Reading this, my thought was that there may be a correlation between personality type and political views. Here is an interesting page that shows the results of a survey of 3000 Americans that asked (among other things) their MBTI personality type and their political party. People who go to graduate school, I think, are often IN types, who typically "are interested in knowledge for its own sake, as well as ideas, theory, and depth of understanding." Among those, the T/F distinction makes a world of difference. The "T" types are more strongly republican (or independent), while the "F" types are strongly democrat.
These results were actually what I was expecting, as I think that the thinking types would be more likely to be found in the hard sciences where there is the link between theory and practice is easiest to substantiate, while the feeling types would be the ones in the social sciences and humanities (I too am lumping them together ), where there are strong overtones of "social justice," as I believe someone said very early on in this thread. Of course, since the data preceded my hypothesis, this is not scientific, but it would make an interesting study for one of you statisticians/social scientists (at least, I think it would be interesting).
P.S. Sorry to those who are unfamiliar with the Myers-Briggs Type Indicator, but I'm sure Google can help you out.