Why are intellectuals overwhelmingly leftist?

On the eve of the Canadian federal election, I made an informal survey among my colleagues - for which party are you going to vote? I wasn't surprised by the answer - no one was even remotely interested in voting for the Conservatives. And this wasn't just the case in the two departments (psychology and sociology - in sociology, there's actually a Marxist-Leninist) that I belong to. It's the same with anthropology, geography, English, and ESPECIALLY history. Looking at the "profiles" of these individuals, there is nothing in common among them - the oldest are in their 60's and the youngest are in their 20's; male and female (of course); ALL ethnicities ("Anglo"-Canadian, French-Canadian, Jewish, Blacks, Arabs, Asians, Greeks, Italians, and plenty of Americans); mostly straight but one or two gay/bisexual; some religious but mostly not. The only denominator that connects all of us - we all have graduate degrees in various disciplines.

I cannot speak for all North American colleges and universities and I am very sure (1) there are exceptions and (2) there certainly exists some important regional differences, but I have the impression that leftists seem to be disproportionately represented among intellectuals and college/university faculties. Why? Is there a "leftist bug" that can be caught by those who read (and probably think) too much?

I would say that it depends on who you talk to.  Literature and Art professors and the like tend to go to the left, but the economics, engineering, and other such departments are more conservative.  It also depends on which institution you go to.  Here at my university, Virginia Tech, it is very conservative as a whole because we were established as a technical school and a lot of our students and professors come from conservative areas.

My opinion is that people like English professors are liberal is because they're isolated from the real world and unlike technical specialists needn't worry about things like efficiency so long as there are intangible aspects which gratify them like "fairness" and "caring".

I'm also an engineering major, and I'm very conservative.

Notice, you still only asked humanities and social scientists.  If you asked engineers, economists, physicists, and chemists you probably would have had some people say they were going to vote for the Conservative party.

Thats an interesting point that I for the most part agree with, engineering types work with math a lot where there is a right and wrong answer.  You are less likely to think in the abstract.  With those who study english there is no right and wrong answer, it is all opinion, therefore you think abstractly rather often.  I don't know if they are isolated from the real world but they think about it in a much different way because of their profession.

Where does this idea that economists swing to the right come from? Not in my world, they don't.

Granted there are some right-wing economists, the majority it seems to me (and I'm an ex-economics lecturer myself) are to the left. $

Quite apart from Marx and Engels, Keynes and his whole school are socialist to social-democratic: I'm sure Joan Robinson would be horrified to see herself described as rightist.

Unfortunately the twaddle-purveyors like Friedman and Hayek get too much attention, and of course right-wing politicians dream up their own 'economic' doctrines (like 'trickle-down') to suit their political agendas. But I'm talking serious, empirical economists as well as the 'welfare economists' and the socialist ones.

That's true, but there's also more to it.  People like engineers and physicist most certainly do have to do abstract thinking, anything that complicated requires abstract thinking.  A lot of their thinking is however goal-oriented as opposed to understanding oriented.  An engineer is usually given a goal like "build a device that does this" and in the end will need to decide on one thing.  Importantly, in their field there is one optimal conclusion, in a lot of the humanities, there isn't, there are just different interpretations and no one is better than the other.