That there is a liberal bent in the teaching ranks of United States universities should be no surprise to anyone. What might be a surprise, though, is the extent of that bent - the American Enterprise Institute recently claimed that liberal professors commonly outnumber conservatives by ten to one, and often by as much as 20 to one.

The study used political party affiliations - data available in many, though not all states - to arrive at its conclusions. "Today's colleges and universities," AEI wrote, "are not, to use the current buzzword, diverse places. Quite the opposite. They are virtual one-party states, ideological monopolies, badly unbalanced ecosystems. They are utterly flightless birds with only one wing to flap. They do not, when it comes to political and cultural ideas, look like America."

Liberals outnumber conservatives 18 to one at Brown University, 26 to one at Cornell, three to one at the University of Houston, 141 to nine at UCLA, 73 to one at UC-Santa Barbara and 66 to seven at UC-Berkeley.

Those who do the hiring deny there's any bias at work. (You have to admit, though, don't you, that this does have a distinctly duck-like waddle?) The result is obvious. "Because there is such a bias," according to the editor in chief of Berkeley's student newspaper, the California Patriot, "because there are so many professors who do identify with more of the Left, you have a lot of professors out there who let their ideology interfere with how they teach a class.

"That's not really learning, that's not really seeking any truth."

Well. no, it isn't. But there may be a reason for it - the University of California at Berkeley has just published a study showing that conservatives are suffering from some kind of psychological malaise, to put it politely.

It's not a wonder that there are so few conservatives in academia. It's a wonder that there any at all. The Berkeley study is called Political Conservatism as Motivated Social Cognition. Just in case you're not familiar with that type of jargon, let me translate for you - Conservatives See Only What They Want to See.

It's a serious study - carried out by four researchers who are reported to have culled through 50 years of research literature about the psychology of conservatism. They conclude that at the core of political conservatism is resistance to change and a tolerance for inequality, and that some of the common psychological factors linked to political conservatism include:

Fear and aggression

Dogmatism and intolerance of ambiguity

Uncertainty avoidance

Need for cognitive closure

Terror management

"From our perspective, these psychological factors are capable of contributing to the adoption of conservative ideological content, either independently or in combination," the researchers wrote.

Disparate conservatives share a resistance to change and acceptance of inequality, the authors said. Hitler, Mussolini, and former President Ronald Reagan were individuals, but all were right-wing conservatives because they preached a return to an idealised past and condoned inequality in some form.

Talk host Rush Limbaugh can be described the same way, the authors said. Just in case you might miss the point, the press release announcing the study described the conservative condition even more clearly: "Concerns with fear and threat, likewise, can be linked to a second key dimension of conservatism - an endorsement of inequality, a view reflected in the Indian caste system, South African apartheid and the conservative, segregationist politics of the late Sen. Strom Thurmond (Republican -South Carolina)."

So there you have it. If you're a conservative, you're a bigot. Don't you try and deny it.

I consider my threshold of outrage to be perhaps a little higher than the next man's (must be the need for cognitive closure in my makeup), but that is the sort of silly nonsense that could actually get me out throwing rocks at symbols of authority from behind a barricade somewhere.

Do you suppose that lumping Ronald Reagan in with Hitler and Mussolini might be a clue that the authors haven't a clue?

You bet it is.

And if you won't buy that, you might be persuaded by the fact that in order to fit lunatics of the left, like Stalin and Khrushchev and Castro, into their theory, they had to suggest that they, too, were political conservatives. in the context of the systems they were defending.

I guess we'll have to forget the ill-fitting fact that today's American conservatives largely started life as liberals who were shocked rightwards by the anti-Americanism, the anti-intellectualism and the willingness of the New Left to embrace violence to achieve its goals.

We'll have to forget the saying that a conservative is a liberal who was mugged by reality.

The Berkeley group concludes that all dictators are conservatives. the conservative sickness, I guess we have to say, spawns dictatorships and despots.

The Wall Street Journal's online column OpinionJournal was so astonished by this Keystone Kops display of intellectual slapstick that they thought it might be a parody - "Is it for real," they asked, "or is some Berkeley prankster enjoying a huge laugh at their (the authors') expense?"

It would be a relief if it were a joke. But it isn't. Instead, it is illustrative of how some theories can survive being disproved over and over again for decades, despite the ground rules of science.

The Berkeley study enlarges upon a body of work in psychology known as authoritarian personality study, whose seminal work was written by a psychologist called TW Adorno in 1951. It was originally an attempt to explain German anti-Semitism, and has been shown often, since then, to be a turkey.

Doesn't seem to matter, though. Like the Energiser Bunny, authoritarian personality study just keeps on going and going and going.

For some, it is a most convenient theory. The Berkeley Group were certainly impressed.

They acknowledge their reliance on Adorno and others who embellished on his theories. Dr. John J. Ray of the University of New South Wales in Australia, who works in this field, and who is one of those psychologists who think the Berkeley Group is off the rails, put his disagreement bluntly: "I submit that what psychologists do when they accept authoritarian personality theory is ignore virtually all the evidence. That has got to be intolerance of ambiguity.

"Perhaps because of the poor development of their science, therefore.authoritarian personality theory ideally meets the needs of people who are intolerant of ambiguity.

"Erroneous speculation is preferred to hard data.

"Whether any advancement of scientific knowledge can take place where such an orientation prevails must however be seen as unlikely."

The theory that political conservatives are sick little bigots who resist change, see things in black and white and are less "integratively complex" than others (one of the authors felt bound to point out that that "doesn't mean that they're simple-minded") just doesn't accord with what goes on in the world.

The truth is that people who fit that description don't come from a particular political camp any more than warts come from touching toads.

Michael Riordan, who wrote a great little book called `The Hunting of the Quark', teaches history of physics at Stanford University and the University of California in Santa Cruz.

He wrote in a paper recently that: "The essence of scientific truth rests in the requirement that it should have strong accordance with the natural world that exists outside our minds and beyond human artifice....

"Experimenters must continue ripping away at new ideas to make sure this accordance indeed holds true.

"Their scepticism plays a role like death in natural selection - only the strongest survive to take their place among what actually lives on.

"In this evolutionary metaphor, speculative theorising plays a crucial role, too, by helping to ensure that science investigates the many philosophical niches where truth might lurk.

"My one caveat is that hypotheses resulting from such wide-ranging explorations of possible theory space must ultimately lead to testable consequences - a process that may take years, even decades - if science is to advance. Otherwise, theorists are doing metaphysics, not physics."

Pity those Berkeley psychologists can't be more like real scientists.