Humans classify, categorize, and compartmentalize.

Humans classify and label the world around them. Virtually everything human senses can interpret is put into categories. A single human belongs to numerous categories, simultaneously.

Humans have trouble accepting uncertainty when attempting to classify someone who does not fit nicely into an established category. The ambiguity aversion kicks in and humans feel fear and proceed with caution. This process becomes especially problematic when the categories are social constructs, like race and gender.