The Science of Love

The Science of Love

by Flarespirit and Dreamwalker

“Whatever our souls are made of, his and mine are the same”-Emily Bronte


Throughout the ages, poets and writers have been quite obsessed with the feeling of love and passion. “LOVE” is an emotion cross linking two souls. It is a feeling that is beyond the expression of the mind; beyond the mute utterance of dancing letters across the pages of books.

It is just a small four-letter word, and yet it is more impactful and devastating than any catastrophe. Numerous poets have endeavoured to explore and explain this mystical feeling through their writings and almost all of them have tried to establish a sublime connection with this feeling. The care and affection between partners have been closely knitted with the essence of God and we too have accepted it in the same manner. But in today’s scientific world, where no question can persist unanswered and if unsolved, cannot be ignored; ‘love’ also has a science of its own. It is not merely an indescribable emotion or a heavenly feeling, but a ruthlessly irrepressible concoction of chemicals inside our body!

So what is love? The most common answer given is that it is a profound feeling and that it happens inexplicably. But in reality, it is not a mere co-incidence. It is the cumulative effect of a cocktail of intricately interacting chemicals. In common language, it is a well balanced “chemical locha”.

People are usually in a blissful state, up on ‘cloud nine’, when they fall in love. Flushed cheeks, a racing heart beat and irresistibility are some of the outward signs of being in love. And inside the body there are definite chemical signs that Cupid has fired his arrow.

In reality, these chemicals drive us to form families and have children. Once we have children, those chemicals change to encourage us to stay together to raise those children. So in a sense, love is a chemical addiction that encourages us to reproduce and care for our offspring.

Stages of Love

The ethereal, indescribable feeling of love is not a video game or an organisation but it still has its own stages to clear. Each stage has its own significance and a different set of chemicals expressed within the body, which create their own individual impacts. According to Helen Fisher, one of the premier researchers in this field, we fall in love in three stages: Lust, attraction and attachment.


A pounding heartbeat, flushed skin, sweaty palms, intense energy, sleeplessness, loss of appetite, focused attention and sexual desire for our partner: these are the preliminary activities experienced at the personal level soon after we experience the headlong rush of falling in love. In reality what is felt is not love but lust: merely a primary ingredient in the recipe of love. It manifests itself as a profound desire to be with the other person, and is marked by unbearable longing in his or her absence. We feel an urge to be in more physical contact with our partner.

Biologically, lust is driven by the two sex hormones- testosterone and oestrogen. When we are teenagers, just after puberty, oestrogen( in women) and testosterone( both in men and women) become active in our bodies for the first time and create the desire to experience “love”. These hormones as Helen says, “get you out looking for anything”.


This is the next intoxicating phase in love, when we are completely enamoured. We are lost in flights of fancy in the other person’s presence. The world itself seems to have converged on the other person. In this stage, couples spend many hours getting to know each other. People often lose the ability to think rationally when it comes to their partner. This overwhelming preoccupation and drive is a part of our biology.

The Interplay of Neurotransmitters in the Brain

The Interplay of Neurotransmitters in the Brain

The attraction phase of love is governed by a group of neurotransmitters called ‘monoamines’. This group of neurotransmitters comprises of dopamine, norepinephrine and serotonin.

Dopamine- This is thought to be the “pleasure chemical” as it produces a feeling of esctasy. It can be activated by nicotine and cocaine. It is responsible for pupil dilation at the sight of our beloved.

Norepinephrine- This is similar to adrenaline and causes a racing heartbeat and excitement. It stirs us into action at the sight of our partner or when we are in their company. This neurotransmitter spurs on our motivational decision-making, possibly instigating us to chat up Mr. or Ms. Right. An interesting fact is that norepinephrine is responsible for goading our sweat glands into activation, and since our palms have up to 3,000 miniscule sweat glands per square inch, they can quickly become a telltale signal of sexual interest.

Serotonin- Serotonin is responsible for people affected with ‘obsessive-compulsive disorders’. It is also present in lower levels in people who have fallen in love. Researchers say that these low levels probably explain why people in love are “obsessed” about their partners


Attachment is a longer lasting, less ephemeral commitment and is the bond that keeps couples together when they proceed to have children. This is the phase that marks the longevity of a relationship. Basically two hormones are activated during this stage:

Oxytocin- It is common knowledge that the hormone oxytocin is secreted soon after child birth and bolsters the strong bond between the mother and child. But it is a little known fact that this hormone deepens the feelings of attachment and makes couples feel much closer to one another after copulation. It has even been said that, “the more sex a couple has, the deeper their bond becomes”.

Vasopressin- This is another important hormone in cementing long-term commitment and is released soon after copulation. The actual effect of this hormone was discovered after scientists studied the monogamous prairie vole.

Prairie Vole Research and Commitment: A Veritable Cocktail of Hormones

prairie vole

In prairie vole society, copulation is the prelude to the life-long pair bonding of a male and female. Prairie voles indulge in far more sex than is strictly necessary for the purposes of reproduction.

It was hypothesized that two hormones, vasopressin and oxytocin, are released after mating, and can forge this strong bond. To confirm this theory, male prairie voles were given a drug to suppress the effect of vasopressin. The bond with their partners deteriorated immediately as they lost their devotion and tenacity, and failed to protect their partners from new suitors.

Love at First Sight: A Myth?

“Love looks not with the eyes, but with the mind, and therefore is winged Cupid painted blind.”- William Shakespeare

At a masked gathering, Romeo caught a tantalizing glimpse of Juliet, and there was instant attraction. One glance was all it took: it was love at first sight. With minimal interaction the couple knew intuitively that they were meant to be together forever- or rather, in their case, to die together.

Like the famous ill-fated couple, many couples all over the world fall prey to Cupid’s arrow in a single encounter. Is it fate, chemistry or just another myth? Is love at first sight possible? There have been many anecdotes of couples who claim to have kindled the flame of love and passion at first sight. But is it actually true? Or is it just another false belief?

In reality, it is a convoluted mind-game. Researchers have shown that our brain plays a big role in love at first sight. Instant judgments are made when it comes to sizing up potential mates. The ‘medial prefrontal cortex’, the area near the front of the brain, is responsible for the physical attraction perceived at the sight of a new face. Also, this region of the brain can make potential complex decisions in milliseconds, according to a study in Ireland. It was further discovered that the ‘paracingulate cortex’, located in specific region of medial prefrontal cortex, shows increased activity at the sight of an attractive potential mate.

According to Helen Fisher, ‘three minutes are all you need to know whether someone will be in your life or not.’
Thus, love at first sight is possible, but its durability and longevity lies in the hands of the couple. The chemicals in collaboration with the brain play their part by triggering the emotion of love but the final result may not necessarily be a happy ending.

Love: The Miraculous ‘Motivational Pill’

In ‘A Theory of Human Motivation’, published in 1943, psychologist Abraham Maslow wrote that our need for love and belonging: the primal need to love and be loved in return surpasses physical needs like safety. He asserted that love is something that humans are motivated to achieve.

In 2005, a groundbreaking study using functional magnetic resonance imaging (fMRI), conducted jointly by researchers at three universities, found visual evidences that supported Maslow’s view of love as motivation.
The human motivation system is linked to the reward system in the brain. Once we achieve a goal, the brain releases dopamine into a region of the reward system called the nucleus acumens. We experience this as a profound sense of pleasure and excitement- the sensations we associate with the experience of romantic love.

The imaging also showed that while the emotional centers of the brain were active, no distinct pattern of emotions was followed. This discoverey counters the longstanding view that love is based in emotion; instead, it seems that love springs from our goal-seeking behavior and that the emotions we ascribe to it are secondary to our feelings of motivation.

Infidelity and Cuckoldry

“Love is a game in which one always cheats.” –Honore de Balzac


Romeo and Juliet-esque romance and soul mates notwithstanding, love has a darker side. Infidelity is much commoner than proponents of true love would like to believe. In fact, infidelity is so deeply ingrained in the human psyche that some researchers even go so far as to say that adultery makes evolutionary sense. In the words of Matt Ridley, author of ‘The Red Queen’, the human mating system can be described as “monogamy plagued by adultery”.

One of the first evidences of the prevalence of adultery came from a singularly unlikely source. Little did we know that understanding bird song would be key to unearthing the extent of infidelity.
Animal behaviourists noticed that thrushes, robins and warblers continue singing long after they have paired up in the spring. This contradicts the conventional notion that the principal function of bird song is the attraction of a mate.

In the late 1980s, biologists began DNA-testing birds, to determine which male had fathered which chicks in each nest. They discovered, to their surprise, that females mate often with neighbouring males. This is unexpected, considering that just one male and one female faithfully help each other rear the brood, in every outward show of monogamy. It also explains why male birds sing so hard even after mating. They are looking for ‘affairs’.

Why Cheating Pays

Cuckoldry in birds is also unsettlingly relevant to human relationships. Since men have less parental investment in their offspring than women, men have more time and resources to devote to mating. This makes infidelity a beneficial reproductive strategy for men, allowing them to pass on their genes to more progeny.

However, according to evolutionary biologists, infidelity may be adaptive for women as well. Women may use affairs as a way of finding a more desirable, and more established partner.

Additionally, during the most fertile phase in the menstrual cycle, women are attracted to more masculine men, or men with outward manifestations of good genes. During the rest of the cycle, women are attracted to men with more feminine features, or to men who seem to be better caregivers.

The interpretation of this study is that women seek long-term partners who may not have the best genes, but who seem to be more likely to invest more in their offspring. But during the fertile phase, they seek the best genes, for more genetic quality in their progeny. This seems to imply that infidelity pays for both men and women, in evolutionary terms.

Of course, this does not mean that one should embark on a philandering spree in the name of evolutionary biology. The research merely expounds how such impulses are natural, which can be controlled by conscious choice. In the end, infidelity of any kind is always a decision governed by free will, not by the supposed vagaries of evolution.

Monogamy or Monotony?

Despite incentives for polygamy, monogamy, or at least social monogamy, is prevalent in many societies of the world.

Monogamy may have evolved in early humans, before Homo sapiens sapiens, due to the requirement of bi-parental care. With the evolution of increased hunting abilities, dependency on males for food increased. The long developmental period of young necessitated increased support from males. The lack of resources controlled by males made polygyny unfeasible. Hence, monogamy was the attempt of the males to ensure the paternity of the offspring they supported, to prevent wasting their resources on another male’s progeny.

However, as resources controlled by males increased with evolution, polygyny and other forms of polygamy would have become viable. This implies that a cultural process is responsible for the social mores of monogamy seen today. According to B. S. Low, a researcher at the University of Michigan, culture appears to have a much larger impact on monogamy in humans than the biological forces that are important for non-human animals.
It has been observed that monogamy is strictly prescribed by societies in which resources are transferred across generations. This is seen in Eurasia, where intensive agriculture is prevalent. The partitioning of already scarce land among the progeny of multiple wives would deplete the value of the estates. Thus, in general, the evidence suggests that monogamous marriage may have evolved as a form of ‘monogamous transfer’ of a man’s resources, infidelity notwithstanding.

So it seems that, somewhat ironically, the most prosaic, mundane reasons underlie our romantically beloved notions of monogamy. In fact, according to Laura Betzig, an anthropologist and historian, the Christian Church even institutionalised the concept of monogamous marriage for purely selfish motivations. As is often true of life, romanticism appears to have little impact in our ruthlessly rational world.

The War of the Sexes

Until even the twenty first century, it was tacitly assumed that evolution was primarily driven by the good of the species as a whole. Genes were considered to be servants of the body. They were thought to be passive recipes, quietly awaiting transcription into proteins when the body required.

The reality is far more disturbing. Evolution is not about what is good for the species, or even about what is good for the individual. Evolution is furthered by the aims of the genes. We are merely temporary chariots driven by our genes, haplessly drifting in the eddying stream of evolution. In the words of Matt Ridley, author of Genome, “the body is the victim, plaything, battleground and vehicle for the ambitions of the genes.”

A prime example of the so-called ‘selfishness’ of genes is sexual antagonism. Sexual conflict arises between males and females over an altercation of interests.

It is in the best interest of the males to mate as frequently as possible. Hence males evolve elaborate courtship behaviours and traits, like the peacock’s long tail, in order to entice females to mate more often. However, females must regulate their frequency of mating. Thus females evolve ‘resistance’ in response to male coercion. What results is a constant tussle: males evolve more and more exaggerated traits to seduce females, and females evolve greater and greater resistance to being seduced. This arms-race between the sexes may have led to the evolution of the peacock’s overly long tail, which performs no other function apart from attracting females. The interesting thing is that these decorative exaggerated traits confer no especial benefit to the species, and are, in fact, a hindrance to males. This type of evolution, in which benefits for males are deleterious for females and vice versa, is called chase-away selection.

Coming closer to home, the evolution of human intelligence is also theorised to be due to sexual selection. Modern humans have a brain which is inordinately large, about three times the size of chimpanzee brains. The power-hungry human brain is a luxury, consuming 18% of our total energy expenditure. According to Geoffrey Miller, an evolutionary psychologist, the level of intelligence evolved was unnecessarily sophisticated for the needs of early humans. What then prompted the evolution of our gargantuan energetically expensive brains?

Among the many possible solutions, the most widely accepted answer to this conundrum is sexual selection. Females were attracted to more intelligent males, thus driving males to become more and more intelligent. In order to perceive levels of intelligence, females also had to co-evolve to become more intelligent. This simultaneous co-evolution, also more generally called runaway selection, may have resulted in the increased intelligence of humans that is our species’ defining characteristic.

Thus, it appears that the effects of sexual selection, which may even be glibly considered to be the deeper influences of love, have shaped our evolution.


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