"After we were on a panel together at CUNY a couple of weeks ago, Giovanni Arrighi told me that U.S. workers were more literate a century ago than today. I found that very hard to believe, but I didn't have the facts to make the argument. Does anyone here know about this?"
I have no fact or figures. I had occasion to compare essays written by freshmen in the late seventies with essays written by freshmen in the fifties, and found that the earlier ones were much more articulate and better organized.
To drill down, you could also compare letters written by soldiers from Iraq (or some of the blogs) to letters written by soldiers during the civil war. Anecdotally, the letters that I know of from the civil war were a universe away from what I see on the blogs. Blog: stream of consciousness, vocabulary minimual, structure nonexistent, ability to reflect or drill down even a layer also nonexistent. Civil war letters: articulate, long sentences with dependent clauses, heavily influenced by King James (rhetorical) periodical style, fully articulated emotions that ran the full gamut and were not restricted to despair and cynicism.
Joanna