Over 90% of Americans agree that cheating is morally wrong. Yet, despite this, around 21% of American men, and 10-15% of American women cheat. But what leads them to do this? Could it just be about being with the wrong person or could it be something more intrinsic?
Often, cheating on one’s partner is regarded as a symptom of an unsatisfactory relationship- marital discord, sexual satisfaction and emotional alienation. It is also typically thought to be more likely if the cheating partner has a history of unstable relationships or has a parent who exhibited the same behavior (Guerra: 2018).
Yet, it seems that there may be a genetic factor to consider as well. In a study of almost 7,400 Finnish twins and their siblings, researchers at the University of Queensland, Australia, studied the link between promiscuity and certain variants of vasopressin and oxytocin receptor genes. Vasopressin is a hormone known to influence factors such as trust, empathy and sexual bonding in humans and other animals, whereas oxytocin is known to influence social bonding, sexual reproduction and bonding after childbirth. Thus, it made sense that certain mutations of both receptor genes may influence human sexual behavior (Friedman: 2015).
To begin, the researchers found that gene receptors for oxytocin had no effect on the infidelity of both men and women. However, when looking at vasopressin, although no correlation was found for men, they found an association between five variants of the vasopressin receptor gene and cheating in women. In fact, up to 40% of the variation in promiscuity among women could be attributed to this genetic factor (Zietsch: 2014).
Although further research needs to be conducted to reveal the true implications of these genes in humans, it is worth considering in light of other research conducted on animals. A study by Dr. Thomas R Insel found that tweaking vasopressin receptors in monogamous male prairie voles’ brains and those in polygamous male montane voles made them exhibit behavior outside of the norm ie. when vasopressin receptors in prairie voles were blocked, monogamy was inhibited, although sexual activity was still present. Likewise, when viruses were used to transmit the vasopressin gene to montane voles, they began to exhibit monogamous behavior (Insel: 2010).
Yet, vasopressin receptor gene receptors are not the only genes known to influence our fidelity. A study from 2010 found that the desire to cheat may also be influenced by the dopamine receptor DRD4 polymorphism, or the ‘thrill-seeking’ gene that has also been linked to higher rates of alcoholism and gambling addiction. Analysing the genes and behaviors of 181 young adults, the study found that although everyone has DRD4, the more one has, the more prone they are to thrill-seeking behaviors such as cheating as they require more dopamine to satisfy their receptors (Guerra: 2018).
To conclude, cheating may not just be a socially-driven phenomenon. Although further research is needed, correlations between how our genes respond to certain hormones appears to influence our behavior. Yet, despite their significant influence, there are still among many other factors contributing to the likelihood of cheating- from other genes to other social and environmental circumstances.
Sources
Zietsch, Brendan P.: Evolution and Human Behavior