Okay, here’s the challenge: define love. Seems easy enough, right? The truth is, is harder than you think! You can describe it, use synonyms and metaphors, cite poetry, and share how it transformed you, but you cannot accurately and completely define it. The intoxicating, romantic love we feel for our partner is just as overpowering as the love we feel for our children, but it is altogether different. Yet, it is a primal and ever-present aspect of our being and our species.

    The science of love: an overview of what happens in our brain when we are in love

Maybe it is easier to analyze love from a scientific point of view. How does love happen, biologically speaking? What are the mechanisms in the brain that allow us to fall in love? Let’s take a less romantic, but more scientific look at what happens in our bodies when we are in love.

Our brains run on chemicals

Giving full reverence to the wonder and splendor of the human body, certain aspects can best be explained by seeing the body as a complex, integrated system of organic chemicals. These (bio)chemicals drive every process of the human body, from digestion to romantic love. Thus, if one understands the physical structures/organs implicated, and the biochemicals that mediate the biological processes, one can hope to understand how the body works physically, but also psychologically. We must accept that, whether we like it or not, biochemical reactions are the processes that drive our feelings, thoughts, and emotions.

All our emotions are produced by the brain, including love. They are generated by electrical signals transmitted throughout the brain with the help of some chemicals called neurotransmitters. Don’t worry, is not that complicated, let me explain!

Neurotransmitters mediate the communication between neurons and between different brain regions
Emotions, including love are generated by electrical signals transmitted throughout the brain with the help of some chemicals called neurotransmitters

Neurotransmitters are molecules that mediate the transfer of information from one neuron to another. These chemicals initiate messages that are transported along special fibers (axons) from one brain region to another, the same way the electric company sends electricity through various wires to different homes. The exact same electricity is sent to the refrigerator, the television and the oven, but the final results are vastly different, as each element that receives the electricity produces a very different result. The same is true for the brain. Different brain structures produce their own unique responses when they receive electrical or chemical the signals. However, this is where the analogy between the brain and the house break down. The same brain structure will produce different results when different neurochemicals stimulate them. Some chemicals are excitatory, others are inhibitory. Some elicit the good feeling associated with a tasty meal, others elicit negative emotions.

So, what is the science behind love? What are the changes that occur in our body, especially in the brain when we fall in love? According to research, it takes only a few minutes for a person to determine if they are in love or not. Many biological processes happen in the body in this brief time.

Lust, passion and desire – the beginning of love

When love hits, first we feel a strong attraction towards the other person. This is triggered by the activation of the limbic nervous system (the primitive brain) and the release of sex hormones (estrogen and testosterone). These events produce the feelings of lust and desire.

At the beginning of love our behavior is more “primitive”. Lust, passion and desire control the way people behave, during the first stage of love
First stage of love: lust and desire

Inside the brain, the primitive brain controls automatic body functions, such as breathing and cardiac functions, but also desire, lust and primitive, instinctive reactions. The limbic system is responsible for the sexual attraction and for interpersonal bonding. Interestingly, it is an integral part of the reward system, which causes feelings of euphoria, pleasure and sexual gratification. This is why we end up seeking the presence of the person we love; it triggers the pleasure centers in our brain, similar to what happens in the brain of a person on drugs. This initial stage of love is mostly unconscious, and thus in most cases, it escapes our control.

Falling in love is a stressful event. Scientists have discovered that in the early days of love, the levels of cortisol, a stress hormone, are increased. This is in part due to the struggles associated with the initiation of a relationship. You are trying hard to please the new partner, but it seems difficult since you don’t know the person very well, yet. You are tormented by thoughts and questions: did she like the food I cooked? Did he like my new dress?

The attraction phase, when the real love happens

In the second phase of love, the attraction develops. This is when a person actually starts to feel the real feeling of love. Is the stage in which the euphoria and the excitement settle in and this is why we remember falling in love as some of the most beautiful moments of our lives. At least three biological substances have been shown to play an important role in our brains, in this stage of love.

In the second phase of love the real attraction develops
The second stage of love: the attraction.Now a persons actually starts to feel the real feeling of love

Dopamine is an important neurotransmitter in the biochemistry of love and a strong modulator of sex drive. Not surprisingly, testosterone and estrogen also activate the dopamine pathways in the brain. Dopamine is a critical neurotransmitter within the limbic system, which regulates many of our most primal emotions such as fear, aggression, sexual arousal, pleasure, and reward while interpreting sensory input and helping to form memories (along with many other functions). It is this system that is activated by the use of mind-altering drugs such as heroin, cocaine, methamphetamine, alcohol, benzodiazepines, and marijuana. These drugs produce the same, primal euphoria that humans derive from sex.

Adrenaline is a hormone produced by the adrenal glands and some neurons. The secretion of adrenaline when you see the loved person makes your heart beat like a drum, your palms sweaty and changes your senses. These are the same biological changes that occur in your body when you are in a state of alert (for example when exposed to a potential danger). Basically, as in the case of an alert, it puts the body in an excited state, ready for action whenever necessary. Adrenaline gives an extra boost of energy to any person in love. Moreover, it is responsible for the loss of appetite and sleepless nights. Sounds familiar?

Clcik the image to download The Science Of Love Infographic
The science of love infographic

Serotonin is another neurotransmitter common in some brain areas, sometimes nicknamed “the happy chemical” because it is important in cerebral processes that contribute to happiness and wellbeing. It regulates (amongst other things) social behavior, memory, and sexual desire. Importantly, most of the serotonin in our body is not found in the brain, but in the intestinal tract; maybe this is why we feel the butterflies in our stomach when we are in love. Serotonin levels are believed to decrease during the attraction phase of love. This decrease is in part responsible for the loss of concentration, the hopes and dreams any person in love experiences, and some obsessive-compulsive behaviors.

Love forever – the attachment phase of love      

After the first two stages of love have passed, the attachment stage begins. That is if the relationship has survived this far. By now, the bonding between the two partners should be very strong. The lovers feel attached to each other and this “safe” feeling triggers the desire to live together, to get married, and to have children.

In the attachment phase, the lovers develop long-term future plans
Love forever – the attachment phase of love

At this stage, oxytocin, also known as the “love hormone” bears special mention. It is a hormone and neuromodulator, released both by man and women, with paramount importance in social interactions and attachment. This hormone is secreted by the posterior pituitary gland and neurons from the hypothalamus. It plays an important role in contractions during labor, the release of milk during breastfeeding and in social interactions. The brain concentrations of oxytocin rise during sexual intercourse in both men and women. It is considered an important chemical for sexual attraction. Later, as the relationship matures, this same molecule appears responsible for creating feelings of trust and social bonding.

Oxytocin is important for love, social interactions and attachment
Oxytocin is the love hormone

In this stage of love, serotonin levels increase back to the normal levels. At the same time, the stress hormones are decreased. First, love was a stress; now, it becomes a protecting force against the stress. In the brain, the areas associated with reward and pleasure remain active when we are around the loved person. However, the acute sexual desire and the craving for the partner are now reduced.

The bottom-line

When we first fall in love, we become stressed. The primitive brain stimulates the production of sex hormones and we become driven by our desires. Our brains release oxytocin and dopamine (and more than 100 other signaling molecules, but let’s keep it simple). Their effects are practically immediate. Dopamine activates the limbic system, causing attraction and sexually intense emotions. The secretion of adrenaline also kicks in, resulting in heightened awareness. Furthermore, oxytocin also contributes to sexual attraction and the initial feelings of love, reinforcing the dopamine pathways. Later, oxytocin helps us develop long-term attachments. Finally, the ratios and concentrations of these neurochemicals change, leading to empathy, monogamy, and long-term social bonding.

Regardless how well we will understand the neurochemistry of attraction, we are no closer to truly understanding what love is. In the end, all I can say is this: love must be felt to be understood. It doesn’t need to be defined, it simply needs to be.

Do you have something to say about the science behind love? We would love to hear it, feel free to comment on our Facebook, Twitter and Google+ pages!