Egalitarianism (the belief that everyone should be treated equally) is one of the driving forces behind prosocial behavior (behavior that helps others). Previous studies have hinted that dopamine, the neurotransmitter associated with pleasure and pain, control of movement, and emotional response, may play a role in this helping behavior. This study seeks to provide evidence that dopamine can drive egalitarian behavior in humans by manipulating the levels of dopamine in the brain.

In order to manipulate dopamine levels, the researchers administered tolcapone (a medication which prolongs the effects of dopamine to treat Parkinson’s disease) to the experimental group. Prolonged effects of dopamine are particularly associated with reward and motivation in the prefrontal cortex. On two separate trials, participants took either tolcapone or a placebo and then asked to complete a simple economic task where they had to divide a certain amount of money between themselves and an anonymous participant.

Researchers observed that participants taking the tolcapone exhibited more egalitarian behavior toward the anonymous participant than participants taking the placebo, meaning that they divided the money in a fairer way when the effects of dopamine were prolonged.  Additionally, computer modeling of the behaviors showed that tolcapone also make people more sensitive to inequity (lack of fairness).

The goal of this study was not to develop a philanthropy pill of sorts, but rather to gain a better understanding of how prosocial behavior works in the brain. With the knowledge that dopamine promotes prosocial behavior, we can gain insights into treatment for psychiatric disorders that are commonly associated chemical imbalances in the brain like addiction and schizophrenia. This finding also provides evidence that fair-mindedness is not solely a stable personality trait, but also can be manipulated by targeting specific pathways in the brain .

http://www.iflscience.com/brain/dopamine-makes-us-less-tolerant-inequality