[See correction below.]
Dutch psychologist Christof van Nimwegen has written a dissertation arguing that pens and pencils are crucial in the development of creativity and intelligence:
In "The Paradox of the guided user: assistance can be counter-effective," van Nimwegen asked two groups to perform the same tasks. The first was allowed use a computer; the second group only got a pen and pencil. The second group executed all tasks faster and performed substantially better. In addition, their solutions to complicated problems were more creative.What's crucial of course is not ink or graphite (or paper!) but self-reliance—trusting one's mind rather than the machine.
Paper and pencil, not computer, boosts creativity (eNews 2.0)
[Correction, October 8, 2008: I received an e-mail from Christof van Nimwegen stating that he has never investigated the use of pens, pencils, and paper. The description of his work and the quotations attributed to him in the eNews piece thus appear to be wholly inaccurate.]