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.     

The role of sublexical graphemic processing in reading

Dual-route models of reading postulate the existence of two separate mechanisms: The lexical route allows words to be recognized in their holistic form, and the sublexical route proceeds by converting the written sublexical entities of a word or a nonword into their corresponding phonological equivalents. Sublexical reading is assumed to require three stages of processing: graphemic parsing, graphophonemic conversion, and phoneme blending. This study provides evidence in favor of the existence of a graphemic parsing process which occurs prior to grapheme-phoneme conversion. A group of normal subjects read nonwords which contained multiletter graphemes significantly more slowly than graphemically simple nonwords. These results, best interpretable in the context of a recent dual-route model of reading, confirm previous data obtained in pathology which suggest the functional independence of this cognitive procedure.     

Priming and attentional control of lexical and sublexical pathways during naming

A modified priming task was used to investigate whether skilled readers are able to adjust the degree to which lexical and sublexical information contribute to naming. On each trial, participants named 5 low-frequency exception word primes or 5 nonword primes before a target. The low-frequency exception word primes should have produced a greater dependence on lexical information, whereas the nonword primes should have produced a greater dependence on sublexical information. Across 4 experiments, the effects of lexicality, regularity, frequency, and imageability were all modulated in predictable ways on the basis of the notion that the primes directed attention to specific processing pathways. It is argued that these results are consistent with an attentional control hypothesis.     

Lexical and sublexical semantic preview benefits in Chinese reading

Semantic processing from parafoveal words is an elusive phenomenon in alphabetic languages, but it has been demonstrated only for a restricted set of noncompound Chinese characters. Using the gaze-contingent boundary paradigm, this experiment examined whether parafoveal lexical and sublexical semantic information was extracted from compound preview characters. Results generalized parafoveal semantic processing to this representative set of Chinese characters and extended the parafoveal processing to radical (sublexical) level semantic information extraction. Implications for notions of parafoveal information extraction during Chinese reading are discussed.     

Priming and attentional control of lexical and sublexical pathways in naming: a reevaluation

The authors report 3 naming experiments using J. D. Zevin and D. A. Balota's (2000) multiple prime manipulation. They used 2 sets of nonword primes (fast and slow) and low-frequency exception word primes to separate the effects of prime speed from those of prime type. The size of the regularity effect was unaffected by prime type. Relative to the low-frequency exception word prime condition, the frequency effect was reduced in the fast, but not in the slow, nonword prime condition. Lexicality effect size was reduced in both nonword prime conditions, a result consistent with the lexical checking strategy described by S. J. Lupker, P. Brown, and L. Colombo (1997). The authors suggest that these results are better explained in terms of S. J. Lupker et al.'s time-criterion account than J. D. Zevin and D. A. Balota's pathway control hypothesis.     

Representation of lexical form: evidence from studies of sublexical ambiguity

The authors examined the role of intermediate, sublexical representations in spoken word perception. In particular, they tested whether flaps, which are neutralized allophones of intervocalic /t/s and /d/s, map onto their underlying phonemic counterparts. In 2 shadowing tasks, the authors found that flaps primed their carefully articulated counterparts, and vice versa. Because none of the flapped stimuli were lexically ambiguous (e.g., between rater and raider), these results provide evidence that such priming is sublexically mediated. Therefore, the current study provides further insights into when underlying form-based representations are activated during spoken word processing. In particular, the authors argue that phonological ambiguity, inherent in their flapped stimuli, is one of the conditions leading to the activation of underlying representations.     

The effect of factivity on lexical retrieval and postlexical processes during eye fixations in reading

Subjects were required to read short passages of text while their eye movements were monitored. Each experimental passage contained a critical factive or nonfactive verb that was followed by a false complement. In half of the trials, subjects' reading was unimpaired; in the remainder of the trial, a central visual pattern mask, which moved in synchrony with the eyes, was applied. The results showed that (1) factive and nonfactive verbs did not receive different amounts of fixation time during the reading text. However, (2) false complements that followed nonfactive verbs. On the basis of this, it is concluded that individual word characteristics, such as factivity, are encoded automatically while sentence interpretation requires effort to be completed.     

Tracking the transition from sublexical to lexical processing: On the creation of orthographic and phonological lexical representations

Participants read aloud nonword letter strings, one at a time, which varied in the number of letters. The standard result is observed in two experiments; the time to begin reading aloud increases as letter length increases. This result is standardly understood as reflecting the operation of a serial, left-to-right translation of graphemes into phonemes. The novel result is that the effect of letter length is statistically eliminated by a small number of repetitions. This elimination suggests that these nonwords are no longer always being read aloud via a serial left-to-right sublexical process. Instead, the data are taken as evidence that new orthographic and phonological lexical entries have been created for these nonwords and are now read at least sometimes by recourse to the lexical route. Experiment 2 replicates the interaction between nonword letter length and repetition observed in Experiment 1 and also demonstrates that this interaction is not seen when participants merely classify the string as appearing in upper or lower case. Implications for existing dual-route models of reading aloud and Share's self-teaching hypothesis are discussed.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh–PUNCH) than for high BF primes (e.g., panit–PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

Lexical and sublexical processes in the perception of transposed-letter anagrams

Evidence from priming and lexical decision tasks suggests that nonwords created by transposing adjacent letter pairs (TL nonwords) are very effective in activating lexical representations of their base words, because the process of orthographic matching tolerates minor changes in letter position. However, this account disregards the possible role of sublexical processing in reading. TL nonwords are perceptually ambiguous, with lexical and sublexical processing giving rise to conflicting interpretations. The consequences of this ambiguity were investigated in a lexical decision experiment with primes that were either high or low bigram frequency TL versions of target words. Priming effects were much larger for low BF primes (e.g., pucnh-PUNCH) than for high BF primes (e.g., panit-PAINT). This finding is interpreted as evidence that lexical activation can be inhibited by competing output resulting from sublexical processing of TL letter string. We conclude that phonological processing is an important determinant of responses to TL stimuli, and we consider how this interpretation might be accommodated within the dual-route cascaded (DRC) model of word recognition.     

The lexical bias effect in bilingual speech production: Evidence for feedback between lexical and sublexical levels across languages

The lexical bias effect (LBE) is the tendency for phonological substitution errors to result in existing words (rather than nonwords) at a rate higher than would be predicted by chance. This effect is often interpreted as revealing feedback between the phonological and lexical levels of representation during speech production. We report two experiments in which we tested for the LBE (1) in second-language production (Experiment 1) and (2) across the two languages of a bilingual (Experiment 2). There was an LBE in both situations. Thus, to the extent that the LBE reveals the presence of interactivity between the phonological and the lexical levels of representation, these effects suggest that there is feedback in second-language production and that it extends across the two languages of a bilingual.     

Orthographic error monitoring in old age: lexical and sublexical availability during perception and production

Previous research suggests that older adults suffer declines in producing accurate spellings but retain the ability to accurately detect misspellings. The preservation of perception in the face of impaired production has been used to support a model of aging in which age impairs access to linguistic representations under specific circumstances, while representations themselves remain intact. The current research tests two predictions of this Transmission Deficit Hypothesis (TDH): first, that the differential effect of age on perception and production occurs when tasks are equated on response requirements and underlying representations, and second, that both word and spelling frequency interact to determine the effect of age on performance. Results of two error monitoring tasks supported the predictions of the TDH, demonstrating age-related production impairments that interacted with both word and spelling frequency, but no impairment of older adults' spelling perception, even for low frequency words or spellings.     

Sensitivity to the acoustic correlates of lexical stress and their relationship to reading in skilled readers

The role of suprasegmental information in reading processes is a growing area of interest, and sensitivity to lexical stress has been shown to explain unique variance in reading development. However, less is known about its role in skilled reading. This study aimed to investigate the acoustic features of suprasegmental information using a same/different cross-modal matching task. Sixty-four adult participants completed standardized measures of reading accuracy, reading speed, and comprehension and performed an experimental task. The experimental task required the participants to identify whether non-speech acoustic sequences matched the characteristics of written words. The findings indicated differences in responses depending on where the lexical stress was required for the word. Moreover, evidence was found to support the view that amplitude information is part of the word knowledge retrieval process in skilled reading. The findings are discussed relative to models of reading and the role of lexical stress in lexical access.     

The effect of sublexical and lexical frequency on speech production: An fMRI investigation

There is no consensus regarding the fundamental phonetic units that underlie speech production. There is, however, general agreement that the frequency of occurrence of these units is a significant factor. Investigators often use the effects of manipulating frequency to support the importance of particular units. Studies of pseudoword production have been used to show the importance of sublexical units, such as initial syllables, phonemes, and biphones. However, it is not clear that these units play the same role when the production of pseudowords is compared to the production of real words. In this study, participants overtly repeated real and pseudowords that were similar for length, complexity, and initial syllable frequency while undergoing functional magnetic resonance imaging. Compared to real words, production of pseudowords produced greater activation in much of the speech production network, including bilateral inferior frontal cortex, precentral gyri and supplementary motor areas and left superior temporal cortex and anterior insula. Only middle right frontal gyrus showed greater activation for real words than for pseudowords. Compared to a no-speech control condition, production of pseudowords or real words resulted in activation of all of the areas shown to comprise the speech production network. Our data, in conjunction with previous studies, suggest that the unit that is identified as the basic unit of speech production is influenced by the nature of the speech that is being studied, i.e., real words as compared to other real words, pseudowords as compared to other pseudowords, or real words as compared to pseudowords.     

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.     

Bilingual vocabulary size and lexical reading in Italian

In the present study we investigated how the vocabulary size of English–Italian bilinguals affects reading aloud in Italian (L2) modulating the reader's sensitivity to lexical aspects of the language. We divided adult bilinguals in two groups according to their vocabulary size (Larger — LV, and smaller — SV), and compared their naming performance to that of native Italian (NI) readers. In Experiment 1 we investigated the lexicality and word frequency effects in reading aloud. Similarly to NI, both groups of bilinguals showed these effects. In Experiment 2 we investigated stress assignment – which is not predictable by rule – to Italian words. The SV group made more stress errors in reading words with a non-dominant stress pattern compared to the LV group. The results suggest that the size of the reader's L2 lexicon affects the probability of correct reading aloud.     

Writing nonsense: the interaction between lexical and sublexical knowledge in the priming of nonword spelling

The task of spelling nonwords to dictation necessarily requires the operation of a sublexical or assembled sound-to-spelling conversion process. We report an experiment that shows a clear lexical priming effect on nonword spelling (e.g., /vi:m/ was spelled as VEME more often following the prime word "theme" and as VEAM more often following "dream"), which was larger for lexically low-probability (or low-contingency) than for common (or high-contingency) spellings. Priming diminished when an unrelated word intervened between the prime word and target nonword and did so more for the production of low- than for high-contingency spellings. We interpret these results within an interactive model of spelling production that proposes feedback from the graphemic level to both the lexical and assembled spelling processes.     

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.     

Processing correlates of lexical semantic complexity

This paper explores how verb meanings that differ in semantic complexity are processed and represented. In particular, we compare eventive verbs, which denote causally structured events, with stative verbs, which denote facts without causal structure. We predicted that the conceptually more complex eventive verbs should take longer to process than stative verbs. Two experiments, a lexical decision task and a self-paced reading study, confirmed this prediction. The findings suggest that (a) semantic complexity is reflected in processing time, (b) processing verb meanings involves activating properties of the event structure beyond participants' roles, and (c) more generally, lexical event structures, which subsume thematic roles, may mediate between syntactic knowledge and semantic interpretation.     

An examination of age-related changes in the control of lexical and sublexical pathways in mapping spelling to sound

The current study investigated the extent to which young and older adults are able to direct attention to distinct processes in mapping spelling onto sound. Young and older adults completed either a speeded pronunciation task (reading aloud words) or regularization task (pronouncing words based on spelling-to-sound correspondences, e.g., pronouncing PINT such that it rhymes with HINT) in order to bias processing of lexical, whole-word information, or sublexical, spelling-to-sound mapping, respectively. Both younger and older adults produced reduced word-frequency effects and lexicality effects in the regularization task compared to the normal pronunciation task. Importantly, compared to younger adults, older adults produced exaggerated effects of task (i.e., pronunciation vs. regularization) on the observed frequency and lexicality effects. These results highlight both the flexibility of the lexical processing system and changes in the influence of the underlying lexical route due to additional 50 years of reading experience and/or changes in attentional control.