Dan Harmon does an AMA on Reddit, is generous and warm and expansive
If you're a fan of COMMUNITY you'll want to read the whole thread. Below is just an example of Harmon defending the idea of Britta as not a dumb-blonde but just "the normal one."
I am Dan Harmon, creator of Community, writer of Monster House, and Executive Producer of the upcoming Charlie Kaufman Stop Motion Animated feature Anomalisa, ask me anything! : IAmA
I don't perceive the character as being dumbed down, I think we evolved her into one of the most sophisticated characters in TV comedy. Britta's pop cultural ignorance ("rowboat cop") and the fact that she dropped out of high school and ain't so well-read are human qualities to which I found a lot of women relating and/or joyfully not relating, but in any case BELIEVING. I always felt that the triumph of Britta as a character was that she was the only "real" person, stuck on Gilligan's island, and ironically being punished for it. Sometimes we would cross the line. I did find myself telling the writer's room here and there, "let's not make her a dumb blonde, she's a high school dropout and she's computer illiterate and she's a late bloomer because she's lived a fuller life, but there's a difference between that and an airhead." If we made her an airhead, it was an accident, or an isolated instance of us being too tempted by a funny joke. Troy was an airhead. Britta was a work of art. She was a post post feminist masterpiece and a televised work of art. If I do say so myself.
*Thanks, Jeff!*