As an evolutionary biologist who studies sex and relationships, I’m fascinated by these two truths. We humans make romantic commitments to each other – and some also break those commitments by cheating.
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… Research shows that humans have evolved to seek secure partnership in the form of close pair-bond relationships, but it also shows, just as compellingly, that we’ve evolved a separate appetite for variety. Both drives are alive in us modern human beings, despite being at cross-purposes.
Yet some of us seek novelty more than others. In 2010, my research colleagues and I made a shocking discovery when we found that some people’s genetic makeup does indeed create a predisposition to engage in infidelity.
In the brain, dopamine creates feelings of excitement and anticipation, and past research had shown that people who had the “long” version of specific dopamine genes, rather than the “short” version, tended toward thrill-seeking and risk-taking behaviour. … In our study, we found that people who have the “long” version of the dopamine D4 receptor gene were 50% more likely to report having engaged in infidelity ….
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Of course not everyone with the “infidelity gene” will betray their partners – biology isn’t destiny, genetics being just one of a myriad of factors that influence us – but the study does suggest our ancestors evolved in such a way that some of the population would be more predisposed to sensation-seeking, and specifically sexual novelty, than others.
