non-verbalness

After a morning spent getting very intimate with SO2 emission control data and Excel, I went out to grab lunch, and shared the elevator with a couple of other people. They tried including me in their conversation, but all I could do was smile and nod because I had lost all verbal communication abilities. I couldn't even manage a "hello" or a "see you later"... fortunately, there are non-verbal equivalents so I don't think I came off as rude (and hey, this is MIT, people acting oddly is expected), but it was a little disturbing.