Brain asymmetry and visual word recognition: do we have a split fovea?

In this chapter we discuss how the anatomical divide between the left and the right brain half has implications for visual word recognition. In particular, it introduces the need for massive interhemispheric communication. Unlike what was believed in the traditional view, it looks increasingly likely that interhemispheric integration is already needed from the very first stages of word processing, when the letter information is combined to activate stored word representations. Taking into account these insights not only improves our understanding of the neurophysiological and cognitive mechanisms of reading, it also gives us new ideas to look at individual differences in reading

Fast automatic translation and morphological decomposition in Chinese- English bilinguals

In this study, we investigated automatic translation from English to Chinese and subsequent morphological decomposition of translated Chinese compounds. In two lexical decision tasks, Chinese-English bilinguals responded to English target words that were preceded by masked unrelated primes presented for 59 ms. Unbeknownst to participants, the Chinese translations of the words in each critical pair consisted of a fully opaque compound word (i.e., a compound with two constituent morphemes that were semantically unrelated to the compound) and a monomorphemic word that was either the first or the second morpheme of the compound. The data revealed that bilinguals responded faster to English word pairs whose Chinese translations repeated the first morpheme than to English word pairs whose Chinese translations did not repeat the first morpheme, but no effect of hidden second-morpheme repetition was found. This effect of hidden first-morpheme repetition suggests that participants translated English words to Chinese and decomposed the translated compounds into their constituent morphemes. Because the primes were presented for only 59 ms, translation and morphological decomposition must be fast and automatic

Processing differences across regular and irregular inflections revealed through ERPs

Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test two key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems; and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and while priming for regular and irregular inflections was observed in a time window reflecting processing 400-600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterisation of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approache

Automatic morpheme identification across development : Magnetoencephalography (MEG) evidence from fast periodic visual stimulation

The present study combined magnetoencephalography (MEG) recordings with fast periodic visual stimulation (FPVS) to investigate automatic neural responses to morphemes in developing and skilled readers. Native English-speaking children (N = 17, grade 5–6) and adults (N = 28) were presented with rapid streams of base stimuli (6 Hz) interleaved periodically with oddballs (i.e., every fifth item, oddball stimulation frequency: 1.2 Hz). In a manipulation-check condition, tapping into word recognition, oddballs featured familiar words (e.g., roll) embedded in a stream of consonant strings (e.g., ktlq). In the experimental conditions, the contrast between oddball and base stimuli was manipulated in order to probe selective stem and suffix identification in morphologically structured pseudowords (e.g., stem + suffix pseudowords such as softity embedded in nonstem + suffix pseudowords such as trumess). Neural responses at the oddball frequency and harmonics were analyzed at the sensor level using non-parametric cluster-based permutation tests. As expected, results in the manipulation-check condition revealed a word-selective response reflected by a predominantly left-lateralized cluster that emerged over temporal, parietal, and occipital sensors in both children and adults. However, across the experimental conditions, results yielded a differential pattern of oddball responses in developing and skilled readers. Children displayed a significant response that emerged in a mostly central occipital cluster for the condition tracking stem identification in the presence of suffixes (e.g., softity vs. trumess). In contrast, adult participants showed a significant response that emerged in a cluster located in central and left occipital sensors for the condition tracking suffix identification in the presence of stems (e.g., softity vs. stopust). The present results suggest that while the morpheme identification system in Grade 5–6 children is not yet adult-like, it is sufficiently mature to automatically analyze the morphemic structure of novel letter strings. These findings are discussed in the context of theoretical accounts of morphological processing across reading development

Does linear position matter for morphological processing? Evidence from a Tagalog masked priming experiment

This study investigated morphological decomposition of Tagalog infixed, prefixed, and suffixed words using the masked priming paradigm. We directly compared morphological priming of infixed, ni- prefixed and -in suffixed words to examine whether infixes are processed similarly to other affixes during early and automatic decomposition. We found significant priming effects for infixed, prefixed, and suffixed words, but no semantic or orthographic similarity priming. Magnitudes of priming effects for infixed and prefixed words were not significantly different, suggesting that decomposition of infixed words was not more costly for Tagalog speakers, contrary to phonological readjustment-based accounts of infixation. This is the first psycholinguistic experiment showing that infixed words are decomposed into morphological units during visual word recognition. We provide evidence that the imperfect edge-alignment of the stem within infixed words does not hamper the early morphological decomposition mechanisms, suggesting that edge-alignment might not be critical to trigger activation of morphological units

Activation of the Left Inferior Frontal Gyrus in the First 200 ms of Reading: Evidence from Magnetoencephalography (MEG)

BACKGROUND: It is well established that the left inferior frontal gyrus plays a key role in the cerebral cortical network that supports reading and visual word recognition. Less clear is when in time this contribution begins. We used magnetoencephalography (MEG), which has both good spatial and excellent temporal resolution, to address this question. METHODOLOGY/PRINCIPAL FINDINGS: MEG data were recorded during a passive viewing paradigm, chosen to emphasize the stimulus-driven component of the cortical response, in which right-handed participants were presented words, consonant strings, and unfamiliar faces to central vision. Time-frequency analyses showed a left-lateralized inferior frontal gyrus (pars opercularis) response to words between 100-250 ms in the beta frequency band that was significantly stronger than the response to consonant strings or faces. The left inferior frontal gyrus response to words peaked at approximately 130 ms. This response was significantly later in time than the left middle occipital gyrus, which peaked at approximately 115 ms, but not significantly different from the peak response in the left mid fusiform gyrus, which peaked at approximately 140 ms, at a location coincident with the fMRI-defined visual word form area (VWFA). Significant responses were also detected to words in other parts of the reading network, including the anterior middle temporal gyrus, the left posterior middle temporal gyrus, the angular and supramarginal gyri, and the left superior temporal gyrus. CONCLUSIONS/SIGNIFICANCE: These findings suggest very early interactions between the vision and language domains during visual word recognition, with speech motor areas being activated at the same time as the orthographic word-form is being resolved within the fusiform gyrus. This challenges the conventional view of a temporally serial processing sequence for visual word recognition in which letter forms are initially decoded, interact with their phonological and semantic representations, and only then gain access to a speech code

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

Beyond decomposition: processing zero-derivations in English visual word recognition

Four experiments investigate the effects of covert morphological complexity during visual word recognition. Zero-derivations occur in English in which a change of word class occurs without any change in surface form (e.g., a boat-to boat; to soak-a soak). Boat is object-derived and is a basic noun (N), whereas soak is action-derived and is a basic verb (V). As the suffix {-ing} is only attached to verbs, deriving boating from its base, requires two steps, boat(N)>boat(V)>boating(V), while soaking can be derived in one step from soak(V). Experiments 1 to 3 used masked priming at different prime durations to test matched sets of one and two-step verbs for morphological (soaking-SOAK) and semantic priming (jolting-SOAK). Experiment 4 employed a delayed-priming paradigm in which the full verb forms (soaking and boating) were primed by noun and verb phrases (a soak/to soak, a boat/to boat). In both paradigms, different morphological priming patterns were observed for one-step and two-step verbs, demonstrating that morphological processing cannot be reduced to surface form-based segmentation

A neuronal gamma oscillatory signature during morphological unification in the left occipitotemporal junction

Morphology is the aspect of language concerned with the internal structure of words. In the past decades, a large body of masked priming (behavioral and neuroimaging) data has suggested that the visual word recognition system automatically decomposes any morphologically complex word into a stem and its constituent morphemes. Yet the reliance of morphology on other reading processes (e.g., orthography and semantics), as well as its underlying neuronal mechanisms are yet to be determined. In the current magnetoencephalography study, we addressed morphology from the perspective of the unification framework, that is, by applying the Hold/Release paradigm, morphological unification was simulated via the assembly of internal morphemic units into a whole word. Trials representing real words were divided into words with a transparent (true) or a nontransparent (pseudo) morphological relationship. Morphological unification of truly suffixed words was faster and more accurate and additionally enhanced induced oscillations in the narrow gamma band (60–85 Hz, 260–440 ms) in the left posterior occipitotemporal junction. This neural signature could not be explained by a mere automatic lexical processing (i.e., stem perception), but more likely it related to a semantic access step during the morphological unification process. By demonstrating the validity of unification at the morphological level, this study contributes to the vast empirical evidence on unification across other language processes. Furthermore, we point out that morphological unification relies on the retrieval of lexical semantic associations via induced gamma band oscillations in a cerebral hub region for visual word form processing