BRAIN-STEM SONATA: THE NEUROPHYSIOLOGY OF LOVE
Because humans give birth to so few young, nearly every infant has to live to adulthood. If love had not evolved as a binding force between mother and child, and between men and women, we would not have endured. A mother puts up with a lot of pain to give birth, and risks her own life, health, freedom, and leisure to look after a baby. Love makes it feel worthwhile. However, a baby is born with much of its brain still developing—in fact, most of a baby’s neuronal pathways develop after birth. How they develop depends on what happens in the first few years of the baby’s life, during which time it learns the fine art of being human, including how to give and receive love. More and more evidence supports the conclusion that what a child learns during those early years programs it emotionally for the rest of its life.
Psychophysiologist Gary Lynch has found that deeply emotional events stimulate the brain cells more than usual. Those neurons then become sensitized to similar events. Whenever the experience is repeated, the neurons become more and more responsive. This happens because with each repetition of the experience an enzyme signals more receptors to become available at the synapse, which in turn allows in more and more information. This would explain why “practice makes perfect,” and why one can learn a foreign language, or how to perform dentistry, if one applies oneself long enough. Children learn languages fast and easily when they’re very young, while adults find the same task nearly impossible. This is also true of emotional vocabulary and grammar. As Anthony Walsh wisely remarks,
The information communicated to children during the critical early years of life regarding their self-worth and lovableness contributes strongly to their later evaluations of their own worthiness or un-worthiness. One study of self-esteem showed that early parental nurturance completely overshadowed all other factors examined in explaining levels of self-esteem among college students. If love is so tremendously important to us throughout the lifespan, it is imperative that the brain’s “love trails” be well and truly trodden during this period. Deeply etched love trails in the brain will strongly predispose the infant in later life to respond to the world with caring, compassion, and confidence.
Why is this so important? Because “later communications, even if they are positive, will tend to be relayed along the same negative track as though some mischievous switchman were stationed at a crucial neurological junction ready to derail any train of pleasurable thought or feeling.” To love, one needs to have been loved. Unloved children often grow into adults for whom love is a foreign land, and sometimes their fate can be even more calamitous than that. Without love, a person can sink through the quicksand of depression. Without love, a person can wither and die. The lovability message is delivered in many forms other than verbally, including touching and caressing, which is one reason that breastfeeding should be encouraged if at all possible. Hugging a child, giving it enough reassuring touches, is so crucial to its development that untouched children don’t grow as tall, and they often have lower IQs, learning disabilities, and many allergies and immune system disorders. At the most basic level, they assume that mother will not protect them, that they are disposable, so there is no use wasting energy by continuing to grow. Infants reason with their bodies; they can only feel. So if they are not touched, they naturally assume they have been abandoned, or will be shortly, and they don’t feel safe in the world. Studies done with rats, monkeys, and humans show clearly that those that are stroked and loved develop normally, and those that aren’t become stunted physically and psychologically. Even well-fed babies can suffer from a syndrome called “failure to thrive” if they aren’t being lovingly handled. A nursing baby will sometimes stop and wait for his mother to cuddle him, soothe him, talk to him, before he starts sucking again. To prevail, a child must feel valuable and loved, and much of that information comes from cuddling, kissing, and close body contact.*
When we rack our brains to fathom the existence of evil in the world, we should keep in mind the role that lovelessness plays. Our instincts can teach us only what is normal and life-affirming for our species. They can’t prevent us from acting in ways that will produce neurotic or even criminal behavior in our children. Many studies highlight the connection between crime and lack of love, and show that criminals tend to issue from love-deprived childhoods. When a child’s experiences of love have been negative, abusive, and rejecting, he or she will have difficulty forming friendships and romantic relationships later on; in effect the “switchman” will misread the signals and send them down the only love tracks he can find, the ones built on pessimism, rejection, pain, and lack of trust. Love will not be associated with pleasure; and it may even trigger frustration, rage, violence. A Harvard study of ninety-four men, observed over a thirty-five-year period, found simply that those who had been happy children were happy adults, and those who were unhappy children were unhappy adults. Add to that the ever-increasing evidence of the high correlation between child abuse and criminal behavior. As Ashley Montagu observes:
Show me a murderer, a hardened criminal, a juvenile delinquent, a psychopath, a “cold fish” and in almost every case I will show you a tragedy that has resulted from not being properly loved during childhood.
On two occasions I’ve met men I would characterize as psychopaths. Both were brilliant, inventive, wealthy, powerful, and famous. They had august power over the lives of all around them, courted danger, were publicly insulting to underlings, and committed acts most people would describe as heinous. Each invited me to stay longer, to spend a few days with him, and I declined on both occasions. Something was wrong with their voices, so wrong that I felt unsafe being around them. Their voices lacked all emotional fiber, and a crucial ability to identify with others was missing from their conversations. They did not seem to feel any sense of morality or guilt or fear of punishment. They could as easily marry as murder. I do not know if they were abused, love-deprived children, but they fitted the psychological portrait perfectly.
Unteaching the incorrect, inadvertent lessons of childhood is one of psychotherapy’s hardest tasks, made all the more difficult by the way in which the faulty information was laid down in the brain. According to Daniel Alkon, a researcher at the National Institutes of Health specializing in memory, traumatic childhood memories are probably not erasable. Recorded on the thick trunk of the dendritic tree, they occupy a central position. Later memories are recorded in peripheral areas, and therefore are less powerful or permanent. This is not to say that adults cannot unlearn bad habits or master new skills. They certainly can (hence the popularity of the T-shirt that says It’s never too late to have a happy childhood). But there is a big difference between learning how to keep a kayak afloat in rough seas or mastering the fine art of social dressage, and in reaching emotional equilibrium if you didn’t start out with any. It’s possible, but no picnic. You have to change your patterns of behavior and how you interpret experiences; and that means changing the brain itself, which can be a soul-wrenching process. The brain is flexible and does change, but it does so most easily when we are young. Though love is a natural tonic that all infants crave, it must be fed to them and thus taught. As the lyrics to a pop song warn: Teach your children well …
*For a lengthier discussion of this phenomenon, and how it relates to prematurely born infants, see my A Natural History of the Senses, pp. 71–80.
THE EVOLUTION OF LOVE
Children often draw cavemen and dinosaurs in the same picture, and they love to play games with lilliputian models of the unthinkably large beasts with razory teeth. A child’s capacity to be charmed by the monstrous is one of life’s little imponderables. But in truth there weren’t any people around when dinosaurs ruled, since dinosaurs predated humans by millions of years. Only the misanthropes among us should lament their passing. For if the dinosaurs had not died out, we would not be here. Their extinction made room for the small, timid, squirrel-like mammals that would lead to us. Actually, there weren’t ever a
lot of dinosaurs roaming around, but they were big bruisers with big appetites. In contrast, there were great herds of smaller mammals. Either strategy will work: a few giants most of which survive, or swarms of dwarfs most of which perish.
Whatever catastrophe befell the dinosaurs left enough of our mammalian ancestors alive, and with the dinosaurs gone mammals spread throughout the planet, thrived, evolved, grew in size, changed shape, developed more refined brains. You are reading this because the dinosaurs died. That happenstance of evolution startles me, because it underscores how precarious our humanity really is. In my travels, I’ve seen some wondrous landforms and animals, but nothing more surprising or awe-inspiring than human beings. We are not different or separate from other animals. We are not gods who have the right to destroy our world or other worlds, but we are rare and remarkable creatures to have evolved on this planet. We are amazing bursts of dream and matter. Our minds as mazy as the Grand Canyon. Our needs as stark as warmth in winter. Our wants as murky and voluptuous as oceans. We are natural wonders.
The death of the dinosaurs was only one piece of luck that allowed humans to evolve. There were important others, and one of them was love. By “selecting” the ability to love as a crucial part of our biology, evolution made us what we are. Contrary to what philosophers, moralists, theoreticians, in-laws, and counselors have always argued, love is not a choice. It is a biological imperative. And just as evolution favored human beings who were able to stand upright, it favored human beings who felt love. It favored them because love has great survival value. Those who felt love made sure their offspring survived, those offspring inherited the ability to love, and they lived longer and had more offspring of their own. In time the tendency to love became part of our genetic endowment, and then it became more deeply ingrained than a mere tendency, aptitude, or bequest, and its richness began to subsidize every enterprise of our lives. Humans became emotional venture capitalists.
Matter inherits matter. Emotions, personality, desire all spring from flesh and chemicals. The brain is only three pounds of blood, dream, and electricity, and yet from that mortal stew come Beethoven’s sonatas. Dizzie Gillespie’s jazz. Audrey Hepburn’s wish to spend the last months of her life in Somalia, saving children. It’s not surprising that we have created a host of machines (such as stereo receivers and radar) that are transducers—apparatuses that translate sensations into electricity. Not surprising because we ourselves are transducers. Walt Whitman was accurate when he wrote “I sing the body electric.” Every one of our cells is sheathed in electricity, even our brain cells, crackling with energy, surging like a network of tiny lightning storms. Many of our machines are merely cartoon versions of us, simple versions of the hand, eye, and so on. The world confronts us with its awkward languages of shape, color, movement, sound wave and smell, and we translate all of them into the electric lingo our bodies speak, sending messages by Morse code and semaphore to the brain. When we love with all our heart, all our soul, all our might, it is an electric passion. Love develops in the neurons of the brain, and the way it grows depends on how those neurons were trained when we were children. Evolution hands out a blueprint for the building of the house of one’s life, but, as with a house, much depends on the skill and experience of the builders; the laws and codes of society; the features or quality of the materials; not to mention the random effect of tornadoes, landslides, or floods; plumbing catastrophes; and the caprices of inspectors, supervisors, hooligans, or neighbors. How we love is a matter of biology. How we love is a matter of experience.
THE PLASTIC BRAIN
If the need for love is instinctive, built-in, a part of the wiring, how can it also be molded? Humans are great ad-libbers. We revise, we create, we invent new strategies. If food becomes scarce, we navigate to where there’s more, or we change our diet, or grow food, or synthesize it, or build vehicles to transport distant food to us. The reason we are so flexible is that we cannot create many offspring. With animals that lay numerous eggs or have big litters or give birth often, there is a good chance that some of their genes will survive into the next generation. Life, for them, is cheap. Frog spawn coats a moonlit pond only briefly before most of it is devoured by predators. If but a few eggs survive to become tadpoles, and a few tadpoles frogs, everything is working right. Frogs don’t travel much anyway, and when they do they choose a similar environment. So frogs follow strict rules of behavior. They have no need to do otherwise.
But humans give birth to very few young, only one a year in most cases. If that child dies, there are no backups. And the human species lives in various environments. To get their offspring safely to adulthood, humans must make many decisions, depending on the obstacles and threats they encounter from day to day. This requires a subtle and flexible brain, a brain driven hard by basic instincts, but also adaptable to novelty. Individuals and tribes have different experiences, and so they evolve individual strategies, emotions, beliefs, habits, preferences. We call this “culture” and “personality,” and we say it is something one “develops,” as if it were a photographic image emerging from the darkroom of one’s past. It could not be more natural, or more animal, an enterprise. Faced with a hectic environment, a life-form has the best chance at survival if it can evaluate new experiences, make quick decisions about them, and learn from those decisions. Our genius is our ability to adapt and change. We are nature’s great generalists. We sample. We change our minds. We bend to pressure. We persuade others. We are persuadable. We avoid danger. We court disaster. There is an irony in this, a self-fulfilling prophecy. The more we respond to environmental pressures by changing our way of doing things—living in houses with furnaces to keep us warm, for instance—the more we create our own problems (garbage, pollutants, and the like) for which we must then devise a solution. This combination of rigid behavior on the one hand and the ability to improvise on the other is why all people are basically alike but everyone is very different. Beethoven inherited a sensitivity to music from his parents, who were musical, but it was the hard luck of his childhood that shaped his career as a composer. As Anthony Walsh describes the physical process in The Science of Love:
The human infant greets the world overflowing with slumbering potentialities. The awakening, development, and actualization of these potentialities depends considerably on experience. These experiences that make us what we are and may become are perceived, processed, and acted upon via an intricate electrochemical maze of interactions among roughly 10 billion brain cells (neurons)…. Neurons, the complex building blocks of the nervous system, are units of communication…. Projecting out from the body of the neuron are axons, which transmit information from one cell to another in the form of electrical signals of constant strength but varying frequencies, at infinitesimal junctions or gaps called synapses (“to clasp”).
The information is transmitted across the neuronal synapses by chemical “handshakes” in the form of tiny squirts of chemicals called neurotransmitters. Neuroscientists have identified approximately 60 different kinds of neurotransmitters thus far…. At the molecular level, neurotransmitters are what make us happy or sad, enraged or quiescent, anxious or relaxed.
Endorphins are one brand of neurotransmitter, especially pleasurable because they’re natural opiates that can kill pain, produce a druglike high, or calm someone down. When a mother cuddles her newborn, endorphins pour through the baby’s body and make it feel happy, peaceful, and secure. The baby learns to associate affection with pleasure.
A baby zebra can scramble to its feet and walk soon after birth, and indeed most other animal babies hit the ground running. But human babies are born helpless and unformed. In our distant past, as we evolved our big brains, women did not evolve big hips to go with them. Evolution faced a dilemma. Big-brained humans had a better chance at survival. Small-hipped women died in childbirth. Big-hipped women were too slow on their feet and couldn’t escape predators. It was not the only possible solution by any means, but the one that happened was
that women evolved slightly bigger hips and babies were born while they were still essentially fetuses. Thus a mother could protect her infant while it continued growing and developing, now outside her body but sheltered by the womb of her obsessive concern. And if a father could be persuaded to stick around, he would protect both the mother and the baby during this dangerous period. It was a rather clumsy, iffy, and complicated solution, true, but evolution proceeds by barter and handshake, not by proclamation.
It’s tempting to think of evolution as a sort of city planner, laying out all its designs at once. This reverse logic is terribly seductive, because we crave meaning and anyway we prefer tidy explanations of things. But to describe the actual events would require a rambling sentence with many contingencies and semicolons, something like this: bigger-brained babies survived better and created offspring who also had bigger brains; but many of the mothers died in childbirth, except for those few who happened to have bigger hips; and, despite the awkward features of bigger hips, in time big-brained and big-hipped females had a better survival rate; especially those who protected their infants best, that is, those who were chemically rewarded when they felt a powerful drive to nurture and sacrifice all for their young; especially if they were aided by males who felt similar urges, thus making sure that the male’s genes would survive, even if that required a long-term payoff—his genes reaching into future generations—rather than the short-term goal of not being encumbered by a dependent mother and child.
A Natural History of Love Page 19