As part of its Implicit Bias Initiative, the American Bar Association defines implicit bias as "A preference (positive or negative) for a group based on a stereotype or attitude we hold that operates outside of human awareness and can be understood as a lens through which a person views the world that automatically filters how a person takes in and acts in regard to information. Implicit biases are usually measured indirectly, often using reaction times."
Project Implicit is a non-profit organization that has created an implicit bias test to measure one's on implicit biases. Take the test here.
After taking the test, please view the TEDTalk by Verna Myers entitled How to overcome our biases? Walk boldly toward them.