In a paper in Social Problems, Saperstein and Penner find that there is a surprising amount of variability in racial identification in the NLSY. Some of this variation is due to error or other random factors but some of it also appears to be systematic. In particular, the authors find that if someone has been incarcerated they are more likely to self-identify as black as well as to be independently identified as black. As the authors put it
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. This suggests that race is not a fixed
characteristic of individuals but is flexible and continually negotiated
in everyday interactions.
Here is a key table. In the first column is the respondent's self-identification, European or Black, in 1979. Thus 95% of the people who identified as European in 1979 and who were not incarcerated between 1979 and 2002 identified themselves as White in 2002. In other words, 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. Thus incarceration appears to affect how people identify themselves.
The result is surprising at first but makes sense once one sees it as a natural extension of Akerlof and Kranton's work on identity.
Note that there are some issues with the data since the precise
questions asked and options given changed over time (hence the change
from "European descent" to "White")–nevertheless, the differences
conditioning on incarceration appear to be robust–but see the paper
Hat tip Gabriel Rossman.