We make the Difference
Difference ...a point or way in which people or things are not the same
All of society enables the social construction of "Difference." Sub-consciously and consciously humans make note of "difference" in how people talk, look, dress, sound, act, etc. The subjects they talk about, what they support, what they can't tolerate, how they relate to their family members. Parents and elders have an intolerance for acting outside the norm. While individuals and institutions pressure individuals toward conformity, an equal number is pushing for non-conformity. Noam Chomsky refers to this pressure as Manufacturing Consent.
In David Roediger book, 
The Production of Difference: Race and the Management of Labor in U.S. History is the story of Mr. Block, a 1912 cartoon by Ernest Reibe, of the International Workers of the World. He parodies the creation of pitting one race against the other. As Mr. Block engages each new worker in doing the task, he is constantly trying to uplift that "race" while denigrating another. He refers to how efficient, slow, productive.
Much of this stems from the Capitalism's need to further managerial control over all workers. This is propped up by early 19th century pseudo studies that racialize various aspects of efficient production.
What is important to understand is the Intersectionality of Race, Class and Gender. None of these social constructs stands alone.