Modeling Mechanisms of Persisting and Resolving Delay in Language Development PurposeIn this study, the authors used neural network modeling to investigate the possible mechanistic basis of developmental language delay and to test the viability of the hypothesis that persisting delay and resolving delay lie on a mechanistic continuum with normal development.MethodThe authors used a population modeling approach to study individual ... Research Article
Research Article  |   April 01, 2014
Modeling Mechanisms of Persisting and Resolving Delay in Language Development
 
Author Affiliations & Notes
  • Michael S. C. Thomas
    Developmental Neurocognition Lab, Birkbeck, University of London
  • V. C. P. Knowland
    Developmental Neurocognition Lab, Birkbeck, University of London
  • Disclosure:The authors have declared that no competing interests existed at the time of publication.
    Disclosure:The authors have declared that no competing interests existed at the time of publication.×
  • Correspondence to: Michael S. C. Thomas: m.thomas@bbk.ac.uk
  • Editor: Janna Oetting
    Editor: Janna Oetting×
  • Associate Editor: Pamela Hadley
    Associate Editor: Pamela Hadley×
Article Information
Development / Special Populations / Language Disorders / Attention, Memory & Executive Functions / Language
Research Article   |   April 01, 2014
Modeling Mechanisms of Persisting and Resolving Delay in Language Development
Journal of Speech, Language, and Hearing Research, April 2014, Vol. 57, 467-483. doi:10.1044/2013_JSLHR-L-12-0254
History: Received August 13, 2012 , Revised February 7, 2013 , Accepted June 25, 2013
 
Journal of Speech, Language, and Hearing Research, April 2014, Vol. 57, 467-483. doi:10.1044/2013_JSLHR-L-12-0254
History: Received August 13, 2012; Revised February 7, 2013; Accepted June 25, 2013
Web of Science® Times Cited: 5

PurposeIn this study, the authors used neural network modeling to investigate the possible mechanistic basis of developmental language delay and to test the viability of the hypothesis that persisting delay and resolving delay lie on a mechanistic continuum with normal development.

MethodThe authors used a population modeling approach to study individual rates of development in 1,000 simulated individuals acquiring a notional language domain (in this study, represented by English past tense). Variation was caused by differences in internal neurocomputational learning parameters as well as the richness of the language environment. An early language delay group was diagnosed, and individual trajectories were then traced.

ResultsQuantitative variations in learning mechanisms were sufficient to produce persisting delay and resolving delay subgroups in similar proportions to empirical observations. In the model, persisting language delay was caused by limitations in processing capacity, whereas resolving delay was caused by low plasticity. Richness of the language environment did not predict the emergence of persisting delay but did predict the final ability levels of individuals with resolving delay.

ConclusionMechanistically, it is viable that persisting delay and resolving delay are only quantitatively different. There may be an interaction between environmental factors and outcome groups, with individuals who have resolving delay being influenced more by the richness of the language environment.

Acknowledgments
This research was supported by U.K. Economic and Social Research Council (ESRC) Grant RES-062-23-2721, awarded to Wendy Best (University College London), Jackie Masterson (Institute of Education, London), and Michael S. C. Thomas (Birkbeck College London), and by a Leverhulme Study Abroad Fellowship held at the University of Chicago, awarded to Michael S. C. Thomas (Birkbeck College London).
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