Jonathan Haidt in an interview on Mind the Campus:
So we acknowledge that if there was no discrimination at all, the field [of social psychology] would still lean left. And that’s perfectly fine with us. We don’t give a damn about exact proportional representation. What we care about is institutionalized disconfirmation — that is, when someone says something, other people should be out there saying, “Is that really true? Let me try to disprove it.” That is now much less likely to happen if the thing said is politically pleasing to the left.