Adventures In Good And Evil

Intrigued by the growing evidence that the brain can be altered by experience in fundamental ways—a property called neuroplasticity—Shaver wondered if it would be possible to induce feelings of security and self-worth, thereby strengthening the neural circuitry that underlies compassion and altruism. "If only people could feel safer and less threatened, they would have more psychological resources to devote to noticing other people's suffering and doing something to alleviate it," says Shaver, who as a young man considered entering the priesthood.

To find out, he and Mikulincer had volunteers watch a young woman perform a series of unpleasant tasks. "Liat" looked at gory photographs of people who had been severely injured. She pet a rat. She immersed a hand in ice water. And then she faced the prospect of petting a tarantula. After making a valiant attempt, she whimpered that she couldn't, begging that "maybe the other person can do it." Explaining that the experiment had to continue, the scientists asked a volunteer if he would trade places with Liat (who was actually part of the study). The responses confirmed Shaver's hunch. Volunteers who were trusting and secure in their own skin were four times more likely to swap places as those who were anxious and insecure. Even inducing this sense of trust and security made people more likely to help Liat. "Making a person feel more secure had this beneficial effect," says Shaver. "It worked on everyone." It was an intriguing hint that virtue could be boosted by altering people's emotions.

The Tibetan monk who worried that he would grow to hate his Chinese captors has not had his brain scanned for clues to what accounted for his compassion, but others have. Encouraged by the Dalai Lama to lend their brains to science, Buddhist monks have made regular treks to the University of Wisconsin. There, psychologist Richard Davidson uses fMRI to compare activity in the brains of monks who practice Buddhist compassion meditation (a deep, sustained focus on the wish that all sentient beings be free from suffering) to that in the brains of volunteers who do not. One difference leaped out: heightened activity in regions involved in perspective-taking and empathy—not just during meditation, when you'd expect it, but when the monks viewed pictures of suffering, such as an injured child. "It seems that mental training that cultivates compassion produces lasting changes in these circuits, changes specific to the response to suffering," says Davidson. "The message I've taken from this is that there are virtues that can be thought of as the product of trainable mental skills."

Rewiring the brain to strengthen the circuits that underlie virtues obviously can't explain all the differences between people in their levels of altruism, compassion and willingness to forgive. Meditation, after all, remains a niche activity. But ordinary, everyday experiences leave footprints on the brain no less than effortful mental training does. Dimow attributed his refusal to torture his unseen partner in the Milgram experiment to being brought up in a family that was "steeped in a class-struggle view of society, [which] taught me that authorities would often have a different view of right and wrong than mine," and to his Army training, when "we were told that soldiers had a right to refuse illegal orders."

Psychologist Michael McCullough of the University of Miami calls such experiences "learning histories," and he suspects they explain much of the difference between people in their willingness to forgive and their desire for revenge. In his 2008 book "Beyond Revenge: The Evolution of the Forgiveness Instinct," he argues that both forgiveness and revenge "solved critical evolutionary problems for our ancestors." Forgiveness helps to preserve valuable relationships. Exacting revenge acts as a deterrent against attacks, cheating or freeloading. It also establishes the revenge taker as someone not to be crossed, preempting future attacks. "We have blueprints in the brain for both revenge and forgiveness, and depending on our circumstances as well as our life histories, we are more likely to use one or the other," says McCullough. "By the time I'm an adult, my history of being betrayed, violated, having my trust broken—or their opposites—pushes me toward a strategy tuned to the circumstances of my development."

When people can count on the rule of law to punish infractions, they are less prone to seek personal revenge. Conversely, when society lacks a mechanism to defend people's rights, "parents teach their children to cultivate a tough reputation and not let anyone get away with messing with them," McCullough says. But there is also what he calls an "effortful path to forgiveness. More recently evolved parts of the brain might exert top-down control over the emotional regions" that otherwise compel vengeance—probably something similar to the mental training that the Buddhists undergo. After a gunman took Amish schoolchildren hostage in 2006, killing five girls, the community said they not only forgave the killer, they also donated money to his widow. "Evolution favors organisms that can be vengeful when it's necessary, that can forgive when it's necessary and that have the wisdom to know the difference," says McCullough. If scientists can fathom the roots of the differences between sinner and saint, maybe more of us can move into the latter group.

© 2009