Stages Of Visual Word Recognition Research Articles

Phonology by itself: Masked phonological priming effects with and without orthographic overlap

The activation of the phonological code plays a central role in visual word recognition. However, it is still unclear how this activation is integrated within this mainly bottom-up process. In the present masked priming study we combined Greek and Spanish, two languages with common phonemes and partially overlapping graphemes to investigate this issue. Greek-Spanish bilinguals performed lexical decisions on Greek and Spanish targets, briefly preceded by either phonologically related or orthographically and phonologically related prime words of the nontarget language. Results revealed significant bidirectional cross-script masked phonological priming effects which disappeared under the influence of nearly overlapping orthographic representations. This pattern of effects suggests that there is fast and automatic language nonselective activation of the phonological code during the initial stages of visual word recognition but that this is clearly dependent on the orthographic properties of the input stimulus. The implications of our findings are discussed within the framework of current models of monolingual and bilingual visual word recognition.

ERP evidence of hemispheric independence in visual word recognition

This study examined the capability of the left hemisphere (LH) and the right hemisphere (RH) to perform a visual recognition task independently as formulated by the Direct Access Model ( Fernandino, Iacoboni, & Zaidel, 2007). Healthy native Hebrew speakers were asked to categorize nouns and non-words (created from nouns by transposing two middle letters) into man-made and natural categories while their performance and ERPs were recorded. The stimuli were presented parafoveally to the right and left visual fields. As predicted by the Direct Access Model, ERP data showed that both the left hemisphere and right hemisphere were able to differentiate between words and non-words as early as 170 ms post-stimulus; these results were significant only for the contralaterally presented stimuli. The N1 component, which is considered to reflect orthographic processing, was larger in both hemispheres in response to the contralateral than the ipsilateral presented stimuli. This finding provides evidence for the RH capability to access higher level lexical information at the early stages of visual word recognition, thus lending weight to arguments for the relatively independent nature of this process.

Orthographic combinability and phonological consistency effects in reading Chinese phonograms: An event-related potential study

In this study, event-related potentials (ERPs) were used to trace the temporal dynamics of phonological consistency and phonetic combinability in the reading of Chinese phonograms. The data showed a significant consistency-by-combinability interaction at N170. High phonetic combinability characters elicited greater negativity at N170 than did low phonetic combinability characters, and the combinability effect was only found in the reading of high consistency characters. The results support the phonological mapping hypothesis of the reading-related N170 effect and suggest that the earlier stages of visual word recognition are shaped by the mapping of orthography to phonology even in Chinese. Moreover, our data revealed both consistency and combinability effects at P200 and N400, accounted for by the two-stage framework for visual word recognition. That is, characters with high combinability or high consistency facilitated the earlier stages of orthographic or phonological processing which were due to increased activation at the perceptual level; consequently, less positive P200 was demonstrated. In the later stages, high combinability or high consistency characters were associated with a larger semantic neighborhood, which increased semantic competition and exaggerated the N400 effect. These data support the assumption of radical-based inputs proposed by the lexical constituent model. However, the phonetic consistency effects found at N170 and P200 cannot be reconciled with the current framework of the lexical constituent model. A possible revision will be discussed.

Early decomposition in visual word recognition: Dissociating morphology, form, and meaning

The role of morphological, semantic, and form-based factors in the early stages of visual word recognition was investigated across different SOAs in a masked priming paradigm, focusing on English derivational morphology. In a first set of experiments, stimulus pairs co-varying in morphological decomposability and in semantic and orthographic relatedness were presented at three SOAs (36, 48, and 72 ms). No effects of orthographic relatedness were found at any SOA. Semantic relatedness did not interact with effects of morphological decomposability, which came through strongly at all SOAs, even for pseudo-suffixed pairs such as archer-arch. Derivational morphological effects in masked priming seem to be primarily driven by morphological decomposability at an early stage of visual word recognition, and are independent of semantic factors. A second experiment reversed the order of prime and target (stem-derived rather than derived-stem), and again found that morphological priming did not interact with semantic relatedness. This points to an early segmentation process that is driven by morphological decomposability and not by the structure or content of central lexical representations.

Neural Correlates of Morphological Decomposition during Visual Word Recognition

Considerable behavioral research has demonstrated that the visual word recognition system is sensitive to morphological structure. It has typically been assumed that analysis of morphologically complex words occurs only when the meaning of these words can be derived from the meanings of their constituents (e.g., hunter = hunt + er). However, results from recent behavioral research using the masked priming technique have demonstrated that morphological analysis can occur at an earlier orthographic level, in cases in which the meanings of complex words cannot be derived from their constituents (e.g., corner = corn + er). Here, we combine the logic of behavioral masked priming with the neurophysiological phenomenon of functional magnetic resonance imaging priming suppression to look for evidence of nonsemantic morphological priming at the neural level. Both behavioral and functional magnetic resonance imaging results indicated priming effects associated with the mere appearance of morphological structure (corner-CORN). In addition, these effects were distinguishable from lexical-semantic effects (bucket-PAIL) and orthographic effects (brothel-BROTH). Three left-lateralized occipito-temporal regions showed sensitivity to early morphological components of visual word recognition. Two of these regions also showed orthographic priming ( approximately BA 37, peak: -48 -60 -17; approximately BA 19, peak: -40 -77 -1), whereas one was sensitive only to morphological similarity between primes and targets ( approximately BA 19, peak: -37 -67 -7). These findings provide a neurobiological basis for a purely structural morphemic segmentation mechanism operating at early stages of visual word recognition.

Do transposed-letter similarity effects occur at a morpheme level? Evidence for morpho-orthographic decomposition

When does morphological decomposition occur in visual word recognition? An increasing body of evidence suggests the presence of early morphological processing. The present work investigates this issue via an orthographic similarity manipulation. Three masked priming lexical decision experiments were conducted to examine the transposed-letter similarity effect (e.g., jugde facilitates JUDGE more than the control jupbe) in polymorphemic and monomorphemic words. If morphological decomposition occurs at early stages of visual word recognition, we would expect an interaction with transposed-letter effects. Experiment 1 was carried out in Basque, which is an agglutinative language. The nonword primes were created by transposing two letters that either crossed the morphological boundaries of suffixes or did not. Results showed a transposed-letter effect for non-affixed words, whereas there were no signs of a transposed-letter effect across morpheme boundaries for affixed words. In Experiment 2, this issue was revisited in a non-agglutinative language (Spanish), with prefixed and suffixed word pairs. Again, results showed a significant transposed-letter effect for non-affixed words, whereas there were no signs of a transposed-letter effect across morpheme boundaries for affixed words (both prefixed words and suffixed words). Experiment 3 replicated the previous findings, and also revealed that, for polymorphemic words, transposed-letter priming effects occurred for within-morpheme transpositions. Taken together, these findings support the view that morphological decomposition operates at an early stage of visual word recognition.

Perceptual and lexical effects in letter identification: An event-related potential study of the word superiority effect

Most classical models of visual word recognition are based on sequentially organized levels of representation and involve feedback mechanisms to various extents. In this study, we aim at clarifying which of the early processing stages of visual word recognition are modulated by top-down lexical effects. We studied the identification of letters embedded in briefly presented words (e.g., TABLE) and illegal nonwords (e.g., GTFRS) using event-related potentials (ERPs). Participants were involved in the Reicher–Wheeler paradigm: they were asked to indicate which of two letters displayed above and below a string of hashes was flashed immediately before at fixation within a letter string, which was either a word or a nonword. Event-related potentials were significantly modulated by the lexical status of stimuli around 200 ms after stimulus onset, i.e., in the peaking window of the N1 component. In light of our results, we propose that visual word form representations can constrain letter identification at a prelexical stage i.e., during the extraction of letter-shape information. In addition, we show that this facilitatory top-down effect is sensitive to stimulus exposure duration.

Lexical Processes and Eye Movements in Neglect Dyslexia

Neglect dyslexia is a disturbance in the allocation of spatial attention over a letter string following unilateral brain damage. Patients with this condition may fail to read letters on the contralesional side of an orthographic string. In some of these cases, reading is better with words than with non-words. This word superiority effect has received a variety of explanations that differ, among other things, with regard to the spatial distribution of attention across the letter string during reading. The primary goal of the present study was to explore the interaction between attention and lexical processes by recording eye movements in a patient (F.C.) with severe left neglect dyslexia who was required to read isolated word and non-word stimuli of various length.F.C.’s ocular exploration of orthographic stimuli was highly sensitive to the lexical status of the letter string. We found that: (1) the location to which F.C. directed his initial saccade (obtained approximately 230 ms post-stimulus onset) differed between word and non-word stimuli; (2) the patient spent a greater amount of time fixating the contralesional side of word than non-word strings. Moreover, we also found that F.C. failed to identify the left letters of a string despite having fixated them, thus showing a clear dissociation between eye movement responses and conscious access to orthographic stimuli.Our data suggest the existence of multiple interactions between lexical, attentional and eye movement systems that occur from very initial stages of visual word recognition.

The effects of case mixing on word recognition: evidence from a PET study.

The early stages of visual word recognition were investigated by scanning participants using PET as they took part in implicit and explicit reading tasks with visually disrupted stimuli. CaSe MiXiNg has been shown in behavioral studies to increase reaction times (RTs) in naming and other word recognition tasks. In this study, we found that during both an implicit (feature detection) task and an explicit word-naming task, mixed-case words compared to same-case words produced increased activation in an area of the right parietal cortex previously associated with visual attention. No effect of case was found in this area for pseudowords or consonant strings. Further, lowering the contrast of the stimuli slowed RTs as much as case mixing, but did not lead to the same increase in right parietal activation. No significant effect of case mixing was observed in left-hemisphere language areas. The results suggest that reading mixed-case words requires increased attentional processing. However, later word recognition processes may be relatively unaffected by the disruption in presentation.

Neglect Dyslexia and the Early Stages of Visual Word Recognition

Abstract Neglect dyslexia is an acquired reading disorder in which one side of words or letter strings is misidentified. Caramazza and Hillis (Cognitive Neuropsychology 1990; 7: 391-445) proposed that the disorder reflects an impairment in the early stages of visual word recognition. Three levels of representation are involved, each with corresponding spatial coordinates. These levels reflect a progression away from the physical stimulus toward a more abstract representation of a word. The errors made by a patient with a level one deficit are relative to the location of a word in the visual field. The errors made by a patient with a level two deficit are relative to the spatial position of a letter(s) within the stimulus. The errors made by a patient with a level three deficit are relative to the ordinal position of a letter(s) within a word. We describe how this model may be used to interpret the differing patterns of performance found in neglect dyslexia and evaluate the model according to 19 published single case studies of neglect dyslexia. It is concluded that the model is well supported by these data and may therefore be viewed as a model of the early stages of reading in intact readers.

Neglect dyslexia and the early stages of visual word recognition

Neglect dyslexia and the early stages of visual word recognition

Neglect dyslexia and the early stages of visual word recognition

Neglect dyslexia is an acquired reading disorder in which one side of words or letter strings is misidentified. Caramazza and Hillis (Cognitive Neuropsychology 1990; 7: 391-445) proposed that the disorder reflects an impairment in the early stages of visual word recognition. Three levels of representation are involved, each with corresponding spatial coordinates. These levels reflect a progression away from the physical stimulus toward a more abstract representation of a word. The errors made by a patient with a level one deficit are relative to the location of a word in the visual field. The errors made by a patient with a level two deficit are relative to the spatial position of a letter(s) within the stimulus. The errors made by a patient with a level three deficit are relative to the ordinal position of a letter(s) within a word. We describe how this model may be used to interpret the differing patterns of performance found in neglect dyslexia and evaluate the model according to 19 published single case studies of neglect dyslexia. It is concluded that the model is well supported by these data and may therefore be viewed as a model of the early stages of reading in intact readers.