Recent developments in the NL-Soar garden path theory

This report describes a theory of garden path phenomena that is emerging from work on NL-Soar, a computational model of language comprehension embedded within the Soar architecture. The theory is constrained by a corpus of two kinds of sentences: garden paths (GP), which reveal the limitations of human comprehension in dealing with local ambiguities, and non-garden-paths (NGP), which reveal its power in handling local ambiguities. NL-Soar is a single-path comprehender with a limited capacity to repair misanlysed input. A space of repair mechanisms is explored by hand simulation on the corpus. The importance of phonology and plausible search control is established, leading to a theory up to 95% accurate (76% worst case) in predicting performance on 37 distinct GP and NGP types. This research was sponsored by the Avionics Laboratory, Wright Research and Development Center, Aeronautical Systems Division (AFSC), U.S. Air Force, Wright-Patterson AFB, Ohio 45433-6543 under Contract F33615-90-C-1465, ARPA Order No. 7597. The views and conclusions contained in this document are those of the author and should not be interpreted as representing the official policies, either expressed or implied, of the U.S. government.