An important part of how the human mind (or any mind like ours) works is by responding to environmental regularities.
These regularities are encoded automatically, and retrieved automatically to help guide thought and action.
If we didn't do this, we would die.
Stereotypes
One form of automatic association is the way we stereotype people in order to help navigate the social world.
The tendency to stereotype arises very early and without explicit training.
Moreover, many stereotypes are unconscious and activated automatically.
Aliefs
According to Tamar Gendler, stereotypes are an instance of what she calls aliefs -- arational, automatic, affect-laden associations that influence our thoughts and actions in many ways.
These can co-exist with conflicting beliefs that are thoroughly egalitarian.
Lots of aliefs are very useful, but some can be dangerous in various ways.
Some Epistemic Costs of Implicit Biases
Differences in how same-race vs. other-race (and in-group vs. out-group) faces are encoded and recognized.
Effects of stereotype threat in the performance of various tasks.