Hemispheric sensitivity to grammatical cues: evidence for bilateral processing of number agreement in noun phrases

Reduced right-hemisphere ERP P600 grammaticality effect is associated with greater right-hemisphere inhibition: Evidence from right-handers with familial sinistrality

The present study examined the hypothesis that left hemisphere (LH) equivalent language capabilities in the right hemisphere (RH) are inhibited in neurologically intact individuals by testing healthy young right-handers with a history of familial sinistrality (FS+, i.e. with at least one left handed biological relative), a population documented to show greater variability for RH language processing. Event-Related Potential (ERP) and split visual field presentation techniques were combined to assess LH- and RH- biased responses to syntactic category violations. In addition, a bilateral flanker task was used to measure inter-hemispheric inhibition ability in the same set of participants. Replicating prior findings, in addition to the LH-biased P600 grammaticality effect previously seen for right-handers in general, a fair amount, though not all, of FS + right-handers showed RH-biased P600 responses, leading to a reliable RH P600 grammaticality effect at the group level. Capitalizing on the variability of RH P600 responses, our results further revealed that reduced RH-biased P600 effects were reliably correlated with more effective RH inhibition (indexed by smaller reaction time differences between incongruent and neutral flankers presented to the RH via the left visual field). These results corroborated previous findings that the RH is capable of processing syntactic information in a manner qualitatively similar to that in the LH and further demonstrated that LH-equivalent processing in the RH as indexed by the P600 responses is modulated by RH inhibition, contributing to inter-individual variability in syntactic lateralization.

How reading in single- and multiple-column types influence our cognitive load: an EEG study

Purpose

The impact of different screen-based typography styles on individuals’ cognitive processing of information has not been given much consideration in the literature, though such differences would imply different learning outcomes. This study aims to enrich the current understanding of the impact of reading in single- and multiple-column types on students’ cognitive processing.

Design/methodology/approach

An electroencephalogram (EEG) was used to record and analyze the brain signals of 27 students while reading from single- and multiple- column layouts.

Findings

The results showed a significant difference in students’ cognitive load when reading text from different types of columns. All students exerted less processing efforts when text was presented in two-column format, thus experiencing less cognitive load.

Originality/value

Using EEG, this study examined the neural consequences of reading in single- and multiple-column types on cognitive load during reading. The findings can be used to enrich the current instructional design practices on how different typographical formats facilitate learners’ cognitive performance.

Age-related shifts in hemispheric dominance for syntactic processing

Recent ERP data from young adults have revealed that simple syntactic anomalies elicit different patterns of lateralization in right-handed participants depending upon their familial sinistrality profile (whether or not they have left-handed biological relatives). Right-handed participants who do not have left-handed relatives showed a strongly lateralized response pattern, with P600 responses following left-hemisphere-biased presentations and N400 responses following right-hemisphere-biased presentations. Given that the literature on aging has documented a tendency to change across adulthood from asymmetry of function to a more bilateral pattern, we tested the stability of this asymmetric response to syntactic violations by recording ERPs as 24 older adults (age 60+) with no history of familial sinistrality made grammaticality judgments on simple two-word phrases. Results showed that the asymmetric pattern observed in right-handed adults without familial sinistrality indeed changes with age, such that P600 responses come to be elicited not only with left-hemisphere-biased but also with right-hemisphere-biased presentations in older adults. These findings suggest that, as with many other cognitive functions, syntactic processing becomes more bilateral with age.

It's All in the Family: Brain Asymmetry and Syntactic Processing of Word Class

Although left-hemisphere (LH) specialization for language is often viewed as a key example of functional lateralization, there is increasing evidence that the right hemisphere (RH) can also extract meaning from words and sentences. However, the right hemisphere's ability to appreciate syntactic aspects of language remains poorly understood. In the current study, we used separable, functionally well-characterized electrophysiological indices of lexico-semantic and syntactic processes to demonstrate RH sensitivity to syntactic violations among right-handers with a strong manual preference. Critically, however, the nature of this RH sensitivity to structural information was modulated by a genetically determined factor--familial sinistrality. The right hemisphere in right-handers without left-handed family members processed syntactic violations via the words' accompanying lexico-semantic unexpectedness. In contrast, the right hemisphere in right-handers with left-handed family members could process syntactic information in a manner qualitatively similar to that of the left hemisphere.

Grammatical number agreement processing using the visual half-field paradigm: an event-related brain potential study

Despite indications in the split-brain and lesion literatures that the right hemisphere is capable of some syntactic analysis, few studies have investigated right hemisphere contributions to syntactic processing in people with intact brains. Here we used the visual half-field paradigm in healthy adults to examine each hemisphere's processing of correct and incorrect grammatical number agreement marked either lexically, e.g., antecedent/reflexive pronoun ("The grateful niece asked herself/*themselves…") or morphologically, e.g., subject/verb ("Industrial scientists develop/*develops…"). For reflexives, response times and accuracy of grammaticality decisions suggested similar processing regardless of visual field of presentation. In the subject/verb condition, we observed similar response times and accuracies for central and right visual field (RVF) presentations. For left visual field (LVF) presentation, response times were longer and accuracy rates were reduced relative to RVF presentation. An event-related brain potential (ERP) study using the same materials revealed similar ERP responses to the reflexive pronouns in the two visual fields, but very different ERP effects to the subject/verb violations. For lexically marked violations on reflexives, P600 was elicited by stimuli in both the LVF and RVF; for morphologically marked violations on verbs, P600 was elicited only by RVF stimuli. These data suggest that both hemispheres can process lexically marked pronoun agreement violations, and do so in a similar fashion. Morphologically marked subject/verb agreement errors, however, showed a distinct LH advantage.

Functional specificity in the human brain: a window into the functional architecture of the mind

Is the human mind/brain composed of a set of highly specialized components, each carrying out a specific aspect of human cognition, or is it more of a general-purpose device, in which each component participates in a wide variety of cognitive processes? For nearly two centuries, proponents of specialized organs or modules of the mind and brain--from the phrenologists to Broca to Chomsky and Fodor--have jousted with the proponents of distributed cognitive and neural processing--from Flourens to Lashley to McClelland and Rumelhart. I argue here that research using functional MRI is beginning to answer this long-standing question with new clarity and precision by indicating that at least a few specific aspects of cognition are implemented in brain regions that are highly specialized for that process alone. Cortical regions have been identified that are specialized not only for basic sensory and motor processes but also for the high-level perceptual analysis of faces, places, bodies, visually presented words, and even for the very abstract cognitive function of thinking about another person's thoughts. I further consider the as-yet unanswered questions of how much of the mind and brain are made up of these functionally specialized components and how they arise developmentally.

Priming nouns and verbs: differential influences of semantic and grammatical cues in the two cerebral hemispheres

The current experiment investigated how sentential form-class expectancies influenced lexical-semantic priming within each hemisphere. Sentences were presented that led readers to expect a noun or a verb and the sentence-final target word was presented to one visual field/hemisphere for a lexical decision response. Noun and verb targets in the semantically related condition were compared to an unrelated prime condition, which also predicted part of speech but did not contain any lexical-semantic associates of the target word. The semantic priming effect was strongly modulated by form-class expectancy for RVF/LH targets, for both nouns and verbs. In the LVF/RH, semantic priming was obtained in all conditions, regardless of whether the form-class expectancy was violated. However, the nouns that were preceded by a noun-predicting sentence showed an extremely high priming value in the LVF/RH, suggesting that the RH may have some sensitivity to grammatical predictions for nouns. Comparisons of LVF/RH priming to calculations derived from the LSA model of language representation, which does not utilize word order, suggested that the RH might derive message-level meaning primarily from lexical-semantic relatedness.

Interaction between phonological and grammatical processing in single word production in Kiswahili

Grammatical priming of picture naming was investigated in Kiswahili, which has a complex grammatical noun class system (a system like grammatical gender), with up to 15 noun classes that have obligatory agreements on adjectives, verbs, pronouns and other parts of speech. Participants heard a grammatically agreeing (concordant), nonagreeing (discordant) or neutral prime before seeing a picture of a common object and being asked to name the object. Priming was found, with naming following concordant primes being faster than naming following the neutral prime ('say'). However, more interestingly, effects were found such that where two noun classes share a prefix, the grammatical prime from each of these two noun classes also primed words that have the same prefix but are not in the same noun class, and hence for which the prime was not grammatical. It is concluded that the prime appears to be facilitating the phonological form of the prefix rather than the syntacto-semantic group of words that are known as a noun class, and that the phonological form associated with a grammatical entity may be more significant in its processing than has previously been supposed.

Does right hemisphere damaged patients' impaired performance on a sentence insertion task indicate a syntactic or a lexical level deficit?

The present paper focuses on two studies, one on English (Schneiderman & Saddy, 1988) and the other on Italian (De Vreese, Neri Rubichi, & Salvioli, 1996), which report on right hemisphere damaged subjects' inability to correctly insert a word or phrase into an already well-formed sentence under certain stimulus conditions. Despite their strikingly similar findings, the results of the studies are interpreted quite differently. Schneiderman & Saddy consider the deficit to be syntactic, while De Vreese et al. view it as occurring at the lexical category or morphological level. An analysis and regrouping of the stimulus items from both studies indicate that a single syntactic interpretation could account for their results. Suggestions are made for further analyses and research to increase our understanding of the syntactic capacities of the intact right hemisphere.

Does global context modulate cerebral asymmetries? A review and new evidence on word imageability effects

In this article we examine whether the distribution of function across the right and left cerebral hemispheres for lexical processing is influenced by the global context within which words are presented. A review of previously published studies indicates that the ubiquitous right visual field (RVF)/left hemisphere advantage for word recognition may be reduced or eliminated for nouns, content words, or high image words, but only when such items are presented along with verbs, function words, or low image words. However, paradoxically, when the former items are presented in more homogeneous contexts, the RVF advantage is uniformly observed. We propose that the processing efficiency of a hemisphere for a given stimulus depends on that item's relation to the other stimuli provided, that is, the global context. This was examined in a visual half-field experiment that varied whether high and low image nouns were presented in homogeneous (blocked lists) or heterogeneous (mixed lists) contexts. An unvarying RVF advantage was observed for high image words in homogeneous contexts, but this advantage was eliminated when the same items were presented in heterogeneous contexts. We suggest that stimulus heterogeneity maximizes reliance on differing, but complementary, computational biases across hemispheres. Hence, the extent to which the left and right hemispheres are recruited for the recognition of individual word types can vary dynamically with variation in the stimulus environment.