"Towards an Integrated Model of the Mental Lexicon" by Natawut Monaikul

Publication Date

Spring 2015

Document Type

Thesis

Degree Name

Master of Science

Department

Computer Science

First Advisor

(Clare) Xueqing Tang, Ph.D.

Second Advisor

Kong-Cheng Wong, Ph.D.

Third Advisor

Chris Tweddle, Ph.D.

Abstract

Several models have been proposed attempting to describe the mental lexicon-the abstract organization of words in the human mind. Numerous studies have shown that by representing the mental lexicon as a network, where nodes represent words and edges connect similar words using a metric based on some word feature, a small-world structure is formed. This property, pervasive in many real-world networks, implies processing efficiency and resiliency to node deletion within the system, explaining the need for such a robust network as the mental lexicon. However, each model considered a single word feature at a time, such as semantic or phonological information. Moreover, these studies modeled the mental lexicon as an unweighted graph. In this thesis, I expand upon these works by proposing a model that incorporates several word features into a weighted network. Analyses on this model applied to the English lexicon show that while this model does not exhibit the same small-world characteristics as a weighted graph, by setting a minimum threshold on the weights (reminiscent of action potential thresholds in neural networks), the resulting unweighted counterpart is a small-world network. These results suggest that a more integrated model of the mental lexicon can be adopted while affording the same computational benefits of a small-world network. An increased understanding of the structure of the mental lexicon can provide a stronger foundation for more accurate computational models of speech and text processing and word-learning.

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