Check out this study by Keith Payne. As a black man, the results are pretty disturbing. Especially considering the fact that the same results were found across all races. This study backs up the idea that the media portrays black men as dangerous and that racism is societal.
"Payne and his colleagues conducted two related experiments in which white and Asian Americans viewed on a computer screen a picture of a man, quickly followed by a picture of a either a tool or a gun. Both pictures were visible for only about a fifth of a second each.
When asked to identify – within less than one second — whether the second picture was a tool or a gun, participants were much more likely to misidentify a tool as a gun when the preceding picture was that of an African American.”