I haven't seen any links to this on Lesswrong yet, and I just discovered it myself. It's extremely interesting, and has a lot of implications for how the way that people perceive and think of others are largely determined by their environmental context. It's also a fairly good indict of presumably common psychiatric practices, although it's also presumably outdated by now. Maybe some of you are already familiar with it, but I thought I'd mention it and post a link for those of you who aren't.
There's probably newer research on this, but I don't have time to investigate it at the moment.
http://en.wikipedia.org/wiki/Rosenhan_experiment
Note that 1973 was a long time ago, and that the deinstitutionalization movement got a significant boost in support from the Rosenhan experiment. I imagine things are different now, although diagnostic criteria for mental illness are still primitive at best.
Things are not entirely different.
Here's another one
(Note that the main thing you'll find when you search for replications is Lauren Slater's book. Don't trust it; she won't share any evidence and has a history of lying).