Modeling Hierarchical Syntactic Structures in Morphological Processing

Yohei Oseki, Charles Yang, Alec Marantz


Abstract
Sentences are represented as hierarchical syntactic structures, which have been successfully modeled in sentence processing. In contrast, despite the theoretical agreement on hierarchical syntactic structures within words, words have been argued to be computationally less complex than sentences and implemented by finite-state models as linear strings of morphemes, and even the psychological reality of morphemes has been denied. In this paper, extending the computational models employed in sentence processing to morphological processing, we performed a computational simulation experiment where, given incremental surprisal as a linking hypothesis, five computational models with different representational assumptions were evaluated against human reaction times in visual lexical decision experiments available from the English Lexicon Project (ELP), a “shared task” in the morphological processing literature. The simulation experiment demonstrated that (i) “amorphous” models without morpheme units underperformed relative to “morphous” models, (ii) a computational model with hierarchical syntactic structures, Probabilistic Context-Free Grammar (PCFG), most accurately explained human reaction times, and (iii) this performance was achieved on top of surface frequency effects. These results strongly suggest that morphological processing tracks morphemes incrementally from left to right and parses them into hierarchical syntactic structures, contrary to “amorphous” and finite-state models of morphological processing.
Anthology ID:
W19-2905
Volume:
Proceedings of the Workshop on Cognitive Modeling and Computational Linguistics
Month:
June
Year:
2019
Address:
Minneapolis, Minnesota
Venue:
CMCL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
43–52
Language:
URL:
https://aclanthology.org/W19-2905
DOI:
10.18653/v1/W19-2905
Bibkey:
Cite (ACL):
Yohei Oseki, Charles Yang, and Alec Marantz. 2019. Modeling Hierarchical Syntactic Structures in Morphological Processing. In Proceedings of the Workshop on Cognitive Modeling and Computational Linguistics, pages 43–52, Minneapolis, Minnesota. Association for Computational Linguistics.
Cite (Informal):
Modeling Hierarchical Syntactic Structures in Morphological Processing (Oseki et al., CMCL 2019)
Copy Citation:
PDF:
https://aclanthology.org/W19-2905.pdf
Data
CELEX