Our resident scientist ANNE MARIE REID unveils the biochemical workings of the body when we spot a hottie across the dancefloor or give our grandpa a peck on the cheek.
The English playwright W. Somerset Maugham once claimed that love is only a dirty trick played on us to achieve continuation of the species. No doubt that many of us would object to such a cold, unfeeling description of one of nature’s most profound wonders; why do we Love? The answers to Love’s questions were primarily the realm of poets, musicians and artists, but now scientists are beginning to unravel some of the mysteries behind this elusive emotion and discovering that Love may be ruled more by the head than the heart.
Love comes in many shapes and forms; from the passionate, all-consuming desires of romantic love to the protective, selfless love of a mother to her child, even the bonds of friendship yield strong emotions of loyalty and affection that could be interpreted as Love. Due to advances in the field of neurobio-logy, researchers have been able to analyse brain patterns in the states of romantic and maternal (or parental to be fair to fathers) love, and rather surprisingly they are activated in a similar manner. This is significant as both romantic and parental love have evolutionary importance; romance for the creation of new generations and parental love to develop, support and guide offspring until they are independent and can continue the species themselves.
Unsurprisingly, love activates the brain’s reward regions in the cortex and subcortex; activation of these reward centres leads to the recognisable feelings of pleasure, euphoria, desire, happiness and even addiction, jealousy and hopelessness. The major culprits, or Cupids we could say, that are involved in the signalling within these centres are the brain messengers dopamine, serotonin, oxytocin and vasopressin. Dopamine is one of the most prevalent ‘pleasure molecules’ in the brain; the dopaminergic system is the site of action for many recreational drugs such as cocaine and heroin, even nicotine, and is associated with “feeling good” and elated. Unfortunately, as with drugs, stimulation of this pathway can lead to the dark feelings of addiction and misjudgement, which can overcome all rationality and reason. And due to there being receptors for dopamine along the gastrointestinal tract leading to increased stimulation of the gut, dopamine can in part explain one of Love’s phenomena – “butterflies in the stomach”. Elevation of dopamine during sensations of love, pleasure and desire are coupled with a depletion in another brain messenger – serotonin. Serotonin is responsible for mood and hunger; and a decrease in serotonin levels of “loved up” individuals is similar to that of obsessive-compulsive disorders. The calm-inducing effects of serotonin are dampened by a brain literally awash with dopamine, leading to the obsessive, single-mindedness often experienced by those in both romantic and parental love. Oxytocin, often referred to as the ‘Cuddle Chemical’ and vasopressin are two very similar and inter-linked peptides; they are highly involved in pair bonding, partner selection and social attachment. They contribute to the feelings of trust, loyalty and devotion associated with Love. Indeed, both are released substantially during romantic and parental love interactions such as sexual intercourse and breast-feeding. The ultimate test remains whether increasing or decreasing levels of these ‘cuddle chemicals’ may explain the range in monogamy or promiscuity between humans; discovering if we truly are by nature a promiscuous species and only bound by the social constraints of monogamy.
The cupid molecules described above are only the most recognised and characterised ‘players’ in this rather complex game of Love. But what of Attraction; the initial spark that lights the fuse, the very thing that makes one person catch another’s eyes? Our typically feminine and masculine characteristics of appearance are determined by sex steroids circulating at puberty; such as testosterone in men leading to strong jaws, chins and heavy-set eyebrows, and oestrogen in women creating classically high cheekbones, small noses and chins. However, not all males and females display these obvious gender stereotypes and surely everyone has their own opinion of what makes a person beautiful? Unfortunately, the old adage of “beauty being in the eye of the beholder” does not ring true; and in actual fact, there does appear to be an average ‘Desirable Man’ at least for students at the University of St Andrews. This man is not your typical testosterone-fuelled macho man, but rather an intriguingly smooth-skinned, caring type. The female personification of beauty is much more innate, and even cross-cultural; with oriental ideals being very similar to western preferences. Regularity, symmetry and having large eyes and lips, and a small nose and chin have universal appeal. Accentuation of any of these feminine features may also explain why some women are more strikingly beautiful than others, but the general underlying rules of female beauty appear to be consistent. Olfaction, or the sense of smell is arguably one of the most underrated of our senses; this is never truer than in the case of Love and Attraction. Surely sniffing or smelling makes us no less crude than dogs and cats for selecting a potential mate? Actually though, our pets might be telling us something. Pheromones are chemicals produced by the body that are emitted to the environment. There are currently four known functions of these pheromones throughout the animal kingdom; opposite-sex attraction, same-sex repellence, mother-child bonding and regulation of the female menstrual cycle.Understanding the workings of the brain and its myriad of emotions are still very much in its infancy. Whether our biochemical reactions amount to trickery on behalf of Nature as a means of continuing the human race remains to be seen, but I can’t help wondering why we seem to be the only species that experiences the strange sense of wonder of Love? All the other species continue to procreate without the need of such an elaborate reward mechanism. And because of that ‘wonder‘, it is still better to have loved and lost than never to have loved at all.