Science + Technology

UCLA Researchers Show That Culture Influences Brain Cells

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A thumbs-up signifies "I'm good." The rubbing of onepointed forefinger against the other means "shame on you." The infamousmiddle-finger salute — well, you know. Gestures that convey meaning withoutspeech are used and recognized by nearly everyone in our society, but tosomeone from a foreign country, they may be incomprehensible.

Likewise, an American in a foreign land may be clueless tothe common gestures of that particular culture. This raises a provocativequestion: Does culture influence the brain?

The answer is yes, according to Istvan Molnar-Szakacs, aresearcher at the UCLA Tennenbaum Centerfor the Biology of Creativity, and Dr. Marco Iacoboni, director of theTranscranial Magnetic Stimulation Lab at the Ahmanson-Lovelace Brain Mapping Centerat UCLA's Semel Institute for Neuroscience and Human Behavior. Their researchappears in the current issue of the journal PLoS ONE, available online at www.plosone.org/doi/pone.0000626.

Molnar-Szakacs and Iacoboni wanted to investigate theimprint of culture on the so-called mirror neuron network. Mirror neurons inthe brain fire not only when an individual performs a particular action butalso when he or she watches another individual perform that same action.Neuroscientists believe this "mirroring" is the mechanism by which we can readthe minds of others and empathize with them.

When it comes to the influence of culture, the researchersfound that the mirror neuron network responds differently depending on whetherindividuals are looking at someone who shares their culture or someone whodoesn't.

The researchers had two actors — one American, the otherNicaraguan — perform a series of American, Nicaraguan and meaningless handgestures for a group of American subjects. A procedure called transcranialmagnetic stimulation was used to measure the observers' levels of corticospinalexcitability, which scientists use to gauge the activity of mirror neurons.

Molnar-Szakacs and Iacoboni found that the Americanobservers demonstrated higher mirror neuron activity when observing theAmerican making the gestures — whether they were American, Nicaraguan ormeaningless — than when viewing the Nicaraguan. Even when the Nicaraguan actorperformed American gestures, the observers' mirror neuron activity dropped.

"We believe these are some of the first data to show neurobiologicalresponses to culture-specific stimuli," said Molnar-Szakacs. "Our data showthat both ethnicity and culture interact to influence activity in the brain,specifically within the mirror neuron network involved in social communicationand interaction."

"We are the heirs of communal but local traditions," saidIacoboni. "Mirror neurons are the brain cells that help us in shaping our ownculture. However, the neural mechanisms of mirroring that shape ourassimilation of local traditions could also reveal other cultures, as long assuch cross-cultural encounters are truly possible. All in all, our researchsuggests that with mirror neurons, our brain mirrors people, not simplyactions."

It appears that neural systems supporting memory, empathyand general cognition encode information differently depending on who's givingthe information — a member of one's own cultural or ethnic in-group or a memberof an out-group. Ethnic in-group membership and a culturally learned motor repertoire more strongly influence thebrain's responses to observed actions, specifically actions used in socialcommunication.

"An important conclusion from these results is thatculture has a measurable influence on our brain and, as a result, our behavior.Researchers need to take this into consideration when drawing conclusions aboutbrain function and human behavior," said Molnar-Szakacs.

The findings, the researchers note, may also haveimplications for motor-skill acquisition, language learning and intergroupcommunication, as well as for the study of intergroup attitudes toward othercultures.

Other study authors include Allan D. Wu and Francisco J.Robles, both of UCLA. Molnar-Szakacs and Iacoboni are members of the Foundationfor Psychocultural Research–UCLA Centerfor Culture, Brain and Development, which provided funding for the study.

For more on Iacoboni's research,visit his Web site at http://iacoboni.bmap.ucla.edu.For information on the FPR–UCLA Center for Culture, Brainand Development, visit www.cbd.ucla.edu.

The Semel Institute for Neuroscience and Human Behavior at UCLA isan interdisciplinary research and education institute devoted to theunderstanding of complex human behavior, including the genetic, biological,behavioral and sociocultural underpinnings of normal behavior, and the causesand consequences of neuropsychiatric disorders. For more information, visit www.npi.ucla.edu.

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