprocity (enhances reciprocal altruism), redress of wrongs (moral conflict resolution), shame (moral sense), and turn-taking (conflict prevention).
What these universals reveal is that we are social primates, moral primates, and economic primates, and thus these characteristics belong to the species and transcend the individual members of our species.
From such basic emotions as hunger, arousal, and mate choice to the higher social practice of monogamy and the economic institution of marriage, we cross the bridge from evolutionary psychology to evolutionary economics. We evolved as a pair-bonded primate species. Although anthropologists have classified nearly 80 percent of human societies as practicing polygyny (more than one wife), since the sex ratio is nearly fifty-fifty, in actual practice only a few men have multiple wives, while the vast majority of people are coupled monogamously.8
Yet within this arrangement we see a dramatic difference in the reproductive strategies followed by men and women. As the Billy Crystal character in the film City Slickers quipped, “Women need a reason to have sex; men just need a place.” As I described in my book, Why Darwin Matters, this observation was borne out in an amusing study by the psychologists Russell Clark and Elaine Hatfield, who had an attractive member of the opposite sex approach a fellow college student whom he or she had not previously met and ask one of three questions:
1. Would you go out on a date with me tonight?
2. Would you go back to my apartment with me tonight?
3. Would you sleep with me tonight?
The results will elicit a wry smile even while surprising no one: To the first question, half of both men and women responded positively; to the second question, however, 69 percent of one gender and only 6 percent of the other gender agreed to return to the apartment; and to the third question, 75 percent of one gender agreed to have sex, while 0 percent—not one—of the other gender agreed to a proverbial “zipless fuck,” which even Ms. Jong admitted was rarer than a unicorn.9 I don’t even need to say which gender was which. You already know.
Think of this evolutionary analysis in economic terms. Life, like the economy, is about the efficient allocation of limited resources that have alternative uses. Sperm, which are tiny and plentiful, are virtually unlimited, whereas eggs, which are large and scarce, are exceedingly limited; thus, women far more than men need to be concerned about allocation efficiency. The result is that men compete among themselves for access to women, while women do the selective choosing. Darwin called this sexual selection, and it is a powerful force in evolution.
My point is this: as we saw with the emotions of hunger and arousal, you do not need to compute the economic value of choosing a marital partner; let your emotions guide you. An emotion such as love evolved to tell you if the person you are considering for marriage is healthy, trustworthy, faithful, reliable, and stable; that is, will he or she make a good father or mother for your children? Conversely, a negative emotion such as jealousy is a proxy for evolution’s calculation that it is highly inefficient to invest in someone who is allocating scarce resources to an alternative partner—also known as cuckolding.
Consider how monogamy, adultery, and jealousy play out in an evolutionary analysis. If monogamy had no benefits at all, then we would not practice it. But we do. And there are deep evolutionary reasons why. For example:
• Women practice monogamy as the best reproductive strategy because eggs are limited and bringing a fetus to term and raising a child to reproductive age is a huge investment to make, so women tend to be very selective about choosing a mate and deeply invested in making the pair bond last.10
• Most men practice monogamy because the sex ratio is close to fifty-fifty and even in polygamous societies only a few men have multiple wives.
• Although polygamy and promiscuity afford men greater quantities of reproductive opportunity (in other words, more women), some evolutionary biologists show how the most profitable mating strategy for men is to ensure the quality of a few offspring by investing heavily in one mate, rather than taking the risk of raising some other man’s offspring by being promiscuous and investing in many children.11
• Monogamy protects against sexually transmitted diseases (STDs) that were almost certainly a part of our Paleolithic past.
• Stepchildren suffer significantly higher rates of physical and psychological abuse at the hand of stepparents, especially stepfathers, than do children from biologically intact families.12
• Stepchildren leave home significantly earlier than children in intact families.13
• Stepchildren show higher rates of behavioral, emotional, and physical problems compared to children in biologically intact families.14
• Stepdaughters in particular are at a significantly greater risk of being sexually molested by their stepfathers than daughters are by their biological dads.15 The incest taboo, so powerful in squelching feelings of sexual attraction between relations, becomes a less potent prophylactic against stepfathers, who may have been introduced to the girl well after the incest taboo imprinting period has passed.
• Young single males are more prone to engage in risky, competitive, and even violent behavior as a means of seeking status, controlling females, and competing with other males. Cross-cultural data show that crime rates are higher in polygamous than monogamous societies,16 and that men are twenty times more likely to be killed by another man than a woman is of being killed by another woman.17 Even in modern America, a 1985 study found that 41 percent of adult male offenders were unemployed and 73 percent were unmarried, and that men in general committed 93 percent of robberies, 94 percent of burglaries, and 91 percent of car thefts.18 As the evolutionary psychologist Steven Pinker likes to say, the number one predictor of crime and violence is maleness!19 But unmarried maleness makes it even worse. These guys are competing for status and resources in order to attract females. Once they’ve attained marital stability, such behavioral expressions are attenuated.
In like manner, if adultery had no benefits at all, then we would not practice it. But we do. And there are deep evolutionary reasons why.20 For men, adultery provides an opportunity to allocate one’s virtually unlimited genes with alternative partners. For women, adultery is a chance to trade up for superior genes, better resources, and higher social status. How do we square the circle of monogamy and adultery? Serial monogamy. Most people, most of the time, in most circumstances practice monogamy. Occasionally some people, some of the time, in some circumstances practice adultery. The balance is heavily weighted in favor of monogamy, but not exclusively so, and the reason has to do with the relative risks for both monogamy and adultery. For monogamy, there is the risk that you made a bad choice: your partner has unhealthy genes, is infertile, is untrustworthy, unfaithful, unreliable, or unstable, and thus will not make a good parent to your children. For adultery, the hazards are even more serious. For men, revenge by the adulterous woman’s husband can be deadly, and although he is not likely to be killed by his wife if she catches him cheating on her, she can impose significant emotional and social penalties, such as loss of contact with children, depletion of financial resources, social shunning, and risk of sexual retaliation that thereby increases the odds that if he stays he may be allocating his resources toward another man’s offspring. For women, being discovered by the adulterous man’s wife involves little physical risk, but getting caught by one’s own husband can and often does lead to extreme physical abuse and occasionally even death—research shows that most spousal murders are triggered by sexual jealousy.21
Finally, for children, being raised by nonbiological parents turns out to be one of the riskiest and even deadliest factors ever discovered in research on childhood neglect and abuse—Martin Daly and Margo Wilson found that a child living with one or more stepparents was 100 times more likely to die from abuse than a child raised by biological parents.22 (As in the saying, “beaten like a red-headed stepchild.”) Perhaps this is why a study on the response of extended family members commenting on the resemblance of newborn babies to their parents found that the family members—most notably those on the mother’s side—were likely to voice their opinion that the newborn looks like the father.23 This makes sense in the context of additional studies on genetic paternity that found that anywhere from 5 to 30 percent of husbands in a maternity ward were not the biological fathers of the infants they were holding.24 No wonder Shakespeare waxed poetic as he did in Othello:
That green-ey’d monster was born out of an evolutionary context—jealousy is an evolved emotion that stands in for an evolutionary computation that has weighed the relative costs and benefits of sexual infidelity. This has produced the emotional tension most of us have felt between the desire for sexual variety and the fear of the consequences of getting caught acting on that longing. Here again we see the role of such evolved emotions as guilt or pride at having done the wrong or right thing in interplay with these other evolved emotions of love and jealousy. And it is here that morality comes into play, as we make the choice to act on our emotions or hold them in check. I have made the case elsewhere that we have free will and thus can genuinely make moral choices;25 and since this choice has economic consequences, it is an example of virtue economics at work, the virtue here being fidelity, in the economic institution of marriage.
On many mornings, I go on training ride with a group of competitive cyclists in the Southern California area. My routine is to cycle from my office to the start of the ride in order to get in some extra mileage, often wending my way through the congested streets of Glendale to get to the open roads of Griffith Park. One morning, a black Town Car parked on my side of the road caught my eye because the driver was just sitting in the car while what appeared to be his passenger—an elderly and frail-looking woman—was slumped on the sidewalk, struggling to get up. Without even a whisper of conscious thought, I hit the brakes, hopped the curb, dismounted my bike, reached down and slipped my arms beneath the woman’s arms, and hoisted her up to her feet. Once she was stable and able to walk, she thanked me and went on her way, as did I.
A sizable body of psychological literature is devoted to understanding why people are violent, aggressive, malicious, and mean. A far smaller body of literature is devoted to explaining why people are nonviolent, gentle, kind, and compassionate. For every act of violence that reaches the highlight reels of the nightly news, ten thousand acts of kindness go unrecorded and, in most cases, unnoticed in the background noise of general human virtue. Like the fish that does not even notice the water in which it resides, the virtues of our humanity are such a common occurrence that we swim blissfully unaware in its invisible waters. From a “selfish gene” perspective, competitiveness and greed need no particular explanation beyond the obvious—I’ll do whatever I can to get my genes into the next generation, even if that means stomping on all the little people on my way to the top. But if helping others by being selfless and altruistic decreases the chances of getting my genes into the next generation, why would I do it? The short answer is that it is a myth that evolution is driven by selfishness; it is, in fact, driven by adaptability, and in a social primate species like ours, more often than not the most adaptable thing you can do to survive and reproduce is to be cooperative and altruistic.
Over the course of millions of years, our moral emotions have evolved, primarily under biological control. In the early stages of our evolution, the individual, family, extended family, and small groups were molded primarily by natural selection, and the individual’s need for survival and reproduction is met through the family, extended family, and local group members.
But around thirty-five thousand years ago, a transition took place, and cultural factors increasingly assumed control in shaping our moral behavior. In later stages, communities and societies were shaped primarily by cultural selection. Basic psychological and social needs—security, bonding, socialization, affiliation, acceptance, affection—evolved to aid and reinforce cooperation and altruism, and all facilitate genetic propagation through children. Such kin altruism works indirectly—siblings and half siblings, grandchildren and great-grandchildren, cousins and second cousins, nieces and nephews, all carry portions of our genes.26 Anyone who is genetically related to us is included. In larger communities and societies, in which an individual has no genetic relationship to most others, reciprocal altruism (I’ll scratch your back if you’ll scratch mine) and blind altruism (if you scratch my back now, I’ll scratch yours later) are needed to supplement kin altruism. We become less inclusive and more exclusive.27 The more a moral emotion reaches beyond ourselves, the further it goes in the direction of helping someone genetically less related, the less support it receives from underlying evolutionary mechanisms.
In this social context, fairness evolved as an Evolutionary Stable Strategy (ESS) for maintaining social harmony in our ancestors’ small bands, where cooperation was reinforced and became the rule and freeloading was punished and became the exception. For example, in experimental economics research utilizing exchange games in which cooperation and defection are both strategies in which subjects can gain or lose depending on what the other subject does, the most successful—and thus most commonly employed—strategy is called “tit for tat,” where you start off cooperating and continue cooperating as long as your partner does, but punish defectors. The theory holds that an ESS will be selected for because it leads to greater survival by its practitioners, and will thus be passed along to future generations.
The reason hunter-gatherer bands are egalitarian is not because they are naturally altruistic or lack some impulse for competitiveness and avarice, but because excessive greed and selfishness is kept in check by the fellow group members. Anyone who attempts to hoard food, amass tools and other products, or steal someone else’s spouse is likely to be shunned or punished by the rest of the group, and unless that individual is a high-status “big man” with an inner circle of loyal followers who must, in turn, be well nourished and paid for their services, excessive selfishness is kept in check by the collective power of the group. Being ousted from a tiny band of hunter-gatherers in the Paleolithic was probably a death sentence, unless one could ingratiate with another group. And if you have a reputation for being self-centered and socially unreliable, you will need to travel far to find people who do not know your reputation.
Evidence for this social enforcement of egalitarianism can be seen in a number of anthropological studies of meat-sharing practices in modern hunter-gatherer societies around the world. It turns out that these small communities—which can cautiously be used as a model for our own Paleolithic ancestors—are remarkably egalitarian. Using portable scales to measure precisely how much meat each family within the group received after a successful hunt, researchers found that the immediate families of successful hunters got no more meat than the rest of the families in the group, even when these results were averaged over several weeks of regular hunting excursions. Hunter-gatherers are egalitarian because selfish acts are effectively counterbalanced by the combined will of the rest of the group. The anthropologist Chris Boehm has discovered in a number of hunter-gatherer societies the use of gossip to ridicule, shun, and even ostracize individuals whose competitive drives and selfish motives interfere with the overall needs of the group.28 In other words, we are competitive and selfish, but we are also cooperative and altruistic—tendencies that are created and reinforced by the group in which the individual lives. In this manner does a human group become a moral group in which “right” and “wrong” coincide with group welfare and self-serving acts, respectively.29
Some of this cooperative behavior may be accounted for by reciprocal altruism or inclusive fitness, but a deeper interpretation is that an emotional sense of “right” and “wrong” action evolved in humans living in hunter-gatherer communities through genetic transmission of such traits, as well as their cultural spread through modeling and learning. 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 the anthropologist Signe Howell, who has studied the Chewong, punen can be defined as “a calamity or misfortune, owing to not having satisfied an urgent desire.”30 In the Chewong world, strong desires are connected with food, and the powerful norms about food sharing are associated with the myth about “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 by the concept of punen, and are linked to a most practical matter of individual and group survival—eating and sharing of food. Thus, says Howell, the Chewong avoid provoking punen at all costs. When food is caught away from the village, it is promptly brought back, publicly displayed, and equitably distributed among all households and among all individuals within each home. To reinforce the sanction against punen, someone from the hunter’s family touches the catch, 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.
My point with this example is that we do not need to make social and moral computations about what is right and wrong. Evolution has done the calculating for us, and our emotions guide our behaviors. This is why being shunned by one’s family, extended family, or social circle feels so bad, and it shows the power of emotions to guide our social choices, such as deciding to be fair in an economic exchange.
Kin selection, inclusive fitness, and reciprocal altruism explain most of the behaviors we consider to be moral toward others—relations and strangers. But there are some actions that have no apparent benefit to the giver and cannot be reciprocated by the receiver, such as handouts to beggars, donations to nonprofit charities, donating blood, “adopting” a child in another country whom you will never meet, and the like. The Israeli evolutionary biologists Amotz and Avishag Zahavi suggest a mechanism they call Costly Signaling Theory (CST) to explain such kinds of altruistic acts.31 In a CST model, people sometimes do things not just to help those related to them genetically, and not just to help those who will return the favor, either now or later, but to send a signal, or a message, that says, in essence, “My altruistic and charitable acts prove that I am an honest and trustworthy member of the community, and that I am so successful that I can afford to make such sacrifices for others and for the group.” That is, altruism is a form of information that carries a signal to others of trust and status—trust that I can be counted on to help others when they need it so that I can expect others to do the same for me; status that I have the health, intelligence, and resources to afford to be so kind and generous. To repeat my earlier point, it is not enough to fake being a moral person (because others will find you out eventually); you have to be (or believe you are) a moral person.
In yet another line of evidence that we evolved moral emotions, brain scans reveal that we evolved powerful neurological mechanisms to reinforce cooperation and prosocial behavior, and through social exchange create and reinforce bonds between unrelated people.32 The neuroeconomist Kevin McCabe, for example, scanned the brains of subjects participating in a “trust and reciprocity” game, revealing that areas of the prefrontal cortex related to impulse control and the delay of immediate gratification are more active in the brains of cooperators than defectors, suggesting that cooperation requires “attention to mutual gains with the inhibition of immediate reward gratification to allow cooperative decisions.”33 In her study of both humans and the great apes, neuroscientist Katerina Semendeferi found that Area 10 of the frontal lobe is associated with such higher cognitive functions as the undertaking of initiatives and the planning of future actions, and that this area, while larger in apes than in monkeys, is in humans the largest of all the apes and is more connected to higher order brain areas. She concludes that “the neural substrates supporting cognitive functions associated with this part of the cortex enlarged and became specialized during hominid evolution.”34
The reason for this cortical expansion is that humans evolved to become the preeminent social and moral primate. Another neuroscientist, Jorge Moll of the National Institutes of Health, and his colleagues, for example, found that moral emotions activate both the amygdala (emotions) and the orbital and medial prefrontal cortex (cognitions), showing that moral acts are as much a function of moral emotions as they are of moral reasoning.35 In a subsequent study on charitable donations, Moll found that when subjects had an opportunity to donate to or oppose real charitable organizations related to prominent social causes, the mesolimbic reward system was activated by donations in the same manner as when subjects are rewarded with monetary gains for a task. In other words, the moral feeling that comes from being charitable is directly analogous to the feeling of getting paid for any other act.36
Since morality principally involves our responses to others in social situations, we cannot separate the moral from the social. In order to be a moral agent one must be both self-aware and aware that others are self-aware, functions that are located in two different areas of the brain. Self-awareness, at least in part, appears to be located in the medial prefrontal cortex, whereas representing others’ actions and intentions appears to be centered in the temporal cortex.37 There even appear to be specific neurons in the brain evolved for social and moral emotions.
Since we are a social primate species, one would expect that other social primate species have evolved specialized cells for dealing with others in social situations. One candidate is a special class of cells called spindle cells, or Von Economo neurons, first discovered in 1925 by the Romanian-Austrian brain anatomist Constantin von Economo. Cigar-shaped and tapered at each end, spindle cells are located in just two regions of the frontal lobes: (1) the anterior cingulate cortex (ACC), an evolutionarily ancient region of the brain common to all mammals that lies beneath the midline of the cerebral cortex, and (2) the frontoinsular cortex (FIC), just behind the eyes. Spindle cells are also the exclusive property of the great apes: humans, chimpanzees, bonobos, gorillas, and orangutans. They have not been found in monkeys or other mammals. According to the Caltech primatologist and brain specialist John Allman, spindle cells appear to be unique to our evolutionary line, and the more distant the ape relation, the lower the spindle cell count. Orangutans have the least, humans the most, with chimps, bonobos, and gorillas in between.
The significance of spindle cells for social emotions is inferred from their location. Brain scan studies have shown that the ACC guides attention, senses pain and errors, taps into the body’s autonomic control systems, and generally acts as a central hub between thoughts and emotions. The FIC is especially active in response to others in social situations, such as in a mother when she hears her infant cry, when we observe others whom we love experiencing pain, and even when we are being deceived. “All these responses have something in common,” Allman explained. “They all represent value judgments within a social context. I think spindle cells are the home of the complex social emotions.” The size of the spindle cells is key, especially in their large axons. Neural axons carry signals to other neurons, and the larger the axons, the faster the signal. And speed is the key to rapid cognition in social situations.
In other words, our emotions are guiding our decisions, and doing so in the blink of an emotional moment—“this feels right” or “this feels wrong.” This fits my model of moral emotions. As Allman noted, “The main thing spindle cells do is to adjust your behavior in a rapid real-time interaction in a complex social environment. It is so simple that I think it is entirely reasonable that it could be performed by about 100,000 neurons.” And spindle cells feature receptors for the neurotransmitters serotonin, dopamine, and vasopressin, associated with reward value, bonding, and love. Thus, Allman suggests that spindle cells evolved sometime in the past ten million years, presumably before the ape-human split some six to seven million years ago.38
The final step in establishing a deep evolutionary basis for our moral emotions is to identify the underlying neural architecture that generates behaviors and feelings involved in acting moral. We now have that foundation in the form of mirror neurons, specialized neurons that “mirror” the actions of others and thus are directly involved in imitation, anticipation, and empathy, all key ingredients in the evolution of the moral emotions.
In the late 1980s and early 1990s, the Italian neuroscientist Giacomo Rizzolatti and his colleagues at the University of Parma discovered mirror neurons serendipitously when they were recording the activity of single neurons in the ventral premotor cortex of macaque monkeys. Poking hair-thin electrodes into individual neurons allows neuroscientists to monitor the rate and pattern of single cell activity, and in this case the action from the monkey’s F5 neurons spiked whenever it reached for a peanut placed in front of it in the experimental apparatus. The serendipity came when one of the experimenters reached in and grabbed one of the peanuts, and the same neurons in the monkey’s brain fired. Monkey do was the same as monkey see. The motor neurons were “mirroring” the motor activity of others—hence they became known as mirror neurons. As Rizzollati recalled, “We were lucky, because there was no way to know such neurons existed. But we were in the right area to find them.”39
Neuroscientists throughout the 1990s scrambled to learn more about mirror neurons, finding them in other parts of the brain, such as the inferior frontal and inferior parietal regions of the brain, and not only in monkeys but in humans as well.40 Since research ethics committees generally frown upon open brain research on human subjects, individual mirror neurons have not been monitored in people, but employing the next best technology—fMRI—UCLA neuroscientist Marco Iacoboni and his colleagues imaged the brains of subjects as they watched people make finger movements and then imitated those same finger movements, discovering that the same areas of the frontal cortex and parietal lobe in both conditions were active.41
The purpose of mirror neurons, and why they would have evolved, is a subject of controversy. Rizzolatti’s original thesis—that mirror neurons are just motor neurons responding to seeing as well as doing—is uncontroversial and makes sense. When you see an action, it is recorded on your visual cortex, but to more deeply understand what the act means in terms of its consequences, the observation must be linked to the motor system of the brain so that there is an internal check with the external world. With this basic neural network in place, higher order functions can be layered onto it, such as imitation. In order to imitate someone’s actions, you need both a visual memory of how the action looks and a motor memory of how the action feels when implemented, and there is now considerable research linking the mirror neural network to imitation learning.
Being able to imitate others, however, can go much deeper than the mere repetition of their actions.42 Actions have intentions, and so mirror neurons have also been implicated in what is called Theory of Mind (ToM), or the ability to understand that others have beliefs, desires, and intentions. A higher order ToM allows one to realize that others’ intentions may be the same as or different from your own. This is sometimes called “mind reading,” or the process of inferring the intentions of others by projecting yourself into their minds and imagining how you would feel. A still higher level ToM means that you understand that others also have a theory of mind, and that you know that they know that you know they have a theory of mind. Here we may find ourselves in an intentional loop not unlike a bit from the 1950s television series The Honeymooners, in which Jackie Gleason tells Art Carney, “You know that I know that you know that I know that . . .” But how does ToM mind reading actually operate in the brain?
In a review of the research on what brain scans have revealed about the location of Theory of Mind, Glasgow University neuroscientists Helen Gallagher and Christopher Frith conclude that there are three areas consistently activated whenever ToM is needed: the anterior paracingulate cortex, the superior temporal sulci, and the temporal poles bilaterally. The first two brain structures are involved in processing explicit behavioral information, such as the perception of intentional behavior on the part of other organisms—for example, “That wolf intends to eat me.” The temporal poles are essential for the retrieval from memory of personal experiences, such as “The last time I saw a wolf, it tried to eat me.” All three of these structures are necessary for ToM, and Gallagher and Frith go so far as to posit that the anterior paracingulate cortex (located just behind your forehead) is the seat of the Theory of Mind mechanism.43 Theory of Mind is a high-road automatic system that kicks in for specified activities involving other people, particularly in social situations. It most likely evolved out of a number of preexisting neural networks used for other related activities, such as the ability to distinguish between animate and inanimate objects, to hold the attention of another through eye gaze, the ability to distinguish the actions of self and others, and the ability to represent actions that are goal directed. All of these functions are basic to survival in any social mammal, and thus Theory of Mind is most likely an exaptation, a feature co-opted for a different purpose from the one for which it was originally evolved.
A number of specific brain scan studies support this idea. In one 1998 fMRI experiment, people were shown two different hand actions, one without a context and one with a context that revealed the intention of the action. The latter scene activated the subject’s mirror neuron network, revealing where ToM is located in the brain.44 In 2005, a very clever experiment was conducted in which monkeys watched a person either grasp an object and place it in a cup or grasp an apple and bring it to his mouth—similar action, different intention. Recording forty-one individual mirror neurons in the inferior parietal lobe of the monkeys’ brains, it was discovered that the “grasp-to-eat” motion triggered fifteen mirror neurons to fire, but these were silent when observing the “grasp-to-place” motion. Yet four other mirror neurons were active for the opposite condition. Interestingly, the neuroscientists concluded, the mirror neurons in this part of the brain “code the same act (grasping) in a different way according to the final goal of the action in which the act is embedded.”45 In other words, there are neurons specialized for discriminating between different intentions: grasping in order to place versus grasping in order to eat. More generally, this implicates mirror neurons in both predicting others’ actions and inferring their intention.
From imitation to intention to emotion, additional fMRI studies point to a mirror neuron network involved in empathy. In one such study, Christian Keysers and his neuroscientist colleague Bruno Wicker scanned the brains of fourteen subjects as they were exposed to two different conditions: (1) a disgusting odor (butyric acid, which gives off the smell of rotten butter) and (2) short clips of people making facial expressions of disgust. Wicker and Keysers found that the feeling of disgust and watching someone else express disgust activated the same network of neurons called the anterior insula, involved in the processing of emotion. It appears that experiencing disgust and seeing disgust are indistinguishable to the insula. In a related study, they examined “tactile empathy” and found that lightly touching someone on the leg activated the same area of the somatosensory cortex as when they were shown photographs of someone being touched in the same spot.46 It appears that experiencing touch and seeing touch are indistinguishable to the somatosensory cortex. A related fMRI experiment confirmed the finding for more general emotions, linking the observation and imitation of facial expressions in the anterior insula—seeing someone’s facial expression registered the same activity in the insula as making the expression yourself.47
To further refine the difference between the imitation of motion and the empathy of emotion, Marco Iacoboni and his colleagues scanned the brains of twenty-three subjects as they watched videos of a hand picking up a teacup. In the first clip, a hand is reaching for the cup sitting on a well-set table, implying that the intention was to grasp the cup and take a sip. In the second clip, the table is messed up, with cookie crumbs strewn about, implying that the intention was to clear the table. As a control, a third clip shows the hand reaching for the cup by itself, with no context. The results revealed a distinct difference between the first two clips and the third clip, with strong activity in the mirror neuron network of the premotor cortex for the intention versus no-intention scenes, and a stronger signal for the drinking condition than the cleaning condition. As Iacoboni concluded: “The stronger activation of the inferior frontal cortex in the ‘drinking’ as compared to the ‘cleaning’ intention condition is consistent with our interpretation that a specific chain of neurons coding a probable sequence of motor acts underlies the coding of intention.”48
As with all other human traits, empathy varies among individuals, and the research on mirror neurons lends neural credence to this folk observation. People who score high on self-report questionnaires measuring empathy also show stronger activity in mirror neuron networks for both movement and emotions. Likewise, women show stronger EEG readings linked to mirror neuron activity than men do, lending scientific credibility to the intuition that women are more empathetic than men.49 As for a more literal meaning of empathy, research on observed versus felt pain, particularly when the pain was imposed on someone who is loved by the observer, activated the same brain circuitry.50 Empathy has its very own brain network. Adam Smith would not have been surprised.
There is also some evidence that a dysfunctional mirror neuron network might be involved in autism, because of the difficulty autistic children have in relating to people and social situations. When shown a short clip of a hand making grasping motions and then asked to imitate that grasping motion, autistic children show dramatically different EEG readings than nonautistic children. If you can’t read others’ intentions, then their actions will appear random and thus meaningless, requiring no response, or a random and thus inappropriate response.51 Sound similar to trying to read others’ intentions in the stock market?
The research on mirror neurons and autistic children was conducted by the always colorful and cleverly creative University of California, San Diego, neuroscientist V. S. Ramachandran. “Rama” (to those who know him) has taken the implications of mirror neuron research and run with it to the high table of evolutionary theory. Calling the discovery of mirror neurons “the single most important ‘unreported’ (or at least, unpublicized) story of the decade,” Rama holds that mirror neurons are one of the key steps in making humans different from all other animals, in that by being able to imitate, we can override natural selection—and consequently we can modify the environment instead of the environment modifying us. In a period of global cooling, for example, natural selection will favor those animals with more effective thermoregulation features, such as a thick fur coat. But this can take hundreds or thousands of generations to evolve, whereas a big-brained primate with a mirror neuron network can observe a thick-furred mammal looking toasty warm in a blizzard and immediately grasp the idea of killing the animal and wearing its fur coat rather than waiting around for evolution to grow him one. Others see and do what our erstwhile hominid ancestors discovered, and with language we can quickly spread the fur-coat meme (along with the stone-tool meme, the fire meme, the bow-and-arrow meme, and the art, music, and religion memes) throughout Cro-Magnondom. It’s a bit of a just-so story, but one that has merit given what we know about the power of imitation, intention, and empathy in our neural architecture.52
From the neurophysiology of empathy, we can begin to understand another biological basis of economics. “Understanding the intentions of others while watching their action is a fundamental building block of social behavior,” Marco Iacoboni reflected. “Our findings show for the first time that intentions behind actions of others can be recognized by the motor system using a mirror mechanism in the brain. The same area of the brain responsible for understanding behavior can predict behavior as well.” In other words, there is empirical evidence for Adam Smith’s philosophical deductions in The Theory of Moral Sentiments: “How selfish soever man may be supposed, there are evidently some principles in his nature, which interest him in the fortune of others, and render their happiness necessary to him, though he derives nothing from it except the pleasure of seeing it. Of this kind is pity or compassion, the emotion which we feel for the misery of others, when we either see it, or are made to conceive it in a very lively manner.”53
Addressing such problems as preserving the planet’s ecosystem and bio-diversity or maximizing within-group amity and minimizing between-group enmity requires social and political action. Unfortunately, such high-minded goals are too far-reaching, and the time frames involved are too long-range, for how we were programmed by nature to think. In the Paleolithic environment, our concern for the environment and biodiversity was restricted to a few tens of kilometers and hundreds of species over a lifetime of only a few decades. The number of people our ancestors encountered in their lifetimes could be numbered in the hundreds, so there was no reason for evolution to produce a principle of tolerance for ethnically diverse members of other groups in faraway lands.
This is why scientists and social activists concerned about global climate change and other long-term environmental threats have had such a difficult time getting people to notice the problem, let alone care about finding a solution. When your evolved moral sense of what is important is restricted to a few dozen people, miles, and years, who cares what happens to some other group thousands of miles away or a thousand years hence?
One answer is to reframe the problem in an intimate, short-term context. Consider how nonprofits concerned with the plight of starving third-world children employ the “adopt a child” strategy in order to tap into potential first-world donors’ natural empathies. The effect of the strategy was endearingly portrayed in the 2002 film About Schmidt, in which Jack Nicholson’s title character adopts a Tanzanian child named Ndugu, with whom he carries on a one-way correspondence that becomes the narrative outline of the story of Schmidt’s search for meaning in his later years. After writing countless self-centric letters about matters trivially irrelevant, Schmidt discovers in the film’s final scene that his foster charge cannot read or write. But the letter from the nun who looks after the boy brings redemption, as it is accompanied by a stick-figure drawing made for Schmidt by Ndugu that depicts an adult and child holding hands beneath a deep blue sky and radiant yellow sun. The scene is so moving in its emotional simplicity that it evokes empathetic tears.54 By touching one small child worlds away—a child with a name and a face and a visual acknowledgment for a small but significant act of kindness—Schmidt’s life became meaningful. Call it the Ndugu Effect.
We care more about one named child with a face than we do about tens of thousands of nameless and faceless children. In the modern world, it is an irrational moral calculation—rational economic man should care more for the many than the one. But an apparently irrational calculation becomes a rational moral choice in the ancient world of our evolved brains, where we care more for the one than the many, especially when the one is a proxy for those we evolved to care about—our immediate family, extended family, friends, community, and fellow in-group members. The effect is deep and emotional, and it works. Indeed, after watching again that final scene from About Schmidt, I went online through World Vision’s program to sponsor an eleven-year-old girl named Suada Isaku from Tirana, Albania, who lives in the rural farming district of Elbasan with her parents and sister struggling to survive on bread, vegetables, beans, and dairy products. My modest monthly donation, World Vision tells me, “will help provide Suada and her community with clean water and improved healthcare facilities. Your support will help create educational partnerships between parents and teachers to enhance students’ education. Economic forums will help the community develop plans for growth.”55 An accompanying photograph with additional details about my sponsored child—she enjoys reading, helps at home with housework, likes to play ball games, and is in good health—reinforces my sense of attachment to her. A subsequent search on Google Earth promptly carried me through cyberspace to Suada’s village, pulling on the heartstrings of my brain’s dopamine reward networks, igniting my Middle Land propensity to connect to those near me, transforming a total stranger into honorary family through the power of markets, minds, and morals.