Multipath parsing in the brain
Berta Franzluebbers Donald Dunagan Miloš Stanojević Jan Buys John T. Hale
Humans understand sentences word-by-word, in the order that they hear them.
This incrementality entails resolving temporary ambiguities about syntactic
relationships. We investigate how humans process these syntactic ambiguities by
correlating predictions from incremental generative dependency parsers with
timecourse data from people undergoing functional neuroimaging while listening
to an audiobook. In particular, we compare competing hypotheses regarding the
number of developing syntactic analyses in play during word-by-word
comprehension: one vs more than one. This comparison involves evaluating
syntactic surprisal from a state-of-the-art dependency parser with LLM-adapted
encodings against an existing fMRI dataset. In both English and Chinese data,
we find evidence for multipath parsing. Brain regions associated with this
multipath effect include bilateral superior temporal gyrus.