Sense of Fair Play tied to Serotonin Levels

Are you a person that gets really combative and aggressive, or grouchy when you don’t eat? Are you one of those people who are uncomfortable in social situations, or who are unusually sensitive to being treated unfairly? It turns out your serotonin levels may contribute to more than just depression or compulsive disorders. In a new Science study, UCLA and Cambridge researchers report that people with low serotonin levels were found to be more sensitive to being treated unfairly.

A new study, published in the June 6 issue of Science suggests that the neurotransmitter serotonin, which has long been known to act as “…a chemical messenger between nerve cells…” and has been recognized to play “… a critical role in regulating emotions such as aggression during social decision-making…” is also responsible for turning on the brains “reward circuitry.”

The study suggests that the “human brain responds to being treated fairly the same way it responds to winning money and eating chocolate; being treated fairly turns on the brain's reward circuitry.”

The study involved 20 subjects who were each presented with several offers, some skewed and some fair, for dividing sums of money. If they declined the offer neither they, nor the person making the offer would receive anything. After this round of initial offers and responses were recorded, participants were given a drink that “significantly reduced” their serotonin levels before a second round of offers began.

The study discovered that participants rejected 82 percent of the unfair offers when their serotonin levels were reduced as compared to only rejecting 67 percent of the unfair offers when their serotonin levels were normal. The report concluded that people with low serotonin levels were more likely to reject unfair offers.

Serotonin levels can fluctuate in regard to how regularly we eat, since “the essential amino acid necessary for the body to create serotonin can only be obtained through diet…” which suggests that a person’s perception of fairness can also fluctuate. What I view, for instance, as fair on the day I have three full meals, may differ from the day I skip breakfast.

It seems the study proves that the human sense of fairness is not based on rational processes, and unlike the solid mathematical formulas we learn, fairness is a fluid and fluctuating process that flows with the levels of our brain chemistry.

Sources:
UCLA Eureka Alert: http://www.eurekalert.org/pub_releases/2008-06/uoc--sma060608.php
Science: http://www.sciencemag.org/cgi/content/abstract/1155577
About.com: http://depression.about.com/b/2008/06/10/serotonin-levels-related-to-sense-of-fairness.htm