Assessing the role of different spatial frequencies in word perception by good and poor readers

Numerous studies indicate that dyslexic and nondyslexic individuals exhibit different patterns of sensitivity to spatial frequency. However, the extension of this effect to normal (nondyslexic) adults of good and poor reading abilities and the role played by different spatial frequencies in word perception have yet to be determined. In this study, using normal (nondyslexic) adults, we assessed reading ability, spatial frequency sensitivity, and perception of spatially filtered words and nonwords (using a two-alternative forced choice paradigm to avoid artifactual influences of nonperceptual guesswork). Good and poor readers showed different patterns of spatial frequency sensitivity. However, no differences in accuracy of word and nonword perception were found between good and poor readers, despite their differences in spatial frequency sensitivity. Indeed, both reading abilities showed the same superior perceptibility for spatially filtered words over nonwords across different spatial frequency bands. These findings indicate that spatial frequency sensitivity differences extend to normal (nondyslexic) adult readers and that a range of spatial frequencies can be used for word perception by good and poor readers. However, spatial frequency sensitivity may not accurately reveal an individual's ability to perceive words.     

A multistream model of visual word recognition

Four experiments are reported that test a multistream model of visual word recognition, which associates letter-level and word-level processing channels with three known visual processing streams isolated in macaque monkeys: the magno-dominated (MD) stream, the interblob-dominated (ID) stream, and the blob-dominated (BD) stream (Van Essen & Anderson, 1995). We show that mixing the color of adjacent letters of words does not result in facilitation of response times or error rates when the spatial-frequency pattern of a whole word is familiar. However, facilitation does occur when the spatial-frequency pattern of a whole word is not familiar. This pattern of results is not due to different luminance levels across the different-colored stimuli and the background because isoluminant displays were used. Also, the mixed-case, mixed-hue facilitation occurred when different display distances were used (Experiments 2 and 3), so this suggests that image normalization can adjust independently of object size differences. Finally, we show that this effect persists in both spaced and unspaced conditions (Experiment 4)—suggesting that inappropriate letter grouping by hue cannot account for these results. These data support a model of visual word recognition in which lower spatial frequencies are processed first in the more rapid MD stream. The slower ID and BD streams may process some lower spatial frequency information in addition to processing higher spatial frequency information, but these channels tend to lose the processing race to recognition unless the letter string is unfamiliar to the MD stream—as with mixed-case presentation.     

词素位置概率在中文阅读中的作用：词汇判断和眼动研究

中文词切分的认知机制一直是心理语言学关注的焦点问题之一,研究发现中文读者可使用词素位置概率等语言学线索帮助词切分,而首、尾词素位置概率的重要程度以往研究观点并不一致。本研究通过词汇判断和眼动实验,考察中文读者对首、尾词素位置概率的利用情况。实验1a和1b采用词汇判断任务,考察在不同词频条件下词首与词尾词素位置概率对词汇识别的影响。在错误率和反应时指标上,高频词条件下词首与词尾词素位置概率效应不显著;低频词条件下词首词素位置概率效应显著,词尾词素位置概率效应不显著。实验2a和2b采用句子阅读任务,考察在自然阅读情境中被试对词素位置概率的运用。在凝视时间、回视路径时间和总注视时间指标上,低频词条件下词首词素位置概率效应显著,词尾词素位置概率效应不显著。高频词条件下词首与词尾词素位置概率效应均不显著。词汇判断和眼动证据共同表明,词素位置概率信息是中文读者重要的语言词切分线索,且与词尾词素位置概率相比,词首词素位置概率在词汇切分与识别过程中发挥的作用更大。同时,词素位置概率线索的运用会受到词频的影响,研究结果支持复合词加工的混合通达表征模型。     

On the role of competing word units in visual word recognition: the neighborhood frequency effect

Current models of word recognition generally assume that word units orthographically similar to a stimulus word are involved in the visual recognition of this word. We refer to this set of orthographically similar words as an orthographic neighborhood. Two experiments are presented that investigate the ways in which the composition of this neighborhood can affect word recognition. The data indicate that the presence in the neighborhood of at least one unit of higher frequency than the stimulus word itself results in interference in stimulus word processing. Lexical decision latencies (Experiment 1) and gaze durations (Experiment 2) to words with one neighbor of higher frequency were significantly longer than to words without a more frequent neighbor. This neighborhood frequency effect is discussed in terms of the different types of candidate selection process postulated by contemporary models of visual word recognition.     

Spoken word recognition by eye

Spoken word recognition is thought to be achieved via competition in the mental lexicon between perceptually similar word forms. A review of the development and initial behavioral validations of computational models of visual spoken word recognition is presented, followed by a report of new empirical evidence. Specifically, a replication and extension of Mattys, Bernstein & Auer's (2002) study was conducted with 20 deaf participants who varied widely in speechreading ability. Participants visually identified isolated spoken words. Accuracy of visual spoken word recognition was influenced by the number of visually similar words in the lexicon and by the frequency of occurrence of the stimulus words. The results are consistent with the common view held within auditory word recognition that this task is accomplished via a process of activation and competition in which frequently occurring units are favored. Finally, future directions for visual spoken word recognition are discussed.     

Stimulus-based lexical distinctiveness as a general word-recognition mechanism

Word recognition is generally assumed to be achieved via competition in the mental lexicon between phonetically similar word forms. However, this process has so far been examined only in the context of auditory phonetic similarity. In the present study, we investigated whether the influence of word-form similarity on word recognition holds in the visual modality and with the patterns of visual phonetic similarity. Deaf and hearing participants identified isolated spoken words presented visually on a video monitor. On the basis of computational modeling of the lexicon from visual confusion matrices of visual speech syllables, words were chosen to vary in visual phonetic distinctiveness, ranging from visually unambiguous (lexical equivalence class [LEC] size of 1) to highly confusable (LEC size greater than 10). Identification accuracy was found to be highly related to the word LEC size and frequency of occurrence in English. Deaf and hearing participants did not differ in their sensitivity to word LEC size and frequency. The results indicate that visual spoken word recognition shows strong similarities with its auditory counterpart in that the same dependencies on lexical similarity and word frequency are found to influence visual speech recognition accuracy. In particular, the results suggest that stimulus-based lexical distinctiveness is a valid construct to describe the underlying machinery of both visual and auditory spoken word recognition.     

Perceptual salience of derivational suffixes in visual word recognition

This study analyzes the role of derivational suffixes in visual word recognition, tracking the eye movements of 31 participants in a sentence-reading task in Spanish. Perceptual salience of suffixes was operationalized as the proportion of letters represented by the suffixes with respect to the full words, that is, we relate the number of letters comprising the suffixes to the number of letters in the words in which they appear. The results reveal a significant role in first fixation duration of both word frequency – the more frequent the word, the shorter the fixations, and perceptual salience – the more salient the suffix, the longer the fixations. Moreover, in gaze duration, our results show a main effect of word length – the longer the word, the longer the fixations; word frequency; and significant interactions between word frequency and perceptual salience of suffixes on the one hand – the effect of word frequency is only significant when perceptual salience of suffixes is high, and between word frequency and word length on the other hand – the frequency effect decreases as word length increases. Overall results are interpreted in the light of the dual route models by which full-form and morphological processing interactively cooperate in visual word recognition.     

The Modulation of Visual and Task Characteristics of a Writing System on Hemispheric Lateralization in Visual Word Recognition—A Computational Exploration

Through computational modeling, here we examine whether visual and task characteristics of writing systems alone can account for lateralization differences in visual word recognition between different languages without assuming influence from left hemisphere (LH) lateralized language processes. We apply a hemispheric processing model of face recognition to visual word recognition; the model implements a theory of hemispheric asymmetry in perception that posits low spatial frequency biases in the right hemisphere and high spatial frequency (HSF) biases in the LH. We show two factors that can influence lateralization: (a) Visual similarity among words: The more similar the words in the lexicon look visually, the more HSF/LH processing is required to distinguish them, and (b) Requirement to decompose words into graphemes for grapheme‐phoneme mapping: Alphabetic reading (involving grapheme‐phoneme conversion) requires more HSF/LH processing than logographic reading (no grapheme‐phoneme mapping). These factors may explain the difference in lateralization between English and Chinese orthographic processing.     

The contribution of rapid visual and auditory processing to the reading of irregular words and pseudowords presented singly and in contiguity

This study examined the relative involvement of rapid auditory and visual temporal resolution mechanisms in the reading of phonologically regular pseudowords and English irregular words presented both in isolation and in contiguity as a series of six words. Seventy-nine undergraduates participated in a range of reading, visual temporal, and auditory temporal tasks. The correlation analyses suggested a general timing mechanism across modalities. There were more significant correlations between the visual temporal measures and irregular word reading and between the auditory measures and pseudoword reading. Auditory gap detection predicted pseudoword reading accuracies. The low temporal frequency flicker contrast sensitivity measure predicted the accuracies of isolated irregular words and pseudowords presented in contiguity. However, when a combined speed-accuracy score was used, visible persistence at both low and high spatial frequencies and auditory gap detection were active in the reading of pseudowords presented in contiguity. Sensory processing skills in both visual and auditory modalities accounted for some of the variance in the reading performance of normal undergraduates, not just reading-impaired students.     

The role of letter recognition in word recognition

In a paradigm that avoids methodological problems of earlier studies, evidence was gathered addressed to the question of whether we read letter by letter. If word recognition involves letter recognition, then the difficulty of recognizing a word should vary with the difficulty of recognizing its letters. This was tested by assessing letter difficulty in two letter discrimination tasks and in a letter naming task, and then comparing 15 adult subjects' visual recognition latency to 72 easy-letter words and to 72 difficult-letter words. Word frequency and word length were also manipulated. Results indicated no effect for letter difficulty, although recognition latency reliably decreased with word frequency and monotonically increased with word length (21 msec/letter), suggesting that we do not read letter by letter, but that whatever plays a role in word recognition is smaller than the word and correlated with word length in letters.     

Word frequency and laterality effects in lexical decision: right hemisphere mechanisms

Three experiments investigated the role of the right cerebral hemisphere in the word frequency effect observed in visual word recognition. The experiments examined lexical decisions to low and high frequency words as well as non-words in a divided visual field paradigm. Experiment 1 showed a significant word frequency effect only for left visual field presentation. Experiment 2 provided a partial replication of the results of Experiment 1 with a different set of words. In Experiment 3, case alternation was implemented to investigate a possible explanation of the findings. Results of the first experiment were replicated in the condition without case alternation. In the case-alternated condition, the word frequency effect was significant only for right visual field presentations. The present findings emphasize the need to consider that information processing strategies relevant to hemispheric asymmetries might account in part for the word frequency effect.     

Spatial frequency content of visual imagery

Three experiments employing the McCollough paradigm were conducted to determine the spatial-frequency content of visual imagery. In Experiment 1, large and reliable pattern-contingent color aftereffects were obtained after adaptation to visual imagery. The direction of the aftereffects indicated that subjects were adapting to higher spatial frequencies in their imagery. These results contrast with the data of Experiment 2, which demonstrate that color aftereffects obtained with adaptation to physically present stimuli are mediated by the fundamental spatial frequency components. The magnitude of the imagery-induced aftereffects in Experiment 1 equaled the magnitude of the externally induced aftereffects obtained in Experiment 2 with the same subjects. By blurring the to-be-imaged patterns (Experiment 3), the fundamental Fourier components became the salient perceptual features of the stimuli, and the direction of the imagery-induced aftereffects was reversed from that of Experiment 1, indicating that the spatial frequency content of the imagery had changed from higher to lower frequencies. Under normal viewing conditions, subjects use the higher spatial frequencies associated with the perceptually salient edges of stimuli to construct their images. The results of Experiments 1 and 3 are discussed in light of a current controversy over the nature of information representation in imagery, and it is concluded that support has been obtained for the analog model of visual imagery.     

The Role of Attention in Word Recognition: Results from OB1-Reader

When reading, orthographic information is extracted not only from the word the reader is looking at, but also from adjacent words in the parafovea. Here we examined, using the recently introduced OB1-reader computational model, how orthographic information can be processed in parallel across multiple words and how orthographic information can be integrated across time and space. Although OB1-reader is a model of text reading, here we used it to simulate single-word recognition experiments in which parallel processing has been shown to play a role by manipulating the surrounding context in flanker and priming paradigms. In flanker paradigms, observers recognize a central word flanked by other letter strings located left and right of the target and separated from the target by a space. The model successfully accounts for the finding that such flankers can aid word recognition when they contain bigrams of the target word, independent of where those flankers are in the visual field. In priming experiments, in which the target word is preceded by a masked prime, the model accounts for the finding that priming occurs independent of whether the prime and target word are in the same location or not. Crucial to these successes is the key role that spatial attention plays within OB1-reader, as it allows the model to receive visual input from multiple locations in parallel, while limiting the kinds of errors that can potentially occur under such spatial pooling of orthographic information.     

Neighborhood frequency effects in visual word recognition: a comparison of lexical decision and masked identification latencies

Recent research suggests that the time to recognize a visually presented word may be a function of the frequencies of orthographically similar words. More precisely, recognition latencies and errors appear to increase significantly as soon as the stimulus word is orthographically similar to at least one other higher frequency word. This phenomenon, referred to as the neighborhood frequency effect, was subjected to further experimental testing, using a larger selection of words of varying frequency and length, and using a new experimental technique that proved to be extremely sensitive to such effects. The results provide additional support for earlier observations of neighborhood frequency effects. It is also demonstrated that clear word-frequency effects do obtain when neighborhood frequency is held constant. The results support activation-based accounts of the word-recognition process.     

汉语字词识别中词频和语义透明度的交互作用

该研究通过词汇判断作业考察了中文双字合成词的心理表征问题。目标刺激为高频透明、高频不透明、低频透明、低频不透明词各12个和48个假词,被试任务为即既又准的判断目标刺激是否是一个词。结果发现,高频词的词汇判断速度快于低频词,透明词的词汇判断速度快于不透明词,词频和语义透明度有显著的交互作用。透明度对低频词的识别所起的作用大于对高频词的识别所起的作用。     

From "logographic" to normal reading: the case of a deaf beginning reader

Visual word recognition of a profoundly deaf girl (AH) with developmental reading disorders was explored using an experimental technique that measures performance as a function of eye fixation within a word. AH's fixation-dependent word recognition profile revealed that she was inferring the identity of words using a "logographic" reading strategy (i. e., using salient visual features). Following this observation a special training program that enhances the understanding of grapheme-phoneme relations was applied. After few months of training, AH's reading skills improved, while her fixation-dependent performance changed to become like that of normal readers. We discuss the impact of our technique for the early diagnosis of reading impairments.     

The word frequency effect in recognition memory versus repetition priming

The role of word frequency in recognition memory and repetition priming was investigated by using a manipulation of attention. In Experiment 1, the lexical decision task produced greater repetition priming for low-frequency words than for high-frequency words following either the attended or the unattended study condition. The recognition memory test, on the other hand, showed a low-frequency word advantage only following the attended study condition. Furthermore, this advantage was limited to the measure of recognition memory based on conscious recollection of the study episode. In Experiment 2, a speeded recognition memory test replicated the pattern obtained with the unspeeded recognition memory test in Experiment 1. These results argue against the view that the word frequency effects in recognition memory and repetition priming have the same origin. Instead, the results suggest that the word frequency effect in recognition memory has its locus in conscious recollection.     

Frequency effects in spoken and visual word recognition: evidence from dual-task methodologies

The authors report 3 dual-task experiments concerning the locus of frequency effects in word recognition. In all experiments, Task 1 entailed a simple perceptual choice and Task 2 involved lexical decision. In Experiment 1, an underadditive effect of word frequency arose for spoken words. Experiment 2 also showed underadditivity for visual lexical decision. It was concluded that word frequency exerts an influence prior to any dual-task bottleneck. A related finding in similar dual-task experiments is Task 2 response postponement at short stimulus onset asynchronies. This was explored in Experiment 3, and it was shown that response postponement was equivalent for both spoken and visual word recognition. These results imply that frequency-sensitive processes operate early and automatically.     

What's in a word? A parametric study of semantic influences on visual word recognition

To what extent does semantic information play a functional role in visual word recognition? Theories of word recognition vary in the importance assigned to semantic information in visual lexical decision, with past research suggesting that the nature of the foils is a crucial determinant of semantic reliance. Here, we explored the conditions under which semantic variables influence lexical decision. Normal readers performed visual lexical decision tasks in which imageability and semantic priming were manipulated, with nonword foils varying systematically in their orthographic and phonological similarity to the real words. The effects of imageability and semantic priming increased in magnitude as nonword foils became progressively more wordlike. These findings provide a clear illustration of the flexible use of semantic information to support normal visual word recognition.     

Influence of visual guidance on braille recognition: Low lighting also helps touch

This study was an attempt to clarify the mechanisms responsible for the benefits of visual guidance in tactual braille recognition. Subjects touched +90° tilted braille under normal room lighting, or with low lighting, with or without visual guidance. Both visual information about finger angle and spatial reference information were manipulated with stained glass and light-emitting diodes. The provision of visual information about finger angle alone was no help to braille recognition, and performance was low. Adding visual spatial reference information to vision of finger angle raised performance. However, recognition accuracy was also substantially improved by low lighting. The benefits of darkness for haptics did not generalize to the reading of upright, two-letter braille words. It was proposed that extraneous visual information may distract sighted subjects in haptic tasks that require mental rotation of visual images.