18 July 2007
Mirror Neurons Show Their Xenophobic Side
by Kate Melville
The infamous middle finger salute is recognized by nearly everyone in our society, but to someone from a foreign country, it may be incomprehensible - or even worse, interpreted as some kind of precopulatory come-on. Likewise, Americans are likely to be clueless about the common gestures of a different culture. Which raises an intriguing question - particularly in the context of recent findings that linked cultural differences between China and America to varying degrees of cooperative behavior - about how culture influences the human brain.
Istvan Molnar-Szakacs, a researcher at UCLA's groovily-named Center for the Biology of Creativity, and Marco Iacoboni, director of the scarily-named Transcranial Magnetic Stimulation Lab at UCLA, contend that culture does indeed influence how the human brain develops. Their research, appearing in the current issue of PLoS ONE, looked specifically at the imprinting effects of culture on the brain's mirror neuron network.
Mirror neurons "fire" when an individual performs an action, but they also fire when someone watches another individual perform that same action. Neuroscientists believe this mirroring is the neural mechanism by which we can "read" the minds of other people and empathize with them. When it comes to the influence of culture, they found that the mirror neuron network responds differently depending on whether we are looking at someone who shares our culture, or someone who doesn't.
The researcher's used two actors, one an American, the other a Nicaraguan, to perform a series of gestures - American, Nicaraguan, and meaningless hand gestures, to a group of American subjects. Transcranial magnetic stimulation was then used to gauge levels of "corticospinal excitability" - a measure of mirror neuron activity. They found that the American participants demonstrated higher mirror neuron activity while observing the American making gestures compared to the Nicaraguan. And when the Nicaraguan actor performed American gestures, the mirror neuron activation of the observers dropped.
"We believe these are some of the first data to show neurobiological responses to culture-specific stimuli," said Molnar-Szakacs. "Our data show that both ethnicity and culture interact to influence activity in the brain, specifically within the mirror neuron network involved in social communication and interaction."
"We are the heirs of communal but local traditions," added Iacoboni. "Mirror neurons are the brain cells that help us in shaping our own culture. However, the neural mechanisms of mirroring that shape our assimilation of local traditions could also reveal other cultures, as long as such cross-cultural encounters are truly possible. All in all, our research suggests that with mirror neurons our brain mirrors people, not simply actions."
According to the study, the neural systems supporting memory, empathy and general cognition encode information differently depending on who's giving the information - a member of one's own tribe, or an outsider. "An important conclusion from these results is that culture has a measurable influence on our brain and, as a result, our behavior. Researchers need to take this into consideration when drawing conclusions about brain function and human behavior," noted Molnar-Szakacs. The findings, the researchers note, may also have implications for motor skill and language learning, intergroup communication, as well as the study of intergroup attitudes toward other cultures.
Source: University of California, Los Angeles