Cultural differences alter brain's hard-wiring

Interesting:

New research finds that social perspective influences how we see the world
By Clara Moskowitz
updated 12:28 p.m. MT, Fri., Jan. 18, 2008


It's no secret culture influences your food preferences and taste in music. But now scientists say it impacts the hard-wiring of your brain.

New research shows that people from different cultures use their brains differently to solve basic perceptual tasks.

Neuroscientists Trey Hedden and John Gabrieli of MIT's McGovern Institute for Brain Research asked Americans and East Asians to solve basic shape puzzles while in a functional magnetic resonance imaging (fMRI) scanner. They found that both groups could successfully complete the tasks, but American brains had to work harder at relative judgments, while East Asian brains found absolute judgments more challenging.

Previous psychology research has shown that American culture focuses on the individual and values independence, while East Asian culture is more community-focused and emphasizes seeing people and objects in context. This study provides the first neurological evidence that these cultural differences extend to brain activity patterns.

"It's kind of obvious if you look at ads and movies," Gabrieli told LiveScience. "You can tell that East Asian cultures emphasize interdependence and the U.S. ads all say things like, 'Be yourself, you're number one, pursue your goals.' But how deep does this go? Does it really influence the way you perceive the world in the most basic way? It's very striking that what seems to be a social perspective within the culture drives all the way to perceptual judgment."

The results of the study were published in the January issue of the journal Psychological Science.

Hard work
The scientists asked 10 Americans and 10 East Asians who had recently arrived in the U.S. to look at pictures of lines within squares.

In some trials, subjects decided whether the lines were the same length, regardless of the surrounding squares, requiring them to judge individual objects independent of context. In others, participants judged whether different sets of lines and squares were in the same proportion, regardless of their absolute sizes, a task that requires comparing objects relative to each other.

The fMRI revealed that Americans' brains worked harder while making relative judgments, because brain regions that reflect mentally demanding tasks lit up. Conversely, East Asians activated the brain's system for difficult jobs while making absolute judgments. Both groups showed less activation in those brain areas while doing tasks that researchers believe are in their cultural comfort zones.

"For the kind of thinking that was thought to be culturally unpreferred, this system gets turned on," Gabrieli said. "The harder you have to think about something, the more it will be activated."

Individual flexibility
The researchers were surprised to see so strong an effect, Gabrieli said, and interested in the reasons for individual variations within a culture.

So they surveyed subjects to find out how strongly they identified with their culture by asking questions about social attitudes, such as whether a person is responsible for the failure of a family member.

In both groups, participants whose views were most aligned with their culture's values showed stronger brain effects.

"There's a hint that six months in a culture already changes you," he said, referring to psychological, rather than neurological, research. "It suggests that there's a lot of flexibility."

The big divide
Scientists have long wondered about the biological root of cultural differences.

"One question was, when people see the line and box, do they look different all the way, starting at your retina?" Gabrieli said. "Or do you see the same thing to start with but then your mind focuses on one dimension or another. These data indicate that it's at that later stage. In parts of the brain that are involved in early vision, we didn’t see a difference. Rather we saw a difference in higher-processing brain areas. People from different cultures don’tsee the world differently, but they think differently about what they see."

Gabireli said he does worry about unintended consequences of his research.

"The downside of these cultural studies is that one ends up stereotyping a culture," he said. "Are you creating big differences between people? I like to think the more you understand different cultures, the better you understand their perspectives."