Contextual control over lexical and sublexical routines when reading English aloud

Are the processes responsible for reading aloud single well-formed letter strings under contextual control? Despite the widespread contention that the answer to this question is “yes,” it has been remarkably difficult to provide a compelling demonstration to that effect. In a speeded naming experiment, skilled readers read aloud exception words (such asPint) that are atypical in terms of their spelling sound correspondences and nonwords (such asFlad) that appeared in a predictable sequence. Subjects took longer to name both words and nonwords when the item on the preceding trial was from the other lexical category, relative to when the preceding item was from the same lexical category. This finding is consistent with the relative contributions of lexical and sublexical knowledge being controlled. We note a number of different ways that this control could arise and suggest some directions for future research.     

There goes the neighbourhood: contextual control over the breadth of lexical activation when reading aloud

There are currently two computational accounts of how the time to read pseudohomophones (like BRANE) and their nonword controls (like FRANE) varies with changes in context. In Reynolds and Besner's (2005) account, readers vary the breadth of lexical activation in response to changes in context. A competing account proposed by Kwantes and Marmurek (2007) and independently by Perry, Ziegler, and Zorzi (2007) has readers varying their response criterion in response to changes in context. The present work adjudicates between these two accounts by examining how the effect of neighbourhood density changes as a function of list context when reading pseudohomophones aloud. The results of an experiment and simulations from a leading computational model support the lexical breadth account, but are inconsistent with the response criterion account.     

There goes the neighbourhood: Contextual control over the breadth of lexical activation when reading aloud

There are currently two computational accounts of how the time to read pseudohomophones (like BRANE) and their nonword controls (like FRANE) varies with changes in context. In Reynolds and Besner's (2005) account, readers vary the breadth of lexical activation in response to changes in context. A competing account proposed by Kwantes and Marmurek (2007 Kwantes, P. and Marmurek, H. 2007. Controlling lexical contributions to the reading of pseudohomophones. Psychonomic Bulletin & Review, 14: 373–378. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and independently by Perry, Ziegler, and Zorzi (2007 Perry, C., Ziegler, J. C. and Zorzi, M. 2007. Nested incremental modeling in the development of computational theories: The CDP+ model of reading aloud. Psychological Review, 114: 273–315. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) has readers varying their response criterion in response to changes in context. The present work adjudicates between these two accounts by examining how the effect of neighbourhood density changes as a function of list context when reading pseudohomophones aloud. The results of an experiment and simulations from a leading computational model support the lexical breadth account, but are inconsistent with the response criterion account.     

Intention and performance when reading aloud: Context is everything

A widely held account asserts that single words are automatically identified in the absence of an intent to process them in the form of identifying a task set, and implementing it. We provide novel evidence that there is no fixed relation between intention and visual word identification. Subjects were randomly cued on a trial-by-trial basis as to whether to read aloud a single target word (Go) or not (No-go). When the Go-No Go probability was 50% (Experiment 1) the effect of stimulus quality (bright vs. dim targets) was the same size as in a separate block of 100% Go trials. In Experiment 2, where the Go-No Go probability was 80% in the cued condition, the stimulus quality effect was smaller than in the block of all Go trials. These results can be understood in terms of Go trial probability moderating whether subjects (i) hold off beginning to process the target until an intention in the form of a Task Set has been implemented, or (ii) begin to identify the target during the time taken to implement a Task Set. The additivity of stimulus quality and cueing conditions in Experiment 1 support the view that target processing only begins when a Task Set is in place, whereas the under-additivity of stimulus quality and cueing condition in Experiment 2 supports the interpretation that target identification can start during the time that a Task Set is being implemented. Taken together with other results, we conclude that there is no fixed relation between an intention and word identification; context is everything.     

The interaction of pronunciation rules and lexical representations in reading aloud

Two experiments examined the role of pronunciation rules and of lexical information in pronouncing letter strings. In Experiment 1, subjects pronounced pseudowords varying in the strength of the rules needed to pronounce them, as well as in the availability of a lexical model. In Experiment 2, the stimuli were words varying in rule strength and in usage frequency. The pronunciation times from both experiments displayed an interaction between rules and lexical information: When the rules necessary were strong, the relative availability of lexical information was less important than when the rules were weak. The results were discussed with respect to both traditional dual-process models of pronunciation and models proposing the use of lexical analogies.     

Lexical processing while deciding what task to perform: reading aloud in the context of the task set paradigm

The results of two experiments provide the first direct demonstration that subjects can process a word lexically despite concurrently being engaged in decoding a task cue telling them which of two tasks to perform. These results, taken together with others, point to qualitative differences between the mind‘s ability to engage in lexical versus sublexical processing during the time they are engaged with other tasks. The emerging picture is one in which some form of resource(s) plays little role during lexical processing whereas the need for some form of resource(s) during sublexical processing serves to bottleneck performance.     

On the dominance of whole-word knowledge in reading aloud

The localist dual-route model of visual word recognition assumes a routine thataddresses the pronunciation of all words known to the reader (the lexical-semantic pathway) and another routine, operating in parallel, thatassembles pronunciations on the basis of sublexical spelling-sound correspondences. The present experiment exploits theexception effect (in which words that are atypical in terms of their spelling-sound correspondences are named more slowly than typical ones) because it is considered a marker of the joint operation of these two routines. Participants named high- and lowfrequency regular and exception words that were repeated across two blocks of trials. The widely reported interaction between regularity and word frequency is present in Block 1 but is reduced in magnitude in Block 2. DRC, an implemented dual-route model, simulates the data. Taken in conjunction with other reports, the results provide further evidence for a double dissociation between addressed and assembled routines and are consistent with the view that skill in recognizing printed words known to the reader reflects the dominance of orthographic over phonological processing.     

Typing versus thinking aloud when reading: Implications for computer-based assessment and training tools

The goal of this study was to assess the impact of modality of production of think-aloud protocols on reading strategies. Readers in two studies spoke or typed protocols for narrative or science texts and completed comprehension tests for each text. Human judges identified the presence of paraphrasing, bridging inferences, and elaborating within the protocols. Reading comprehension skill was assessed with the Nelson-Denny test. With respect to narrative texts, paraphrasing and bridging were less frequent when readers were typing than when they were thinking aloud. With respect to science texts, less-skilled readers made bridging inferences more frequently when typing than when speaking. Conversely, skilled readers generated more paraphrases than bridges when typing thoughts but not when speaking. These results have implications for computer-based tools for reading assessment and intervention.     

Serial processing in reading aloud: no challenge for a parallel model

K. Rastle and M. Coltheart (1999) challenged parallel models of reading by showing that the cost of irregularity in low-frequency exception words was modulated by the position of the irregularity in the word. This position-of-irregularity effect was taken as strong evidence of serial processing in reading. This article refutes Rastle and Coltheart's theoretical conclusions in 3 ways: First, a parallel model, the connectionist dual process model (M. Zorzi, G. Houghton, & B. Butterworth, 1998b), produces a position-of-irregularity effect. Second, the supposed serial effect can be reduced to a position-specific grapheme-phoneme consistency effect. Third, the position-of-irregularity effect vanishes when the experimental data are reanalyzed using grapheme-phoneme consistency as the covariate. This demonstration has broader implications for studies aiming at adjudicating between models: Strong inferences should be avoided until the computational models are actually tested.     

Serial processing in reading aloud: reply to Zorzi (2000)

K. Rastle and M. Coltheart (1999; see also M. Coltheart & K. Rastle, 1994) reported data demonstrating that the cost of irregularity in reading aloud low-frequency exception words is modulated by the position of the irregularity in the word. They argued that these data implicated a serial process and falsified all models of reading aloud that operate solely in parallel, a conclusion that M. Zorzi (2000) challenged by successfully simulating the position of irregularity effect with such a model. Zorzi (2000) further claimed that a reanalysis of K. Rastle and M. Coltheart's (1999) data demonstrates sensitivity to grapheme-phoneme consistency (which he claimed was confounded across the position of irregularity manipulation) rather than the use of a serial process. Here, the authors argue that M. Zorzi's (2000) reanalyses were inappropriate and reassert that K. Rastle and M. Coltheart's (1999) findings are evidence for serial processing.     

On the dissociation between reaction time and response duration as a function of lexical and sublexical reading: An examination of phonetic decoding and computational models

Neurobiological models of reading account for two ways in which orthography is converted to phonology: (1) familiar words, particularly those with exceptional spelling-sound mappings (e.g., shoe) access their whole-word lexical representations in the ventral visual stream, and (2) orthographically unfamiliar words, particularly those with regular spelling-sound mappings (i.e., pseudohomophones [PHs], which are orthographically novel but sound like real words; e.g., shue) are phonetically decoded via sublexical processing in the dorsal visual stream. The present study used a naming task in order to compare naming reaction time (RT) and response duration (RD) of exception and regular words to their PH counterparts. We replicated our earlier findings with words, and extended them to PH phonetic decoding by showing a similar effect on RT and RD of matched PHs. Given that the shorter RDs for exception words can be attributed to the benefit of whole-word processing in the orthographic word system, and the longer RTs for exception words to the conflict with phonetic decoding, our PH results demonstrate that phonetic decoding also involves top-down feedback from phonological lexical representations (e.g., activated by shue) to the orthographic representations of the corresponding correct word (e.g., shoe). Two computational models were tested for their ability to account for these effects: the DRC and the CDP+. The CDP+ fared best as it was capable of simulating both the regularity and stimulus type effect on RT for both word and PH identification, although not their over-additive interaction. Our results demonstrate that both lexical reading and phonetic decoding elicit a regularity dissociation between RT and RD that provides important constraints to all models of reading, and that phonetic decoding results in top-down feedback that bolsters the orthographic lexical reading process.     

The role of lexical expertise in reading homophones

In Experiment 1, university students classified on lexical expertise on the basis of spelling plus nonword pronunciation accuracy made lexical decisions to homophones and control words. Homophones were accepted as words more slowly than control words, but lexical experts showed a smaller homophone cost than the less skilled group. In Experiment 2, similarly classified groups showed a large difference in their ability to detect homophones, with the low-expertise group showing a yes bias to high-frequency words, and having difficulty detecting homophones when mate-frequency was low. The results suggest superior use of orthography in the lexical experts and more reliance on semantic information in nonexperts, and support the importance of facility with orthography–phonology mappings in lexical expertise.     

Thinking aloud during reading: A descriptive model and its application

The problem-solving aspect of reading was studied by a thinking-aloud procedure. A model was developed, describing the information attended to, the thought operation used, and the result derived. Four main operations were identified: Reading, Evoking, Interpreting , and Comparing. A coding system, based upon this model, was developed. Its interrater reliability was between 0.86 and 0.92. This system was used to study the effect of reading purpose. An experimental group was instructed to apply a text concerning creativity to the problem of inducing constructive learning at the university. A control group was assigned reading with no particular purpose in mind. The experimental group used the Interpreting operation more often. Also, the Comparing operation, applied to a comparison between the text and the subjects' own knowledge, less often resulted in disagreement. Thus, the coding system is detailed enough to reflect differences in thought processes.     

Qualitative differences between the joint effects of stimulus quality and word frequency in reading aloud and lexical decision: extensions to Yap and Balota (2007)

There have been multiple reports over the last 3 decades that stimulus quality and word frequency have additive effects on the time to make a lexical decision. However, it is surprising that there is only 1 published report to date that has investigated the joint effects of these two factors in the context of reading aloud, and the outcome of that study is ambiguous. The present study shows that these factors interact in the context of reading aloud and at the same time replicate the standard pattern reported for lexical decision. The main implication of these results is that lexical activation, at least as indexed by the effect of word frequency, does not unfold in a uniform way in the contexts reported here. The observed dissociation also implies, contrary to J. A. Fodor's (1983) view, that the mental lexicon is penetrable rather than encapsulated. The distinction between cascaded and thresholded processing offers one way to understand these and related results. A direction for further research is briefly noted.     

Reading aloud: when the effect of stimulus quality distinguishes between cascaded and thresholded components

A central feature of many formal accounts of reading aloud, and of Coltheart and colleagues dual-route cascaded model in particular, is that activation across various modules is cascaded. Evidence is reviewed that this assumption is problematic in a particular context, along with a solution that involves thresholding the output of the letter level to the nonlexical routine. Consideration of the known effects of repetition leads to the prediction of a three-way interaction between stimulus quality, repetition, and lexicality in which repetition and stimulus quality interact when reading aloud exception words, but produce additive effects when reading aloud nonwords. The result of such an experiment confirms this prediction, and appears consistent with the localized dual-route model. Implications for other accounts are briefly noted.     

Verb-noun double dissociation in aphasic lexical impairments: the role of word frequency and imageability

Neurolinguistic studies have provided important evidence regarding the organization of lexical representations and the structure of underlying conceptual knowledge; in particular, it has been shown that the retrieval of verbs and nouns can be damaged selectively. Dissociated lexical damage is proof of an independent mental organization of lexical representations and/or of the underlying processes. The aim of the present study is to estimate the rate of dissociated impairments for nouns and verbs on a large sample of mild to moderate aphasic patients and to investigate the mechanisms underlying such phenomena. In addition, the authors wished to verify to what degree the impairment for nouns and verbs is related to a specific type of language disorder. A confrontation naming task for verbs and nouns was administered to 58 aphasic patients. The major lexical (word frequency and age of acquisition) and semantic variables (familiarity and imageability of the underlying concept) were considered for each noun and verb used in the task. Verbs were distinguished by major functional classes (transitive, intransitive, and ergative verbs). The data collected from this task were analyzed twice: (i) as a group study comparison of major aphasic subgroups and (ii) as a multiple single case study to evaluate the differences on the naming of verbs and nouns and the effect of the lexical semantic variables on each individual patient. The results confirm the existence of dissociated naming impairments of verbs and nouns. Selective impairment of verbs is more frequent (34%) than that of nouns (10%). In many cases, the dissociated pattern of naming impairment disappeared when the effect of the concomitant variables (word frequency and imageability) was removed, but in approximately one-fifth of the cases the noun or verb superiority was preserved. Noun superiority emerged in five of six agrammatic patients. Both the naming of verbs (n = 9) or of nouns (n = 6) could be impaired selectively in fluent aphasic patients. The results lend support to the hypothesis of an independent mental organization of nouns and verbs, but a substantial effect of imageability and word frequency suggests an interaction of the naming impairment with underlying lexical and semantic aspects.     

The relationship between reading ability and lateralized lexical decision

Although lexical decision remains one of the most extensively studied cognitive tasks, very little is known about its relationship to broader linguistic performance such as reading ability. In a correlational study, several aspects of lateralized lexical decision performance were related to vocabulary and reading comprehension measures, as assessed using the Nelson-Denny Reading Test. This lateralized lexical decision task has been previously shown to demonstrate (1) independent contributions from both hemispheres, as well as (2) interhemispheric interactions during word recognition. Lexical decision performance showed strong relationships with both reading measures. Specifically, vocabulary performance correlated significantly with left visual field (LVF) word accuracy and LVF non-word latency, both measures of right hemisphere performance. There were also significant, though somewhat weaker, correlations between reading comprehension and RVF non-word latency. Lexicality priming, a measure of interhemispheric communication during lexical decision, was also correlated with reading comprehension. These results suggest that hemispheric interaction during word recognition is common, and that lexical processing contribution from the right hemisphere, something commonly taken as minor and inconsequential, can lead to significant performance benefits and to individual differences in reading.     

Reading: dissociation of the lexical and phonologic mechanisms

Three distinct reading mechanisms have been proposed: the phonologic conversion system in which letters are converted to their sound equivalents (phonemes) before meaning is established, and two lexical or whole-word mechanisms in which a word (or root morpheme) is identified as a single unit rather than by phonologic conversion. The two lexical mechanisms differ in that one is inextricably linked to semantics but the other is not. The phonologic conversion system may depend more on the perisylvian phonologic system than do the lexical mechanisms, which may be mediated by left parietal or occipital areas or by the right hemisphere. Described here is a patient who had an infarction that partially isolated the perisylvian speech areas and disconnected the partially preserved lexical systems from the phonologic mechanism. He read visually presented orthographically irregular words but could not pronounce orally spelled irregular words. Although he could not read nonwords, he could pronounce orally spelled nonwords and orthographically regular words. These observations suggest that the lexical and phonologic conversion systems are functionally and anatomically distinct.