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Social Science 101: This is Your Brain on Social

May 17, 2017

By now, we have all learned that being social is good for us. We, as humans, are meant to be social, as American psychologist Abraham Maslow’s famous hierarchy of human needs lists love, belonging and social interaction as fundamental to the psychological wellbeing of a person. We also now know that being socially connected leads to increased lifespans and stronger immune systems.

Being social even contributes to brain health, as studies have proven that seniors who were highly social had a 70% lower rate of cognitive decline (dementia and alzheimer’s) than their less social peers. We understand that being social is beneficial overall, and makes us feel good, but what physically happens in our brains when we socially engage with others? When discussing our physiology in relation to the benefits of being social, it all comes down to organic chemicals and hormones. There are two that play a huge part in human social connectedness.

The first is the organic chemical dopamine, which is produced by our bodies and travels through important pathways in our brains. In the brain, dopamine’s role is as a neurotransmitter, sending signals between nerve cells. Clinical psychologist Vaughan Bell refers to dopamine as the “celebrity among brain chemicals,” as it is widely known and linked to pleasure (as well as a number of other functions, including movement, memory and attention). But when it comes to a pleasurable situation, dopamine dominates your brain and encourages a person to seek out more of the ‘good stuff’; it is “naturally rewarding” you for certain experiences. Food, sex and drugs are often linked to the release of this chemical in parts of the brain, such as the nucleus accumbens and prefrontal cortex (the former is a brain region “known for its centrality to the reward system”).

Recent studies have also shown that dopamine shows up in response to desirable experiences and not just pleasurable ones. So, what does dopamine have to do with social connection or isolation? Researchers from the MRC London Institute of Medical Sciences recently discoveredthat by activating dopamine neurons in mice, the animals began interacting with each other. When they inhibited the same neurons, the mice began interacting less. The results of this study suggest that “when an animal is on its own, these neurons are sensitized, or primed, which indicated to the animal that it’s alone — and encourages it to seek out social interaction.”

These findings are important for future studies on social isolation and mental health, as interestingly, conditions like schizophrenia and depression are also linked to dopamine dysfunction in the brain. However, dopamine is not the only thing that is released when we are social: the hormone oxytocin is right there alongside it. Oxytocin is known as the “love hormone” and is associated with mother-child bonding and sexual attachments. Because these types of attachments are one-on-one, oxytocin was considered for a long time to be linked to monogamous pairings. However, it is known that for our human ancestors, social living preceded pair living by 35 million years, suggesting that one-on-one bonding behaviour likely evolved from group bonding behaviour.

Researchers at Stanford University did a similar blocking exercise with mice, only this time inhibiting oxytocin, rather than dopamine. They were trying to understand the role of oxytocin in socializing behaviour for people with autism-spectrum disorders. Dr. Robert Malenka explained that for those with autism, “social interactions can be downright painful.” His team wanted to understand one thing: “What in the brain makes you enjoy hanging out with your friends?” The team at Stanford constructed a house for the mice consisting of two rooms they could enter at any time. They made the mice spend 24 hours together in one room, and then 24 hours by themselves in the other.

On the third day of the experiment, they gave the mice freedom to move into whichever room they wanted to spend time in — and, unsurprisingly, they picked the room they had previously spent time in as a group. But when the researchers blocked oxytocin in their respective nucleus accumbens, that preference vanished. Interestingly, the only factor that was affected by blocking oxytocin was the propensity for social activity, as it did not affect their movement or other behaviours at all.

Mice aren’t the only rodent being monitored by scientists to understand the important factors at play in the brain during social interactions. Prairie voles are also monitored because, just like humans, they form long-term pair bonds (unlike 97% of other mammals). In addition, both male and female voles care for their offspring, another behaviour rarely seen in the mammal world.

Furthermore, Prairie voles exhibit a specialized social-spatial understanding, similar to humans, as they can identify respective territories and where other prairie voles are located relative to that area. Cornell University psychologists conducted a study involving neglect and social interaction in prairie voles. In a maze environment, prairie voles that were raised without a father, and then subsequently alone, were not very good at recognizing their peers or where they had met them. Voles that had some social interaction, either raised by two parents or housed in social groups, were much better at the recognition test.

Perhaps most interestingly, the neglected group of voles “also exhibited higher levels of oxytocin receptor, which can dampen the animals’ ability to recognize others”; but when they had more social interaction later on, they were able to better identify the other animals and their locations. Oxytocin is also connected to our sense of altruism and generosity. In a 2007 study published in the Public Library of Science (PLOS) journal, participants were infused with oxytocin or a placebo and were asked to make a decision on splitting a sum of money with a stranger. Those that were infused with the oxytocin were found to be 80% more generous than those given the placebo. This suggests that oxytocin has a positive impact on social relationships and interactivity. How do these studies help us to understand human social connectedness?

Above all, they demonstrate that social behaviour produces positive physiological responses in our bodies beyond our control. The studies have also played a huge part in the search for solutions to social anxiety and mental health challenges. In recent years, two clinical trials have explored the use of nasal sprays that deliver oxytocin to the brain as a way to improve social functioning for autistic individuals. Perhaps over the next decade, studies like these will continue to improve our understanding of social connectedness and the important role it plays in our physiological and mental health and wellbeing.