Lexical Processing System Research Articles

Individual differences in Cantonese Chinese word recognition: Insights from the Chinese Lexicon Project

The Chinese Lexicon Project is a repository of lexical decision data for 25,286 Cantonese Chinese two-character compound words. To create that repository, 594 participants responded to approximately 1,404 words and 1,404 nonwords over three sessions. Using the data in this repository, the present study examines the variability and reliability of Chinese lexical decision performance, along with the moderating influence of individual differences on lexical processing. We generally found high to very high within- and between-session reliabilities for mean response times, ex-Gaussian parameters, accuracy rates, and a composite proficiency measure tapping lexical processing fluency. Using linear mixed effects models, we also found reliable interactions between fluency and two lexical effects. Specifically, more fluent readers showed larger effects of word frequency and semantic transparency. These results attest to the stability of Chinese word recognition performance, and are most consistent with a flexible lexical processing system that adapts optimally to task demands.

Dynamic adjustment of lexical processing in the lexical decision task: Cross-trial sequence effects.

There has been growing interest in dynamic changes in the lexical processing system across trials, which have typically been assessed via linear mixed effect modelling. In the current study, we explore the influence of previous trial lexicality and previous trial perceptual degradation on the effect of lexicality and degradation on the current trial. The results of analyses of three datasets (two previously published studies and a new study) provide evidence for a robust four-way interaction among previous trial lexicality and degradation and current trial lexicality and degradation effects. Discussion emphasizes how priming of relevant dimensions (clear vs. degraded or word vs. nonword) within the experimental context modulates the influence of degradation on the current trial as a function of lexicality. These results suggest that in lexical decision there are robust lingering effects of the previous stimulus and response that carry over to the current stimulus and response, and participants cannot tune task-related systems to only the present trial. Importantly, although these complex relationships are theoretically important regarding lexical and decision level processes, these complexities also reinforce Keith Rayner's emphasis on on-line eye-tracking measures during reading as the most straightforward window into word-level processes engaged during reading.

Recovery of orthographic processing after stroke: A longitudinal fMRI study

An intact orthographic processing system is critical for normal reading and spelling. Here we investigate the neural changes associated with impairment and subsequent recovery of the orthographic lexical processing system in an individual with an ischemic left posterior cerebral artery (PCA) stroke. This work describes a longitudinal case study of a patient, whose initials are MMY, with impairments in orthographic lexical processing for reading and spelling at stroke onset, and who recovered these skills within 1 year post stroke. We tested the hypothesis that this acute impairment to reading and spelling would be associated with a selective loss of neural activation in the left fusiform gyrus (FG), and that subsequent recovery would be associated with a gain of neural activation in this region. MMY's case provided a unique opportunity to assess the selectivity of neural changes because she demonstrated a behavioral recovery of naming as well; i.e., if there is neural recovery for reading and spelling, but not naming, then these neural changes are selective to the recovery of orthographic processing. To test our hypothesis, we examined longitudinal behavioral and functional magnetic resonance imaging (fMRI) data of reading, spelling, and visual object naming acquired acutely, 3 weeks, 5 months, and one year post stroke. In confirmation of our hypothesis, the loss and subsequent gain of orthographic lexical processing was associated with up-regulation of neural activation in areas previously associated with orthographic lexical processing: i.e., the left mid-FG and inferior frontal junction (IFJ). Furthermore, these neural changes were found to be selective to orthographic processing, as they were observed for reading and spelling, but not for visual object naming within the left mid-FG. This work shows that left PCA stroke can temporarily and selectively disrupt the orthographic lexical processing system, not only in the posterior region adjacent to the stroke, but also in relatively distant frontal orthographic processing regions.

Seeking the -ational in derivational morphology

ABSTRACTBackground: Derived words have constituted an important bridge between aphasiology and psycholinguistics by addressing the extent to which morphology affects representation and processing in the mind/brain.Aims: Our goal was to assess how properties of whole words and their overlapping substrings affect the manner in which English derivationally suffixed words are recognised and produced.Methods & Procedures: We probed the processing of multimorphemic words containing strings of two derivational suffixes by healthy adult participants, employing both a progressive demasking naming task and a typing task. The progressive demasking paradigm that we employed integrates word recognition and production by requiring that a participant recognises a progressively demasked stimulus and then say it as quickly as possible. The typing task allowed us to focus on segment by segment aspects of processing during production by enabling us to construct per-letter typing times for each region of a word.Outcomes & Results: We found converging influences across the tasks that correspond to the properties of roots, stems, suffixes and suffix strings.Conclusions: We interpret these effects to accord with a perspective that emphasises the dynamic nature of the lexical processing system and massive interconnectivity within it. This has implications for unimpaired processing and for the word processing challenges experienced by people with aphasia.

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

ABSTRACTThe 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.

Shared Early Pathways of Word and Pseudoword Processing: Evidence from High-density Electrocorticography

UC Berkeley Phonology Lab Annual Report (2012) Shared early pathways of word and pseudoword processing: Evidence from high-density electrocorticography Emily Cibelli ∗ University of California, Berkeley ecibelli@berkeley.edu Introduction In psycholinguistic studies of lexical processing, language users’ responses to real words are often compared to novel pseudoword forms. The goal of these comparisons is to learn something about the architecture of the lexical processing system, by examining or inferring the processing pathways evoked by words, which have full phonological, lexical, grammatical, and semantic representations. These are compared to pseudowords, which are assumed to lack all linguistic information at levels higher than the phonological representation, due to their novel status. However, the precise nature of pseudoword representation is still a subject of inquiry, one that is critical to understanding precisely what is being isolated in the lexical processing system in experiments where words and pseudowords are compared. The present study contributes to this line of research by providing data on the neural processing of words and pseudowords in an auditory listening task. Previous research Theories of pseudoword processing streams In studies of word reading, models of processing have been proposed in which words and pseu- dowords employ different processing pathways, one facilitated by sublexical processes and the other by lexical processes (Coltheart et al. 1993, 2001, see also Marshall and Newcombe 1973). This ar- gument, the dual-route theory, is built upon the observation that readers with different types of dyslexia may or may not be impaired when reading pseudowords, a distinction ascribed to whether or not the sublexical (phonological) level of processing is impaired. Although designed to explain processing with visual presentation of stimuli, this theory has been extended to examine word and pseduworod proccessing in the auditory domain as well (Glosser et al. 1998), making it a more general account of the distinction between novel forms and stored lexical representations. However, on another account, pseudowords and words utilize shared processing pathways, with processing differences attributable to different degrees of engagement of various components of the system. An argument in the connectionist tradition (e.g. Seidenberg and McClelland 1989) argues against the dual-route theory by positing that differences between words and pseudowords reflect differences in how strongly orthography, phonology, and semantics are activated, but not to entirely different Data from this study was collected and made available by the lab of Dr. Edward Chang at UCSF. This study has benefited from suggestions and advice from Edward Chang, Kristofer Bouchard, Nima Mesgarani, Angela Ren, Keith Johnson, Shinae Kang, and Susanne Gahl, and members of the Chang Lab at UCSF and the Phonology Lab at UC Berkeley.

Lexical processing in individuals with high-functioning autism and Asperger’s disorder

The presence or absence of clinically delayed language development prior to 3 years of age is a key, but contentious, clinical feature distinguishing autism from Asperger's disorder. The aim of this study was to examine language processing in children with high-functioning autism (HFA) and Asperger's disorder (AD) using a task which taps lexical processing, a core language ability. Eleven individuals with HFA, 11 with AD and 11 typically developing (TD) individuals completed a masked priming task, a psycholinguistic paradigm that directly examines lexical processes. Within-group analyses revealed the AD and TD groups had intact lexical processing systems and orthographic processing of the written word. The outcomes for the HFA group were ambiguous, suggesting that their lexical processing system is either delayed or is structurally different. This suggests that fundamental differences in lexical processing exist between HFA and AD and remain evident later in development.

Individual differences in the joint effects of semantic priming and word frequency revealed by RT distributional analyses: The role of lexical integrity

Word frequency and semantic priming effects are among the most robust effects in visual word recognition, and it has been generally assumed that these two variables produce interactive effects in lexical decision performance, with larger priming effects for low-frequency targets. The results from four lexical decision experiments indicate that the joint effects of semantic priming and word frequency are critically dependent upon differences in the vocabulary knowledge of the participants. Specifically, across two Universities, additive effects of the two variables were observed in means, and in RT distributional analyses, in participants with more vocabulary knowledge, while interactive effects were observed in participants with less vocabulary knowledge. These results are discussed with reference to [Borowsky, R., & Besner, D. (1993). Visual word recognition: A multistage activation model. Journal of Experimental Psychology: Learning, Memory, and Cognition, 19, 813–840] multistage account and [Plaut, D. C., & Booth, J. R. (2000). Individual and developmental differences in semantic priming: Empirical and computational support for a single-mechanism account of lexical processing. Psychological Review, 107, 786–823] single-mechanism model. In general, the findings are also consistent with a flexible lexical processing system that optimizes performance based on processing fluency and task demands.

A case study of the effect of age-of-acquisition on reading aloud in Chinese dyslexia

This paper reports the influence of age-of-acquisition (AoA) effects on the oral reading accuracy of a Chinese brain-injured individual, FWL, who has anomia and dyslexia resulting from moderate-to-severe semantic deficits. We found an effect of the phonological consistency of a character and tentative evidence for an interaction between AoA and consistency. These observations converge on previous reports of an effect of AoA on reading and spelling of alphabetic scripts and in the reading of Japanese Kanji, a non-alphabetic script. An effect of AoA is also the expected outcome of the arbitrary mapping hypothesis which assumes that the locus of the AoA effect resides in the connection between levels of representations in the lexical processing system. We consider alternative interpretations of the AoA effect being located at the representations themselves, including phonological output and the semantic system. We propose that future studies of dyslexic individuals who rely primarily on the semantic reading route for reading in Chinese may reveal effects of semantic variables, including those associated with the semantic radical in phonetic compound characters.

Lexical-Semantic Activation in Broca's and Wernicke's Aphasia: Evidence from Eye Movements

Lexical processing requires both activating stored representations and selecting among active candidates. The current work uses an eye-tracking paradigm to conduct a detailed temporal investigation of lexical processing. Patients with Broca's and Wernicke's aphasia are studied to shed light on the roles of anterior and posterior brain regions in lexical processing as well as the effects of lexical competition on such processing. Experiment 1 investigates whether objects semantically related to an uttered word are preferentially fixated, for example, given the auditory target "hammer," do participants fixate a picture of a nail? Results show that, like normal controls, both groups of patients are more likely to fixate on an object semantically related to the target than an unrelated object. Experiment 2 explores whether Broca's and Wernicke's aphasics show competition effects when words share onsets with the uttered word, for instance, given the auditory target "hammer," do participants fixate a picture of a hammock? Experiment 3 investigates whether these patients activate words semantically related to onset competitors of the uttered word, for example, given the auditory target "hammock," do participants fixate a nail due to partial activation of the onset competitor hammer? Results of Experiments 2 and 3 show pathological patterns of performance for both Broca's and Wernicke's aphasics under conditions of lexical onset competition. However, the patterns of deficit differed, suggesting different functional and computational roles for anterior and posterior areas in lexical processing. Implications of the findings for the functional architecture of the lexical processing system and its potential neural substrates are considered.

Processing of sub-syllabic speech units in the posterior temporal lobe: An fMRI study

The objective of this study was to investigate phonological processing in the brain by using sub-syllabic speech units with rapidly changing frequency spectra. We used isolated stop consonants extracted from natural speech consonant–vowel (CV) syllables, which were digitized and presented through headphones in a functional magnetic resonance imaging (fMRI) paradigm. The stop consonants were contrasted with CV syllables. In order to control for general auditory activation, we used duration- and intensity-matched noise as a third stimulus category. The subjects were seventeen right-handed, healthy male volunteers. BOLD activation responses were acquired on a 1.5-T MR scanner. The auditory stimuli were presented through MR compatible headphones, using an fMRI paradigm with clustered volume acquisition and 12 s repetition time. The consonant vs. noise comparison resulted in unilateral left lateralized activation in the posterior part of the middle temporal gyrus and superior temporal sulcus (MTG/STS). The CV syllable vs. noise comparison resulted in bilateral activation in the same regions, with a leftward asymmetry. The reversed comparisons, i.e., noise vs. speech stimuli, resulted in right hemisphere activation in the supramarginal and superior temporal gyrus, as well as right prefrontal activation. Since the consonant stimuli are unlikely to have activated a semantic–lexical processing system, it seems reasonable to assume that the MTG/STS activation represents phonetic/phonological processing. This may involve the processing of both spectral and temporal features considered important for phonetic encoding.

Dissociation of Semantic and Phonological Errors in Naming

We report the naming performance of a fluent aphasic, DP, who shows a striking dissociation between semantic and phonological (nonword) errors: he produced numerous semantic errors but virtually no phonological errors. DP's pattern of performance is the reverse of that reported for patient DM (Caramazza, Papagno, & Ruml, 2000), who only made phonological errors in a naming task. These patterns of performance are inconsistent with the proposal by Dell, Schwartz, Martin, Saffran, and Gagnon (1997) that the naming deficit in fluent aphasia is the result of global damage to all levels of the lexical access system and support instead the hypothesis that brain damage can selectively disrupt distinct subcomponents of the lexical processing system.

Model-based semantic treatment for naming deficits in aphasia.

An interactive activation model for picture naming was used to guide treatment of a semantic-level deficit in 4 individuals with aphasia and severe picture-naming problems. Participants exhibited a profile consistent with Broca's aphasia with severe naming deficits, part of which was attributable to a semantic impairment based on testing of the lexical system. A semantic-based treatment was used to train naming of nouns in two semantic categories using a single-participant multiple baseline across behaviors and participants. Additional treatment, which included orthographic and phonological information about target words, then was applied. Treatment responses and error patterns demonstrated that semantic treatment resulted in improved naming of both trained and untrained items for 2 of 4 participants. Two participants did not show improved naming until treatment emphasizing the phonological form of the word was provided. This study demonstrates the utility of using an interactive activation model to plan treatment based on levels of disruption in the lexical processing system.

Neurological Distribution of Processing Resources Underlying Language Comprehension

Using a cross-modal lexical priming technique we provide an on-line examination of the ability of aphasic patients to construct syntactically licensed dependencies in real time. We show a distinct difference between Wernicke's and Broca's aphasic patients with respect to this form of syntactic processing: the Wernicke's patients link the elements of dependency relations in the same manner as do neurologically intact individuals; the Broca's patients show no evidence of such linkage. These findings indicate that the cerebral tissue implicated in Wernicke's aphasia is not crucial for recovering syntactically licensed structural dependencies, while that implicated in Broca's aphasia is. Moreover, additional considerations suggest that the latter region is not the locus of syntactic representations per se, but rather provides the resources that sustain the normal operating characteristics of the lexical processing system-characteristics that are, in turn, necessary for building syntactic representations in real time.

The role of semantic transparency in the processing and representation of Dutch compounds

Abstract The processing and representation of Dutch compound words was investigated as a function of their semantic transparency. The first experiment, with immediate partial repetition of the constituents of the compounds, provided clear evidence for the sensitivity of the lexical processing system to morphological complexity, independent of semantic transparency. This was confirmed in a second experiment, with semantic priming of the meaning of the constituents. Unlike compounds that are semantically fully or partially transparent, completely opaque compounds did not prime the associates of their constituents. The results for completely opaque compounds were the same as for monomorphemic words that accidentally contain two existing morphemes of the language. It is concluded that completely opaque compounds are not connected with their constituents at the level of semantic representations.