Deborah Tannen, of the gender styles in communication fame,
had an interesting article in NY Times magazine (I think) a while
ago about how women are "marked" by their appearance more than men.
So in evaluating a woman, people see the appearance first and then
the person while for men it's the opposite. I'm obviously not
doing justice to the article, but it certainly hit home for me.
Maybe her next book will be about this.
Also, someone asked about how to get useful evaluations. In one class,
the teacher let us spend a class period midway through the semester
discussing the class (he gave us some guidelines about what to think
about) while he left the room. We wrote comments on the board and he
came back in and went over them with us in the last 15 minutes. The
class itself was fairly unusual in that we always did problem solving
as a class or in small groups anyway, so his evaluation approach fit
the style of the class. People probably felt intimidated about making
inane comments about dress and appearance and so we were able to give him
good feedback about a non-traditional approach to teaching
probability. Of course, the written evaluation is needed also
because there are legitimate comments that we'd like to make privately,
but I think we helped him with the oral evaluation too.