Most of us have received those letters, indicating that some learners will require special accommodations. And students learn to fit the description. Reminds me of those learners in my classes who expressed surprise at obtaining a high grade on an assignment.

For instance, a musician in my ethnomusicology course, back in 2006, came to me with something of a complaint:

You gave me an A on this assignment!

Right. What's the problem?

I have a learning disability!

Erm... Not in my course, you don't! ;-)

Students like this musician had done exactly the work required to fulfill the requirements... which didn't match expected requirements (which are overwhelmingly scriptocentric).

Conversely, some learners assume they'll always get good grades ("I'm an A student!"), typically because their writing style matches academic expectations.

Surely, there's research on this labelling effect. Now, I'm not saying that it's the only effect coming from these letters (or from "dean's lists"). Accommodations can be particularly important in courses where there's a pressure to perform in a certain way. And it sounds like grade-based rewards are important in several social systems. I'm merely thinking of links between Howie Becker's best-known book and his unsung work.

Reminds me of: http://itre.cis.upenn.edu/~myl/languagelog/archives/001961.html