Your Brain, Race, and Criminal Justice
"Researchers have used pictures of faces like these to study something called implicit bias. University of Washington psychologist Anthony G. Greenwald aNd his colleagues devised an "implicit association test" or IAT - in which people are instructed to match words and pictures that represent concepts, and response time and accuracy are used as indicators of the strength of the association between these concepts. this test is based on the premise that it is less mentally taxing to match concepts that are closely related in our minds (e.g., names of flowers like 'tulip' and pleasant-meaning words like 'happy'). People respond faster and more accurately when pairing concepts that are automatically associated. Racial bias has been measured in this way, and the test results show that participants are faster at pairing positive words with white faces than they are at pairing positive words with black faces. The converse is true with negative words. It turns out, most Americans - regardless of their own racial group - exhibit unconscious pro-white, anti-black attitudes on the IAT."
Related Document: State of the Science: Implicit Bias Review 2014