"Pati Cum. These two Latin words blend together to form the root of 'compassion,' and they literally mean 'to suffer with.' While we can empathize with a whole rainbow of emotions in others, compassion requires the capacity to tenderly feel another's pain.

"When I think of compassion, the figure who inevitably comes to mind is Abraham Lincoln. There is a story about a town drunk who was sleeping on the road in his own vomit one winter night when Lincoln and his friends walked by. Lincoln took the man home. And in his second inaugural speech, he made this remarkable and unforgettable statement 'With malice toward none, with charity for all, with firmness in the right as God gives us to see the right, let us strive on to finish the work we are in, to bind up the nation's wounds.' It is in binding up another's wounds that we offer true compassion.

"Compassionate acts are innumerable: a hug to a friend, a donation to victims of a disaster, volunteer work, thoughtful advice, or in a rare case like that of a Mother Teresa, an entire life spent tending others in pain. Compassion is a way of living that you can cultivate, and it will soften and brighten your world.

"Everyone from the Dalai Lama to the towering thinker Adam Smith has pointed to compassion as the most human, and humane, quality. David Hume, possibly the greatest of all Enlightenment philosophers, stated that though reason guides ideas, math, logic, and fact, it cannot move us to act. Only emotions stir us in that way. The German philosopher Arnold Schopenhauer stated it bluntly: 'Compassion is the basis of morality.'

"Compassion is immediate. We are moved by suffering that is right before us, and we're less likely to be stirred by pain halfway across the world. In that case, we might need to make a little extra effort to 'feel' our way into lives that are unconnected to us.

"Of all the research on compassion, I find new brain imaging studies most fascinating. These studies allow us to see the act of compassion lighting up certain areas of the brain. There is a neurocircuitry that seems necessary for compassion. . . .

"Compassion begins at birth. Compassion is the hallmark of perhaps the most important kind of love in our species: that of mother for child. The brains of moms show a distinct and powerful response to their baby's distress — certain parts of their brains light up in response to a just-born infant, and different parts of the brain light up months later as the relationship evolves.

"Compassion calms and connects up. The wellspring of compassion may be in the hormone oxytocin — a neuropeptide produced in a part of the brain called the hypothalamus, which penetrates the whole nervous system and has become famous for its link to pair-bonding, devotion, and nurturing attachment. Some researchers now feel that oxytocin represents a unique axis of the nervous system that they call 'calm and connection' — the exact opposite of the well-known fight-or-flight hormones.

"Compassion allows us to mirror others' feelings. New research at Princeton is beginning to show that a brain area called the insula, located within the cerebral cortex, is associated with empathy and compassion. It's a hot topic in neuroscience right now, because it is the place where mirror neurons — neurons that 'mirror' an experience another person is having, almost as if we're having it ourselves at the same time — seem to be located.

"Compassion increases positive emotions. We may be able to cultivate compassion through regular meditation and visualization and permanently shift our brain patterns. Pilot studies with Buddhist monks show that regular compassionate meditation may permanently change brain patterns, leading to greater happiness. Compassionate feelings and actions, even when they involve the ability to sense and empathize with another's pain, help trigger positive emotions.

"Compassion is linked to spirituality. One researcher's new findings suggest that compassion and spirituality are hardwired and linked. He has measured the 'attachment' hormone, oxytocin, and the activity of the vagus nerve, a major nerve extending from our heart area to our brain, and found that both correlate with high compassion and intense spiritual experiences. Though these findings are preliminary, they hint that compassion is linked with other powerful, feel-good experiences like connectedness and spirituality."