If you always thought that you had no prejudices against black people, even deep in your subconscious, take this test and get probably amazed (not very positively amazed) as i did.
https://implicit.harvard.edu/implicit/Study?tid=-1
And here's a wide range of other tests that measure our preconceived beliefs about many different subjects.
https://implicit.harvard.edu/implici...lectatest.html