"When asked what unites the ethics of the world's religions, scholar Karen Armstrong responded with the simplest of answers: 'compassion.' If faced with their own version of the question — What is the central moral adaptation produced in the evolution of human sociality? — evolutionists would converge on a similar answer: 'compassion.' On this, the religiously inclined and evolutionists would agree.

"The centrality of compassion to cooperative, high jen communities makes it a ready, and necessary, target of attack by those with contrasting visions of human social life. Hitler knew that compassion — sympathy breakthroughs — could undermine his master plan:

" 'My pedagogy is hard. What is weak must be hammered away. In my fortresses of the Teutonic Order a young generation will grow up before which the world will tremble. I want the young to be violent, domineering, undismayed, cruel. The young must be all these things. They must be able to bear pain. There must be nothing weak or gentle about them. The free, splendid beast of prey must once again flash from their eyes.'

"Early practices of Hitler's SS — shooting women and children in face-to-face encounters — led to drinking, depression, and desertion. As a result, the training of the SS officers shifted, in ways that hammered out of the soul all that was gentle, leaving only that flash in the eyes of the predator. SS officers were ordered to use Jews for target practice. Some SS officers were asked to kill their pets with their own hands. Jews were dehumanized, treated as animals in cattle cars, made to defecate in public, and used in scientific experiments on the limits of pain.

"Today, we are engaged in a more subtle struggle over compassion. It is not found in a demagogue's ideology or Fascist's social engineering but in the content of our culture. Violent video games, ad-filled Internet sites, and the new digital world of 'weak ties' all diminish the face-to-face and skin-to-skin basis of compassion. This struggle is likely shaping the nervous systems of our children, perhaps in permanent ways. Recent neuroscientific evidence suggests that the regions of the brain that enable compassion — portions of the frontal lobes involved in empathy and perspective taking — continue to develop into the twenties. Compassion can be cultivated.

"When Richie Davidson scanned the brain of a Tibetan monk, he found it to be off the charts in terms of its resting activation in the left frontal lobes. This region of the brain supports compassion-related action, feeling, and ideation. After years of devotion and discipline, his was a different brain, humming with compassion-related neural communication.

"Okay, you're rightfully critiquing, whose resting brain state wouldn't shift to the left if you had the time and steadfastness to meditate for four to five hours a day upon loving kindness, as Tibetan Buddhists do? Fair enough. When Richie and Jon Kabat-Zinn and colleagues had software engineers train in the techniques of mindfulness meditation — an accepting awareness of the mind, loving kindness toward others — six weeks later these individuals showed increased activation in the left frontal lobes. They also showed enhanced immune function. They may not have been donning the saffron robes of the monk, but at least their minds were moving in that kind direction.

"Recent scientific studies are identifying the kinds of environments that cultivate compassion. This moral emotion is cultivated in environments where parents are responsive, and play, and touch their children. So does an empathic style that prompts the child to reason about harm. So do chores, as well as the presence of grandparents. Making compassion a motif in dinnertime conversations and bedtime stories cultivates this all-important emotion. Even visually presented concepts like 'hug' and 'love' at speeds so fast participants couldn't report what they had seen increase compassion and generosity.

"Compassion is that powerful an idea. It is a strong emotion, attuned to those in need. It is a progenitor of courageous acts. It is wired into our nervous systems and encoded in our genes. It is good for your children, your health, and, recent studies suggest, it is vital to your marriage. In the words of the Dalai Lama: 'If you want to be happy, practice compassion; if you want others to be happy, practice compassion.' It has taken a sympathy breakthrough for science to catch up to this wisdom of the ages. Ironically enough, compassion may be a prerequisite to the pursuit of self-interested happiness."