Reicher-Wheeler Task Research Articles

Orthographic and feature-level contributions to letter identification.

Word recognition is facilitated by primes containing visually similar letters (dentjst-dentist), suggesting that letter identities are encoded with initial uncertainty. Orthographic knowledge also guides letter identification, as readers are more accurate at identifying letters in words compared with pseudowords. We investigated how high-level orthographic knowledge and low-level visual feature analysis operate in combination during letter identification. We conducted a Reicher-Wheeler task to compare readers' ability to discriminate between visually similar and dissimilar letters across different orthographic contexts (words, pseudowords, and consonant strings). Orthographic context and visual similarity had independent effects on letter identification, and there was no interaction between these factors. The magnitude of these effects indicated that high-level orthographic information plays a greater role than low-level visual feature information in letter identification. We propose that readers use orthographic knowledge to refine potential letter candidates while visual feature information is accumulated. This combination of high-level knowledge and low-level feature analysis may be essential in permitting the flexibility required to identify visual variations of the same letter (e.g., N-n) while maintaining enough precision to tell visually similar letters apart (e.g., n-h). These results provide new insights on the integration of visual and linguistic information and highlight the need for greater integration between models of reading and visual processing.

Word and pseudoword superiority effects: Evidence from a shallow orthography language.

The word superiority effect (WSE) denotes better recognition of a letter embedded in a word rather than in a pseudoword. Along with WSE, also a pseudoword superiority effect (PSE) has been described: It is easier to recognise a letter in a legal pseudoword than in an unpronounceable nonword. At the current state of the art, both WSE and PSE have been mainly tested with English speakers. This study uses the Reicher-Wheeler paradigm with native speakers of Italian (a shallow orthography language). Different from English and French, we found WSE for reaction times (RTs) only, whereas PSE was significant for both accuracy and RTs. This finding indicates that in the Reicher-Wheeler task, readers of a shallow orthography language can effectively rely on both the lexical and the sublexical routes. As to the effect of letter position, a clear advantage for the first-letter position emerged, a finding suggesting a fine-grained processing of the letter strings with coding of letter position and indicating the role of visual acuity and crowding factors.

Word and pseudoword superiority effects on letter position processing in developing and skilled readers.

Studies have shown that letter position processing changes as reading develops. Whether these changes are driven by the development of the orthographic lexicon is currently unclear. In this study, we administered a novel variant of the Reicher-Wheeler task to children aged 7-12 years (Experiment 1) and adults (Experiment 2) to clarify the role of the developing lexicon in letter position processing. The task required participants to report the identity of a letter at a specified position within 3 orthographic contexts: anagram words (e.g., slime - which has the anagram partner, smile), pseudowords (e.g., blire - brile), and illegal nonwords (e.g., bfgsv - bsgfv). The influence of a reader's whole-word orthographic representations was investigated by comparing the performance of words to pseudowords (word superiority effect or WSE), and the influence of their knowledge of orthotactic constraints was investigated by comparing pseudowords to illegal nonwords (pseudoword superiority effect or PSE). While the PSE increased with developing orthographic skills (as indexed by irregular word reading) in primary schoolchildren, the WSE emerged only in adult readers. Furthermore, the size of the WSE increased with orthographic skill in adults. The findings are discussed in regards to current models and theories of visual word recognition and reading development. (PsycINFO Database Record

Evaluating Effects of Divided Hemispheric Processing on Word Recognition in Foveal and Extrafoveal Displays: The Evidence from Arabic

BackgroundPrevious studies have claimed that a precise split at the vertical midline of each fovea causes all words to the left and right of fixation to project to the opposite, contralateral hemisphere, and this division in hemispheric processing has considerable consequences for foveal word recognition. However, research in this area is dominated by the use of stimuli from Latinate languages, which may induce specific effects on performance. Consequently, we report two experiments using stimuli from a fundamentally different, non-Latinate language (Arabic) that offers an alternative way of revealing effects of split-foveal processing, if they exist.Methods and FindingsWords (and pseudowords) were presented to the left or right of fixation, either close to fixation and entirely within foveal vision, or further from fixation and entirely within extrafoveal vision. Fixation location and stimulus presentations were carefully controlled using an eye-tracker linked to a fixation-contingent display. To assess word recognition, Experiment 1 used the Reicher-Wheeler task and Experiment 2 used the lexical decision task.ResultsPerformance in both experiments indicated a functional division in hemispheric processing for words in extrafoveal locations (in recognition accuracy in Experiment 1 and in reaction times and error rates in Experiment 2) but no such division for words in foveal locations.ConclusionsThese findings from a non-Latinate language provide new evidence that although a functional division in hemispheric processing exists for word recognition outside the fovea, this division does not extend up to the point of fixation. Some implications for word recognition and reading are discussed.

The influence of ‘Tall Man’ lettering on errors of visual perception in the recognition of written drug names

Visual errors in the perception of written drug names can reflect orthographic similarity amongst certain names. Drug names are typically printed in lowercase text. ‘Tall Man’ lettering, the capitalisation of the portions that differ amongst orthographically similar drug names, is employed in the field of medication labelling and prescribing to reduce medication errors by highlighting the area most likely to prevent confusion. The influence of textual format on visual drug name perception was tested amongst healthcare professionals (n = 133) using the Reicher-Wheeler task. Relative to lowercase text, Tall Man lettering improved accuracy in drug name perception. However, an equivalent improvement in accuracy was obtained using entirely uppercase text. Thus, character size may be a key determinant of perceptual accuracy for Tall Man lettering. Specific considerations for the manner in which Tall Man lettering might be best formatted and implemented in practice to reduce medication errors are discussed. Statement of Relevance:Tall Man lettering aims to prevent medication errors by reducing visual confusions amongst orthographically similar drug names. It was found that, compared to lowercase text, Tall Man lettering improved accuracy in drug name perception. Character size appeared to be a key determinant of perceptual accuracy for Tall Man lettering.

The Effect of Character’s Whole Recognition on the Processing of Components in the Processes of Chinese Characters

The word superiority effect is an important evidence that whole word processing facilitates letter processing in English word recognition. However, such effect still remains controversial in Chinese character recognition. In this study, two experiments were carried out to explore the effect of Chinese whole character recognition over component processing. There was manipulation of three types of stimuli: real characters, pseudo characters and radical characters, only right-left or up-down structures of which are chosen. The target radicals could be placed either at the left or the right (either the up or the down) side of the three types of character stimuli. Reicher-Wheeler task was used in experiment 1. The stimuli were presented for 350ms, followed by a mask for 200ms, then two radicals for 1700ms. The participants were asked to choose the target radical in the two radicals. Radical judgment task was performed in experiment 2. The target radical was presented for 350ms, followed by three types of stimuli. Participants were asked to judge whether the stimuli character contained the target radical or not. The reaction time and the error rate were recorded by the computer. Twenty-seven healthy female college students participated in this study. The results were as the following: 1) In both experiments, the reaction time of radical judgment in the radical character condition was shorter than the real characters and the pseudo characters. Word superiority effect was found in radical characters. Compared with the pseudo characters, no word superiority effect was found in real characters. These findings indicated that Chinese character’s whole recognition blocked radical processing. 2) The reaction time of left-right structure characters was shorter than that of the up-down ones. That is to say, the structure effect was significant in Chinese characters. 3) The spatial position of radicals in a stimulus had a significant influence on radical recognition. The position effect was found across three kinds of characters. The reaction time of the left radicals was the shortest and the reaction time of the down radicals was the longest among four positions in the three types of characters.

Word and pseudoword superiority effects reflected in the ERP waveform

A variant of the Reicher-Wheeler task was used to determine when in the event-related potential (ERP) waveform indices of word and pseudoword superiority effects might be present, and whether ERP measures of superiority effects correlated with standardized behavioral measures of orthographic fluency and single word reading. ERPs were recorded to briefly presented, masked letter strings that included real words (DARK/PARK), pseudowords (DARL/PARL), nonwords (RDKA/RPKA), and letter-in-xs (DXXX, PXXX) stimuli. Participants decided which of two letters occurred at a given position in the string (here, forced-choice alternatives D and P). Behaviorally, both word (more accurate choices for letters in words than in baseline nonwords or letter-in-xs) and pseudoword (more accurate choices for letters in pseudowords than in baseline conditions) superiority effects were observed. Electrophysiologically, effects of orthographic regularity and familiarity were apparent as early as the P150 time window (100-160 ms), an effect of lexicality was observed as early as the N200 time window (160-200 ms), and peak amplitude of the N300 and N400 also differentiated word and pseudoword as compared to baseline stimuli. Further, the size of the P150 and N400 ERP word superiority effects was related to standardized behavioral measures of fluency and reading. Results suggest that orthographic fluency is reflected in both lower-level, sublexical, perceptual processing and higher-level, lexical processing in fluently reading adults.

Is there room for the BBC in the mental lexicon? On the recognition of acronyms

It has been suggested that acronyms like BBC are processed like real words. This claim has been based on improved performance with acronyms in the Reicher-Wheeler task, the letter string matching task, the visual feature integration task, and the N400 component in event-related potential (ERP) studies. Unfortunately, in all these tasks performance on acronyms resembled performance on pseudowords more than performance on words. To further assess the similarity of acronyms and words, we focused on the meaning of the acronyms and used masked priming to examine whether target words can be primed to the same extent with associatively related acronyms as with associatively related words. Such priming was possible at a stimulus onset asynchrony (SOA) of 84 ms. In addition, the priming of the acronyms did not depend on the letter case in which they were presented: The target word "books" was primed as much by isbn and iSbN as by ISBN.

A bilingual word superiority effect in Irish speakers

The present study employed a dual-language version of the Reicher-Wheeler task to examine the word superiority effect (WSE) in Irish-English bilinguals and L1 English speakers with some Irish language proficiency. Superior skills in written English would be expected in both groups. Forty-nine participants completed a word–letter WSE forced-choice task in both Irish and English. For both languages, and for both groups, an advantage was found for words over letters. The word–letter difference for English stimuli exceeded that for Irish stimuli, at 9% and 4% respectively; however this difference between the languages did not reach statistical significance. Performance did not differ significantly between the two groups, despite a trend suggesting a lower WSE in English for the bilingual group. The lack of difference based on proficiency may reflect the high frequency words employed or similar exposure to written Irish in the two groups, given the dominance of the English language.

Visuo-Attentional Processing by Dyslexic Readers on the Reicher-Wheeler Task

A reading-level comparison was used to investigate visuo-attentional processing in the perception of letters in words by dyslexics as compared to reading-level-control children (RL-controls). Two paradigms were used: the Reicher-Wheeler paradigm with a forced-choice procedure to elicit a word-superiority effect (WSE, difference between performance on pseudoword targets and word targets) and a pseudoword-superiority effect (PSE, difference between performance on nonword targets and pseudoword targets), and the visual-field paradigm to evaluate processing in the fovea and parafovea (in the left visual field -LVF- and the right visual field -RVF). Performance was analyzed in terms of the percentage of correct responses (correct letters given). Adults were tested first. Their results indicated a WSE and a PSE for all target locations in the visual field. Unlike adults, children exhibited only a PSE but no WSE. The PSE was located in the fovea for dyslexics and in the LVF for RL-controls. The fact that dyslexic children produced a result pattern that strongly resembled that of the RL-controls did not allow us to consider that they suffered from abnormal visuo-attentional processing of letters in words.

Perception of words and non-words in the upper and lower visual fields

The findings of previous investigations into word perception in the upper and the lower visual field (VF) are variable and may have incurred non-perceptual biases caused by the asymmetric distribution of information within a word, an advantage for saccadic eye-movements to targets in the upper VF and the possibility that stimuli were not projected to the correct retinal locations. The present study used the Reicher–Wheeler task and an eye-tracker to show that, using stringent methodology, a right over left VF advantage is observed for word recognition, but that no differences were found between the upper and the lower VF for either word or non-word recognition. The results are discussed in terms of the neuroanatomy and perceptual abilities of the upper and the lower VF and implications for other studies of letter-string perception in the upper and the lower VF are presented.

What do lateralized displays tell us about visual word perception? A cautionary indication from the word-letter effect

A common assumption underlying laterality research is that visual field asymmetries in lateralized word perception indicate the hemispheric specialisation of processes generally available for the perception of words, including words viewed in a more typical setting (i.e. in the central visual field). We tested the validity of this assumption using a phenomenon (the word-letter effect) frequently reported for displays viewed in the central visual field, where letters in words are perceived more accurately than the same letters in isolation. Words and isolated letters were presented in the left visual field (LVF), right visual field (RVF) and central visual field (CVF), the Reicher-Wheeler task was used to suppress influences of guesswork, and an eye-tracker ensured central fixation. In line with previous findings, lateralized displays revealed a RVF–LVF advantage for words (but not isolated letters) and CVF displays revealed an advantage for words over isolated letters (the word-letter effect). However, RVF and LVF displays both produced an advantage for isolated letters over words (a letter-word effect), indicating that processing subserving the advantage for words when participants viewed stimuli in the central visual field was unavailable for lateralized displays. Implications of these findings for studies of lateralized word perception are discussed.

Assessing effects of stimulus orientation on perception of lateralized words and nonwords

Numerous studies of the processes of visual word recognition in the left and right cerebral hemispheres have attempted to control for confounding differences in the retinal placement (and hence visual acuity) of the beginnings of words by re-orientating normally-horizontal words vertically. However, despite the popularity of this approach, little is known about the precise effects that vertically orientating normally-horizontal words exert on hemispheric processes of word recognition. In this study, we investigated perception of horizontal and vertical English words and nonwords in the left visual field (LVF) and right visual field (RVF). An eye-tracking device ensured central fixation and a 2AFC paradigm (Reicher–Wheeler task) suppressed influences of non-perceptual bias. Horizontal stimuli produced a strong right visual field advantage for words but not for nonwords, whereas, vertical stimuli produced no hemifield differences at all. Moreover, vertical stimuli produced an advantage for words over nonwords in both visual fields whereas horizontal stimuli produced this effect only in the right visual field. Implications of these findings for the sensitivity of processes of word perception to stimulus orientation in the two cerebral hemispheres are discussed.

Assessing the Role of Hemispheric Specialisation, Serial-Position Processing, and Retinal Eccentricity in Lateralised Word RecognitioN

The advantage for words in the right visual hemifield (RVF) has been assigned parallel orthographic processing by the left hemisphere and sequential by the right. However, an examination of previous studies of serial position performance suggests that orthographic processing in each hemifield is modulated by retinal eccentricity. To investigate this issue, we presented words at eccentricities of 1, 2, 3, and 4 degrees. Serial position performance was measured using the Reicher-Wheeler task to suppress influences of guesswork and an eye-tracker controlled fixation location. Greater eccentricities produced lower overall levels of performance in each hemifield although RVF advantages for words obtained at each eccentricity (Experiments 1 and 2). However, performance in both hemifields revealed similar U-shaped serial position performance at all eccentricities. Moreover, this performance was not influenced by lexical constraint (high, low; Experiment 2) or status (word, nonword; Experiment 3), although only words (not nonwords) produced an RVF advantage. These findings suggest that although each RVF advantage was produced by left-hemisphere function, the same pattern of orthographic analysis was used by each hemisphere at each eccentricity.

In search of perceptual influences of sentence context on word recognition.

A major issue in the study of word perception concerns the nature (perceptual or nonperceptual) of sentence context effects. The authors compared effects of legal, word replacement, nonword replacement, and transposed contexts on target word performance using the Reicher-Wheeler task to suppress nonperceptual influences of contextual and lexical constraint. Experiment 1 showed superior target word performance for legal (e.g., "it began to flap/flop") over all other contexts and for transposed over word replacement and nonword replacement contexts. Experiment 2 replicated these findings with higher constraint contexts (e.g., "the cellar is dark/dank") and Experiment 3 showed that strong constraint contexts improved performance for congruent (e.g., "born to be wild") but not incongruent (e.g., mild) target words. These findings support the view that the very perception of words can be enhanced when words are presented in legal sentence contexts.

Lateralized word recognition: assessing the role of hemispheric specialization, modes of lexical access, and perceptual asymmetry.

The processing advantage for words in the right visual field (RVF) has often been assigned to parallel orthographic analysis by the left hemisphere and sequential by the right. The authors investigated this notion using the Reicher-Wheeler task to suppress influences of guesswork and an eye-tracker to ensure central fixation. RVF advantages obtained for all serial positions and identical U-shaped serial-position curves obtained for both visual fields (Experiments 1-4). These findings were not influenced by lexical constraint (Experiment 2) and were obtained with masked and nonmasked displays (Experiment 3). Moreover, words and nonwords produced similar serial-position effects in each field, but only RVF stimuli produced a word-nonword effect (Experiment 4). These findings support the notion that left-hemisphere function underlies the RVF advantage but not the notion that each hemisphere uses a different mode of orthographic analysis.

The Use of Assembled Phonology during Performance of a Letter Recognition Task and Its Dependence on the Presence and Proportion of Word Stimuli

Although predominant accounts of the word superiority effect (WSE) as produced by the Reicher–Wheeler task (Reicher, 1969; Wheeler, 1970) emphasize an orthographic code, evidence is mounting that a phonological code may have a role in the performance of other tasks. The present study tested the influence of a phonological code as a determinant of performance in the Reicher–Wheeler task. Pseudohomophones and matched controls were presented in a letter identification task using a two alternative, forced choice method. Subjects performed significantly worse when the test letters spelled a pseudohomophone and the incorrect alternative formed the sound alike word, for example, whenWERDis followed by the choice alternativesEandOfor the second position. This effect was greater when words were included in the experiment. Implications for current models of lexical access and word recognition are discussed.

Lexical factors in the word-superiority effect

In the Reicher-Wheeler paradigm, fluent readers can identify letters better when they appear in a word than when they appear in either a pronounceable pseudoword (a lexicality effect) or a single letter (a word-letter effect). It was predicted that if both of these effects involve a lexical factor, then adult acquired dyslexic subjects whose deficit prevents access to visual word form should show disruptions of the normal effects on the Reicher-Wheeler task. The results were that dyslexic subjects as well as matched control subjects showed a lexicality effect; however, while the control subjects showed a normal word-letter effect, the dyslexic subjects showed a reverse letter-superiority effect. Both effects, however, showed a systematic variation: As performance on lexical decision improved, the subjects' performance on words in the Reicher-Wheeler task was better than that for all the other conditions. These subject correlations were replicated by using data from a second lexical decision experiment, which utilized the same words and pseudowords that were used in the Reicher-Wheeler task. In addition, an item analysis showed that the words that the subjects had discriminated correctly in lexical decision showed a significant advantage over those that they had not, as well as an improvement relative to the other conditions. These results suggest that there is a lexical factor underlying the lexicality and word-letter effects, and it is proposed that the abnormal letter-superiority effect can be accounted for as the manifestation of other competing factors.

The Reicher-Wheeler effect and models of deep and phonological dyslexia

Current accounts of the functional impairment underlying phonological dyslexia (PD) do not postulate any disturbance of accessing the orthographic lexicon. For deep dyslexia (DD), only the righthemisphere hypothesis involves such a disturbance. However, neither PD nor DD subjects showed the normal word-superiority effects in a Reicher-Wheeler experiment (forced-choice identification of single letters that had been displayed briefly either as single letters or in words or nonwords with a backward mask). Since these word-superiority effects have been argued to lie at the word-specific level, the existing accounts cannot explain the observed results for both PD and DD subjects. Three other accounts are proposed. The most parsimonious account is a degradation hypothesis: as stress is placed on the reading system, reading performance will be seen to degrade gracefully across a number of different tasks and types of stimuli, resulting in symptoms of PD or DD and producing the correlated pattern of performance in oral reading, repetition, lexical decision, and the Reicher—Wheeler task, which was observed for the nine subjects reported here and which is consistent with many previously reported PD and DD subjects.

Specific word transfer as a measure of processing in the word-superiority paradigm.

Explanations of context effects in the Reicher-Wheeler task and the letter-identification task appeal to word-based processing, yet these tasks provide no explicit measure of word processing. An experiment is reported which was designed to investigate the use of transfer in the word-identification task as a measure of word-based processing in letter-identification tasks. It was found that encoding manipulations that determined whether a word-superiority effect was or was not found in a letter-identification task (e.g., Thompson & Massaro, 1973) also determined whether transfer was or was not found in a subsequent word-identification task. The results of the experiment are discussed in terms of the utility of using transfer experiments as converging evidence about the presence and/or absence of processes that cannot be directly measured in other experimental paradigms.