Scientists Test if Humans are Biologically Programmed to Cheat on Their Partners

Everyone throws a lot of flack at cheaters. We grow up learning that we need to be faithful to our partners and never let our eyes and our hearts wander.

While staying faithful and keeping away from cheating seems like it’s engrained into our minds, scientists have actually spent years researching whether or not we’re programmed to cheat on our partners.

Scientists have gone back through evolutionary history and discovered that a greater percentage of early civilizations practiced polygamy – having more than one partner – than monogamy – having just one partner. Polygamy actually supports the theory of survival of the fittest.

If people are free to be with whomever they chose and experience more than one partner, then that ensures that the traits better suited for human survival will live to be carried on through generations. While this was important for early civilizations, it’s not as necessary for our modern, developed society.

As it turns out, most humans don’t even practice true monogamy. We typically practice a form of polygamy that we call serial monogamy. A person is faithful to their partner until that relationship ends. When it ends, the person moves on and develops a relationship with another partner.

Scientists have concluded that we’re genetically programmed to seek multiple partners, whether it’s all at one time or one at a time.

While our bodies might be programmed for polygamy, we actually have a chemical within our bodies that is geared more towards monogamy. This chemical is oxytocin, which has often been nicknamed the “love chemical.”

Oxytocin is the chemical that is responsible for the bond between a mother and child immediately after birth before the pair has even had a chance to develop any deeper relationship. So, scientists hypothesized that the chemical might also be helpful in keeping a couple faithful to each other.

Specifically, researchers decided to test if the levels of oxytocin in our bodies determine whether we stay faithful to or cheat on our partners. They tested the theory on voles, a rodent that is known to carry faithful partners and polygamists within its species.

Prairie voles are monogamists; they mate for life. They share home-building and parenting responsibilities and show recognizable signs of grief and depression when their partner dies.

Meadow voles, on the other hand, are the complete opposite in their relationships. They immediately move on to another partner when their current one becomes pregnant, often without any memory of their former partner.

Todd Ahern /

Interestingly, there’s one huge biological difference between prairie voles and meadow voles: the gene that controls the oxytocin and vasopressin receptors in the brain. Prairie voles’ gene keeps these receptors open and ready for oxytocin while meadow voles’ gene shuts the receptors down.

In an experiment at Emory University, one researcher, Larry Young, and his team were able to turn the polygamous meadow voles into family-oriented voles by manipulating that one gene which controls these receptors. This experiment causes researchers to believe that if we increase the production of oxytocin in our bodies, then we’ll be better able to remain faithful to our partners.

On the plus side, increasing oxytocin production isn’t exactly hard. Oxytocin can be increased through light touch or light pressure, massage-like stroking, a calm and supportive environment, and physical warmth. For those who have no problems staying faithful, doing a few of these things regularly can simply help make your relationship more close and connected.