Oxytocin and the biological basis of love, attachment and social bonding
By Katherine Gombay
It’s got a good rep, and a great nickname – the “love hormone.”
Oxytocin helps women give birth and breastfeed. At orgasm, both men and women release it. And lots of scientific evidence suggests that it plays some role in bonding and attachment in everything from prairie voles to humans. So when researchers started paying serious attention to the role of oxytocin in human social behavior, there were those who hoped that, because it also seems to increase our trust in one another, it might become a panacea for a range of social ills.
But according to McGill psychology researcher Jennifer Bartz, although oxytocin may motivate the desire to affiliate and form bonds (as it appears to do in some animals), it’s not quite that simple.
Bartz is interested in the biological basis of love and attachment in humans. From an evolutionary standpoint, attachment, especially in humans, is designed to promote the survival of the infant and hence of the species as a whole. “The idea is that we develop attachment bonds with our close others, beginning with our primary caregiver,” says Bartz. “And because infants can’t care for themselves for a very long time, they need a mechanism to keep their care givers close and nurturing. But these ‘attachment models’ continue to influence us and our close relationships throughout our lifespan.”
Increasing our desire to connect?
There’s already been a lot of animal research done that confirms the importance of oxytocin in attachment and social bonding. Researchers have compared attachment in Prairie Voles (highly social, mate for life, share the care for the offspring – and have lots of oxytocin receptors in the part of the brain associated with reward and reinforcement), with Montane Voles (asocial critters who abandon their young early in life and have few oxytocin receptors in the part of the brain associated with reward). But it’s a lot harder to do this kind of neuroscientific research in humans, because it’s difficult to measure and manipulate the availability of oxytocin in our brains.
Research in animals has found that as well as making us want to connect with and become attached to certain people, oxytocin also seems to play a role in biasing our attention to social cues in the environment in general. The idea that oxytocin increases the desire to connect with others and increases attention to social information led Bartz and her colleagues to speculate that it may have different effects on different people – in particular that it might be especially helpful for people who are not very socially engaged and not very attentive to social information (like those who are suffering from diseases like autism).
“But by the same token,” explains Bartz, “oxytocin might not be so helpful for people who are hypersensitive to social cues, preoccupied with closeness and concerned about being rejected, because it might increase their awareness of the very thing they are already worrying about in their lives.”
Bartz has done a number of studies where she administered oxytocin through nasal spray in order to find out whether it activated the attachment system itself. Participants were asked both how caring their mothers were and how close they had felt to their mothers in childhood. The researchers discovered that those who were securely attached remembered their mother as more caring and close when they were given oxytocin, compared to when they were given a placebo. But for those who were more anxious about their attachment, a dose of oxytocin led them to remember their mothers as less caring and close. In other words, oxytocin didn’t make everyone feel better; instead it appeared to intensify whatever feelings people had, including chronic concerns about closeness.
Although the results of the studies vary depending on their focus, to Bartz, they all suggest a need for a more nuanced understanding of the role oxytocin plays in attachment and social behaviour.
“It may well be that oxytocin increases the desire to affiliate for everybody,” says Bartz. “But the way that this desire is going to play out depends on who you are and what you bring to the situation.”