From Robert Trasincki's recent piece in The Federalist:
"A recent study that has been making the rounds argues that “academic psychology once had considerable political diversity, but has lost nearly all of it in the last 50 years.” The paper examines historical data and concludes that party and ideological affiliation in university psychology departments used to be split close to 50-50. By the 1960s, the ratio of Left to Right had climbed to about 4-to-1, and then in the 1990s academia was transformed. Conservatives were chased out, and current left-to-right ratios are estimated at 11-to-1 or higher.
Jonathan Haidt, the lead author of the study, is an honest liberal who admits—and the paper goes on to demonstrate this—that the dominance of the Left distorts the scientific output of academic psychologists. When there are no dissenting voices, it’s a lot easier to confirm each others’ biases.
I’m pretty confident you would get similar results for most other academic disciplines. When I was in college in the late 1980s and early 90s, my sense was that there was a generation of elderly scholars holding the line against “political correctness”—the term had just become popular—but as they retired or died, the new orthodoxy was taking over among their replacements. I’ve seen the same thing elsewhere: an older generation who are at the very least non-ideological and apolitical, followed by a younger generation who are steeped in the neo-Marxist dogmas of “race, class, and gender.”"