The Science of Love

Love. The dreaded L word for many of us, more so than lecture or library, or last Krispy Kreme. Love. 

It is a double edged sword though, isn’t it? Although the masses fear rejection or commitment or the next stage in a relationship, love is a phenomenon we have known since the moment we were born. Before we knew how to walk or talk, we knew what it was to be loved. From then on, the majority of us have probably dabbled in the skills of love from school crushes, to college kisses, to having a ‘real’ significant other – proved by the change in your Facebook status. It is all around us and there are many different types, but is there any evidence to suggest that science can underpin the whole thing? Do you have any control for who you will fall hopelessly in love with?

Let’s go back to basics, shall we? What is love? I am writing this with a flatmate either side of me and they define it as:

Zac: ‘When you can spend your entire life with someone and be truly happy. When you look at them and think you would do anything for them.’

Imogen: ‘It is a chemical reaction caused by hormones, and all that sort of stuff, to increase your chances of survival.’

Love has been hopelessly and countlessly defined throughout the ages and can be described as a feeling of intense affection – the numerous definitions making it difficult to measure. There are several theories on how we form bonds with people and why we feel what we feel. This article will talk about the  three earliest stages of love: lust, attraction, and attachment, as well as seven hormones that are vital for these processes. 

So you see someone across the hall. They’re captivating, holding their tray loaded up with catered food and only looking slightly sleep deprived. The feeling of being drawn to this person is commonly known as lust. Lust is defined as a desire for physical intimacy and sexual pleasure, which then may lead to reproduction and ultimately offspring. Testosterone and estrogen play a part in this, as well as the hypothalamus (a structure in the brain). 

Testosterone levels in men and women have opposite patterns during the first stages of a relationship or a crush. Women in love have increased testosterone levels for the first months of their relationships, compared to women who are not in relationships or those in long term relationships. Opposingly, men in the first few months of a relationship have lower testosterone levels than single men or men with a long-term partner. Their testosterone levels are thought to increase throughout the duration of the relationship until they go back to their initial levels, pre-relationship.

When women ovulate their estrogen levels are at their highest. It is thought that this is when women are more likely to have sex due to increased libido, but results vary across women, particually if they use a hormonal contraceptive. 

Attraction is closely related to lust but is distinct, as you may be attracted to someone without lusting for them, and vice versa. Dopamine, norepinephrine, and serotonin are all involved in this stage but have separate roles. Dopamine is linked with reward activation, the euphoric sense given from alcohol,  gambling or drugs, is the same as the high people get when they are in love. Isn’t that mad? You can literally get high off another being. The mind boggles. 

Norepinephrine is rather similar to adrenaline so produces the butterflies, nerves, and excitement you can get when in love. It increases your heart rate, causing increased blood flow to your brain and muscles. This rapid change of heart rate can lead to the giddy and dizzy feeling sometimes sung about in love songs. 

Lastly, let’s talk about serotonin. Serotonin levels dip with people experiencing obsessive compulsive disorders, but also with people in love. Love can change the structure of your brain and your hormone levels, leading to a fixation on a person, and physically being unable to get them off your mind. 

After attraction, attachment occurs. A variety of factors play into attachment, including attachment styles (this will be featured in another article) but also two more hormones, oxytocin and vasopressin. 

You may have heard of oxytocin before, it is sweetly referred to as the cuddle hormone and is released by the pituitary gland (in the brain). It is used to strengthen social bonds and is released with physical contact, breast feeding, and after childbirth. It also negates the effect of cortisol, the stress hormone, so if you’re feeling stressed with deadlines and uni work, a hug from a flatmate may do the trick.

Vasopressin is also released by the pituitary gland and helps to form attachment to specific people. It can also be known as the commitment hormone. When studying promiscuous prairie voles, scientists increased the prairie vole’s vasopressin levels to discover that this lead to the males being interested in only one female at a time, even when there was only one male in a group  of multiple females. Both vasopressin and oxytocin are vital in order for animals and humans to make strong and lasting social bonds.

Love is a complex phenomenon and skill, probably never to be fully understood by biologists, psychologists, sociologists, or philosophers. For thousands of years it has captivated us and will probably continue to fascinate us until the climate breaks down or the sun explodes. Although chemistry isn’t everything, and we are not slaves to our biology, we are undoubtedly influenced by it.

*All names have been changed to keep the anonymity of students who have contributed to this article.