Blog Archives
The “Perceptual Wedge Hypothesis” as the basis for bilingual babies’ phonetic processing advantage: New insights from fNIRS brain imaging
In a neuroimaging study focusing on young bilinguals, we explored the brains of bilingual and monolingual babies across two age groups (younger 4–6 months, older 10–12 months), using fNIRS in a new event-related design, as babies processed linguistic phonetic (Native English, Non-Native Hindi) and nonlinguistic Tone stimuli. We found that phonetic processing in bilingual and monolingual babies is accomplished with the same language-specific brain areas classically observed in adults, including the left superior temporal gyrus (associated with phonetic processing) and the left inferior frontal cortex (associated with the search and retrieval of information about meanings, and syntactic and phonological patterning), with intriguing developmental timing differences: left superior temporal gyrus activation was observed early and remained stably active over time, while left inferior frontal cortex showed greater increase in neural activation in older babies notably at the precise age when babies’ enter the universal first-word milestone, thus revealing a first-time focal brain correlate that may mediate a universal behavioral milestone in early human language acquisition. A difference was observed in the older bilingual babies’ resilient neural and behavioral sensitivity to Non-Native phonetic contrasts at a time when monolingual babies can no longer make such discriminations. We advance the “Perceptual Wedge Hypothesis” as one possible explanation for how exposure to greater than one language may alter neural and language processing in ways that we suggest are advantageous to language users. The brains of bilinguals and multilinguals may provide the most powerful window into the full neural “extent and variability” that our human species’ language processing brain areas could potentially achieve.
from Brain and Language
A statistical model of the grammatical choices in child production of dative sentences
Focusing on children’s production of the dative alternation in English, we examine whether children’s choices are influenced by the same factors that influence adults’ choices, and whether, like adults, they are sensitive to multiple factors simultaneously. We do so by using mixed-effect regression models to analyse child and child-directed datives extracted from the Child Language Data Exchange System corpus. Such models allow us to investigate the collective and independent effects of multiple factors simultaneously. The results show that children’s choices are influenced by multiple factors (length of theme and recipient, nominal expression type of both, syntactic persistence) and pattern similarly to child-directed speech. Our findings demonstrate parallels between child and adult speech, consistent with recent acquisition research suggesting that there is a usage-based continuity between child and adult grammars. Furthermore, they highlight the utility of analysing children’s speech from a multi-variable perspective, and portray a learner who is sensitive to the multiple cues present in her input.
Shedding light on words and sentences: Near-infrared spectroscopy in language research
Investigating the neuronal network underlying language processing may contribute to a better understanding of how the brain masters this complex cognitive function with surprising ease and how language is acquired at a fast pace in infancy. Modern neuroimaging methods permit to visualize the evolvement and the function of the language network. The present paper focuses on a specific methodology, functional near-infrared spectroscopy (fNIRS), providing an overview over studies on auditory language processing and acquisition. The methodology detects oxygenation changes elicited by functional activation of the cerebral cortex. The main advantages for research on auditory language processing and its development during infancy are an undemanding application, the lack of instrumental noise, and its potential to simultaneously register electrophysiological responses. Also it constitutes an innovative approach for studying developmental issues in infants and children. The review will focus on studies on word and sentence processing including research in infants and adults.
from Brain and Language
A computational model of word segmentation from continuous speech using transitional probabilities of atomic acoustic events
Word segmentation from continuous speech is a difficult task that is faced by human infants when they start to learn their native language. Several studies indicate that infants might use several different cues to solve this problem, including intonation, linguistic stress, and transitional probabilities between subsequent speech sounds. In this work, a computational model for word segmentation and learning of primitive lexical items from continuous speech is presented. The model does not utilize any a priori linguistic or phonemic knowledge such as phones, phonemes or articulatory gestures, but computes transitional probabilities between atomic acoustic events in order to detect recurring patterns in speech. Experiments with the model show that word segmentation is possible without any knowledge of linguistically relevant structures, and that the learned ungrounded word models show a relatively high selectivity towards specific words or frequently co-occurring combinations of short words.
from Cognition
Tracking irregular morphophonological dependencies in natural language: Evidence from the acquisition of subject-verb agreement in French
This study examines French-learning infants’ sensitivity to grammatical non-adjacent dependencies involving subject-verb agreement (e.g., le/les garçons lit/lisent ‘the boy(s) read(s)’) where number is audible on both the determiner of the subject DP and the agreeing verb, and the dependency is spanning across two syntactic phrases. A further particularity of this subsystem of French subject-verb agreement is that number marking on the verb is phonologically highly irregular. Despite the challenge, the HPP results for 24- and 18-month-olds demonstrate knowledge of both number dependencies: between the singular determiner le and the non-adjacent singular verbal forms and between the plural determiner les and the non-adjacent plural verbal forms. A control experiment suggests that the infants are responding to known verb forms, not phonological regularities. Given the paucity of such forms in the adult input documented through a corpus study, these results are interpreted as evidence that 18-month-olds have the ability to extract complex patterns across a range of morphophonologically inconsistent and infrequent items in natural language.
from Cognition
Balancing generalization and lexical conservatism: An artificial language study with child learners
Successful language acquisition involves generalization, but learners must balance this against the acquisition of lexical constraints. Such learning has been considered problematic for theories of acquisition: if learners generalize abstract patterns to new words, how do they learn lexically-based exceptions? One approach claims that learners use distributional statistics to make inferences about when generalization is appropriate, a hypothesis which has recently received support from Artificial Language Learning experiments with adult learners (Wonnacott, Newport, & Tanenhaus, 2008). Since adult and child language learning may be different (Hudson Kam & Newport, 2005), it is essential to extend these results to child learners. In the current work, four groups of children (6 years) were each exposed to one of four semi-artificial languages. The results demonstrate that children are sensitive to linguistic distributions at and above the level of particular lexical items, and that these statistics influence the balance between generalization and lexical conservatism. The data are in line with an approach which models generalization as rational inference and in particular with the predictions of the domain general hierarchical Bayesian model developed in Kemp, Perfors & Tenenbaum, 2006. This suggests that such models have relevance for theories of language acquisition.
from the Journal of Memory and Language
A statistical model of the grammatical choices in child production of dative sentences
Focusing on children’s production of the dative alternation in English, we examine whether children’s choices are influenced by the same factors that influence adults’ choices, and whether, like adults, they are sensitive to multiple factors simultaneously. We do so by using mixed-effect regression models to analyse child and child-directed datives extracted from the Child Language Data Exchange System corpus. Such models allow us to investigate the collective and independent effects of multiple factors simultaneously. The results show that children’s choices are influenced by multiple factors (length of theme and recipient, nominal expression type of both, syntactic persistence) and pattern similarly to child-directed speech. Our findings demonstrate parallels between child and adult speech, consistent with recent acquisition research suggesting that there is a usage-based continuity between child and adult grammars. Furthermore, they highlight the utility of analysing children’s speech from a multi-variable perspective, and portray a learner who is sensitive to the multiple cues present in her input.
Three-year-olds are sensitive to semantic prominence during online language comprehension: A visual world study of pronoun resolution
Recent evidence from adult pronoun comprehension suggests that semantic factors such as verb transitivity affect referent salience and thereby anaphora resolution. We tested whether the same semantic factors influence pronoun comprehension in young children. In a visual world study, 3-year-olds heard stories that began with a sentence containing either a high or a low transitivity verb. Looking behaviour to pictures depicting the subject and object of this sentence was recorded as children listened to a subsequent sentence containing a pronoun. Children showed a stronger preference to look to the subject as opposed to the object antecedent in the low transitivity condition. In addition there were general preferences (1) to look to the subject in both conditions and (2) to look more at both potential antecedents in the high transitivity condition. This suggests that children, like adults, are affected by semantic factors, specifically semantic prominence, when interpreting anaphoric pronouns.
Three ideal observer models for rule learning in simple languages
Children learning the inflections of their native language show the ability to generalize beyond the perceptual particulars of the examples they are exposed to. The phenomenon of “rule learning”—quick learning of abstract regularities from exposure to a limited set of stimuli—has become an important model system for understanding generalization in infancy. Experiments with adults and children have revealed differences in performance across domains and types of rules. To understand the representational and inferential assumptions necessary to capture this broad set of results, we introduce three ideal observer models for rule learning. Each model builds on the next, allowing us to test the consequences of individual assumptions. Model 1 learns a single rule, Model 2 learns a single rule from noisy input, and Model 3 learns multiple rules from noisy input. These models capture a wide range of experimental results—including several that have been used to argue for domain-specificity or limits on the kinds of generalizations learners can make—suggesting that these ideal observers may be a useful baseline for future work on rule learning.
from Cognition
Accessing the unsaid: The role of scalar alternatives in children’s pragmatic inference
When faced with a sentence like, “Some of the toys are on the table”, adults, but not preschoolers, compute a scalar implicature, taking the sentence to imply that not all the toys are on the table. This paper explores the hypothesis that children fail to compute scalar implicatures because they lack knowledge of relevant scalar alternatives to words like “some”. Four-year-olds were shown pictures in which three out of three objects fit a description (e.g., three animals reading), and were asked to evaluate statements that relied on context-independent alternatives (e.g., knowing that all is an alternative to some for the utterance “Some of the animals are reading”) or contextual alternatives (e.g., knowing that the set of all three visible animals is an alternative to a set of two for the utterance “Only the cat and the dog are reading”). Children failed to reject the false statements containing context-independent scales even when the word only was used (e.g., only some), but correctly rejected equivalent statements containing contextual alternatives (e.g., only the cat and dog). These results support the hypothesis that children’s difficulties with scalar implicature are due to a failure to generate relevant alternatives for specific scales. Consequences for number word learning are also discussed.
from Cognition
Word learning does not end at fast-mapping: Evolution of verb meanings through reorganization of an entire semantic domain
This paper explores the process through which children sort out the relations among verbs belonging to the same semantic domain. Using a set of Chinese verbs denoting a range of action events that are labeled by carrying or holding in English as a test case, we looked at how Chinese-speaking 3-, 5-, and 7-year-olds and adults apply 13 different verbs to a range of carrying/holding events. We asked how children learning Chinese originally divide and label the semantic space in this domain, how they discover the boundaries between different words, and how the meanings of verbs in the domain as a whole evolve toward the representations of adults. We also addressed the question of what factors make verb meaning acquisition easy or hard. Results showed that the pattern of children’s verb use is largely different from that of adults and that it takes a long time for children to be able to use all verbs in this domain in the way adults do. We also found that children start to use broad-covering and frequent verbs the earliest, but use of these verbs tends to converge on adult use more slowly because children could not use these verbs as adults did until they had identified boundaries between these verbs and other near-synonyms with more specific meanings. This research highlights the importance of systematic investigation of words that belong to the same domain as a whole, examining how word meanings in a domain develop as parts of a connected system, instead of examining each word on its own: learning the meaning of a verb invites restructuring of the meanings of related, neighboring verbs.
from Cognition
Modeling human performance in statistical word segmentation
The ability to discover groupings in continuous stimuli on the basis of distributional information is present across species and across perceptual modalities. We investigate the nature of the computations underlying this ability using statistical word segmentation experiments in which we vary the length of sentences, the amount of exposure, and the number of words in the languages being learned. Although the results are intuitive from the perspective of a language learner (longer sentences, less training, and a larger language all make learning more difficult), standard computational proposals fail to capture several of these results. We describe how probabilistic models of segmentation can be modified to take into account some notion of memory or resource limitations in order to provide a closer match to human performance.
from Cognition
Early lexical development of children with cochlear implants
Vocabulary size and grammatical composition in 11 children who received a cochlear implant at a mean age of 15 months were compared to that of the Quebec French normative sample for the Words and Sentences questionnaire of the MacArthur-Bates Communicative Development Inventories (MBCDI). Results showed that, as age increases in children, age equivalent scores according to total vocabulary size approach hearing age (equivalent to the duration of device use) and diverge from chronological age. Distribution of grammatical categories according to vocabulary size followed the same pattern as in the normative sample. These results suggest that the lexical profile of children with implants was very similar to that of normally-hearing children who had the same number of words.
from the Canadian Journal of Speech-Language Pathology and Audiology http://www.scopus.com/record/display.url?eid=2-s2.0-77955569303&origin=inward&txGid=sIp-vf8ivngpV1_PhaY80lJ%3a2
Children’s verbalizations of motion events in German
Recent studies in language acquisition have paid much attention to linguistic diversity and have begun to show that language properties may have an impact on how children construct and organize their representations. With respect to motion events, Talmy (Towards a cognitive semantics: Concept structuring systems, Cambridge University Press, 2000) has proposed a typological distinction between satellite-framed (S) languages that encode path in satellites, leaving the verb root free for the expression of manner, and verb-framed (V) languages that encode path in the verb, requiring manner to be expressed in the periphery of the sentence. This distinction has lead to the hypothesis (Slobin, From “thought and language” to “thinking for speaking”, Cambridge University Press, 1996) that manner should be more salient for children learning S-languages, who should have no difficulty combining it with path, as compared to those learning V-languages. This hypothesis was tested in a corpus elicited from German children and adults who had to verbalize short animated cartoons showing motion events, and the results are compared with previous analyses of French and English corpora elicited in an identical situation (Hickmann et al., Journal of Child Language, 36: 705–741, 2009). As predicted, and as previously found for English, German children from three years on systematically express both manner (in the verb root) and path (in particles), in sharp contrast to French children, who rarely package manner and path together. These results suggest that, when they are engaged in communication, children construct spatial representations in accordance with the particular properties of their mother tongue. Future research is necessary to determine the extent to which cross-linguistic differences in production may reflect deeper differences in the allocation of attention and in conceptual organization.
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