Incarceration Makes You More Black

It's well known that African American men are disproportionately imprisoned. They are seven times more likely to go to prison than whites to the extent that 30% of black men will spend some time there. What you may not know is that spending time in prison will actually make you perceive yourself as more black. Here's the study:

Results show that respondents who have been incarcerated are more likely to
identify and be seen as black, and less likely to identify and be seen as white,
regardless of how they were perceived or identified previously.

Here are the exact numbers from Marginal Revolution:

racial identification for the non-incarcerated was quite stable. But only 80% of the people who identified as European in 1979 and who were incarcerated between 1979 and 2002 identified themselves as White in 2002.

This seems to suggest what I've thought all along, that race in America is more about culture and perception than ethnicity.