Implicit bias, also known as implicit prejudice or implicit attitude, is a negative attitude, of which one is not consciously aware, against a specific social group.
Implicit bias is thought to be shaped by experience and based on learned associations between particular qualities and social categories, including race and/or gender. Individuals’ perceptions and behaviors can be influenced by the implicit biases they hold, even if they are unaware they hold such biases. Implicit bias is an aspect of implicit social cognition: the phenomenon that perceptions, attitudes, and stereotypes can operate prior to conscious intention or endorsement.
Adapted from the APA Dictionary of Psychology and Wikipedia
