The multiplex structure of the mental lexicon influences picture naming in people with aphasia Nichol Castro1,+ and Massimo Stella2,3,+ 1School of Psychology, Georgia Institute of Technology, USA 2Institute for Complex Systems Simulation, University of Southampton, UK 3Complex Science Consulting, Italy *Corresponding authors:
[email protected],
[email protected] +These authors contributed equally to this work. October 17, 2018 Abstract An emerging area of research in cognitive science is the utilization of networks to model the structure and processes of the mental lexicon in healthy and clinical populations, like aphasia. Previous research has focused on only one type of word similarity at a time (e.g., semantic relationships), even though words are multi-faceted. Here, we investigate lexical retrieval in a picture naming task from people with Broca's and Wernicke's aphasia and healthy controls by utilizing a multiplex network structure that accounts for the interplay between multiple semantic and phonological relationships among words in the mental lexicon. Ex- tending upon previous work, we focused on the global network measure of closeness centrality which is known to capture spreading activation, an important process supporting lexical retrieval. We conducted a series of logistic regression models predicting the probability of correct picture naming. We tested whether multiplex closeness centrality was a better predictor of picture naming performance than single-layer closeness central- ities, other network measures assessing local and meso-scale structure, psycholinguistic variables, and group differences. We also examined production gaps, or the difference between the likelihood of producing a word with the lowest and highest closeness centralities.