The Science of Infidelity: Why Do People Cheat On Their Partners?

There is not one answer to this question as there are many reasons why people cheat on their partners. Some of the reasons include: the person has a higher level of the hormone dopamine which has been linked to cheating, the person has a higher level of the hormone vasopressin which has been linked to being more loyal, or the person earns more money than their partner. Other reasons could be that the person has unresolved emotional issues, or that the person is trying to get revenge from a past relationship.

Love is undoubtedly one of the purest emotions that human being can experience; the world simply wouldn’t be as beautiful if it weren’t for love. There are many forms and manifestations of love that arise in different situations and scenarios, but in this article, we are going to talk about ‘romantic’ love, namely the loving relationships shared by partners and spouses.

Credit: Voyagerix/Shutterstock

Credit: Voyagerix/Shutterstock

Trust forms the foundation of any romantic relationship; if trust is lost, an ever-lasting relationship seems close to impossible. However, this is no secret; everyone knows this about love and trust, yet we see trust being compromised all the time in relationships. Why do some people tend to cheat on their partners and spouses, whom they claim to “love”? Is there a scientific explanation behind this?

Recommended Video for you:

Infidelity (AKA: Cheating)

Approximately 3% of all mammals in the world are monogamous, which is rather low in comparison to other animal groups, such as birds (roughly 90% monogamy rate). Monogamy, for those unfamiliar with the term, means staying with one partner for one’s entire life. Humans fall in this category of mammals, and this is not without its reasons. There is an evolutionary basis to monogamy.

Throughout evolutionary history, two partners staying together for their entire life meant that one partner could go out looking for food and resources, while the other could provide nourishment to their young. Despite the obvious benefits of such a loyal lifestyle, extra-pair mating, more commonly known as cheating, is fairly common.

The Role of Dopamine Receptors in Infidelity

credits: Zerbor/Shutterstock

credits: Zerbor/Shutterstock

If you would take a comprehensive scientific look at human happiness and feelings of pleasure, you would quickly come across the word ‘dopamine’, which is a powerful hormone in the body. The genetic coding of dopamine receptors plays an important role in a person’s loyalties. Dopamine, also referred to as the ‘happy hormone’, is a neurotransmitter that is released after (or during) certain pleasurable activities, including exercising, eating food, having sex etc.

It has been found that people who possess a long-alleled variant of dopamine receptor are 50% more likely to cheat on their partners than individuals with the short-alleled variant, who happen to cheat about 20% of the time. People with long-allele variant are also more likely to indulge in thrill-seeking and addictive behaviors.

Levels of Vasopressin

baby cuddle

A hormone called vasopressin also plays an important role. This hormone is pretty similar to oxytocin (sometimes referred to as the ‘cuddle hormone’), which influences feelings of trust, affection and empathy. Thus, a person with higher vasopressin levels is more likely to be more loyal.

Money Matters!

Credit: wavebreakmedia/Shutterstock

Credit: wavebreakmedia/Shutterstock

Many would not find money to be much of a scientific reason behind infidelity, but it is a very common reason behind people cheating on their partners. It has been observed that men who earn far more money than their wives are more likely to cheat. Although this is not true in every case, the chances of infidelity drop significantly when the earnings of both partners is similar.

These are not the only reasons that lead people to cheat; in practice, it would be impossible to list down all the feasible reasons of why a person cheats on their partner. Still, the reasons that surface rather commonly in cases of infidelity include issues from past relationships, excessive alcohol use (or other forms of intoxication), and unresolved emotional issues are also very common reasons behind infidelity.

cheating meme

This shows that biology does play an important role in your loyalty levels, but it doesn’t mean that you have no control over your own actions. The famous quote of Bruce Wayne from Batman sums this idea up quite nicely: ‘It’s not who you are underneath, but what you do that defines you.’

Suggested Reading

Was this article helpful?
Help us make this article better

Follow ScienceABC on Social Media:

About the Author

Ashish is a Science graduate (Bachelor of Science) from Punjabi University (India). He spearheads the content and editorial wing of ScienceABC and manages its official Youtube channel. He’s a Harry Potter fan and tries, in vain, to use spells and charms (Accio! [insert object name]) in real life to get things done. He totally gets why JRR Tolkien would create, from scratch, a language spoken by elves, and tries to bring the same passion in everything he does. A big admirer of Richard Feynman and Nikola Tesla, he obsesses over how thoroughly science dictates every aspect of life… in this universe, at least.

Science ABC YouTube Videos

  1. Slowing or Reversing Aging: Can We Live for 180 years?Slowing or Reversing Aging: Can We Live for 180 years?
  2. Detectives Use this Simple Technique to Find Your Fingerprints (Even AFTER You Have Wiped Them Off)!Detectives Use this Simple Technique to Find Your Fingerprints (Even AFTER You Have Wiped Them Off)!
  3. Why is a Circle 360 Degrees, Why Not a Simpler Number, like 100?Why is a Circle 360 Degrees, Why Not a Simpler Number, like 100?
  4. Quantum Physics: Here’s Why Movies Always Get It WrongQuantum Physics: Here’s Why Movies Always Get It Wrong
  5. Do Fish Get Thirsty and Do They Need to Drink Water?Do Fish Get Thirsty and Do They Need to Drink Water?
  6. Gasoline (Petrol) vs Diesel: Which one is better? A Beginner’s GuideGasoline (Petrol) vs Diesel: Which one is better? A Beginner’s Guide
  7. Black Holes Explained: What Is a Black Hole? How They Form?Black Holes Explained: What Is a Black Hole? How They Form?
  8. Gut Microbiome Explained in Simple WordsGut Microbiome Explained in Simple Words