David Ewing Duncan

A View from David Ewing Duncan

How Altruistic Is Your Brain?

Brain scans suggest that altruism may be as much a part of our genes and gray matter as it is a function of free will.

  • February 5, 2007

Free will just took another small hit. This time the news comes from a team of neuroscientists at Duke University studying why we give to strangers and to causes that provide us no direct benefit.

Let’s say you sit down and write a check once a year to Save the Toucans. It’s your choice, right?

Maybe, though now, thanks to the Duke researchers, it appears that the brain has a say too. Their evidence comes from an experiment that identified a region of the brain that lights up during brain scans when a person is inclined toward giving.

Humans are not alone in altruistic behavior, actions that help others that do not result in a direct benefit for the helper. Many other mammals and the odd fish or bird display what some scientists classify as altruism, though why remains a mystery.

Now, at least, we know what part of our brain is activated when we give–and it wasn’t in the region the researchers expected.

The Duke experiment asked 45 students to lie in the tube of a Functional Magnetic Resonance Imaging (fMRI) scanner, a device that can take real-time images of brain activity. The researchers then asked the students to first fess up about their altruism. Did they tend to give, or not to give? Then they asked both the altruistic and the stingy to play a game, offering payments to the winners. The givers handed over their cash to charity, and the nongivers got to keep their winnings. The idea was to see if brain activity could be a predictor for self-described altruism.

The game involved reacting to targets appearing on a screen. Winning depended on speed, which reduced the time for reflection and concentrated on immediate responses and motivations. A weakness in this experiment is that the students might have been motivated by factors others than altruism, such as wanting to please the researchers–a drawback that lead researcher Scott Huettel admits.

Huettel expected altruism to activate the region of the brain that rewards actions–that makes us feel good when we do things we like. Instead, giving away money to toucans, or whatever cause the students chose, activated a region in the superior temporal cortex, part of the parietal lobe. This region has been associated with our extracting meaning from how we perceive things we see.

For instance, if we see a rock sitting on the ground, this area does not light up. If we see a person reach down to pick up the rock and accomplish his or her goal, bam! The superior temporal cortex fires off. A possible explanation for this is that people who give are motivated by a perception that their behavior (winning a game!) will result in a certain goal being accomplished (toucans are saved!), though what exactly is going on in the superior temporal cortex when college students play computer games for charity remains a mystery.

“Although understanding the function of this brain region may not necessarily identify what drives people like Mother Theresa,” Huettel told Reuters, “it may give clues to the origins of important social behaviors like altruism.”

It may also require us to revise Rene Descartes’s famous dictum: “Cogito ergo sum”–“I think, therefore I am.” This assumes an active choice to think and to be. Perhaps soon we’ll revise this to say (in English, as my college Latin fails me) “My brain tells me I am thinking that I am, therefore I am.”


Nature Neuroscience Article

Reuters Article

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