Brain-based individual difference measures of reading skill in deaf and hearing adults.

Most deaf children and adults struggle to read, but some deaf individuals do become highly proficient readers. There is disagreement about the specific causes of reading difficulty in the deaf population, and consequently, disagreement about the effectiveness of different strategies for teaching reading to deaf children. Much of the disagreement surrounds the question of whether deaf children read in similar or different ways as hearing children. In this study, we begin to answer this question by using real-time measures of neural language processing to assess if deaf and hearing adults read proficiently in similar or different ways. Hearing and deaf adults read English sentences with semantic, grammatical, and simultaneous semantic/grammatical errors while event-related potentials (ERPs) were recorded. The magnitude of individuals' ERP responses was compared to their standardized reading comprehension test scores, and potentially confounding variables like years of education, speechreading skill, and language background of deaf participants were controlled for. The best deaf readers had the largest N400 responses to semantic errors in sentences, while the best hearing readers had the largest P600 responses to grammatical errors in sentences. These results indicate that equally proficient hearing and deaf adults process written language in different ways, suggesting there is little reason to assume that literacy education should necessarily be the same for hearing and deaf children. The results also show that the most successful deaf readers focus on semantic information while reading, which suggests aspects of education that may promote improved literacy in the deaf population.

Conceptual Integration of Arithmetic Operations With Real-World Knowledge: Evidence From Event-Related Potentials.

Research on language processing has shown that the disruption of conceptual integration gives rise to specific patterns of event-related brain potentials (ERPs)-N400 and P600 effects. Here, we report similar ERP effects when adults performed cross-domain conceptual integration of analogous semantic and mathematical relations. In a problem-solving task, when participants generated labeled answers to semantically aligned and misaligned arithmetic problems (e.g., 6 roses + 2 tulips = ? vs. 6 roses + 2 vases = ?), the second object label in misaligned problems yielded an N400 effect for addition (but not division) problems. In a verification task, when participants judged arithmetically correct but semantically misaligned problem sentences to be "unacceptable," the second object label in misaligned sentences elicited a P600 effect. Thus, depending on task constraints, misaligned problems can show either of two ERP signatures of conceptual disruption. These results show that well-educated adults can integrate mathematical and semantic relations on the rapid timescale of within-domain ERP effects by a process akin to analogical mapping.

Effects of Grammaticality and Morphological Complexity on the P600 Event-Related Potential Component.

We investigated interactions between morphological complexity and grammaticality on electrophysiological markers of grammatical processing during reading. Our goal was to determine whether morphological complexity and stimulus grammaticality have independent or additive effects on the P600 event-related potential component. Participants read sentences that were either well-formed or grammatically ill-formed, in which the critical word was either morphologically simple or complex. Results revealed no effects of complexity for well-formed stimuli, but the P600 amplitude was significantly larger for morphologically complex ungrammatical stimuli than for morphologically simple ungrammatical stimuli. These findings suggest that some previous work may have inadequately characterized factors related to reanalysis during morphosyntactic processing. Our results show that morphological complexity by itself does not elicit P600 effects. However, in ungrammatical circumstances, overt morphology provides a more robust and reliable cue to morphosyntactic relationships than null affixation.

ERP responses to cross-cultural melodic expectancy violations.

In this preliminary study, we measured event-related potentials (ERPs) to melodic expectancy violations in a cross-cultural context. Subjects (n= 10) were college-age students born and raised in the United States. Subjects heard 30 short melodies based in the Western folk tradition and 30 from North Indian classical music. Each melody was presented in its original and deviation form, and subjects were asked to judge the congruence of the melody. Results indicated that subjects found the Indian melodies less congruous overall and were less sensitive to deviations in the Indian melody condition. ERP data were partly consistent with the behavioral data with significant P600 responses to deviations in both cultural conditions, but less robust in the Indian context. Results are interpreted in light of previous research on listeners' abilities to generate expectancies in unfamiliar cultures and the possibility of overlap in the scale systems influencing the findings.

Unintentional covert motor activations predict behavioral effects: Multilevel modeling of trial-level electrophysiological motor activations.

The present experiment measured an EEG indicator of motor cortex activation, the lateralized readiness potential (LRP), while participants performed a speeded category classification task. The LRP data showed that visually masked words triggered covert motor activations. These prime-induced motor activations preceded motor activations by subsequent (to-be-classified) visible target words. Multilevel statistical analyses of trial-level effects, applied here for the first time with electrophysiological data, revealed that accuracy and latency of classifying target words was affected by both (a) covert motor activations caused by visually masked primes and (b) spontaneous fluctuations in covert motor activations. Spontaneous covert motor fluctuations were unobserved with standard subject-level (multi-trial) analyses of grand-averaged LRPs, highlighting the utility of multilevel modeling of trial-level effects.

Neural responses to partner rejection cues.

Little is known about neural responses in the early automatic-stage processing of rejection cues from a partner. Event-related potentials (ERPs) offer a window to study processes that may be difficult to detect via behavioral methods. We focused on the N400 ERP component, which reflects the amount of semantic processing prompted by a target. When participants were primed by attachment-related contexts ("If I need help from my partner, my partner will be ..."), rejection-related words (e.g., dismissing) elicited greater N400 amplitudes than acceptance-related words (e.g., supporting). Analyses of results for nonattachment primes suggest that these findings were not simply caused by target valence; the brain responds differentially to cues of partner rejection (vs. acceptance) in under 300 ms. Moreover, these early-stage neurophysiological responses were heightened or dampened as a function of individuals' adult attachment; women characterized by high anxiety and low avoidance showed the greatest N400 responses to cues of partner rejection (vs. acceptance).

Second-language learning and changes in the brain.

Presumably, second-language (L2) learning is mediated by changes in the brain. Little is known about what changes in the brain, how the brain changes, or when these changes occur during learning. Here, we illustrate by way of example how modern brain-based methods can be used to discern some of the changes that occur during L2 learning. Preliminary results from three studies indicate that classroom-based L2 instruction can result in changes in the brain's electrical activity, in the location of this activity within the brain, and in the structure of the learners' brains. These changes can occur during the earliest stages of L2 acquisition.

The effect of phonological realization of inflectional morphology on verbal agreement in French: evidence from ERPs.

The present study examined the impact of the phonological realization of morphosyntactic agreement within the inflectional phrase (IP) in written French, as revealed by ERPs. In two independent experiments, we varied the presence vs. absence of phonological cues to morphological variation. Of interest was whether a graded ERP response to these different conditions could be found in native speakers (Experiment 1), and whether non-native learners would benefit from the presence of phonological cues (Experiment 2). The results for native French speakers showed that compared to grammatically correct instances, phonologically realized inflectional errors produced a significant P600 response, which was statistically larger than that produced by errors that were silent. German L1-French L2 learners showed similar benefits of the phonological realization of morphemes. Phonologically realized errors produced a robust P600 response whereas silent errors produced no robust effects. Implications of these results are discussed in reference to previous studies of L2 acquisition of morphosyntax.

ERPs reveal comparable syntactic sentence processing in native and non-native readers of English.

L2 syntactic processing has been primarily investigated in the context of syntactic anomaly detection, but only sparsely with syntactic ambiguity. In the field of event-related potentials (ERPs) syntactic anomaly detection and syntactic ambiguity resolution is linked to the P600. The current ERP experiment examined L2 syntactic processing in highly proficient L1 Spanish-L2 English readers who had acquired English informally around the age of 5 years. Temporary syntactic ambiguity (induced by verb subcategorization information) was tested as a language-specific phenomenon of L2, while syntactic anomaly resulted from phrase structure constraints that are similar in L1 and L2. Participants judged whether a sentence was syntactically acceptable or not. Native readers of English showed a P600 in the temporary syntactically ambiguous and syntactically anomalous sentences. A comparable picture emerged in the non-native readers of English. Both critical syntactic conditions elicited a P600, however, the distribution and latency of the P600 varied in the syntactic anomaly condition. The results clearly show that early acquisition of L2 syntactic knowledge leads to comparable online sensitivity towards temporal syntactic ambiguity and syntactic anomaly in early and highly proficient non-native readers of English and native readers of English.

Neural correlates of second-language word learning: minimal instruction produces rapid change.

Adult second-language (L2) learning is often claimed to be slow and laborious compared to native language (L1) acquisition, but little is known about the rate of L2 word learning. Here we report that adult second-language learners' brain activity, as measured by event-related potentials (ERPs), discriminated between L2 words and L2 'pseudowords' (word-like letter strings) after just 14 h of classroom instruction. This occurred even while the learners performed at chance levels when making overt L2 word-nonword judgments, indicating that the early acquisition of some aspects of a new language may be overlooked by current behavioral assessments.

Morphological decomposition involving non-productive morphemes: ERP evidence.

It is generally believed that readers decompose a complex word into its constituent morphemes only when those morphemes participate productively in word formation. Here we recorded event-related potentials (ERPs) to words (e.g. muffler, receive), non-words containing no morphemes (e.g. flermuf), and non-words containing a prefix and a non-productive bound stem (e.g. in-ceive). Prior work has shown that pronounceable non-words elicit larger-amplitude N400 components than words. If readers treat non-words containing non-productive morphemes as unanalyzed wholes, then these non-words should elicit larger N400 s than matched words. We report here, however, that bound-stem non-words elicit a brain response highly similar to that elicited by real words. This finding suggests that morphological decomposition and representation extend to non-productive morphemes.

Brain potentials elicited by prose-embedded linguistic anomalies.

Linguistic theories distinguish between syntax (sentence form) and semantics (sentence meaning). Correspondingly, recent studies have shown that syntactic and semantic anomalies elicit distinct changes in the event-related brain potential (ERP). However, these results have been obtained with highly artificial methodologies and have not yet been generalized to more natural reading conditions. Here, we recorded ERPs while subjects read a naturalistic prose passage. The subjects either read for comprehension with no other task being assigned or read for comprehension and made acceptability judgments after each sentence. Consistent with prior work and regardless of the subjects' assigned task, syntactic anomalies elicited a large positive wave (P600), whereas semantic anomalies elicited a large increase in N400 amplitude. These results demonstrate that the qualitatively distinct ERP responses elicited by syntactic and semantic anomalies are not artifacts of unnatural aspects of previously used stimuli, thereby providing additional evidence that separable syntactic and semantic processes exist.