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We modeled word reading growth in typically developing (n= 118) and children with dyslexia (n= 20), Grades 2–5, across multiple exposures to 30 words. We explored the facilitative versus inhibitory effects of exposures to differential mixes of words that support high- versus low-frequency vowel pronunciations. One training corpus contained a ratio of 80%–20% high- to low-frequency pronunciations (e.g., for ea; 80% eapronounced as /i/ as in beadand 20% eapronounced /ε/ as in dead), whereas the other consisted of a ratio of 20%–80%. We also modeled accuracy at the final exposure for a subset of 12 shared words across conditions using item-level crossed-random effects models with reading skill (i.e., typically developing vs. dyslexic), condition, word frequency, and vowel pronunciation (i.e., high- vs. low-frequency vowel pronunciation) as predictors in the model. We were particularly interested in the interaction between condition and vowel pronunciation across reading groups. Results suggest typically developing children were influenced by the interaction between condition and vowel pronunciation, suggesting both facilitation and inhibition, whereas children with dyslexia were influenced by condition and vowel pronunciation without an interaction. Results are interpreted within the overfitting model of dyslexia.

Word reading in alphabetic language involves a cortical system with multiple components whose division of labor depends on the transparency of the writing system. To gain insight about the neural division of labor between phonology and semantics subserving word reading in Chinese, a deep non-alphabetic writing system, functional magnetic resonance imaging (fMRI) was used to investigate the effects of phonological and semantic training on the cortical circuitry for oral naming of Chinese characters. In a training study, we examined whether a training task that differentially focused readers' attention on the phonological or semantic properties of a Chinese character changes the patterns of cortical activation that was evoked by that character in a subsequent naming task. Our imaging results corroborate that the cortical regions underlying reading in Chinese largely overlap the left-hemisphere reading system responsible for reading in alphabetic languages, with some cortical regions in the left-hemisphere uniquely recruited for reading in Chinese. However, in contrast to findings from studies of English word naming, we observed considerable overlap in the neural activation patterns associated with phonological and semantic training on naming Chinese characters, which we suggest may reflect a balanced neural division of labor between phonology and semantics in Chinese character reading. The equitable division of labor for Chinese reading might be driven by the special statistical structure of the writing system, which includes equally systematic mappings in the correspondences between written forms and their pronunciations and meanings.

Using functional magnetic resonance imaging, we explored the role of semantics in mediating orthographic-to-phonological processing in reading aloud, focusing on the interaction of imageability with spelling-to-sound consistency for low-frequency words. Behaviorally, high-imageable words attenuate the standard latency and accuracy disadvantage for low-frequency inconsistent words relative to their consistent counterparts. Neurobiologically, high-imageable words reduced consistency-related activation in the inferior frontal gyrus but increased posterior activation in the angular and middle temporal gyri, representing a possible neural signature of the tradeoff between semantics and phonology in reading aloud. We discuss implications for neurobiological models of reading in terms of understanding the interplay among areas associated with component processes and suggest that the results constitute an important step toward integrating neurobiological and computational models of reading.

The effects of morphological regularities on the behavior of connectionist networks were studied by training identical networks on orthographic-semantic mappings that either contained such regularities or did not. Morphological regularities had a substantial impact on both the amount of training needed to learn a mapping and the number of words that could be included in the training set. A variety of analyses demonstrated how morphological regularities structure the organization and componentiality of a network's internal representations.

In the primate visual system, the identification of objects and the processing of spatial information are accomplished by different cortical pathways. The computational properties of this “two-systems” design were explored by constructing simplifying connectionist models. The models were designed to simultaneously classify and locate shapes that could appear in multiple positions in a matrix, and the ease of forming representations of the two kinds of information was measured. Some networks were designed so that all hidden nodes projected to all output nodes, whereas others had the hidden nodes split into two groups, with some projecting to the output nodes that registered shape identity and the remainder projecting to the output nodes that registered location. The simulations revealed that splitting processing into separate streams for identifying and locating a shape led to better performance only under some circumstances. Provided that enough computational resources were available in both streams, split networks were able to develop more efficient internal representations, as revealed by detailed analyses of the patterns of weights between connections.

Spoken words are easier to identify if they have been heard recently. This phenomenon, known as repetition priming, can be used to investigate the processes underlying word recognition. Using an implicit memory paradigm, this study looked at the effect of changing the voice of the speaker on repetition priming. Voice effects occur if repetition priming is reduced when a spoken word has been heard in different voices at study and test. Voice effects have been found in implicit memory tasks, such as word identification and word‐stem completion [B. A. Church and D. L. Schacter, JEP:LMC 20, 521–533 (1994); S. D. Goldinger, doctoral dissertation, 1992]. This study investigated if these results could be generalized to other implicit memory tasks—specifically, lexical decision, naming, and a new task, auditory fragment completion. No voice effects were found with any of these three tasks. These results are problematic for current accounts of word recognition and imply that as yet unidentified factors control the occurrence of voice effects.