Exploring the science behind love

WE’VE all felt it at some time. Poets write about it, singers sing about it – and a whole industry has grown up around finding it, expressing it and maintaining it. But what is love? Where does it reside? What triggers it? And what’s really going on in our minds and bodies when we fall “head over heels”?

Romantic love, often difficult to define, includes the development of a strong emotional bond – known as “attachment” – sexual attraction and care giving. Those “in love” experience a range of intense feelings, such as intrusive thoughts, emotional dependency and increased energy – though these feelings may be limited to the early phases of the relationship.

Brain activity

Numerous brain regions, particularly those associated with reward and motivation, are activated by the thought or presence of a romantic partner. These include the hippocampus, hypothalamus and anterior cingulated cortex.

Activation may serve to inhibit defensive behaviour, reduce anxiety and increase trust in the romantic partner. Areas such as the amygdala and frontal cortex are deactivated in response to romantic love, a process which may function to reduce the likelihood of negative emotions or judgment of the partner.

Hence brain activation in response to romantic partners appears to reward social interaction and impede negative responses. The extent to which the brain is activated during early stages of a romantic relationship appears to influence both our own well-being and the extent to which the relationship is a success or failure.

Hormonal Influence

Oxytocin and vasopressin are the hormones most closely associated with romantic love. They are produced by the hypothalamus and released by the pituitary gland; and while men and women are both influenced by oxytocin and vasopressin, women are more sensitive to oxytocin and men more sensitive to vasopressin.

Concentrations of both increase during intense stages of romantic love. These hormones act on numerous systems within the brain, and receptors are present in a number of brain areas associated with romantic love. Oxytocin and vasporessin interact with the dopaminergic reward system and stimulate dopamine release by the hypothalamus.

The dopaminergic pathways activated during romantic love create a pleasurable feeling. The pathways are also associated with addictive behaviour, consistent with the obsessive behaviour and emotional dependency often observed in the initial stages.

Love and Loss

Romantic love may serve an important evolutionary function, for example by increasing the level of parental support available to subsequent children. We typically enter a series of romantic relationships in our search for “the one” – and the loss of romantic love is widespread, either through the break-up of a relationship or bereavement. While distressing, most people are able to cope and move on from this loss.

For a minority of people experiencing loss through bereavement, complicated grief develops, characterised by recurrent painful emotions and preoccupation with the deceased partner. All bereaved partners experience pain in response to loss-related stimuli. It is argued that for those experiencing complicated grief, the stimuli also activate reward centres in the brain, producing a form of craving or addiction which reduces their ability to recover from the loss.

Maternal Love

There are a number of parallels between the physiological responses to romantic and maternal love. For example, the brain regions activated by maternal love overlap with those activated by romantic love. Specifically, the reward areas of the brain which contain high concentrations of oxytocin and vasopressin are activated, while the regions deactivated during romantic love – including those related with judgment and negative emotions – are deactivated during maternal love.

Increased and decreased concentrations of oxytocin promote and reduce maternal behaviour respectively. Differences between responses to maternal and romantic love do occur as maternal love activates a number of regions (such as the periaqueductal grey matter) that are not activated during romantic love, highlighting the unique nature of the maternal bond.

Few things feel as effortless as the early stages of “true love” or the love felt by a mother for her child, but the reality is more complex, a pantomime of hormones and complex physiological interactions that make it a little wonder of the world. – The Conversation

Romantic love may serve an important evolutionary function, for example, by increasing the level of parental support