Narrator:    This is Science Today. How does the brain react to getting a fair offer as opposed to an unfair offer? That's the question a team of UCLA researchers asked before using functional magnetic resonance imaging, or fMRI, to find out. Matt Lieberman, an associate professor of psychology, describes their findings.

Lieberman:    This region of the brain called the nucleus accumbens is a region that seems to be commonly recruited and we saw this region significantly more active when people were treated fairly, compared to when they were treated unfairly.

Narrator:     This brain region is associated with reward processing.

Lieberman:     These are the same regions that you see when people are eating chocolate or if you have someone who's addicted to a particular drug and you show them pictures associated with that drug.

Narrator:    Lieberman says we tend to think that we really only have an emotional reaction to unfair treatment.

Lieberman:    But it turns out that there is this measurable, emotional response to fair treatment as well.

Narrator:    For Science Today, I'm Larissa Branin.