Angela Stimpson donated a kidney to a complete stranger. Why did she do it? Researchers found that the brains of Stimpson and other altruists are sensitive to fear and distress in a stranger's face.
People like Stimpson are "extraordinary altruists," according to Abigail Marsh. She's an associate professor of psychology at Georgetown University and one of the country's leading researchers into altruism.
Marsh wanted to know more about this type of extraordinary altruism, so she decided to study the brains of people who had donated a kidney to a stranger.
The amygdala was significantly larger in the altruists compared to those who had never donated an organ. Additionally, the amygdala in the altruists was extremely sensitive to the pictures of people displaying fear or distress.