Narrator: This is Science Today. Sociologist Herman Gray of the University of California, Santa Cruz studies the ways that television reflects race relations in the United States.

Gray: In its earliest moments, of course, African-Americans were sources of derision, stereotypes, exaggerations. I'm really thinking about the signal programs that are described as televisions's Golden Age -- Jack Benny, Beulah.

Narrator: In the 60s and 70s, the pendulum swung the other way with shows that fought against stereotypes. But those shows were still produced by whites.

Gray: At the high moment that's pointed to, sort of the Norman Lear years, clearly it was white liberalism in the form of Norman Lear's sort of attempts to make some needed corrections.

Narrator: The 90s saw the arrival of black-produced and written programs. Gray says that was part of a larger trend in all the arts.

Gray: It's only when you get in film, in popular music, in literature a whole sort of critical mass of black self-critical debate and dialogue that it spills over into television.

Narrator:For Science Today, I'm Steve Tokar.