Extreme altruists have bigger brains, Georgetown University study shows

As if giving a perfectly good kidney to a total stranger wasn't enough of a distinction, it turns out that extreme altruists have bigger brains and are better than the rest of us at reading signs of distress in facial expressions.

That's what Georgetown University neuroscientists found when they scanned the brains of 39 kidney donors, according to a study published online in the journal Proceedings of the National Academy of Sciences.

Psychologist Abigail Marsh thought it would be tough to round up a significant number of people who had donated kidneys to strangers. She was pleasantly surprised. They were easy to find because many now advocate for organ donation. And they really want to do good things.

"What was amazing about them - and I guess it shouldn't have surprised me, in retrospect - was how incredibly easy they were to work with," Marsh said. "They could not have been more delightful study participants."

Many didn't even want reimbursement for travelling to the university, thinking it was taking money away from science.

The participants stayed motionless during multiple brain scans, patiently looked at lots of facial expressions flashed at them for milliseconds, and didn't take umbrage to answering 154 questions usually posed to those suspected of being psychopaths. And when the results came in, many thought the data proved just how much organ donation improves humans, Marsh said.