NRSC 4132 Blog

In the early ages, mankind was very segregated. There were nomads, warriors, hunters, etc. who occupied distinct geographical areas and practiced a very specific way of life. Over time, these cultures began to mesh, and today, nearly every nation is comprised of constituents hailing from all parts of the globe.

Interestingly, a recent study in Nature Neuroscience (http://www.nature.com/neuro/journal/v6/n12/abs/nn1156.html) indicates a neural mechanism for the integration of cultures. Specifically, Jennifer Richeson et. al conducted fMRI studies that identified regions of the brain allocated to repressing racial biases and prejudices.

Jennifer Richeson et. al designed their study to examine a previously proposed theory called "resource depletion". Prior research suggests that central executive processes are recruited "to combat the expression of stereotypes and negative attitudes that often come to mind automatically and unintentionally". The resource depletion theory postulates that the suppression of racial attitudes upon interracial contact temporarily depletes central executive control, and hence, performance on tasks requiring central executive control following interracial contact is diminished.

The study consisted of two experiments conducted on 15 Caucasian, American undergraduates. The first experiment involved individuals completing a survey on racial bias, then interacting with a black individual, and then completing an unrelated Stroop-color naming test that assesses executive control. In the second experiment, these individuals were presented with pictures of unfamiliar male black faces, and fMRI imaging was used to examine the activity of brain regions implicated in executive control during and immediately after the images were presented.

The fMRI imaging revealed heightened activity in the dorsolateral prefrontrol cortex (DLPFC) in individuals that exhibited racial biases. As expected, this increased activity in the DLPFC correlated to diminished performance on the Stroop-color naming test, indicating that executive control resources had been depleted following interracial contact. In contrast, there was no heightened activity in the DLPFC in controls (those who did not show racial biases on the initial survey), and these controls did not show diminished performance on the Stroop-color test.

The DLPFC is believed to directly influence the engagement of inhibition responses, such as suppression of racial biases. Another area of interest, the anterior cingulated cortex (ACC), is believed to sense situations/circumstances when such control is necessary. While fMRI imaging revealed increased activity of the DLPFC and ACC in racially biased individuals, only DLPFC activity correlated to diminished Stroop-color test performance. This indicates that while both areas may be important in regulating racial biases, the DLPFC region more directly affects performance on executive control tasks following interracial contact.

It is surprising that regions of the brain function to repress racial biases and stereotypes. More research is needed to identify what brain structures contribute to the development of these biases in the first place. Perhaps such research will lead to the development of drugs that promote cultural awareness and tolerance, something we could all use a dose of.