West Brain, East Brain——What a difference culture makes
By now, it should come as no surprise when scientists discover yet another case of experience changing the brain. From the sensory information we absorb to the movements we make, our lives leave footprints on the bumps and fissures of our cortex, so much so that experiences can alter "hard-wired" brain structures. Through rehab, stroke patients can coax a region of the motor cortex on the opposite side of the damaged region to pinch-hit, restoring lost mobility; volunteers who are blindfolded for just five days can reprogram their visual cortex to process sound and touch.
Still, scientists have been surprised at how deeply culture—the language we speak, the values we absorb—shapes the brain, and are rethinking findings derived from studies of Westerners. To take one recent example, a region behind the forehead called the medial prefrontal cortex supposedly represents the self: it is active when we ("we" being the Americans in the study) think of our own identity and traits. But with Chinese volunteers, the results were strikingly different. The "me" circuit hummed not only when they thought whether a particular adjective described themselves, but also when they considered whether it described their mother. The Westerners showed no such overlap between self and mom. Depending whether one lives in a culture that views the self as autonomous and unique or as connected to and part of a larger whole, this neural circuit takes on quite different functions.
"Cultural neuroscience," as this new field is called, is about discovering such differences. Some of the findings, as with the "me/mom" circuit, buttress longstanding notions of cultural differences. For instance, it is a cultural cliché that Westerners focus on individual objects while East Asians pay attention to context and background (another manifestation of the individualism-collectivism split). Sure enough, when shown complex, busy scenes, Asian-Americans and non-Asian--Americans recruited different brain regions. The Asians showed more activity in areas that process figure-ground relations—holistic context—while the Americans showed more activity in regions that recognize objects.
Psychologist Nalini Ambady of Tufts found something similar when she and colleagues showed drawings of people in a submissive pose (head down, shoulders hunched) or a dominant one (arms crossed, face forward) to Japanese and Americans. The brain's dopamine-fueled reward circuit became most active at the sight of the stance—dominant for Americans, submissive for Japanese—that each volunteer's culture most values, they reported in 2009. This raises an obvious chicken-and-egg question, but the smart money is on culture shaping the brain, not vice versa.
