Çarşamba, Şubat 24, 2010

Cultural Neuroscience

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.

The medial prefrontal cortex supposedly represents the self: it is active when we 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.

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.

Drawings of people in a submissive pose (head down, shoulders hunched) or a dominant one (arms crossed, face forward) was shown 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.

Chinese speakers use a different region of the brain to do simple arithmetic (3 + 4) or decide which number is larger than native English speakers do, even though both use Arabic numerals. The Chinese use the circuits that process visual and spatial information and plan movements (the latter may be related to the use of the abacus). But English speakers use language circuits. It is as if the West conceives numbers as just words, but the East imbues them with symbolic, spatial freight. (consider about Asian math geniuses.) Neural processes involving basic mathematical computations seem to be culture-specific.

Sharon Begley
West Brain, East Brain: What a difference culture makes.

Mar 1, 2010

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