 Stereotyping is a type of heuristic that people use to form opinions or make judgments about things they have never seen or experienced.They work as a mental shortcut to assess everything from the social status of a person (based on their actions), to whether a plant is a tree based on the assumption that it is tall, has a trunk, and has leaves (even though the person making the evaluation might never have seen that particular type of tree before).Stereotypes, as first described by journalist Walter Lippmann in his book "Public Opinion" (1922), are the pictures we have in our heads that are built around experiences as well as what we are told about the world.