“Love is a many-splendoured thing”…according to the popular culture that we consume. Films, music, books and other media have been singing the praises of love since the dawn of time – but as much as we love to celebrate love, its dictionary definition remains rather abstract. Love can be considered through a sociological lens, as a construct arising from interpersonal relationships and social dynamics. Or, we can reduce it down to its most essentialist parts: in other words, its underlying neurochemical processes.

We can all recognise the physical manifestations of running into our latest crush, or visiting a new partner: elevated heart rate, nervousness, rushed speech or even clumsiness. These physical processes are triggered by numerous unseen chemical processes happening internally, namely, the interaction of specific hormones in the brain. Feelings of lust are mediated by oestrogen and testosterone, while attraction involves dopamine, norepinephrine and serotonin, and longer-term attachment involves oxytocin and vasopressin. Different hormones are at play, because different types of love are thought to serve different evolutionary purposes – whether that’s sexual gratification, “reward”-seeking or the maintenance of long-term partnerships. 

The initial stage of love, in which we “chase” after our latest person of interest, is mediated by dopamine, which could explain why this early stage is particularly exciting for many people. The production of dopamine in the brain lets us know that we are about to be “rewarded” – our needs are soon to be met if we fulfil certain conditions. Oxytocin is released when we take part in various love-related activities, such as holding hands, sex, or caring for children, and its primary purpose is to build social bonds. This tangle of chemical pathways explains why break-ups can cause such emotional turmoil; dopamine is a hormone involved not only in processes of attraction, but also of addiction. The brain activity underlying the process of falling in love is the same as when we eat foods containing sugar, or when we take addictive drugs. All three examples involve dopamine signalling and the brain’s reward pathway – just as an addict experiences negative withdrawal symptoms in the absence of a drug, people may experience the absence of a romantic partner in a similarly traumatic fashion. 

If you were to simplify the social behaviours of humans even further, you could point out that the neuroendocrinology of love boils down to the need to survive and reproduce; love is the body’s way of “tricking” us into finding a mating partner with whom we can continue our genetic lineage. Such a reductionist model is a stark contrast to the subjective experiences of love which we write about in romance novels and sing about in songs. While neurochemical processes in the brain are likely to be highly influential over our feelings and behaviours, it is always important not to downplay the influence of our individual external worlds – our families, friends and colleagues, the education we receive, the media we consume. Perhaps the most comprehensive way to describe love is to use an integrated model – “bio-psycho-social” – wherein our biology and our social environment interact on a daily basis, to encourage certain behaviours. 

Enjoyed this article? Read more from Sci&Tech here:

Animal Testing in Drug Development: An Interview with Dr Pandora Pound

Solar Farms in Space Are Possible, Say The Universities of Surrey and Swansea

Is It Time to Blow The Whistle on UEFA’s Carbon Emissions?