Damage to an area of the brain behind the forehead, inches behind the eyes, transforms the way people make moral judgments in life-or-death situations, scientists reported yesterday. In a new study, people with this rare injury expressed increased willingness to kill or harm another person if doing so would save others’ lives.

The findings are the most direct evidence that humans’ native revulsion to hurting others relies on a part of neural anatomy, one that evolved before the higher brain regions responsible for analysis and planning.

http://www.nytimes.com/2007/03/22/science/22brain.html?ex=1333080000&en=0d0c748df905c44f&ei=5124&partner=permalink&exprod=permalink