How City Life Changes the Brain
Growing up in a big city trains the brain's social instincts.
Posted Jun 23, 2011
I recently came across a post on the wonderful MSNBC.com's Body Odd blog titled:
"City living stresses you out, study confirms." But the actual finding of the study is far more ambiguous -- and differs enough from this interpretation that I thought it was worth a response.
The study recruited both people who had grown up in big cities, and folks who were raised in the country. Once in the laboratory, participants were put through a difficult math test (all while having their brain activity monitored by an fMRI machine).
After participants inevitably made math mistakes, they "accidentally overhead" the experimenter criticize them and say to another experimenter that maybe the participant wasn't cut out for this study. Of course, this was all a ruse: researchers wanted to know how the participants' brains would respond to social criticism.
The key finding: People who grew up in big cities showed a stronger response in the amygdala than the country-born participants.
Now, it's true that the amygdala is often referred to as the "stress center" of the brain, and it does ignite the fight-or-flight stress response. But an amygdala response doesn't always mean a stress response.
More recent thinking in neuroscience has expanded the amygdala's role to social cognition -- in other words, understanding other people's motivations, and skillfully reacting to social demands. It may be an "early responder" to important social signals, including social conflict and threat, before the rest of the brain gets the message.
A study published earlier this year found that among non-human animals species, a bigger and better-connected amygdala reflects a more complex social system. As a species developed greater social challenges like cooperation, communication, and conflict management, this area of the brain seemed to "step up" and provide an instinctive basis for social skills -- or, if you grew up in a big city, what you might call "street smarts."
So when I read this new study's findings, my first thought wasn't city-living stresses you out, but that growing up in a city puts demands on the developing brain to get better at navigating a complex social system. In urban areas, you're exposed to far greater diversity and population density than in rural areas. You have to get good at quickly recognizing social cues, avoiding social threat, and learning from social conflicts. In the social criticism study, the experimenter's words were a signal that the participant wasn't meeting the demands of the situation, and a warning of possible social conflict.
Of course, the two aren't mutually exclusive. Cities can be stressful, and they may make the brain more sensitive to stress. But city life may also teach us to be especially sensitive to social cues, and shape a brain that can best navigate the complexity of the urban world.