Stereotyping is based on categorization, and rather than getting to know and understand people as unique individuals the human mind thinks with the aid of categorizing.
Categorization forms large classes and clusters for guiding our daily adjustments.
Categorization assimilates as much as it can to the clusters or categories that we already have in our minds, thus allowing us some way to immediately know how to identify and to relate to what ever we have labeled. The categorization generalizes and saturates all that it contains with the same ideational and emotional flavor. Categorization may be more or less rational. The inappropriate categorizations are many times stereotypes when it comes to people. The above theory of categorization is adapted from a presentation of calegorization presented in Gordon W. Alport's book, The Nature of Prejudice , Addison and Wesley, Reading, MA 1979.