26 May 2009
Brain: Our Culture Influences How Our Brains Function
From Denny: This is the first time a brain imaging study about this question of culture has been done. It was reported in the Psychological Science January 2008 issue.
What did the MIT researchers find?
People from different cultures around the world actually use their brains differently to solve the same visual perceptual tasks.
What are the differences in the cultures?
American culture values greatly the individual which in turn “emphasizes the independence of objects from their contexts.”
Asian cultures “emphasize the collective and the contextual interdependence of objects.”
Studying an impersonal brain scan is far different than behavioral studies researchers have done. Behavioral studies learned that memory and perception can be influenced by cultural differences. What scientists wanted to know: But can this be proven in brain activity patterns?
Organizing the team was John Gabrieli, professor at the McGovern Institute for Brain Research at MIT. It was a very small study of 10 East Asians recently arrived in the USA (I guess so they would not be tainted by their now new culture) and 10 Americans. Researchers asked the subjects to make quick perceptual judgments while they were being scanned in an fMRI (Magnetic Resonance Imaging). An fMRI is a new technology that while a person’s brain is responding to a test, this machine starts mapping the blood flow changes in the brain, corresponding to the brain’s responses.
What were those mental tasks?
They were abstract stimuli like lines within squares. People were shown a progression of this kind of stimuli and then asked to compare to the last one given. In some of these trials, people were being asked for an absolute judgment of individual objects that were independent of context. Researchers accomplished this by asking if the lines were the same length regardless of the surrounding squares.
In other trials, researchers were looking for relative judgment of interdependent objects. They accomplished this by asking people to decide whether the lines were in the same proportion to the squares, regardless of absolute size.
What happened during these tests?
Different brain activation patterns were present for these two groups when performing these tasks. Apparently, Americans find it more difficult to make relative judgments. What happened to them is that these tasks activated the brain regions involved in attention-demanding mental tasks. Americans fared better in more culturally familiar absolute judgments and there was less activation of these regions.
East Asians proved to show the opposite tendency. They had to engage the attention-demanding part of their brains more so for making absolute judgments. Relative judgments were easier for them.
Trey Hedden was a lead author of the paper and also a researcher scientist at McGovern. Hedden remarked, “We were surprised at the magnitude of the difference between the two cultural groups, and also at how widespread the engagement of the brain’s attention system became when making judgments outside the cultural comfort zone.”
What else did they find that was significant?
The effect was greater in individuals who identified more closely with their culture. It was shown that a stronger cultural association presented a culture-specific pattern of brain-activation. A bit of how researchers went about being able to identify this was by the use of questionnaires. They asked about preferences and values in social relations – like do you think an individual is responsible for the failure of a family member? This helped gauge cultural identification.
Researchers have long wondered how these differences came to be
Gabrieli thinks, “Everyone uses the same attention machinery for more difficult cognitive tasks. They are trained to use it in different ways. It’s the culture that does the training. It’s fascinating the way the brain responds to these simple drawings, reflects, in a predictable way, how the individual thinks about independent or interdependent social relationships.”
Society does affect our brains; that much is established both in behavioral and now brain scan studies. Perhaps we need to be careful what we teach…