Stereotypes are generalizations about people. How we react to certain people because of their nationality, colour, race and positioning can be positive or negative, accurate or inaccurate.
Society generalizes certain categories or groups of people in unconscious biases as a mental shortcut.
We respond to stereotypes to anticipate to differences in people from the outset.
Stereotypes can cause us to unintentionally respond to people in some ways which elicit from behaviours that confirm our generalizations.
As in discrimination unconscious biases needs to be addressed.