English Vowel Discrimination and Perceptual Assimilation by Japanese Listeners

This study examined whether the discrimination accuracy of nonnative vowels could be predicted by how listeners assimilate nonnative phones into their L1. The results demonstrated that Japanese listeners discriminated between English /æ/ and /ʌ/ better than they did between /ɑ/ and /ʌ/, although they categorized all those stimuli as the Japanese /a/. Given that the acoustic distance between stimuli was controlled to be identical, this result was attributed not to the acoustic difference but to the category-goodness difference. The goodness-of-fit to the Japanese /a/ phoneme differed between the English /æ/ and /ʌ/ but not between the English /ɑ/ and /ʌ/, suggesting that it is more difficult to discriminate between vowels when the category-goodness difference between two nonnative stimuli is smaller. In addition, this study examined the relationship between perceptual assimilation and the focalization effect. Focalization affects directional asymmetry in a manner that renders detecting a sound change from a more-focal to a less-focal vowel more difficult than detecting a change in the opposite direction. The results demonstrated that this directional asymmetry is only observed when listeners assimilate two nonnative phones into a single L1 phonemic category, with no category-goodness difference between the two nonnative phones.

Developmental Language Disorder as Syntactic Prediction Impairment

We provide evidence that children with Developmental Language Disorder (DLD) are impaired in predictive syntactic processing. In the current study, children listened passively to auditorily-presented sentences, where the critical condition included an unexpected "filled gap" in the direct object position of the relative clause verb. A filled gap is illustrated by the underlined phrase in "The zebra that the hippo kissed the camel on the nose…", rather than the expected "the zebra that the hippo kissed [e] on the nose", where [e] denotes the gap. Brain responses to the filled gap were compared to a control condition using adverb-relative clauses with identical substrings: "The weekend that the hippo kissed the camel on the nose [e]…". Here, the same noun phrase is not unexpected because the adverb gap occurs later in the structure. We hypothesized that a filled gap would elicit a prediction error brain signal in the form of an early anterior negativity, as we have previously observed in adults. We found an early (bilateral) anterior negativity to the filled gap in a control group of children with Typical Development (TD), but the children with DLD exhibited no brain response to the filled gap during the same early time window. This suggests that children with DLD fail to predict that a relativized object should correspond to an empty position after the relative clause verb, suggesting an impairment in predictive processing. We discuss how this lack of a prediction error signal can interact with language acquisition and result in DLD.

Informative use of "not" is N400-blind

While sentence processing is generally a highly incremental and predictive process, negation seems to present an exception to this generalization. Two-step models of negation processing claim that predicate negation is computed only after the meaning of the core proposition has been computed. Several ERP studies eliciting the N400 (an index of semantic integration or lexical expectation) have found a "negation-blind" pattern of N400 results, suggesting that the negation has not been integrated into the overall sentence meaning by the time the critical word for the N400 is encountered. Recent research, however, showed that the N400 was sensitive to the negation-modulated truth value of the sentence when negation was pragmatically licensed. We investigate the possibility that negation-blind N400 is due to under-informativeness of stimuli in past experiments. We found that ERPs to simple class-exclusion statements ("A hammer is not a bird") still exhibit negation blindness, even when negation is presented in a more meaningful context. The current findings provide new support for late/non-incremental interpretation of negation even when negation is pragmatically licensed.

Automaticity of speech processing in early bilingual adults and children

We examine whether early acquisition of a second language (L2) leads to native-like neural processing of phonemic contrasts that are absent in the L1. Four groups (adult and child monolingual speakers of English; adult and child early bilingual speakers of English and Spanish, exposed to both languages before 5 years of age) participated in a study comparing the English /I/ - /ε/ contrast. Neural measures of automatic change detection (Mismatch Negativity, MMN) and attention (Processing Negativity, PN and Late Negativity, LN) were measured by varying whether participants tracked the stimulus stream or not. We observed no effect of bilingualism on the MMN, but adult bilinguals differed significantly from adult monolinguals on neural indices of attention. The child bilinguals were indistinguishable from their monolingual peers. This suggest that learning a L2 before five years of age leads to native-like phoneme discrimination, but bilinguals develop increased attentional sensitivity to speech sounds.

Abstractness of human speech sound representations

We argue, based on a study of brain responses to speech sound differences in Japanese, that memory encoding of functional speech sounds-phonemes-are highly abstract. As an example, we provide evidence for a theory where the consonants/p t k b d g/ are not only made up of symbolic features but are underspecified with respect to voicing or laryngeal features, and that languages differ with respect to which feature value is underspecified. In a previous study we showed that voiced stops are underspecified in English [Hestvik, A., & Durvasula, K. (2016). Neurobiological evidence for voicing underspecification in English. Brain and Language], as shown by asymmetries in Mismatch Negativity responses to /t/ and /d/. In the current study, we test the prediction that the opposite asymmetry should be observed in Japanese, if voiceless stops are underspecified in that language. Our results confirm this prediction. This matches a linguistic architecture where phonemes are highly abstract and do not encode actual physical characteristics of the corresponding speech sounds, but rather different subsets of abstract distinctive features.

Processing Binding Relations in Specific Language Impairment

PURPOSE

This sentence processing experiment examined the abilities of children with specific language impairment (SLI) and children with typical language development (TD) to establish relations between pronouns or reflexives and their antecedents in real time.

METHOD

Twenty-two children with SLI and 24 age-matched children with TD (7;3-10;11 [years;months]) participated in a cross-modal picture priming experiment to determine whether they selectively activated the correct referent at the pronoun or reflexive in sentences. Triplets of auditory sentences, identical except for the presence of a pronoun, a reflexive, or a noun phrase along with a picture probe were used.

RESULTS

The children with TD were slightly more accurate in their animacy judgments of pictures, but the groups exhibited the same reaction time (RT) pattern. Both groups were slower for sentences with pronouns than with reflexives or noun phrases. The children with SLI had longer RTs than their peers with TD.

CONCLUSIONS

Children with SLI activated only the appropriate antecedent at the pronoun or reflexive, reflecting intact core knowledge of binding as was true for their TD peers. The overall slower RT for children with SLI suggests that any deficit may be the result of processing deficits, perhaps attributable to interference effects.

Neurobiological evidence for voicing underspecification in English

In long-term memory, the phoneme units that make up words are coded for the distinctive features and feature values that are necessary to distinguish between words in the mental lexicon. Underspecification theory says that the phonemes that have unmarked feature values are even more abstract in that the feature is omitted from the representation altogether. This makes phoneme representations in words more sparse than the fully specified phonetic representations of the same words. Eulitz and Lahiri (2004) demonstrated that this theory predicts certain asymmetries in the Mismatch Negativity (MMN) response to phoneme contrasts. We expand on this research by demonstrating underspecification-driven asymmetry in the brain response to laryngeal feature contrasts in English (i.e. what makes /d/ and /t/ different). We add a new test by showing that the asymmetry disappears if the MMN paradigm is modified to encourage the formation of phonetic memory traces instead of phonemic memory traces. This result adds further neurobiological evidence that long-term phonological representations are more sparsely represented than phonetic representations.

ERPs reveal atypical processing of subject versus object Wh-questions in children with specific language impairment

BACKGROUND

Children with specific language impairment (SLI) show particular difficulty comprehending and producing object (Who did the bear follow?) relative to subject (Who followed the tiger?) wh-questions.

AIMS

To determine if school-age children with SLI, relative to children with typical development (TD), show a more distinct unevenness, or asymmetry, in the comprehension of these questions. In addition, this study examined whether the sustained left-anterior negativity (LAN) in event-related potentials (ERP) could be used as a marker for atypical processing of these questions in children with SLI. The LAN effect signals the greater working memory processes for maintaining in memory the dislocated object in object wh-questions and reflects working memory capacity in adults. It was predicted that the amplitude of the LAN would be greater in children with SLI, reflecting the characteristic low working memory capacity in this population. The concomitance of these behavioural and electrophysiological effects would suggest that the subject-object asymmetry in SLI should be investigated in relation to poor working memory skills.

METHODS & PROCEDURES

Groups including 13 children with SLI, 17 same-age TD children and 18 normal adults completed an auditory sentence comprehension task requiring button responses while continuous electroencephalography (EEG) was collected. Accuracy for subject and object questions was calculated. The mean amplitude values of the ERP data for the wh-questions were examined to identify differential processing of subject and object questions.

OUTCOMES & RESULTS

TD children demonstrated asymmetrical comprehension of subject and object wh-questions, whereas children with SLI comprehended both question types poorly and adults did not show subject-object asymmetry. ERP waveforms spanning the wh-dependency revealed a large and widespread sustained anterior positivity for object relative to subject questions in the TD group, indicating differential processing of these questions. This effect was attenuated and non-significant in the SLI group. The adults' grand average waveforms showed the expected LAN effect, which was opposite in polarity relative to the children, although it only approached significance.

CONCLUSIONS & IMPLICATIONS

The finding of less differential processing of subject and object wh-questions in SLI relative to TD children suggests inefficient maintenance of sentential information in working memory for object questions in SLI. Whereas behavioural methods did not identify subject-object asymmetry in SLI, the more fine-grained method of ERPs elucidated this effect. Further analysis of working memory as the basis for the subject-object asymmetry in SLI is critical for identifying appropriate intervention targets for this population.

Perception and bias in the processing of compound versus phrasal stress: evidence from event-related brain potentials

Previous research using picture/word matching tasks has demonstrated a tendency to incorrectly interpret phrasally stressed strings as compounds. Using event-related potentials, we sought to determine whether this pattern stems from poor perceptual sensitivity to the compound/phrasal stress distinction, or from a post-perceptual bias in behavioral response selection. A secondary aim was to gain insight into the role played by contrastive stress patterns in online sentence comprehension. The behavioral results replicated previous findings of a preference for compounds, but the electrophysiological data suggested a robust sensitivity to both stress patterns. When incongruent with the context, both compound and phrasal stress elicited a sustained left-lateralized negativity. Moreover, incongruent compound stress elicited a centro-parietal negativity (N400), while incongruent phrasal stress elicited a late posterior positivity (P600). We conclude that the previous findings of a preference for compounds are due to response selection bias, and not a lack of perceptual sensitivity. The present results complement previous evidence for the immediate use of meter in semantic processing, as well as evidence for late interactions between prosodic and syntactic information.

Working memory effects of gap-predictions in normal adults: an event-related potentials study

The current study examined the relationship between verbal memory span and the latency with which a filler-gap dependency is constructed. A previous behavioral study found that low span listeners did not exhibit antecedent reactivation at gap sites in relative clauses, in comparison to high verbal memory span subjects (Roberts et al. in J Psycholinguist Res 36(2):175-188, 2007), which suggests that low span subjects are delayed at gap filling. This possibility was examined in the current study. Using an event-related potentials paradigm, it was found that low span subjects have an onset latency delay of about 200 ms in brain responses to violations of syntactic expectancies after the gap site, thus providing a time course measure of the delay hypothesized by previous literature.

Syntactic structural assignment in Brazilian Portuguese-speaking children with specific language impairment

PURPOSE

In this study, the authors examined the comprehension of sentences with predicates and reflexives that are linked to a nonadjacent noun as a test of the hierarchical ordering deficit (HOD) hypothesis. That hypothesis and more modern versions posit that children with specific language impairment (SLI) have difficulty in establishing nonadjacent (hierarchical) relations among elements of a sentence. The authors also tested whether additional working memory demands in constructions containing reflexives affected the extent to which children with SLI incorrectly structure sentences as indicated by their picture-pointing comprehension responses.

METHOD

Sixteen Brazilian Portuguese-speaking children (8;4-10;6 [years;months]) with SLI and 16 children with typical language development (TLD) matched for age (± 3 months), gender, and socioeconomic status participated in 2 experiments (predicate and reflexive interpretation). In the reflexive experiment, the authors also manipulated working memory demands. Each experiment involved a 4-choice picture selection sentence comprehension task.

RESULTS

Children with SLI were significantly less accurate on all conditions. Both groups made more hierarchical syntactic construction errors in the long working memory condition than in the short working memory condition.

CONCLUSION

The HOD hypothesis was not confirmed. For both groups, syntactic factors (structural assignment) were more vulnerable than lexical factors (prepositions) to working memory effects in sentence miscomprehension.

Relative clause gap-filling in children with specific language impairment

Children with Specific Language Impairment (SLI) have been observed to have production and perception difficulties with sentences containing long-distance dependencies, but it is unclear whether this is due to impairment in grammatical knowledge or in processing mechanisms. The current study addressed this issue by examining automatic on-line gap-filling in relative clauses, as well as off-line comprehension of the same stimulus sentences. As predicted by both knowledge impairment and processing impairment models, SLI children showed lack of immediate gap-filling after the relative clause verb, in comparison to a control group of typically developing children. However, on the off-line measure of comprehension of the same stimuli sentences, SLI children and TD children did not differ qualitatively. This finding is incompatible with knowledge impairment. We interpret the results to show that SLI children have impaired processing mechanisms (such as temporally delayed gap-filling) but are not impaired in their grammatical knowledge.

Linguistic and auditory temporal processing in children with specific language impairment

BACKGROUND

Several studies suggest the association of specific language impairment (SLI) to deficits in auditory processing. It has been evidenced that children with SLI present deficit in brief stimuli discrimination. Such deficit would lead to difficulties in developing phonological abilities necessary to map phonemes and to effectively and automatically code and decode words and sentences. However, the correlation between temporal processing (TP) and specific deficits in language disorders--such as syntactic comprehension abilities--has received little or no attention.

AIM

To analyze the correlation between: TP (through the Frequency Pattern Test--FPT) and Syntactic Complexity Comprehension (through a Sentence Comprehension Task).

METHOD

Sixteen children with typical language development (8;9 +/- 1;1 years) and seven children with SLI (8;1 +/- 1;2 years) participated on the study.

RESULTS

Accuracy of both groups decreased with the increase on syntactic complexity (both p < 0.01). On the between groups comparison, performance difference on the Test of Syntactic Complexity Comprehension (TSCC) was statistically significant (p = 0.02).As expected, children with SLI presented FPT performance outside reference values. On the SLI group, correlations between TSCC and FPT were positive and higher for high syntactic complexity (r = 0.97) than for low syntactic complexity (r = 0.51).

CONCLUSION

Results suggest that FPT is positively correlated to syntactic complexity comprehension abilities.The low performance on FPT could serve as an additional indicator of deficits in complex linguistic processing. Future studies should consider, besides the increase of the sample, longitudinal studies that investigate the effect of frequency pattern auditory training on performance in high syntactic complexity comprehension tasks.

Brain responses to filled gaps

An unresolved issue in the study of sentence comprehension is whether the process of gap-filling is mediated by the construction of empty categories (traces), or whether the parser relates fillers directly to the associated verb's argument structure. We conducted an event-related potentials (ERP) study that used the violation paradigm to examine the time course and spatial distribution of brain responses to ungrammatically filled gaps. The results indicate that the earliest brain response to the violation is an early left anterior negativity (eLAN). This ERP indexes an early phase of pure syntactic structure building, temporally preceding ERPs that reflect semantic integration and argument structure satisfaction. The finding is interpreted as evidence that gap-filling is mediated by structurally predicted empty categories, rather than directly by argument structure operations.

Antecedent reactivation by surface and deep anaphora in Norwegian

Anaphora are expressions in language that depend on other linguistic entities for their full meaning. They can furthermore be divided into two types according to the level of representation where they find their antecedents: Surface anaphora, which resolve their reference at the sentence representation level, and deep anaphora, which resolve their reference at the non-grammatical level of discourse representation. The linguistic theory of these two anaphor types, and recent findings about processing differences at these two levels, combine to predict that surface anaphora should show fast and immediate reactivation of their antecedents, whereas deep anaphora should have a slower time course of antecedent re-access. These predictions were confirmed with two lexical decision task experiments with Norwegian stimuli.

How do adults and children process referentially ambiguous pronouns?

In two eye-tracking experiments, we investigate adults' and children's on-line processing of referentially ambiguous English pronouns. Sixteen adults and 16 four-to-seven-year-olds listened to sentences with either an unambiguous reflexive (himself) or an ambiguous pronoun (him) and chose a picture with two characters that corresponded to those in the sentence. For adults, behavioural data, responses and reaction times indicate that pronouns are referentially ambiguous. Adults' eye movements show a competition between the looks to sentence-internal and -external referents for pronouns, but not for reflexives. Children overwhelmingly prefer the sentence-internal referent in the off-line picture selection task. However, their eye movements reveal implicit awareness of referential ambiguity that develops earlier than their explicit knowledge in the picture selection task. This discrepancy between performance on a looking measure and a pointing measure in the children's processing system is explained by a general dissociation between implicit and explicit knowledge proposed in recent literature on cognitive development.

Charting the time-course of VP-ellipsis sentence comprehension: Evidence for an initial and independent structural analysis

We exploited the properties of VP-ellipsis constructions containing inherently reflexive and inalienable possession verbs that severely constrained final interpretation (e.g., "The policeman perjured himself, and the fireman did too…"). Using the cross-modal lexical priming task, we found that listeners reactivated the subject NP from the first clause at the elided position in the second clause (i.e., the "strict" reading), even though verb properties disallowed such an interpretation. We also found that listeners reactivated the subject NP from the second clause, demonstrating the "sloppy" interpretation. In a final experiment we examined VP-ellipsis constructions that did not contain anaphors (e.g., "The mailman bought a tie for Easter, and his brother did too…"). We found that only the object NP of the first clause was reconstructed in the second clause. We interpret these findings as support for a parser that computes multiple interpretations on-line, yet is initially insensitive to lexical and probabilistic information.

On-line comprehension of VP-ellipsis: syntactic reconstruction and semantic influence

We describe two experiments that explored the on-line processing of coordinated (e.g., The policemen defended himself and the fireman did [e] too, according to someone who was there) and subordinated VP-ellipsis (e.g., The policeman defended himself because the fireman did [e], according to someone who was there). Such constructions have two possible interpretations: The "sloppy" reading is that the fireman defended himself, where himself corefers with the fireman. The "strict" reading is that the fireman defended him, where him corefers with the policeman. In our experiments we examined the strict reading, and found different time courses of processing the coordinated and subordinated structures. In coordination we found immediate reaccess of the nonlocal subject at the gap. In subordinated structures we found the reaccess effect only downstream from the gap. We interpret these patterns as reflecting the automatic nature of gap filling in coordinated ellipsis, but in subordinated ellipsis a causal relation must be computed between the two clauses, " drawing out" reaccess of the filler.