Tibetan Buddhists believe that for anyone who practices diligently enough, compassion can become second nature, an unhesitating reaction to every situation. At the Wisconsin lab, a tape of a woman's blood-curdling scream was unexpectedly sprung on a monk in the midst of his compassion meditation. Rather than eliciting the predicted negative reaction, his scan showed an unexpected activation in the left prefrontal area of the brain, a region associated with positive emotion. A compassionate response to others' suffering had become so ingrained as to be automatic.
— Marc Ian Barasch, Field Notes on the Compassionate Life