Bias in academia

As the article says, these types of numbers don't come about by randomness. I have a discussion of this bias in my book Freedomnomics.

It was identified by Jonathan Haidt, a social psychologist at the University of Virginia who studies the intuitive foundations of morality and ideology. He polled his audience at the San Antonio Convention Center, starting by asking how many considered themselves politically liberal. A sea of hands appeared, and Dr. Haidt estimated that liberals made up 80 percent of the 1,000 psychologists in the ballroom. When he asked for centrists and libertarians, he spotted fewer than three dozen hands. And then, when he asked for conservatives, he counted a grand total of three. . . .
“I consider myself very middle-of-the-road politically: a social liberal but fiscal conservative. Nonetheless, I avoid the topic of politics around work,” one student wrote. “Given what I’ve read of the literature, I am certain any research I conducted in political psychology would provide contrary findings and, therefore, go unpublished. Although I think I could make a substantial contribution to the knowledge base, and would be excited to do so, I will not.” . . .