The development of reading skill and bases of developmental dyslexia were explored using connectionist models. Four issues were examined: the acquisition of phonological knowledge prior to reading, how this knowledge facilitates learning to read, phonological and non phonological bases of dyslexia, and effects of literacy on phonological representation. Compared with simple feedforward networks, representing phonological knowledge in an attractor network yielded improved learning and generalization. Phonological and surface forms of developmental dyslexia, which are usually attributed to impairments in distinct lexical and nonlexical processing “routes,” were derived from different types of damage to the network. The results provide a computationally explicit account of many aspects of reading acquisition using connectionist principles.

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Effects of orthographic neighborhood in visual word recognition in Spanish were examined in 5 paradigms: progressive demasking, standard lexical decision, lexical decision with bloeldng of neighborhood density, naming, and semantic categorization. The results showed inhibitory effects of neighborhood frequency in the progressive-demasking task, in both lexieal-decision tasks, as well as for low-density words in the naming task, and for high-density words in the semantic-categorization task. Higher levels of neighborhood density produced an inhibitory trend in the progressive-demasking task, facilitation in lexieal decision (significant only when neighborhood density was blocked), and a robust facilitation effect in naming (only for words with higher frequency neighbors). A global analysis across tasks and one simulation study helped outline some of the underlying task-specific and task-independent mechanisms. It is a well established fact that words that are read more frequently (measured in terms of the number of occurrences in a given corpus) are recognized more rapidly and/or with fewer errors in the classical word-recognition paradigms than less frequently read words (see Balota, 1994, and

The influence of semantic ambiguity on word identification processes was explored in a series of word naming and lexical-decision experiments. There was no reliable ambiguity effect in 2 naming experiments, although an ambiguity advantage in lexical decision was obtained when orthographi-cally legal nonwords were used. No ambiguity effect was found in iexical decision when orthographically illegal nonwords were used, implying a semantic locus for the ambiguity advantage. These results were simulated by using a distributed memory model that also produces the ambiguity disadvantage in gaze duration that has been obtained with a reading comprehension task. Ambiguity effects in the model arise from the model's attempt to activate multiple meanings of an ambiguous word in response to presentation of that word's orthographic pattern. Reasons for discrepancies in empirical results and implications for distributed memory models are considered. Any comprehensive theory of mental representation and process must accommodate the complex means by which concepts are communicated through language. Through the course of history, humans have developed tools of communica-tion that facilitate the relaying of ideas and concepts, such as a writing system or orthography. This mapping of concepts to orthography is not entirely one to one, however, resulting in some words that correspond to multiple concepts, which are known as semantically ambiguous words. When reading text, the context provided by preceding words and sentences pro-vides a means of disambiguating such words. As a result, we may not even notice the ambiguity in words that we are reading in context. If, on the other hand, semantically ambiguous words are presented in isolation, their alternative meanings are readily accessible, and thus their ambiguous nature is noticed. In the research reported in this article, we compare performance on semantically ambiguous words with that of semantically unambiguous words in isolated word identifica-tion tasks and describe simulations of the empirical effects within the framework of a distributed memory architecture

In reading, lexical form-form relations may be more reliable than form-meaning relations. Accordingly, phonological forms (activated by graphic forms) become actual constituents, rather than addenda, of word identification. These considerations suggest that access to phonological forms can precede meaning access in single-word reading in many circumstances. The time course of form and meaning activation during Chinese word reading was tested in 2 primed-naming experiments varying prime type and prime-target stimulus onset asynehrony (SOA). The results showed a sequence of facilitation over SOA: (a) graphic, (b) phonological, (e) semantic. Words with precise meanings produced more rapid semantic priming than words with vague meanings. Graphic prime facilitation at a 43-ms SOA gave way to inhibition at longer SOAs. The onset of graphic inhibition coincided with the onset of phonological facilitation, suggesting a single identification moment. The authors describe an interactive constituency model that accounts for the pattern of data. Writing systems vary in how they represent the phonology of the language they encode. How are these differences reflected in visual word identification? Three classes of hypotheses have been proposed. According to the universal direct access hypothesis, word reading is accomplished by a visual route in all writing systems and in all orthographies. Phonological processing, to the extent that it occurs, is a product of individual reader and word characteristics (e.g., word frequency; Baluch & Besner, 1991; Besner, 1987;

The development of reading depends on phonological awareness across all languages so far studied. Languages vary in the consistency with which phonology is represented in orthography. This results in developmental differences in the grain size of lexical representations and accompanying differences in developmental reading strategies and the manifestation of dyslexia across orthographies. Differences in lexical representations and reading across languages leave developmental “footprints ” in the adult lexicon. The lexical organization and processing strategies that are characteristic of skilled reading in different orthographies are affected by different developmental constraints in different writing systems. The authors develop a novel theoretical framework to explain these cross-language data, which they label a psycholinguistic grain size theory of reading and its development. Reading is the process of understanding speech written down. The goal is to gain access to meaning. To acquire reading, children must learn the code used by their culture for representing speech as a series of visual symbols. Learning to read is thus fundamentally a process of matching distinctive visual symbols to units of sound (phonology). In most languages, the relationship between symbol

this article was supported by National Science Foundation Grant SBR-9616519. We are grateful to Max Coltheart, Laurie Feldman, Rumjahn Hoosain, Yuriko Kayamoto, and Sandy Pollatsek for their thoughtful comments. We thank Li Long for her assistance in recruiting participants in Beijing. Correspondence concerning this article should be addressed to Li Hal Tan or Charles A. Perfetti, Learning Research and Development Center, 3939 O'Hara Street, University of Pittsburgh, Pittsburgh, Pennsylvania 15260. Electronic mall may be sent to tanlh@hkucc.hku.hk. Recent research with Chinese single-character words, however, has suggested a stronger role for phonology in Chinese reading. In a primed perceptual-identification paradigm, Perfetti and Zhang (1991, Experiment 3) observed a synchrony of phonologic and semantic priming effects when a single-character prime was exposed for 50 ms, followed by a character target of 35 ms. Using a backward-masking procedure, Tan, Hoosain, and Peng (1995) exposed a target character for 60 ms, followed by a mask character that was presented for 40 ms. As in Perfetti and Zhang's experiment, they found no evidence for semantic effects in the absence of phonological effects. Equally interesting, when the target character had vague meaning, they found phonological effects in the absence of semantic effects. Such results suggest a very rapid activation of phonology and are not consistent with a meaning-first hypothesis (see Tan & Perfetti, 1998, for a detailed review of recent discoveries). The generality of these demonstrations of phonology is limited, however, because the research has used exclusively single-character words. Estimates of modem Chinese show that multiple-character words are actually more common than single-character words. According to...

The authors examine the implications of research on Chinese for theories of reading and propose the lexical constituency model as a general framework for word reading across writing systems. Word identities are defined by 3 interlinked constituents (orthographic, phonological, and semantic). The implemented model simulates the time course of graphic, phonological, and semantic priming effects, including immediate graphic facilitation followed by graphic inhibition with simultaneous phonological facilitation, a pattern unique to the Chinese writing system. Pseudocharacter primes produced only facilitation, supporting the model’s assumption that lexical thresholds determine phonological and semantic, but not graphic, effects. More generally, both universal reading processes and writing system constraints exist. Although phonology is universal, its activation process depends on how the writing system structures graphic units. The development of models of word reading has been informed primarily by studies of English word identification. This is true for both symbolic models that postulate an internal lexicon and multiple pathways to pronunciation (Besner & Smith, 1992; Coltheart,

Recent neuroimaging studies of language processing are examining the neural substrate of phonology because of its critical role in mapping sound information onto higher levels of language processing (e.g., words) as well as providing codes in which verbal information can be temporarily stored in working memory. However, the precise role of the inferior frontal cortex in spoken and written phonological tasks has remained elusive. Although lesion studies have indicated the presence of selective deficits in phonological processing, the location of lesions underlying these impairments has not revealed a consistent pattern. Despite efforts to refine methods and tasks, functional neuroimaging studies have also revealed variability in activation patterns. Reanalysis of evidence from these neuroimaging studies suggests that there are functional subregions within the inferior frontal gyrus that correspond to specific components of phonological processing (e.g., orthographic to phonological

According to the Universal Writing System Constraint, all writing systems encode language, and thus reflect basic properties of the linguistic system they encode. According to a second universal, the Universal Phonological Principle, the activation of word pronunciations occurs for skilled readers across all writing systems. We review recent research that illustrates the implications of these two universal principles both across and within writing systems. Within the family of alphabetic systems, differences between Korean and English arise in the languages, rather than the orthographies, while the reverse appears to be true for German and English differences. Across writing systems, new Event Related Potentials (ERP) experiments show the robustness of phonology across Chinese and English systems and chart the time course of word reading in Chinese and English for Chinese bilinguals and for English speakers learning Chinese. The ERP results show differences between Chinese and English for both groups and suggest that the time course of word processes and the brain areas identified as sources for the ERP components differ both as a result of writing system and the skill of the reader. We propose the System Accommodation Hypothesis, that reading processes and the neural structures that support them accommodate to specific visual and structural features of a new writing system.