Orthographic and phonological preview benefits: Parafoveal processing in skilled and less-skilled deaf readers

Many deaf individuals do not develop the high-level reading skills that will allow them to fully take part into society. To attempt to explain this widespread difficulty in the deaf population, much research has honed in on the use of phonological codes during reading. The hypothesis that the use of phonological codes is associated with good reading skills in deaf readers, though not well supported, still lingers in the literature. We investigated skilled and less-skilled adult deaf readers' processing of orthographic and phonological codes in parafoveal vision during reading by monitoring their eye movements and using the boundary paradigm. Orthographic preview benefits were found in early measures of reading for skilled hearing, skilled deaf, and less-skilled deaf readers, but only skilled hearing readers processed phonological codes in parafoveal vision. Crucially, skilled and less-skilled deaf readers showed a very similar pattern of preview benefits during reading. These results support the notion that reading difficulties in deaf adults are not linked to their failure to activate phonological codes during reading.     

Instantiation in skilled and less skilled comprehenders

Previous research has shown that adults tend to infer particular meanings of words, according to their context, a process that has been termed instantiation. An experiment was carried out to investigate the relation between 7 to 8 year olds' skill at reading comprehension and their ability to instantiate. A cued recall paradigm was used: the subjects were presented with a series of short sentences, and either the general noun that had appeared in the original sentence, or a particular noun that fitted the context, was given as a cue. The results showed that both skilled and less skilled comprehenders recalled the original sentences equally well, given the original nouns, but that the performance of the skilled group was superior when they were given the particular word cues, indicating that the skilled comprehenders were instantiating more readily. An independent test showed that their superior performance was not attributable to their better general knowledge.     

Speed of phonological and orthographic processing as factors in dyslexia: electrophysiological evidence

The author investigated the hypothesis that speed of processing in the phonological and orthographic systems is one of the underlying variables of word-reading effectiveness. Speed of processing was assessed using measures of behavioral reaction time and electrophysiological latencies during phonological and orthographic task performance. Participants were 20 dyslexic and 20 normal-reading, male college students. An electrophysiological component complex (N1-P2-N2), as well as 2 other components (P3 and N4), was identified in both groups on each of the experimental tasks. Significant group differences were obtained only on the phonological tasks. Speed of processing during phonological judgment tasks was significantly prolonged among the dyslexic readers compared with the controls as reflected by P2, P3, and N4 latencies and reaction time. Between-task comparisons revealed significantly prolonged P2, P3, and N4 latencies on phonological compared with orthographic tasks in both dyslexic and normal readers, indicating that phonological classification of words may demand more time than orthographic classification. However, the gap score between speed of processing on the phonological and orthographic tasks was larger among the dyslexic readers and was observed mainly in P3 latency and reaction time. The highest correlation between word-reading accuracy score and the experimental measures was obtained in the dyslexic group with P3 latency gap score and in the control group with P2 latency gap score. The author proposes that slow phonological processing may cause "asynchrony" between the processing speeds within and between phonological and orthographic systems and may lead to a lack of efficient integration among the various subprocesses activated in reading, may slow down reading rate, and may impair word-reading effectiveness.     

Frequency and predictability effects in eye fixations for skilled and less-skilled deaf readers

The illiteracy rate in the deaf population has been alarmingly high for several decades, despite the fact that deaf children go through the standard stages of schooling. Much research addressing this issue has focused on word-level processes, but in the recent years, little research has focused on sentence-levels processes. Previous research (Fischler, 1985) investigated word integration within context in college-level deaf and hearing readers in a lexical decision task following incomplete sentences with targets that were congruous or incongruous relative to the preceding context; it was found that deaf readers, as a group, were more dependent on contextual information than their hearing counterparts. The present experiment extended Fischler's results and investigated the relationship between frequency, predictability, and reading skill in skilled hearing, skilled deaf, and less-skilled deaf readers. Results suggest that only less-skilled deaf readers, and not all deaf readers, rely more on contextual cues to boost word processing. Additionally, early effects of frequency and predictability were found for all three groups of readers, without any evidence for an interaction between frequency and predictability.     

汉字识别中亚词汇语音和语义信息在N170上的神经适应

视觉词汇识别的事件相关电位(ERP)研究发现早期的脑电成分N170具有对词汇的敏感性, 可能反映了字形、语音和语义加工, 目前还没有得到统一的结论。本研究利用汉字形声字声旁表音和形旁表义的独特性, 使用神经适应范式深入考察了N170对汉字亚词汇语音和语义信息的敏感性。实验1操纵了连续汉字的声旁和整字读音重复呈现探究其诱发的神经适应性, 结果发现了左侧电极的N170对声旁和整字读音重复都产生了神经适应。实验2进一步操纵形旁和整字语义的重复呈现, 结果发现左侧N170仅对整字语义相似性具有神经适应性, 而右侧N170对形旁和整字语义重复都产生了神经适应。实验结果表明, 左侧N170不仅对整字语音和语义信息敏感, 还对亚词汇的声旁信息敏感; 而右侧N170对整字语义以及亚词汇的形旁信息敏感。     

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.     

Event-related potentials, reaction time, and response selection of skilled and less-skilled cricket batsmen

The differences in P300 latency, P300 amplitude, response selection, and reaction time between skilled and less-skilled cricket batsmen have been investigated. Eight skilled and ten less-skilled right-handed batsmen each viewed 100 in-swing, 100 out-swing, and 40 slower deliveries displayed in random sequence from projected video footage whilst their responses and electroencephalograms were recorded. Logistic regression was used to derive a discriminative function for the P300 data. This was done to determine whether the skilled batsmen differed from the less-skilled batsmen on the basis of pooled P300 amplitude and latency data. All the batsmen were correctly characterised as being skilled or less-skilled. Logistic regression equations with reaction time and correctness of response data indicated that behavioural data do not correctly classify skilled performance. It is suggested that skilled cricket batsmen have a superior perceptual decision-making ability compared with less-skilled cricket batsmen, as measured by P300 latency and amplitude. This appears to be the first study showing a link between skill and cerebral cortical activity during a perceptual cricket batting task and it could pave the way for future studies on mental processing in cricket batsmen.     

Developmental differences in sensitivity to semantic relations among good and poor comprehenders: evidence from semantic priming

Semantic priming for category coordinates (e.g. CAT-DOG; AEROPLANE-TRAIN) and for pairs of words related through function (e.g. BROOM-FLOOR; SHAMPOO-HAIR) was assessed in children with good and poor reading comprehension, matched for decoding skill. Lexical association strength was also manipulated by comparing pairs of words that were highly associated with pairs that shared low association strength. Both groups of children showed priming for function-related words, but for the category co-ordinates, poor comprehenders only showed priming if the category pairs also shared high association strength. Good comprehenders showed priming for category-related targets, irrespective of the degree of prime-target association. These findings are related to models of language development in which category knowledge is gradually abstracted and refined from children's event-based knowledge and it is concluded that in the absence of explicit co-occurrence, poor comprehenders are less sensitive to abstract semantic relations than normal readers.     

汉字阅读的语义神经回路及其与语音回路的协作机制

从神经网络的角度研究词汇阅读的大脑神经机制, 需要揭示语义和语音神经回路的动态协作机制, 而语义加工神经回路是探讨该问题的一个亟待解决的瓶颈问题。利用汉字表义的独特性, 以形旁语义作用的神经机制为切入点, 计划开展的4个fMRI实验拟探讨汉字阅读的语义神经回路及其与语音回路的动态协作机制。实验1利用多参数相关分析技术, 识别与汉字语义和语音属性相关的功能脑区; 实验2和实验3集中考察形旁语义加工的大脑神经机制, 深入探讨形旁语义作用的实质, 揭示汉字阅读中语义加工的神经回路; 实验4通过建构汉字阅读的动态因果模型, 考察在刺激驱动和任务调节下, 阅读相关脑区联结模式的动态变化, 阐明语义和语音神经回路的相互协作机制。研究结果将从跨语言的角度, 阐明阅读神经网络的内部动态机制, 为联结主义理论提供神经生理方面的直接证据; 并为基于脑科学的教育教学和阅读障碍矫治等实践应用提供理论依据。     

Dissociating semantic and phonological maintenance using fMRI

Functional magnetic resonance imaging (fMRI) distinguished regions of neural activity associated with active maintenance of semantic and phonological information. Subjects saw a single word for 2 sec, and following a 10-sec delay, made a judgment about that word. In the semantic task, subjects focused on the meaning of the word and decided whether a second word was synonymous with it. In the phonological task, subjects repeated the word silently and decided whether it shared a vowel sound with a nonsense word. Analyses allowed for isolation of neural activity during the maintenance delay. Semantic maintenance elicited greater activity in bilateral inferior frontal gyrus and left middle temporal gyrus regions of interest (ROI). In contrast, there was greater activity for phonological maintenance in the left superior parietal ROI. These results show a frontal-temporal network involved in actively maintaining the meanings of words, and they indicate that semantic and phonological maintenance processes are dissociable within working memory.     

Activation of semantic and phonological codes during reading

Three experiments used a new paradigm to examine word-coding processes during reading. Subjects read text passages and occasionally responded to lexical-decision probes. Experiment 1 focused on semantic and surface codes. The activation of semantic codes appeared to increase over time, whereas surface codes did not. In addition, subjects who were instructed to remember the exact wording of the passages showed stronger activation of surface codes than did subjects who read for comprehension. Experiments 2 and 3 explored the role of phonological codes. Experiment 2 showed that phonological codes were activated by specific words in a passage. In contrast, Experiment 3 found no evidence that phonological codes were activated by the more general passage context. Taken together, the experiments suggest some of the roles semantic and phonological codes may play during reading.     

An electrophysiological investigation into the automaticity of emotional face processing in high versus low trait anxious individuals

To examine the extent of automaticity of emotional face processing in high versus low trait anxious participants, event-related potentials (ERPs) were recorded to emotional (fearful, happy) and neutral faces under varying task demands (low load, high load). Results showed that perceptual encoding of emotional faces, as reflected in P1 and early posterior negativity components, was unaffected by the availability of processing resources. In contrast, the postperceptual registration and storage of emotion-related information, as reflected in the late positive potential component at frontal locations, was influenced by the availability of processing resources, and this effect was further modulated by level of trait anxiety. Specifically, frontal ERP augmentations to emotional faces were eliminated in the more demanding task for low trait anxious participants, whereas ERP enhancements to emotional faces were unaffected by task load in high trait anxious participants. This result suggests greater automaticity in processing affective information in high trait anxious participants.     

An activation-based model of sentence processing as skilled memory retrieval

We present a detailed process theory of the moment-by-moment working-memory retrievals and associated control structure that subserve sentence comprehension. The theory is derived from the application of independently motivated principles of memory and cognitive skill to the specialized task of sentence parsing. The resulting theory construes sentence processing as a series of skilled associative memory retrievals modulated by similarity-based interference and fluctuating activation. The cognitive principles are formalized in computational form in the Adaptive Control of Thought–Rational (ACT–R) architecture, and our process model is realized in ACT–R. We present the results of 6 sets of simulations: 5 simulation sets provide quantitative accounts of the effects of length and structural interference on both unambiguous and garden-path structures. A final simulation set provides a graded taxonomy of double center embeddings ranging from relatively easy to extremely difficult. The explanation of center-embedding difficulty is a novel one that derives from the model' complete reliance on discriminating retrieval cues in the absence of an explicit representation of serial order information. All fits were obtained with only 1 free scaling parameter fixed across the simulations; all other parameters were ACT–R defaults. The modeling results support the hypothesis that fluctuating activation and similarity-based interference are the key factors shaping working memory in sentence processing. We contrast the theory and empirical predictions with several related accounts of sentence-processing complexity.     

Reduced short-term memory capacity in Alzheimer's disease: the role of phonological, lexical, and semantic processing

Individuals with Alzheimer's disease (AD) are often reported to have reduced verbal short-term memory capacity, typically attributed to their attention/executive deficits. However, these individuals also tend to show progressive impairment of semantic, lexical, and phonological processing which may underlie their low short-term memory capacity. The goals of this study were to assess the contribution of each level of representation (phonological, lexical, and semantic) to immediate serial recall performance in 18 individuals with AD, and to examine how these linguistic effects on short-term memory were modulated by their reduced capacity to manipulate information in short-term memory associated with executive dysfunction. Results showed that individuals with AD had difficulty recalling items that relied on phonological representations, which led to increased lexicality effects relative to the control group. This finding suggests that patients have a greater reliance on lexical/semantic information than controls, possibly to make up for deficits in retention and processing of phonological material. This lexical/semantic effect was not found to be significantly correlated with patients' capacity to manipulate verbal material in short-term memory, indicating that language processing and executive deficits may independently contribute to reducing verbal short-term memory capacity in AD.     

Reduced short-term memory capacity in Alzheimer's disease: The role of phonological,lexical, and semantic processing

Individuals with Alzheimer's disease (AD) are often reported to have reduced verbal short-term memory capacity, typically attributed to their attention/executive deficits. However, these individuals also tend to show progressive impairment of semantic, lexical, and phonological processing which may underlie their low short-term memory capacity. The goals of this study were to assess the contribution of each level of representation (phonological, lexical, and semantic) to immediate serial recall performance in 18 individuals with AD, and to examine how these linguistic effects on short-term memory were modulated by their reduced capacity to manipulate information in short-term memory associated with executive dysfunction. Results showed that individuals with AD had difficulty recalling items that relied on phonological representations, which led to increased lexicality effects relative to the control group. This finding suggests that patients have a greater reliance on lexical/semantic information than controls, possibly to make up for deficits in retention and processing of phonological material. This lexical/semantic effect was not found to be significantly correlated with patients’ capacity to manipulate verbal material in short-term memory, indicating that language processing and executive deficits may independently contribute to reducing verbal short-term memory capacity in AD.     

Making sense of sentences in schizophrenia: electrophysiological evidence for abnormal interactions between semantic and syntactic processing

Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words.     

Effect of phonological processing on temporal processing

Many studies have reported that the effect of concurrent nontemporal processing on time estimation depends on the difficulty of the nontemporal task. The perceived duration of a given temporal interval decreases as the difficulty of the concurrent nontemporal task increases. A question thus arises as to whether any kind of nontemporal task will have the same effect on temporal processing. Two experiments were conducted in which the level of the nontemporal task demand was systematically varied. In Experiment 1, the effect of phonological processing on concurrent time estimation was shown to vary linearly with the number of items to be processed. Experiment 2 showed that the concurrent time estimation did not vary with the level of figural processing demands. This suggests selective interference with temporal processing on the part of concurrent phonological processing.     

Decision latencies for phonological and semantic information in object identification

Several on-line studies in the literature have been cited in support of a two-stage model of name-retrieval in which semantic processing precedes and mediates access to phonology. Because of inconsistencies in prior studies an off-line experiment was designed to provide converging evidence on this issue. An experiment is reported in which young and elderly adults were required to give speeded judgments of whether a pictured object matched a named category, a named physical attribute, or a rhyming cue. Latencies for the young adults were fastest for category judgments and slowest for rhyming judgments. For the elderly adults physical attributes and rhyming judgments were equivalent. Results are discussed in terms of "lemma" theory in object naming.     

An investigation of time course of category and semantic priming

Low semantically similar exemplars in a category demonstrate the category-priming effect through priming of the category (i.e., exemplar-category-exemplar), whereas high semantically similar exemplars in the same category demonstrate the semantic-priming effect (i.e., direct activation of one high semantically similar exemplar by another). The author asked whether the category- and semantic-priming effects are based on a common memory process. She examined this question by testing the time courses of category- and semantic-priming effects. She tested participants on either category- or semantic-priming paradigm at 2 different time intervals (6 min and 42 min) by using a lexical decision task using exemplars from categories. Results showed that the time course of category priming was different from that of semantic priming. The author concludes that these 2 priming effects are based on 2 separate memory processes.