Do humans care more about distributing goods efficiently or fairly? Is this decision rational or emotional? Steven Quartz of the California Institute of Technology in Pasadena and his colleagues used functional magnetic resonance imaging to investigate.
The team made participants pretend to take meals away from orphans. They could take away either fewer meals in a more efficient distribution, or more meals in a fairer distribution. The researchers found that more efficient decisions correlated with more activity in a brain region called the putamen, whereas decisions that emphasized fairness correlated with more activity in the insula, which is involved with emotional processing. Differences in decisions came down to how averse participants were to inequity.