Spring 2011

Chemistry of love includes cheating

The problem: The love of your life has cheated on you. Again. The excuse? “I couldn’t help it.”

The researcher: Justin Garcia, SUNY Doctoral Diversity Fellow in the laboratory of evolutionary anthropology and health at Binghamton.

The research: In a first-of-its-kind study, Garcia and his team of investigators have looked at sexual behavior, matching choices with genes, and have come up with a theory on what makes humans “tick” when it comes to sexual activity.

The strategy: Gathering a detailed history of the sexual behavior and intimate relationships of 181 young adults, along with samples of their DNA, Garcia and his team determined that individual differences in sexual behavior could be influenced by individual variation in the dopamine receptor D4 polymorphism, or DRD4 gene. Already linked to sensation-seeking behavior such as gambling, DRD4 is known to influence the brain’s chemistry and, thus, an individual’s behavior.

“What we found was that individuals with a certain variant of the DRD4 gene were more likely to have a history of uncommitted sex, including one-night stands and acts of infidelity,” Garcia says. “The motivation seems to stem from a system of pleasure and reward, which is where the release of dopamine comes in. In cases of uncommitted sex, the risks are high, the rewards substantial and the motivation variable — all elements that ensure a dopamine ‘rush.’”

This doesn’t excuse the transgressor; nor does it mean someone with the gene will commit infidelity and someone without it won’t, he says.

Little is known about how genetics and neurobiology influence one’s sexual propensities and tendencies, but Garcia is hopeful that this study will add to the growing base of knowledge — in particular, how genes might predispose individuals to pursue sensation seeking across all sorts of domains — from substance use to sexuality.

–Gail Glover