The Biblical parable of the Good Samaritan, a traveler who stops on the road to help a badly wounded robbery victim that others had passed by, is a story that we see repeated again and again in the news.
In Fort Lauderdale, Fla., after a woman lost control of her car on an Interstate freeway and flipped into a water-filled ditch, a man jumped in to rescue her from drowning. In Arizona, after a community college student lost a wallet containing her cash, credit cards, student ID and immigrant work permit, an unidentified person found it and dropped it off at her school's office. In Oklahoma, after a teenage skateboarder tumbled from his board and suffered a concussion, a man he didn't know found him by the side of the road and took him to get help.
What motivates people to stop and help others that they didn't previously know, with no apparent benefit to themselves?
Traditionally, we've viewed people who engage in prosocial behavior -- that is, voluntary acts performed to benefit others or society as a whole -- as being motivated by moral character or spiritual beliefs. But in recent years, increasing evidence has emerged to suggest that the tendency to be a do-gooder may be influenced by genes.
In a newly-published study in the journal Social Neuroscience, for example, researchers found that a single variation in a genotype seems to affect whether or not a person engages in prosocial acts. Individuals who have one variation of the genotype have a tendency toward social anxiety -- that is, unease around other people, and are less inclined to help others in ways that involve personal interaction.
Those who have another variation, in contrast, not only were less anxious, but also were more likely to be helpful. The genetic region involved is 5-HTTLPR, which regulates transport of serotonin, a neurotransmitter chemical in the brain. The researchers studied the genomes of 398 college students, and asked the subjects to fill out a questionnaire to provide information about their behavior and anxiety levels.
University of Missouri social psychologist Gustavo Carlo, one of the study's co-authors, said that the the genotype variation is just one "indirect pathway" that could lead a person to being a Good Samaritan. Another potential influence, he said, is the brain's ability to use dopamine, another brain chemical. Other genetic variations in brain chemistry may play a role as well.
"This is a really exciting area for research," Carlo said. "There are a lot of studies being done right now that focus on the micro-level biological processes associated with altruistic behavior."