Thumbs, Toes, and Tears

by Chip Walter

  Sustenance and kissing have even been tied up in the linguistics of ancient Egypt. For a while Egyptologists mistakenly translated the hieroglyph for “eat” as the word for “kiss,” but kiss fit so well in sentences that involved eating that it took years for them to realize they had it wrong. Looking at it this way, it is not so difficult to see how our kissing may have migrated from satisfying one form of hunger to satisfying others.

  …

  Despite its pleasures, kissing does entail some risks. By one count a single meeting of the lips can exchange 278 species of bacteria and viruses, some good, some not so good.15 Colds, flu, bubonic plague—all can lurk behind a loving buss. But on balance, kissing seems mostly to have helped our kind survive because it leads so pleasurably and naturally to sex, and sex, rather inevitably, leads to babies.

  This path has been, of course, problematic for the millions of teenagers over the years who have been shocked to suddenly find themselves parents. The onset of puberty, and the oceans of hormones that go with it, evolved long before modern culture did, and they drive behaviors today that once made better sense in a world where fourteen-year-old mothers and fifteen-year-old fathers were more the norm than the exception.

  In those days the emphasis was less on developing deep and emotionally abiding relationships, and far more focused on the survival of the species. Though there were surely prehistoric examples of warm primate relationships, the main goal would have been to find a mate with the most promising genes and the very best survival skills. Personal compatibility would have been welcome but secondary.

  These old forces still drive a lot of our behavior. Most evolutionary psychologists, for example, hold that prehistoric women, their mobility hampered by pregnancy and mothering, would have gravitated to men who were strong hunters, high in the tribal pecking order, and likely to be the sort of fathers upon whom they could rely to help parent their offspring. If the realities of childbearing made them more dependent, then it would have made sense for females to gravitate to power and fidelity, probably in that order. A strong mate—physically, socially, and mentally—not only carried promising genes, but also enough strength and social power to put a couple in a position to provide well for their children. We see the resonances of this sort of decision-making everywhere today. There are few women who would avoid a man who is honest, reliable, powerful, and wealthy.

  Prehistoric men, on the other hand, would have preferred women who were healthy and who housed nice strings of DNA. They would have looked for clear signs of physical beauty—features like round bottoms, ample breasts, shapely hips, a winning smile—all clear signals of health, especially in a brutal world that battered even the strong. Not much has changed here.

  These traits may help explain some of the differences scientists see in the brains of men and women. One brain scanning study conducted recently by scientists at the University of California at Irvine and the University of New Mexico reveals that while men and women are of equal intelligence, they have significantly different brain anatomies. Men have about six and a half times the gray matter related to general intelligence than women have, but women have almost ten times the amount of white matter related to intelligence than men. Gray matter generally provides the neuronal wattage for the brain’s information processing centers. White matter provides the synaptic connections between these processing centers.

  The team that conducted the study speculates that this helps explain why “men tend to excel in tasks requiring more local processing—like mathematics—while women tend to excel at integrating and assimilating information from distributed gray-matter regions in the brain, such as required for language facility.” Very possibly these differences evolved because our male and female ancestors dealt with different environmental and social pressures.16

  The conclusion of the paper was that evolution seems to have come up with different brain anatomies in each sex that get the same job done just as well, but in different ways. This may also mean that men and women experience the world and one another in fundamentally different ways.

  The more interconnected nature of women’s brains and their greater facility with language, for example, may explain why women often seem better at communicating what is on their minds, and at the same time they seem to have a knack for reading what is on the minds of others. Cambridge University psychologist Simon Baron-Cohen has found, for example, that when men look at the world, they start with the very small and work outward. Women, on the other hand, tend to get the big picture first and then work inward. Do these views simply reflect the different structures of our brains—men’s localized and focused, women’s distributed and highly interconnected?

  Baron-Cohen, who heads Cambridge’s Autism Research Centre, says the research shows that the male brain acts more like an autistic’s than a woman’s does. Several studies reveal a correlation between the localized, less interconnected nature of men’s brains, and their ability to excel at mathematical reasoning and tests that require the mental rotation of three-dimensional objects.17 Men, says Baron-Cohen, focus first on minute detail, and operate best with a certain detachment. They like to systemize and organize objects, and they tend to be less people-oriented.

  This behavior resembles autistics, who are “mindblind,” clueless as to the feelings of other people, as if their mirror neurons are malfunctioning. Like men, they also love to systematize and organize, except far more aggressively. Most autistics are also male—overwhelmingly so, in fact. Of those who suffer from Asperger’s syndrome, a milder form of autism, there are ten male victims for every female.18

  These peculiarly male cerebral attributes also may explain why men are more verbally impatient than women (they tend to give orders rather than negotiate), or why they navigate according to an imagined geometric grid while women mostly personalize space by finding familiar landmarks. And it may explain why boys like to play with trucks and guns as opposed to dolls with which they sit down to tea for imagined conversation. They have more of an affinity for things than for people.

  But dolls and tea play precisely to women’s perceptual and mental skills, which are less analytical, more intuitive, and top-down rather than bottom-up. The interconnected nature of women’s brains seems to help them more intuitively read other people. Females are more gifted at absorbing the context of situations, inferring intentions, and then responding in emotionally appropriate ways.

  The brain’s ability to empathize and socialize is far from well understood, but scientists have found that a cluster of neurons dedicated to reading the feelings and intentions of others lies on the left side of the brain, near Broca and Wernicke’s areas, cerebral areas that are usually more developed in women.19 Altogether this seems to make the females among us more adept social animals, hardwired to get the big picture.

  Given what we have gleaned over the years about prehistoric human life, the divergence of male and female brains along these lines makes sense. Men would have done the bulk of the hunting (studies even reveal that men have a very specialized talent that women do not generally have for hitting targets when they throw something at it); they also would have tended to be more analytical, direct, and focused, and less social—all traits that would have favored their survival in a dangerous environment as they foraged and hunted for food. And they would have tended to do the hunting because they were not the sex that became pregnant. They were simply more mobile more of the time.20

  The reality that women and not men get pregnant would have shaped other roles and behaviors, too, ones in which we often remain entangled today. Women have a limited number of eggs, for example, and pregnancy was (and remains) costly on every possible level. As a result, our female ancestors had to be very careful about the mates they chose. The high stakes would have made the competition among women more fierce. But under the circumstances it could rarely become overt because women in camp also would have needed to get along. A delicate balance had to have been struck in a world where your friends were
also your potential competitors. Thoughtfulness and adept social communication would have favored the survival of the women who possessed those traits, both with their children and then with one another. (Maybe this is why mothers, as a group, tend to be more nurturing than fathers.)

  While men were dealing with the vicissitudes of the hunt and the dangers that go with it, females would have been faced with handling the complex social world at camp—getting along with one another and handling the kids at the same time they were keeping an eye out for competitors and positioning themselves adeptly in the social hierarchy. If a female was adroit at tuning into her role among those around her, if she had a knack for knowing who her friends and enemies were and a talent for building useful alliances, she would have tended to do quite well.21,22

  For men the situation was different. Not radically, but different enough. They also would have needed to cooperate with one another on a day-to-day basis while simultaneously competing for the best possible sexual partners. But since men have millions of sperm and evolved to spread their DNA wherever they could find a willing partner, and since they didn’t pay the heavy price of pregnancy, they might not have tended to be quite as careful about the females they mated with. (Men generally remain less careful about this today, for the simple reason that if sex leads to pregnancy, the man is not the one who becomes pregnant.)

  In this sense, men’s choices were less complicated. It was not as important for them to find females who were “true.” The main thing was to find females, period, and the healthier the better. This may explain why men seem to be more preoccupied with beauty, shape, and external appearance than women. They were the best indicators of physical health, and to men, physical health was what mattered most—find the best set of complementary chromosomes.

  The point is, if form follows function, then differing circumstances may well have shaped different brains, and in one arcing feedback loop those different brains have in turn generated different behaviors and attitudes toward sex and relationships that continue to make the interactions of men and women both so complementary and so complicated. Yet the primal need to bring more children into the world requires that we find a way to meld minds and hearts as well as bodies, even if neither sex sees the world in quite the same way.

  …

  Recently evolved differences in our cerebral anatomy are not the only influences that affect whom we decide to kiss. The limbic system, which is another ancient part of our brains that is well connected to more recently evolved areas, also has a lot to say about why we react to one another the way we do. The limbic system generates a lot of what we label emotion and feeling. When we miss someone, feel warm in the company of a lover, grow angry, jealous, or overjoyed—these experiences are generated by the chemical and electrically charged neuronal conversations that incessantly rattle around our limbic systems.

  The whole brain is massively interconnected, but the limbic system seems to be a particularly well-traveled crossroads, a place where the very ancient parts of our brain that govern extremely primal operations like breathing, pleasure, fear, and hunger meet with the high-end thinking and planning we do in the prefrontal cortex. Because of our limbic system it is difficult to disconnect emotion from our memories, actions, or decisions. It also explains why intense emotions reveal themselves in physical reactions like a fast-beating heart, trembling hands, dilated pupils, perspiration, sudden waves of nausea, or equally sudden bursts of joy.

  The limbic parts of us help explain a lot of apparently senseless human behavior. Presidents, premiers, senators, and royalty have famously let their limbic systems get the better of them. Think of the headlines that announced the trysts of Senator Gary Hart, President Bill Clinton, or Louisiana Representative Robert Livingston. Even when the career stakes are as high as they can get, this part of the brain has a way of making sure it is heard.

  IQ apparently has no bearing on the dictates of our primal drives.

  Because the limbic system governs emotional memory, it is a crossroads in another way. It links adult experiences such as kissing and pheromones, sex and love to the memories we gather and carry with us from our childhoods. We have a sense of time and self partly because of our limbically charged memories. They guarantee that many of the emotional patterns from our past, even our very early past, are emotionally saved and colored for the present and the future.

  Maybe this is why it is so difficult to write sensibly and logically about kissing. It sits at the nexus of high intellect and primal drives, and the two can’t seem to quite get into sync. Kissing symbolizes the entanglements of the human heart. It’s an object lesson in the ways lust and love collide in the human race.

  Why does this happen to us but not to emus, sea turtles, and the Indri lemurs of Madagascar? Because beginning with the first tools Homo habilis fashioned more than two million years ago, human culture has evolved far more rapidly than human DNA. Today, despite all of the genetic rearrangements natural selection has wrought, many of our primal drives remain fully intact. Yet our big brains, in one of the great ironies of the human condition, have entirely refashioned the world into a place profoundly different from the one we originally evolved to live in.

  The truth is that kissing, pheromones, and the limbic systems to which they link us often place our feet in each of these camps: the primal one for which we evolved, and the modern one we invented. One shaped by our DNA, the other created by our big brains. Sometimes they seem to be diametrically opposed. It is not that simple, of course, but it is difficult to dispute that the blistering speed of our cultural evolution has placed our DNA and the brains it created at odds.

  Genes, for example, demand that we procreate at the earliest possible age. But today sex at age thirteen in many cultures is far from appropriate. Modern teenagers don’t have the same career agendas they did 190,000 years ago. But they still have the same bodies and drives.

  There are other examples. Partly because of advances in hygiene and medicine, many of us in so-called First World countries can count on living well into our seventies, eighties, and nineties. Monogamous relationships can go on for forty, fifty, or sixty years, far longer than our short-lived ancestors could ever have imagined. As a result, we look not simply for enjoyable sex in a partner that results in new offspring, we also look for fulfilling relationships that can hold up and blossom over the decades. Were we built for that?

  Finding and building enduring relationships has not been easy, at least partly because of our limbic and DNA-shaped drives. We value monogamy and fidelity, yet the biggest moneymaker on the Internet is pornography, affairs between both sexes in the modern world are on the rise, and half of all marriages end in divorce in the United States.

  A perfect object lesson in the limbic/DNA-driven conflicts that kissing symbolizes is jealousy—the “green-ey’d monster,” as Iago so devilishly put it to Othello, “which doth mock the meat it feeds on.” Like so many of our primal drives (including kissing itself), jealousy has a hijacker’s ways about it. It commandeers parts of the brain like a virus takes control of a cell’s genetic machinery. We have even, on occasion, accepted the power of this emotion into our courts of law. In one of the most celebrated cases of the twentieth century, an industrialist from Pittsburgh named Harry K. Thaw pleaded, for the first time in legal history, that he was temporarily insane when he walked up to New York’s leading architect, Stanford White, one summer night in 1906 and in full view of a restaurant filled with diners shot him dead at point-blank range.

  He did it, he later testified, because a few years earlier White had once enjoyed a relationship with the woman to whom Thaw was married, the great beauty Evelyn Nesbit. A storm erupted in his brain, his lawyers argued at trial, and Thaw had lost all control.23 The defense worked. Thaw was found not guilty and walked. He was the first, but not the last, person to escape prison on the grounds that he had lost his mind.

  When we feel jealous—and almost all of us have felt at least a twinge, if not murderou
s tides of it—it does seem as though the weather has suddenly changed in our brain. And in some sense it has, if you can describe weather as coursing hormones, activated brain cells, and agitated cerebral molecules.

  But it is because the limbic system is connected to our prefrontal cortex that something like jealousy or envy can evolve into premeditated acts of murder or revenge. Using the newer parts of our brain, we can jealously imagine the very worst possible scenarios that in turn feed back to further agitate limbically connected centers such as the hypothalamus and amygdala and hippocampus, which are themselves linked to even more ancient parts of the brain that kick in some of our most primal behaviors—rage, anger, fear. In short, our intellect amplifies the primeval parts of us. A storm in our brain is not a bad analogy.

  Truth, Beauty, and the Archaeology of Desire

  Who would have thought that the shape of hips and shoulders would so deeply affect the shapes of brains and the evolution of species?

  For aeons sexual selection has been tweaking our inborn definitions of beauty and attractiveness, and today those definitions still drive much of our personal behavior as well as explain a lot of what we seem to value in mainstream culture. Cultures everywhere do differ in what they find attractive. Plumper bodies may be more valued in one country than another, and clothing, jewelry, and hairstyles differ in popularity from place to place. But there are some basic elements that all people everywhere, even infants, find attractive. The common determinant seems to be that the traits indicate health of one kind or another, particularly as it relates to the opposite sex, because health is the outward evidence of strong genes, and strong genes lead to individuals who are likely to survive long enough to pass their DNA along to the next generation. In the end, that is the evolutionary bottom line.