"Implicit bias is a mental process that stimulates negative attitudes about people who are not members of one’s own “in group.” Implicit racial bias leads to discrimination against people who are not members of one’s own racial group. In his book, The Political Brain: The Role of Emotion in Deciding the Fate of the Nation, Professor Drew Westen tells us that “Irrespective of what we may feel and believe consciously, most White Americans—including many who hold consciously progressive values and attitudes—harbor negative associations toward people of color.” Implicit bias affects the way that we think about “out groups” and it influences the way that we react to and interact with out group members. Implicit bias operates in what researchers call our “implicit mind,” the part of the brain that we commonly call the “subconscious” or the “unconscious.” This means that implicit bias can operate in an individual’s mind without a conscious awareness of this process. Westen suggests that, typically, our subconscious attitudes are less egalitarian than our conscious attitudes."
from the Kirwan Institute at Ohio State University