This excerpt from An Invitation to Cognitive Science - 2nd Edition: Vol. 1. Lila R. Gleitman and Mark Liberman, editors. © 1995 The MIT Press. is provided in screen-viewable form for personal use only by members of MIT CogNet. Unauthorized use or dissemination of this information is expressly forbidden. If you have any questions about this material, please contact cognetadmin@cognet.mit.edu.