Related Experiment Video
Updated: Jun 17, 2026
06:26
Meta-analysis of Voxel-Based Neuroimaging Studies using Seed-based d Mapping with Permutation of Subject Images (SDM-PSI)
Published on: November 27, 2019
SD-squared revisited: reply to Coltheart, Tree, and Saunders (2010)
Anna M Woollams1, Matthew A Lambon Ralph, David C Plaut
1Neuroscience and Aphasia Research Unit, School of Psychological Sciences, Zochonis Building, University of Manchester, Brunswick Street, Manchester M139PL, England. anna.woollams@manchester.ac.uk
Psychological Review
|January 13, 2010
Summary
The connectionist triangle model better explains surface dyslexia in semantic dementia patients than the dual route cascaded model. Simulations show semantic activation is crucial for reading exception words.
Area of Science:
- Cognitive Psychology
- Neuroscience
- Computational Linguistics
Background:
- The connectionist triangle model emphasizes semantic activation for phonological processing in reading aloud.
- Surface dyslexia is characterized by difficulties with low-frequency exception words.
Purpose of the Study:
- To compare the explanatory power of the connectionist triangle model and the dual route cascaded (DRC) model for reading aloud deficits.
- To re-evaluate simulations of semantic dementia (SD) patients' reading abilities, termed "SD-squared."
Main Methods:
- Computational simulations using the connectionist triangle model.
- Analysis of reading aloud data from 51 semantic dementia patients.
- Comparison with simulations from the dual route cascaded (DRC) model.
Main Results:
- Reduction of semantic activation in simulations led to deficits characteristic of surface dyslexia.
- The connectionist triangle model simulations provided a superior fit to patient data compared to DRC simulations.
- The "SD-squared" phenomenon was robustly demonstrated.
Conclusions:
- Semantic activation is critical for reading low-frequency exception words.
- The connectionist triangle model offers greater explanatory and predictive power for surface dyslexia in semantic dementia.
- The DRC model's fit to "SD-squared" data was less accurate than initially suggested.
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