What was the basis and conclusion of Minard's 1952 study?

for prejudice I believe

In 1952, Minard did a study on the effects of discrimination and prejudice are influenced by society.

Minard studied African American and Caucasian coal miners and found that they worked together completely integrated with little racial tensions, but in their home lives had little to no interaction with other races. He believed that this study was proof that prejudice and discrimination were dependent upon social norms.