We Are Our Brains (37 page)

The origins of empathy lie in a mother animal's caring behavior toward her offspring. It's an automatic response that involves not just the PFC, a comparatively recent brain area, but also much more ancient regions of our brains. Almost all humans—with the exception of psychopaths—show empathy. There's no doubting the importance of competition, whether in the monkey world or in human society, but cooperation and the pleasant feeling of sharing fairly and helping others are just as crucial. If you reward two apes equally for the same task, all is sweetness and light, but if you suddenly give one of them a nice grape instead of the piece of cucumber that his fellow ape is still getting, then the underpaid ape will stop cooperating and hurl the cucumber out of his cage in protest.

More than in his previous books, De Waal cites examples from
neuroscience to explain behavioral mechanisms. (Indeed, so many new discoveries are being made in neuroscience that his next book could profitably explore the integration of behavior and neurobiology.) He of course mentions mirror neurons, which react to the emotions of others and thus form the basis of empathy. He also looks at gender differences. Women, it turns out, empathize with cheaters when they are punished, while men do not feel any empathy in such situations. Quite the opposite: Their reward circuitry (
fig. 16
) is activated, demonstrating that justifiable punishment generates actual pleasure.

I'm not yet quite convinced, however, by De Waal's claim that von Economo neurons (VEN cells or spindle cells) underpin self-consciousness, as expressed in the ability to recognize oneself in a mirror. To possess any marked degree of empathy, an animal must be able to distinguish itself from its surroundings. This ability has been studied using mirrors in the “mark test.” In the test, a paint mark is made on an animal's forehead, after which the animal is shown its reflection in a mirror. If it realizes that it is seeing itself, it will touch the mark or try to rub it off. Dogs and cats fail this test; children over two, primates, dolphins, and—as De Waal himself showed with a particularly large mirror—elephants pass it.

Acceptance that animals, too, have emotions, is incidentally a fairly recent phenomenon in the Western world. When the first chimpanzee and orangutan were exhibited in the London Zoo in 1835, Queen Victoria pronounced them “frightful, and painfully and disagreeably human.” The young Charles Darwin, however, declared that anybody who thought that man was superior to the apes should go and take a good look. De Waal attributes our difficulty in recognizing that animals have feelings to the religions on which our culture is based. According to the Judeo-Christian doctrine, only humans have souls, and man is the only intelligent creature, having been created in God's image. I don't find his theory convincing. The Chinese have been equally unreceptive to the idea of animal emotions until very recently. But increasing prosperity in China is being
matched by increasing interest in and empathy with animals. More and more Chinese people have pets, animal abuse meets with public outrage, and a gigantic memorial to the rhesus monkeys that were sacrificed in the name of SARS research can be found at Wuhan University.

When a journalist from a religious newspaper asked De Waal what he would change in humans if he were God, he reflected for some time, being suspicious of movements that have sought to impose social change by diktat, like social Darwinism, Marxism, and radical feminism. De Waal pointed out that both sides of human nature, that of the friendly, empathetic, and sexy bonobo and that of the aggressive, dominant chimpanzee, are necessary for a stable society. He concluded that he wouldn't want God to change humans fundamentally but simply to increase their sense of “brotherhood” by endowing them with more empathy. I personally doubt whether this would rid the world of problems. Indeed, De Waal furnishes the other side of the argument. If you're open to everyone and trust everyone—a trait shown by people with Williams syndrome—others will perceive your behavior as abnormal and shut you out. Moreover, empathy has its dark side. The reason humans are so good at torture is precisely because they excel at imagining what others feel. In fact, the more empathetic they are, the crueler they can be. De Waal cites the example of Nazi guards who carried out acts of unimaginable brutality in concentration camps, yet who were loving husbands and fathers in their off-duty hours. We can possess plenty of empathy and at the same time use it very selectively. The millions who revered Hitler, Stalin, and Mao were no less empathetic than we are. So De Waal might do well to ask God if he could also curb our tendency to take our lead from charismatic alpha males. Not only might this prevent future genocides and cultural revolutions, it might also reduce the likelihood of another disaster caused by corporate greed.

The only thing I recall of the international committee on which I sat twenty-five years ago is the infectious laugh of Eric Kandel. It certainly wasn't a laugh that sprang from a happy childhood. He was born in Vienna in 1929 as Erich Kandel and was given a beautiful blue remote-controlled car for his ninth birthday. Two days later, during Kristallnacht, the Jewish Kandel family was ordered to leave their house by two Nazi policemen. When they were allowed to return home a few days later, they found that it had been ransacked. Everything was gone, including the blue car. After waiting a year for a visa, the family emigrated to the United States, where Erich changed his name to Eric. He trained as a psychiatrist, undoubtedly influenced by the fact that his first girlfriend's parents were renowned psychoanalysts who had worked with Sigmund Freud. He was so
fascinated by psychoanalysis that in 1955, while working under the famous electrophysiologist Harry Grundfest at Columbia University, he enthusiastically announced that he wanted to find the biological foundation of Freud's theory of the psyche. Freud divided personality into three parts: the id, the unconscious, primitive component that is driven by the pleasure principle; the ego, which tries to balance the id's desires with reality; and the superego, which acts as conscience and moral guide. Freud himself had never given any thought to where these hypothetical elements were located in the brain. Grundfest, who introduced Kandel to neuroscience, listened patiently to his unfeasible research plans and gave him the most important advice of his career: “If you want to understand the mind, you will have to study the brain cell by cell.” It was this approach, which involved studying first the cellular, then the molecular biology of memory, that ultimately won Kandel a Nobel Prize in 2000. Kandel fascinatingly describes this journey in his autobiography,
In Search of Memory.

Memory is defined as the capacity to store and retrieve information. It provides us with conscious access to our past. Kandel initially focused his research on the hippocampus, a part of the brain that is crucial to memory. But the hippocampus proved too complex, and he went in search of a simpler organism to study, ultimately opting for the giant marine snail
Aplysia.
Kandel said that he had relied on his instincts when making the decision, just as when he took the plunge and decided to marry his girlfriend Denise. (It's perhaps worth noting that he described
Aplysia
as “large, proud, attractive, and obviously highly intelligent.”) In primitive organisms like
Aplysia
, the various aspects of memory are present in simple reflex responses, initiated by a few extremely large neurons that make a relatively small number of synaptic connections. The simplicity of this circuitry made it comparatively easy to study aspects of the way in which neurons learn. Kandel showed that connections between neurons varied, becoming stronger or weaker in response to electrical stimuli. In other words, the nervous system didn't consist of fixed
connections like an old-fashioned telephone exchange; instead its links proved to be plastic. There are circuits, formed during development, in which innate behavioral patterns are fixed. But nervous systems also contain components that can change through learning.

Learning proved to hinge on changes in the strength of synaptic contacts. These became stronger as the neurons learned from repeated stimuli, proof of “practice making perfect.” This is the basis of memory. The various forms of learning, memory, forgetting, and thinking—and thus, in a sense, our minds themselves—are the result of synaptic contacts in different brain areas being affected by the many different chemical messengers contained in neurons.
Aplysia
has both short- and long-term memory, the latter of which, just like its human variant, requires repeated training interspersed with periods of rest. In the case of short-term memory (for instance briefly remembering a telephone number so that we can punch it in) only the strength of the existing synapses changes. In other words, a functional change takes place. The capacity of short-term memory is very limited: In the case of humans it is limited to fewer than twelve words or numbers, and if the information isn't repeated it will be retained for only a few minutes. Long-term memory requires the synthesis of new proteins, because it involves forming new connections between neurons. This amounts to a structural change for which glia cells produce the essential fuel, that is, lactate. Long-term memory is sometimes compared to a computer hard disk in which information is permanently stored. Short-term memory is likened to the working memory or random-access memory (RAM) of a computer, in which information changes every second depending on the tasks and programs being run.

Early on, memory storage can be disrupted by concussion, oxygen shortage after a heart attack, or electroshock treatment for depression. Factors like these can cause retrograde amnesia, wherein a person forgets everything that happened during the preceding period. Since memory can gradually be restored in such cases, it seems
that the problem is caused by disrupted access to information rather than its storage in the brain. After a period of years, stored information is less vulnerable to disruptions of this kind. Ultimately, long-term memory contains an individual's entire knowledge and experience of the world and themselves.

Learning causes structural changes to the brain, as Ramón y Cajal observed back in 1894 (see the epigraph to this section). In professional violinists, for instance, the part of the cerebral cortex that directs the fingers of the left hand is five times as large as in people who don't play a stringed instrument. When I see the speed with which young children send text messages, I get the impression that the thumb areas in their cerebral cortex are considerably bigger than mine.

Kandel also unraveled the molecular processes that take place when synaptic strength alters and new synapses form, setting up a whole new research field in the process: the molecular neurobiology of cognition. He discovered the molecular mechanisms whereby information is transferred, through practice, from the short- to the long-term memory. The hippocampus (
fig. 26
) plays an important role in this process. At the same time, Kandel showed how a highly emotionally charged event bypasses the short-term memory and is immediately stored in the long-term memory. In those cases the amygdala (
fig. 26
) is crucial. Having found the likely molecular basis for normal memory deterioration as a result of aging, Kandel set up a company called Memory Pharmaceuticals. Unfortunately it hasn't yet come up with the perfect learning pill.

Shortly before being awarded the Nobel Prize, the seventy-eight-year-old Kandel was in Amsterdam to receive the Heineken Prize for Medicine. He still had the same old infectious laugh; it rang out during the lunch. After traveling to Stockholm to collect his Nobel Prize, he returned to Vienna, where he organized a symposium on Austria's enthusiastic response to National Socialism. It was his way of denouncing the collective denial of the role played by his homeland
during the Nazi period. The man who had become famous for his work on memory was shocked to discover that schoolchildren in Austria knew nothing about Hitler or the Holocaust. While in Vienna, he was given a blue toy car exactly like the one the Nazis had stolen from him as a child. He responded laconically, saying that he was later glad that he'd had to leave the car behind in Vienna: “I went to the United States, where I had an absolutely wonderful life. And now I've got a Mercedes.”

Contacts between neurons change in response to neural activity. That's how memory is encoded, and it's a characteristic of every neuron. So you could argue that memory is located throughout the nervous system. But some brain structures are preeminently concerned with memory. Functional scans can show whether a brain area is
involved
in certain functions, but data on patients with local brain damage remains crucial in revealing whether or not those areas are actually
necessary
for a particular function. Valuable information on the role of parts of the cerebral cortex in memory has, for instance, been obtained through systematic studies of patients with brain disorders, bullet wounds, and other types of brain damage and of patients undergoing operations on the brain. Before operating on patients, the American-born Canadian neurosurgeon Wilder Penfield (1891–1976) stimulated their temporal lobes (
fig. 1
) with an electrical probe while they were still conscious so that he could more accurately target surgery. This sparked extremely detailed memories; some of the patients sang entire songs while lying on the operating table.