OH yeah.
But most of it is very vague. The only guy who's
addressed it directly/scientifically that I know of
is Dutch psychologist Herman Bouma. Although he
hasn't written a book, he has written a number of
articles/papers which should be available through
a good university library, or at least through ILL.

And if you don't mind referring to a
disreputable source you could check out
my piece in "Graphic Design & Reading":
http://gunnarswanson.com/GDandR/GDandR_Book.html

hhp