A minor tweak of the gene that maps out a receptor for the feel-good neurotransmitter, dopamine, may be all it takes to explain the promiscuous beats of the cheating heart. Researchers have found that people born with this genetic variation are far more likely to cheat or engage in risky sexual behaviors, such as one-night stands, according to a study published this week in PloS ONE.
Earlier studies linked the genetic mutation in question to a tendency to engage in risky behaviors as well as the propensity to become addicted to illicit drugs and alcohol, so the researchers suspected it might also affect a person’s sexual behavior.
At the root of all this research is dopamine. Scientists have long known that when dopamine spurts in the brain, we feel pleasure. It’s what makes us feel good when we eat, have sex or even take illicit drugs. Evolutionarily speaking, this system developed so we would find our way back to tasty morsels – and sexual partners.
So it made sense that dopamine might also be involved in the propensity to promiscuity, says the study’s lead author, Justin Garcia, a SUNY Doctoral Diversity Fellow in the laboratory of evolutionary anthropology and health at Binghamton University, State University of New York.
“The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in,” Garcia explains. “In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable – all elements that ensure a dopamine ‘rush.’”
To test the theory, Garcia rounded up 181 college students and asked them to fill out questionnaires that would reveal sexual habits, along with other proclivities, such as cigarette smoking and the tendency to take risks. Garcia and his colleagues also tested the study volunteers’ DNA to determine which form of dopamine receptor the students had inherited.
The study findings were striking. Students with the genetic variation were twice as likely as others report promiscuous behaviors, including one-night stands. And a full 50 percent reported that they had been unfaithful to a partner, compared to 22 percent of those without the variation.
It would seem that science has provided the cheaters among us with the ultimate excuse. But, as is often the case, DNA isn’t destiny, experts say. Many of the volunteers had the promiscuity gene, but weren’t yielding to their cheating hearts – or genes, says William Pollack, an associate clinical professor in the department of psychiatry at the Harvard University Medical School. An important question to answer in future research is why some were able overcome their genetic proclivity to promiscuity, says Pollack.
One other interesting question left unanswered by the researchers is whether there was a difference between men and women when it comes to resisting the pull of genetics. “The study shows that the gene mutation was equally common in men and women, but other research has found that men tend to be more promiscuous,” Pollack says.
While scientists thrash out that weighty question, it might be nice if you could determine whether that person sitting across from you on a first date was born with the cheating gene. One likes to be able to weigh the benefits and the risks. Along with all the screening questions asked before a date, maybe there should be a DNA test.