What can graph theory tell us about word learning and lexical retrieval?
OBJECTIVE
Graph theory and the new science of networks provide a mathematically rigorous approach to examine the development and organization of complex systems. These tools were applied to the mental lexicon to examine the organization of words in the lexicon and to explore how that structure might influence the acquisition and retrieval of phonological word-forms.


METHODS
Pajek, a program for large network analysis and visualization (V. Batagelj & A. Mvrar, 1998), was used to examine several characteristics of a network derived from a computerized database of the adult lexicon. Nodes in the network represented words, and a link connected two nodes if the words were phonological neighbors.


RESULTS
The average path length and clustering coefficient suggest that the phonological network exhibits small-world characteristics. The degree distribution was fit better by an exponential rather than a power-law function. Finally, the network exhibited assortative mixing by degree. Some of these structural characteristics were also found in graphs that were formed by 2 simple stochastic processes suggesting that similar processes might influence the development of the lexicon.


CONCLUSIONS
The graph theoretic perspective may provide novel insights about the mental lexicon and lead to future studies that help us better understand language development and processing.
Vitevitch
Michael S
MS
Spoken Language Laboratory, Department of Psychology, University of Kansas, Lawrence, KS 66045, USA. mvitevit@ku.edu
D000328:Adult; D006801:Humans; D007804:Language Development; D016571:Neural Networks, Computer; D010700:Phonetics; D013269:Stochastic Processes; D014825:Vocabulary