The Better Angels of Our Nature: Why Vio - By Steven Pinker Page 0,308

with conflicting impulses—the anterior cingulate cortex in the medial wall of the brain, shown in figure 8–4. The people who deduce that it’s all right to smother the baby show greater activation in the dorsolateral cortex.

The temporoparietal junction and dorsolateral prefrontal cortex, which grew tremendously over the course of evolution, give us the wherewithal to perform cool calculations that deem certain kinds of violence justifiable. Our ambivalence about the outputs of those calculations—whether smothering the baby should be thought of as an act of violence or an act that prevents violence—shows that the quintessentially cerebral parts of the cerebrum are neither inner demons nor better angels. They are cognitive tools that can both foster violence and inhibit it, and as we shall see, both powers are exuberantly employed in the distinctively human forms of violence.

My brief tour of the neurobiology of violence barely does justice to our scientific understanding, and our scientific understanding barely does justice to the phenomena themselves. But I hope it has persuaded you that violence does not have a single psychological root but a number of them, working by different principles. To understand them, we need to look not just at the hardware of the brain but also at its software—that is, at the reasons people engage in violence. Those reasons are implemented as intricate patterns in the microcircuitry of brain tissue; we cannot read them directly from the neurons, any more than we can understand a movie by putting a DVD under a microscope. So the remainder of the chapter will shift to the bird’s-eye view of psychology, while connecting the psychological phenomena to the neuroanatomy.

There are many taxonomies of violence, and they tend to make similar distinctions. I will adapt a four-part scheme from Baumeister, splitting one of his categories in two.75

The first category of violence may be called practical, instrumental, exploitative, or predatory. It is the simplest kind of violence: the use of force as a means to an end. The violence is deployed in pursuit of a goal such as greed, lust, or ambition, which is set up by the Seeking system, and it is guided by the entirety of the person’s intelligence, for which the dorsolateral prefrontal cortex is a convenient symbol.

The second root of violence is dominance—the drive for supremacy over one’s rivals (Baumeister calls it “egotism”). This drive may be tied to the testosterone-fueled Dominance or Intermale Aggression system, though it is by no means confined to males, or even to individual people. As we shall see, groups compete for dominance too.

The third root of violence is revenge—the drive to pay back a harm in kind. Its immediate engine is the Rage system, but it can recruit the Seeking system to its cause as well.

The fourth root is sadism, the joy of hurting. This motive, puzzling and horrifying in equal measure, may be a by-product of several quirks of our psychology, particularly the Seeking system.

The fifth and most consequential cause of violence is ideology, in which true believers weave a collection of motives into a creed and recruit other people to carry out its destructive goals. An ideology cannot be identified with a part of the brain or even with a whole brain, because it is distributed across the brains of many people.

PREDATION

The first category of violence is not really a category at all, because its perpetrators have no destructive motive like hate or anger. They simply take the shortest path to something they want, and a living thing happens to be in the way. At best it is a category by exclusion: the absence of any inhibiting factor like sympathy or moral concern. When Immanuel Kant stated the second formulation of his Categorical Imperative—that an act is moral if it treats a person as an end in itself and not as a means to an end—he was in effect defining morality as the avoidance of this kind of violence.

Predation may also be called exploitative, instrumental, or practical violence.76 It coincides with Hobbes’s first cause of quarrel: to invade for gain. It is Dawkins’s survival machine treating another survival machine as a part of its environment, like a rock or a river or a lump of food. It is the interpersonal equivalent of Clausewitz’s dictum that war is merely the continuation of policy by other means. It is Willie Sutton’s answer to the question of why he robbed banks: “Because that’s where the money is.” It lies beneath the advice of a farmer to increase a horse’s efficiency by