Unacknowledged attitudes external to a person’s awareness which nonetheless have measurable effects on people’s response times to stimuli.
Example: A version of an Implicit Attitudes Test (IAT) has participants make the split-second decision whether to “shoot” intruders in a video game based on whether or not they are holding a gun; many people exhibit an implicit bias toward blacks, manifested as faster and more frequent decisions to “shoot” when the intruder pictured is a black man.
Grinnell, R. (2009). Implicit Attitude. Psych Central. Retrieved on September 5, 2015, from http://psychcentral.com/encyclopedia/2009/implicit-attitude/