Rapid word identification in pure alexia is lexical but not semantic

Following the notion that patients with pure alexia have access to two distinct reading strategies-letter-by-letter reading and semantic reading-a training program was devised to facilitate reading via semantics in a patient with pure alexia. Training utilized brief stimulus presentations and required category judgments rather than explicit word identification. The training was successful for trained words, but generalized poorly to untrained words. Additional studies involving oral reading of nouns and of functors also resulted in improved reading of trained words. Pseudowords could not be trained to criterion. The results suggest that improved reading can be achieved in pure alexia by pairing rapidly presented words with feedback. Focusing on semantic processing is not essential to this process. It is proposed that the training strengthens connections between the output of visual processing and preexisting orthographic representations.     

The pseudohomophone effect: The role of visual similarity in non-word decisions

The pseudohomophone effect, that is, the finding that non-words that are pronounced like words (e.g. MEEN) take longer to reject in a lexical decision task than other pronounceable non-words (e.g. NEEN), has been used to support the hypothesis of phonological receding in lexical access. The lexical decision experiments reported here matched pseudohomophones to control non-words that were as visually similar to words as were the pseudohomophones. For both normal and aphasic subjects, reaction times to reject the pseudohomophones were no longer than those for the visual controls. However, the pseudohomophones did take longer to reject than other pronounceable non-words which were not as visually similar to words. The results suggest that most previous findings of the pseudohomophone effect result from the greater visual rather than phonological similarity of the pseudohomophones to words. The absence of a phonological effect on the non-words in the present study implies that phonological coding is an optional rather than a slow, but obligatory process.     

Fluency Training in Phoneme Blending: A Preliminary Study of Generalized Effects

We examined the generalized effects of training children to fluently blend phonemes of words containing target vowel teams on their reading of trained and untrained words in lists and passages. Three second-grade students participated. A subset of words containing each of 3 target vowel teams (aw, oi, and au) was trained in lists, and generalization was assessed to untrained words in lists, trained and untrained words in target passages, and novel words in generalization passages. A multiple probe design across vowel teams revealed generalized increases in oral reading accuracy for target words presented in both lists and passages for all 3 students on 2 vowel teams and for 1 student on all 3 vowel teams. Generalized increases in oral reading fluency in both lists and passages were found for all 3 students on the vowel team that was trained to a fluency criterion, with two students showing increases prior to training on the other two vowel teams. Implications of these results for building fluency in prerequisite phonemic awareness skills as an intervention for promoting generalized oral reading fluency are discussed.     

Impairment of rhyme judgments by silent and overt articulatory suppression

Two experiments showed that articulating “blah” repeatedly aloud or silently interfered with the speed and accuracy of judging whether pairs of words rhymed. Articulation from another voice affected only accuracy, and foot tapping had no effect. This suggests that it is mainly the articulatory component of articulatory suppression that interferes with this task and that rhyme judgments of words depend on an articulatory code or an acoustic code accessed via articulation.

A third experiment confirmed these effects on speed of judgment, but there were no significant effects on errors in this experiment. Non-verbal use of the articulatory musculature in chewing also slowed performance. Similar results were obtained for word and non-word rhyme judgments, though the latter effects were somewhat weaker. It is argued that the results fail to support the theory that there are different methods of accessing phonology for words or non-words and indicate that access to phonology was via articulation, rather than a means to achieving articulation. If the task incorporated mechanisms employed in normal reading, the results refute suggestions that conversion of print to sound, whether for words or non-words, occurs prior to retrieval of an articulatory code.     

Developmental dyslexia and word retrieval deficits

Developmental dyslexics, selected on the basis of very slow naming rates on the Rapid Automatic Naming Tasks (RAN), were compared to normal readers on oral language, picture categorization, and reading tasks. Findings indicated that the dyslexics' word retrieval deficits were one symptom of a more generalized, however subtle, oral language deficit which involved both receptive and expressive oral language functioning. The dyslexics' word retrieval problem also seemed chiefly related to language processing and not to deficits in semantic memory as there were no significant differences between dyslexics and controls on a nonverbal semantic memory task (picture categorization). In naming and identifying printed words, the dyslexics appeared to rely considerably upon the "indirect" or "assembly-of-phonology" route; they were slower in naming irregularly spelled words compared to regularly spelled words and on a lexical decision task, the dyslexics were slower in making negative decisions for "pseudohomophones" (e.g., "braik") than for other matched nonwords. Results are discussed in terms of the logogen model with some consideration of a developmental model as well.     

The nature of control by spoken words over visual stimulus selection.

Eight retarded adolescents were trained to select one (a trained S+) of two visual stimuli in response to a spoken word (a trained word). Two different visual stimuli alternated randomly as the S-. To determine if the spoken work was merely a temporal discriminative stimulus for when to respond, or if it also specified which visual stimulus to select, the subjects were given intermittent presentations of untrained (novel) spoken words. All subjects consistently selected the trained S+ in response to the trained spoken word and selected the previous S- in response to the untrained spoken words. It was hypothesized that the subjects were responding away from the trained S+ in response to untrained spoken words, and control by untrained spoken words would not be observed when the trained S+ was not present. The two visual S- stimuli selected on trials of untrained spoken words were presented simultaneously. The untrained spoken words presented on these trials no longer controlled stimulus selections for seven subjects. The results supported the hypothesis that previous control by spoken words was due to responding away from the trained S+ in response to untrained spoken words.     

On the dissociation between reaction time and response duration as a function of lexical and sublexical reading: An examination of phonetic decoding and computational models

Neurobiological models of reading account for two ways in which orthography is converted to phonology: (1) familiar words, particularly those with exceptional spelling-sound mappings (e.g., shoe) access their whole-word lexical representations in the ventral visual stream, and (2) orthographically unfamiliar words, particularly those with regular spelling-sound mappings (i.e., pseudohomophones [PHs], which are orthographically novel but sound like real words; e.g., shue) are phonetically decoded via sublexical processing in the dorsal visual stream. The present study used a naming task in order to compare naming reaction time (RT) and response duration (RD) of exception and regular words to their PH counterparts. We replicated our earlier findings with words, and extended them to PH phonetic decoding by showing a similar effect on RT and RD of matched PHs. Given that the shorter RDs for exception words can be attributed to the benefit of whole-word processing in the orthographic word system, and the longer RTs for exception words to the conflict with phonetic decoding, our PH results demonstrate that phonetic decoding also involves top-down feedback from phonological lexical representations (e.g., activated by shue) to the orthographic representations of the corresponding correct word (e.g., shoe). Two computational models were tested for their ability to account for these effects: the DRC and the CDP+. The CDP+ fared best as it was capable of simulating both the regularity and stimulus type effect on RT for both word and PH identification, although not their over-additive interaction. Our results demonstrate that both lexical reading and phonetic decoding elicit a regularity dissociation between RT and RD that provides important constraints to all models of reading, and that phonetic decoding results in top-down feedback that bolsters the orthographic lexical reading process.     

Word learning and individual differences in word learning reflected in event-related potentials

Adults learned the meanings of rare words (e.g., gloaming) and then made meaning judgments on pairs of words. The 1st word was a trained rare word, an untrained rare word, or an untrained familiar word. Event-related potentials distinguished trained rare words from both untrained rare and familiar words, first at 140 ms and again at 400-600 ms after onset of the 1st word. These results may point to an episodic memory effect. The 2nd word produced an N400 that distinguished trained and familiar word pairs that were related in meaning from unrelated word pairs. Skilled comprehenders learned more words than less skilled comprehenders and showed a stronger episodic memory effect at 400-600 ms on the 1st word and a stronger N400 effect on the 2nd word. These results suggest that superior word learning among skilled comprehenders may arise from a stronger episodic trace that includes orthographic and meaning information and illustrate, how an episodic theory of word identification can explain reading skill.     

Visual word recognition is accompanied by covert articulation: evidence for a speech-like phonological representation

Two lexical decision task (LDT) experiments examined whether visual word recognition involves the use of a speech-like phonological code that may be generated via covert articulation. In Experiment 1, each visual item was presented with an irrelevant spoken word (ISW) that was either phonologically identical, similar, or dissimilar to it. An ISW delayed classification of a visual word when the two were phonologically similar, and it delayed the classification of a pseudoword when it was identical to the base word from which the pseudoword was derived. In Experiment 2, a LDT was performed with and without articulatory suppression, and pseudowords consisted of regular pseudowords and pseudohomophones. Articulatory suppression decreased sound-specific ISW effects for words and regular pseudowords but not for pseudohomophones. These findings indicate that the processing of an orthographically legal letter sequence generally involves the specification of more than one sound code, one of which involves covert articulation.     

Effects of contextual diversity on semantic decision and reading aloud: evidence from a word learning study in English as a second language / Efectos de la diversidad contextual en la decisión semántica y la lectura en voz alta: evidencia de un estudio de aprendizaje de palabras en inglés como segundo idioma

This experiment investigated contextual diversity effects on novel word learning in English as a second language (L2). A group of advanced English speakers, whose native language was Spanish, participated in the study. Participants learned the meaning of real but obscure words that were embedded in either two or 12 different sentences and learned over two days (frequency of exposure was kept constant). On day three, participants were tested using reading aloud and semantic decision tasks. The results showed that participants learned the meaning of words in both conditions fairly well as revealed by their accuracy in the semantic decision task. However, words experienced in 12 different contexts generated more accurate and faster reaction times (RTs), suggesting the acquisition of more robust semantic representations. Strikingly, reading latencies were also faster for the 12-sentence condition, which might imply that semantics has an effect on reading newly learned words in English as a second language. These results are discussed and accommodated in view of the DRC and the PDP models of single-word reading.     

The neurobiology of adaptive learning in reading: A contrast of different training conditions

fMRI was used to investigate the separate influences of orthographic, phonological, and semantic processing on the ability to learn new words and the cortical circuitry recruited to subsequently read those words. In a behavioral session, subjects acquired familiarity for three sets of pseudowords, attending to orthographic, phonological, or (learned) semantic features. Transfer effects were measured in an event-related fMRI session as the subjects named trained pseudowords, untrained pseudowords, and real words. Behaviorally, phonological and semantic training resulted in better learning than did orthographic training. Neurobiologically, orthographic training did not modulate activation in the main reading regions. Phonological and semantic training yielded equivalent behavioral facilitation but distinct functional activation patterns, suggesting that the learning resulting from these two training conditions was driven by different underlying processes. The findings indicate that the putative ventral visual word form area is sensitive to the phonological structure of words, with phonologically analytic processing contributing to the specialization of this region.     

Lexical retrieval constrained by sound structure: the role of the left inferior frontal gyrus

Positron emission tomography was used to investigate two competing hypotheses about the role of the left inferior frontal gyrus (IFG) in word generation. One proposes a domain-specific organization, with neural activation dependent on the type of information being processed, i.e., surface sound structure or semantic. The other proposes a process-specific organization, with activation dependent on processing demands, such as the amount of selection needed to decide between competing lexical alternatives. In a novel word retrieval task, word reconstruction (WR), subjects generated real words from heard non-words by the substitution of either a vowel or consonant. Both types of lexical retrieval, informed by sound structure alone, produced activation within anterior and posterior left IFG regions. Within these regions there was greater activity for consonant WR, which is more difficult and imposes greater processing demands. These results support a process-specific organization of the anterior left IFG.     

Lexical and semantic age-of-acquisition effects on word naming in Spanish

We report a study of the factors that affect reading in Spanish, a language with a transparent orthography. Our focus was on the influence of lexical semantic knowledge in phonological coding. This effect would be predicted to be minimal in Spanish, according to some accounts of semantic effects in reading. We asked 25 healthy adults to name 2,764 mono- and multisyllabic words. As is typical for psycholinguistics, variables capturing critical word attributes were highly intercorrelated. Therefore, we used principal components analysis (PCA) to derive orthogonalized predictors from raw variables. The PCA distinguished components relating to (1) word frequency, age of acquisition (AoA), and familiarity; (2) word AoA, imageability, and familiarity; (3) word length and orthographic neighborhood size; and (4) bigram type and token frequency. Linear mixed-effects analyses indicated significant effects on reading due to each PCA component. Our observations confirm that oral reading in Spanish proceeds through spelling–sound mappings involving lexical and sublexical units. Importantly, our observations distinguish between the effect of lexical frequency (the impact of the component relating to frequency, AoA, and familiarity) and the effect of semantic knowledge (the impact of the component relating to AoA, imageability, and familiarity). Semantic knowledge influences word naming even when all the words being read have regular spelling–sound mappings.     

Reading Words and Wirds: Phonology and Lexical Access

Naming latency for printed words is inversely related to their frequency. Four experiments were run to test whether the naming of non-words that are homophones of words (pseudohomophones) is similarly influenced by the frequency of those words. McCann and Besner (1987) failed to find such a frequency effect for pseudohomophones when they were presented in a list of non-words. The present studies show that list structure is critical: A frequency effect occurs for pseudohomophones in a list only of homophones and in a list containing words. The list structure effect was found for three different stimulus lists and suggests that lexical access is strategic. If none of the items in a list has a lexical entry, then pronunciation may be the product of a non-lexical process. If all items have a lexical entry that may be accessed orthographically or phonologically, then pronunciation will be the product of a lexical process.     

Is emotional content obtained from parafoveal words during reading? An eye movement analysis

An eye-movement-contingent display change technique was employed to study whether adult readers extract semantic information from parafoveal words during reading. Three types of parafoveal preview conditions were contrasted: an emotional word, a neutral word, and an identical word condition. To have a maximally effective parafoveal manipulation, high-arousal emotional words (sex- and threat-related and curse words) were used as parafoveal previews. Readers' eye fixation patterns around the target word revealed no evidence for parafoveal semantic processing. Furthermore, the pupil size showed no signs for an emotional response triggered by an emotional word previewed parafoveally. These results are consistent with the view that, as a rule, only the fixated word is processed to a semantic level during reading.     

A Computational Model of the Self‐Teaching Hypothesis Based on the Dual‐Route Cascaded Model of Reading

The self‐teaching hypothesis describes how children progress toward skilled sight‐word reading. It proposes that children do this via phonological recoding with assistance from contextual cues, to identify the target pronunciation for a novel letter string, and in so doing create an opportunity to self‐teach new orthographic knowledge. We present a new computational implementation of self‐teaching within the dual‐route cascaded (DRC) model of reading aloud, and we explore how decoding and contextual cues can work together to enable accurate self‐teaching under a variety of circumstances. The new model (ST‐DRC) uses DRC’s sublexical route and the interactivity between the lexical and sublexical routes to simulate phonological recoding. Known spoken words are activated in response to novel printed words, triggering an opportunity for orthographic learning, which is the basis for skilled sight‐word reading. ST‐DRC also includes new computational mechanisms for simulating how contextual information aids word identification, and it demonstrates how partial decoding and ambiguous context interact to achieve irregular‐word learning. Beyond modeling orthographic learning and self‐teaching, ST‐DRC’s performance suggests new avenues for empirical research on how difficult word classes such as homographs and potentiophones are learned.     

Semantic dementia without surface dyslexia in Spanish: unimpaired reading with impaired semantics

Surface dyslexia has been attributed to an overreliance on the sub-lexical route for reading. Typically, surface dyslexic patients commit regularisation errors when reading irregular words. Also, semantic dementia has often been associated with surface dyslexia, leading to some explanations of the reading impairment that stress the role of semantics in irregular word reading. Nevertheless, some patients have been reported with unimpaired ability to read irregular words, even though they show severe comprehension impairment. We present the case of M.B., the first Spanish-speaking semantic dementia patient to be reported who shows unimpaired reading of non-words, regular words, and - most strikingly - irregular loan words. M.B. has severely impaired comprehension of the same words he reads correctly (whether regular or irregular). We argue that M.B.'s pattern of performance shows that irregular words can be correctly read even with impaired semantic knowledge corresponding to those words.     

Some bodies are easier to read: The effect of consistency and regularity on children's reading

Patterson and Morton (1985) proposed a model for the skilled reading of words and non-words that accommodates two non-lexical routines. One is the grapheme-to-phoneme correspondence system which utilizes the regularity of letter to sound correspondences for single letters and digraphs. The other is a system of “bodies”--the vowel and terminal letters of a monomorphemic, monosyllabic word. The idea of the body segment, as Patterson and Morton use it, is to capture consistency effects in reading aloud--that is, the fact that the spelling-sound pattern of words with similar written endings to the target affects the speed and accuracy of its reading.

In this study consistency and regularity are examined as separate factors in children's reading, by devising stimuli in accordance with the different types of three-letter ending that are proposed within the body sub-system.

A group of 87 children aged seven to nine (reading age range: 6;6 to 13;7) was sub-divided according to reading ability and given words and non-words to read aloud. In all the children, performance was affected by body type for both words and non-words, but the better readers were most affected. The implications of these results for a radical distributed model of reading acquisition (Seidenberg & McClelland, 1989) are considered.     

Levels of processing,context, and the facilitation of pronunciation

This paper examines the nature of processing under semantic and non-semantic orienting instructions. In the experiment subjects were presented with a series of trials; each began with the presentation of a decision word about which they made either a semantic or a non-semantic orienting decision. Following this a second word appeared and they were required to pronounce it as quickly as possible. On half the trials this second word was a primary associate of the decision word whilst on the other half it was normatively unrelated. On completion of the experiment subjects were given an unexpected recall test. The results showed that there was a significant interaction between the effect of association and type of orienting task. With semantic processing pronunciation of the second word was significantly faster on associate trials. With non-semantic processing there was a significantly smaller facilitation of pronunciation on associated trials. The incidental recall data showed that semantically oriented subjects recalled more decision words than those in the non-semantic condition. These data provide another independent measure of the difference in processing depth underlying semantic and non-semantic orienting tasks. However, unlike previous studies, these results suggest that the two types of task differ in the extent to which they allow associative processing, rather than supporting the view that non-semantic orientation precludes processing at an associative level. Discrepancies between the present result and earlier studies are discussed and an explanation offered.