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Germinal centers (GCs) form in lymph nodes after immunization or infection to facilitate antibody affinity maturation and memory and plasma cell (PC) development. PC differentiation is thought to involve stringent selection for GC B cells expressing the highest-affinity antigen receptors, but how this plays out during complex polyclonal responses is unclear. We combine temporal lineage tracing with antibody characterization to gain a snapshot of PCs developing during influenza infection. GCs co-mature B cell clones with antibody affinities spanning multiple orders of magnitude; however, each generates PCs with similar efficiencies, including weak binders. Within lineages, PC selection is not restricted to variants with the highest-affinity antibodies. Differentiation is commonly associated with proliferative expansion to produce "nodes" of identical PCs. Immunization-induced GCs generate fewer PCs but still of low- and high-antibody affinities. We propose that generating low-affinity antibody PCs reflects an evolutionary compromise to facilitate diverse serum antibody responses.
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Afinidade de Anticorpos , Linfócitos B , Centro Germinativo , Plasmócitos , Formação de Anticorpos , Linfócitos B/citologia , Linfócitos B/imunologia , Linfonodos , Linhagem Celular , Humanos , Animais , Camundongos , Cricetinae , Vírus da Influenza A/imunologia , Diferenciação CelularRESUMO
There is substantial evidence that children's apparent omission of grammatical morphemes in utterances such as "She play tennis" and "Mummy eating" is in fact errors of commission in which contextually licensed unmarked forms encountered in the input are reproduced in a context-blind fashion. So how do children stop making such errors? In this study, we test the assumption that children's ability to recover from error is related to their developing sensitivity to longer-range dependencies. We use a pre-registered corpus analysis to explore the predictive value of different cues with regards to children's verb-marking errors and observe a developmental pattern consistent with this account. We look at context-independent cues (the identity of the specific verb being used) and at the relative value of context-dependent cues (the identity of the specific subject+verb sequence being used). We find that the only consistent effect across a group of 2- to 3-year-olds and a group of 3- to 4-year-olds is the relative frequency of unmarked forms of specific subject+verb sequences being used. The relative frequency of unmarked forms of the verb alone is predictive only in the younger age group. This is consistent with an account in which children recover from making errors by becoming progressively more sensitive to context, at first the immediately preceding lexical contexts (e.g., the subject that precedes the verb) and eventually more distant grammatical markers (e.g., the fronted auxiliary that precedes the subject in questions). RESEARCH HIGHLIGHTS: We provide a corpus analysis investigating input effects on young children's verb-marking errors (e.g., Mummy go) across development (between 2 and 4 years of age). We find evidence that these apparent errors of omission are in fact input-driven errors of commission that persist into the third year of life. We compare the relative effect on error rates of context-independent (e.g., verb) and context-dependent (e.g., subject+verb sequence) cues across developmental time. Our findings support the proposal that children recover from making verb-marking errors by becoming progressively more sensitive to preceding context.
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Psycholinguistic research over the past decade has suggested that children's linguistic knowledge includes dedicated representations for frequently-encountered multiword sequences. Important evidence for this comes from studies of children's production: it has been repeatedly demonstrated that children's rate of speech errors is greater for word sequences that are infrequent and thus unfamiliar to them than for those that are frequent. In this study, we investigate whether children's knowledge of multiword sequences can explain a phenomenon that has long represented a key theoretical fault line in the study of language development: errors of subject-auxiliary non-inversion in question production (e.g., "why we can't go outside?*"). In doing so we consider a type of error that has been ignored in discussion of multiword sequences to date. Previous work has focused on errors of omission - an absence of accurate productions for infrequent phrases. However, if children make use of dedicated representations for frequent sequences of words in their productions, we might also expect to see errors of commission - the appearance of frequent phrases in children's speech even when such phrases are not appropriate. Through a series of corpus analyses, we provide the first evidence that the global input frequency of multiword sequences (e.g., "she is going" as it appears in declarative utterances) is a valuable predictor of their errorful appearance (e.g., the uninverted question "what she is going to do?*") in naturalistic speech. This finding, we argue, constitutes powerful evidence that multiword sequences can be represented as linguistic units in their own right.
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Linguística , Fala , Criança , Feminino , Humanos , Idioma , Desenvolvimento da Linguagem , PsicolinguísticaRESUMO
Language is vital for social interaction, leading some to suggest early linguistic ability paves the way for good adolescent mental health. The relation between age-5 vocabulary and adolescent internalizing symptoms was examined in two U.K. birth cohorts that are nationally representative in terms of sex, ethnicity, and socioeconomic status: the 1970 British Cohort Study (BCS; N = 11,640) and the Millennium Cohort Study (MCS born ~2001; N = 14,754). In the BCS, no relation between receptive vocabulary and age-16 self-reported symptoms was observed (ß = 0.00 [-0.03; 0.03]). In the MCS, better expressive vocabulary was associated with more age-14 self-reported symptoms (ß = 0.05 [0.02; 0.07]). The direction of this effect was reversed for parent-reported symptoms. All effect sizes were small. The relation between childhood vocabulary and internalizing symptoms varies by generation and reporter.
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Linguagem Infantil , Vocabulário , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Humanos , Desenvolvimento da Linguagem , LinguísticaRESUMO
What aspects of infants' prelinguistic communication are most valuable for learning to speak, and why? We test whether early vocalizations and gestures drive the transition to word use because, in addition to indicating motoric readiness, they (a) are early instances of intentional communication and (b) elicit verbal responses from caregivers. In study 1, 11 month olds (N = 134) were observed to coordinate vocalizations and gestures with gaze to their caregiver's face at above chance rates, indicating that they are plausibly intentionally communicative. Study 2 tested whether those infant communicative acts that were gaze-coordinated best predicted later expressive vocabulary. We report a novel procedure for predicting vocabulary via multi-model inference over a comprehensive set of infant behaviours produced at 11 and 12 months (n = 58). This makes it possible to establish the relative predictive value of different behaviours that are hierarchically organized by level of granularity. Gaze-coordinated vocalizations were the most valuable predictors of expressive vocabulary size up to 24 months. Study 3 established that caregivers were more likely to respond to gaze-coordinated behaviours. Moreover, the dyadic combination of infant gaze-coordinated vocalization and caregiver response was by far the best predictor of later vocabulary size. We conclude that practice with prelinguistic intentional communication facilitates the leap to symbol use. Learning is optimized when caregivers respond to intentional vocalizations with appropriate language.
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Cuidadores/psicologia , Comunicação , Comportamento do Lactente , Desenvolvimento da Linguagem , Feminino , Fixação Ocular , Gestos , Humanos , Lactente , Idioma , Masculino , VocabulárioRESUMO
Of all the things a person could say in a given situation, what determines what is worth saying? Greenfield's principle of informativeness states that right from the onset of language, humans selectively comment on whatever they find unexpected. In this article, we quantify this tendency using information-theoretic measures and report on a study in which we tested the counterintuitive prediction that children will produce words that have a low frequency given the context, because these will be most informative. Using corpora of child-directed speech, we identified adjectives that varied in how informative (i.e., unexpected) they were given the noun they modified. In an initial experiment ( N = 31) and in a replication ( N = 13), 3-year-olds heard an experimenter use these adjectives to describe pictures. The children's task was then to describe the pictures to another person. As the information content of the experimenter's adjective increased, so did children's tendency to comment on the feature that adjective had encoded. Furthermore, our analyses suggest that children balance informativeness with a competing drive to ease production.
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Teoria da Informação , Psicologia Experimental/métodos , Aprendizagem Verbal/fisiologia , Linguagem Infantil , Pré-Escolar , Feminino , Humanos , Idioma , Desenvolvimento da Linguagem , Linguística , Masculino , SemânticaRESUMO
Despite its recognized importance for cultural transmission, little is known about the role imitation plays in language learning. Three experiments examine how rates of imitation vary as a function of qualitative differences in the way language is used in a small indigenous community in Oaxaca, Mexico and three Western comparison groups. Data from one hundred thirty-eight 3- to 10-year-olds suggests that children selectively imitate when they understand the function of a given linguistic element because their culture makes frequent use of that function. When function is opaque, however, children imitate faithfully. This has implications for how children manage the imitation-innovation trade-off, and offers insight into why children imitate in language learning across development.
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Comportamento Infantil/etnologia , Compreensão , Comparação Transcultural , Comportamento Imitativo , Desenvolvimento da Linguagem , Criança , Pré-Escolar , Humanos , México/etnologia , Suíça/etnologia , Texas/etnologiaRESUMO
PURPOSE: This systematic review and multilevel meta-analysis examines the accuracy of sentence repetition (SR) tasks in distinguishing between typically developing (TD) children and children with developmental language disorder (DLD). It explores variation in the way that SR tasks are administered and/or evaluated and examines whether variability in the reported ability of SR to detect DLD is related to these differences. METHOD: Four databases were searched to identify studies that had used an SR task on groups of monolingual children with DLD and TD children. Searches produced 3,459 articles, of which, after screening, 66 were included in the systematic review. A multilevel meta-analysis was then conducted using 46 of these studies. Multiple preregistered subgroup analyses were conducted in order to explore the sources of heterogeneity. RESULTS: The systematic review found a great deal of methodological variation, with studies spanning 19 languages, 39 SR tasks, and four main methods of production scoring. There was also variation in study design, with different sampling (clinical and population sampling) and matching (age and language matching) methods. The overall meta-analysis found that, on average, TD children outperformed children with DLD on the SR tasks by 2.08 SDs. Subgroup analyses found that effect size only varied as a function of the matching method and language of the task. CONCLUSIONS: Our results indicate that SR tasks can distinguish children with DLD from both age- and language-matched samples of TD children. The usefulness of SR appears robust to most kinds of task and study variation. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.25864405.
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Transtornos do Desenvolvimento da Linguagem , Testes de Linguagem , Humanos , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Criança , Linguagem Infantil , Pré-EscolarRESUMO
Tense/aspect morphology on verbs is often thought to depend on event features like telicity, but it is not known how speakers identify these features in visual scenes. To examine this question, we asked Japanese speakers to describe computer-generated animations of simple actions with variation in visual features related to telicity. Experiments with adults and children found that they could use goal information in the animations to select appropriate past and progressive verb forms. They also produced a large number of different verb forms. To explain these findings, a deep-learning model of verb production from visual input was created that could produce a human-like distribution of verb forms. It was able to use visual cues to select appropriate tense/aspect morphology. The model predicted that video duration would be related to verb complexity, and past tense production would increase when it received the endpoint as input. These predictions were confirmed in a third study with Japanese adults. This work suggests that verb production could be tightly linked to visual heuristics that support the understanding of events.
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Infant facial attractiveness is an important facilitator for adult-infant caregiving behaviour. Disruption to typical infant facial configurations can, however, attenuate their perceived attractiveness, as rated by adult observers. Previous research has either focused on how ratings are affected by observer characteristics (e.g., male/female), or alterations to infant faces, either experimentally, or naturalistically induced, such as the presence of a cleft lip. Little research has however been conducted on the effects of observer experience on adult ratings of infant facial attractiveness. Such effects could inform clinical work and policies aimed at promoting positive perception of facial malformations. The present study thus explored the effects of familiarisation on how typical and atypical infant facial configurations are evaluated by adults. We recruited two groups of female participants and compared their subjective attractiveness ratings of infant faces (24 typical and 24 cleft-affected), at baseline, and at one-week post-test. Between the two assessments, one group (n = 41) underwent a week-long training phase, where they were familiarised with cleft lip/palate-related visual and informational stimuli, while the control group (n = 44) received no training. Significantly higher ratings were provided for faces of typically developing versus cleft-affected infants by both groups of participants at baseline. At post-test, this pattern of ratings was repeated in participants belonging to the control group, while familiarised participants showed an increase, compared to baseline, in their ratings of cleft-affected faces and no difference between their evaluation of the latter and that of typically developing faces. These findings extend our understanding of the observer's experience in the evaluation of infant faces, beyond the effects of the structural characteristics of the observed faces. Results also highlight familiarity as a potentially protective influence against the negative consequences of alterations to typical facial configurations, suggesting avenues for intervention in supporting adult caregivers in the context of neonatal facial malformations.
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Fenda Labial , Fissura Palatina , Adulto , Recém-Nascido , Humanos , Masculino , Lactente , Feminino , Reconhecimento Psicológico , Cuidadores , PercepçãoRESUMO
Despite recent development of vaccines to prevent SARS-CoV-2 infection, treatment of critically ill COVID-19 patients remains an important goal. In principle, genome-wide association studies (GWASs) provide a shortcut to the clinical evidence needed to repurpose existing drugs; however, genes identified frequently lack a causal disease link. We report an alternative method for finding drug repurposing targets, focusing on disease-causing traits beyond immediate disease genetics. Sixty blood cell types and biochemistries, and body mass index, were screened on a cohort of critically ill COVID-19 cases and controls that exhibited mild symptoms after infection, yielding high neutrophil cell count as a possible causal trait for critical illness. Our methodology identified CDK6 and janus kinase (JAK) inhibitors as treatment targets that were validated in an ex vivo neutrophil extracellular trap (NET) formation assay. Our methodology demonstrates the increased power for drug target identification by leveraging large disease-causing trait datasets.
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Theories of grammatical development differ in how much abstract knowledge they attribute to young children. Here, we report a series of experiments using a computational model to evaluate the explanatory power of child grammars based not on abstract rules but on concrete words and phrases and some local abstractions associated with these words and phrases. We use a Bayesian procedure to extract such item-based grammars from transcriptions of 28+ h of each of two children's speech at 2 and 3 years of age. We then use these grammars to parse all of the unique multiword utterances from transcriptions of separate recordings of these same children at each of the two ages. We found that at 2 years of age such a model had good coverage and predictive fit, with the children showing radically limited productivity. Furthermore, adding expert-annotated parts of speech to the induction procedure had little effect on coverage, with the exception of the category of noun. At age 3, the children's productivity sharply increased and the addition of a verb and a noun category markedly improved the model's performance.
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Conhecimento , Idioma , Modelos Psicológicos , Fala , Teorema de Bayes , Pré-Escolar , Humanos , Linguística , Memória , Probabilidade , Comportamento Verbal , VocabulárioRESUMO
BACKGROUND AND OBJECTIVES: A set of important pragmatic skills emerge during infancy and pave the way for later language learning. It is thought these early social communication skills develop through infant-caregiver interaction. In a microanalysis, we tested whether deaf and hard of hearing (DHH) infants (typically at high risk of reduced access to rich communicative interaction in infancy) are less likely to engage in gestural and vocal pragmatic behaviors. METHODS: We coded the naturalistic communication of 8 DHH infants who had no additional needs, who were not preterm or low birth weight, whose parents were hearing, monolingual English speakers, and who had spoken English as their primary target language. The frequency of use of 5 types of infant communication known to positively predict later language development (show gestures, give gestures, index-finger pointing, communicative vocalizations, and early word use) was compared with that of 8 typically hearing infants matched for age, sex, and socioeconomic status. RESULTS: Hearing loss had a significant negative effect on the frequency with which infants engaged in all types of early communication that predict later language development. CONCLUSIONS: DHH infants are at high risk of delay in the gestural and vocal communicative skills that lay the foundations for later language. Delay in the gestural domain suggests this is not simply a consequence of difficulties in imitating auditory stimuli. There is significant potential to lift DHH infants onto a positive developmental trajectory by supporting caregivers to nurture interaction from the first year.
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Linguagem Infantil , Surdez/psicologia , Comunicação não Verbal , Relações Pais-Filho , Pessoas com Deficiência Auditiva/psicologia , Comportamento Verbal , Humanos , Lactente , Interação Social , Habilidades SociaisRESUMO
This preregistered study tested three theoretical proposals for how children form productive yet restricted linguistic generalizations, avoiding errors such as *The clown laughed the man, across three age groups (5-6â¯years, 9-10â¯years, adults) and five languages (English, Japanese, Hindi, Hebrew and K'iche'). Participants rated, on a five-point scale, correct and ungrammatical sentences describing events of causation (e.g., *Someone laughed the man; Someone made the man laugh; Someone broke the truck; ?Someone made the truck break). The verb-semantics hypothesis predicts that, for all languages, by-verb differences in acceptability ratings will be predicted by the extent to which the causing and caused event (e.g., amusing and laughing) merge conceptually into a single event (as rated by separate groups of adult participants). The entrenchment and preemption hypotheses predict, for all languages, that by-verb differences in acceptability ratings will be predicted by, respectively, the verb's relative overall frequency, and frequency in nearly-synonymous constructions (e.g., X made Y laugh for *Someone laughed the man). Analysis using mixed effects models revealed that entrenchment/preemption effects (which could not be distinguished due to collinearity) were observed for all age groups and all languages except K'iche', which suffered from a thin corpus and showed only preemption sporadically. All languages showed effects of event-merge semantics, except K'iche' which showed only effects of supplementary semantic predictors. We end by presenting a computational model which successfully simulates this pattern of results in a single discriminative-learning mechanism, achieving by-verb correlations of around râ¯=â¯0.75 with human judgment data.
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Julgamento , Idioma , Adulto , Criança , Pré-Escolar , Humanos , Japão , Desenvolvimento da Linguagem , SemânticaRESUMO
Parkinson's Disease can be understood as a disorder of motor habits. A prediction of this theory is that early stage Parkinson's patients will display fewer errors caused by interference from previously over-learned behaviours. We test this prediction in the domain of skilled typing, where actions are easy to record and errors easy to identify. We describe a method for categorizing errors as simple motor errors or habit-driven errors. We test Spanish and English participants with and without Parkinson's, and show that indeed patients make fewer habit errors than healthy controls, and, further, that classification of error type increases the accuracy of discriminating between patients and healthy controls. As well as being a validation of a theory-led prediction, these results offer promise for automated, enhanced and early diagnosis of Parkinson's Disease.
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Hábitos , Doença de Parkinson/diagnóstico , Doença de Parkinson/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Desempenho Psicomotor/fisiologiaRESUMO
Four experiments examined the effects of word and phrase frequency on free recall. Word frequency did not affect word recall, but when participants studied and recalled lists of compositional adjective-noun phrases (e.g. alcoholic beverages), phrase frequency had a consistently beneficial effect: both words from frequent phrases were more likely to be recalled than for infrequent phrases, providing evidence that long-term memory for phrases can aid in pattern completion, or redintegration. We explain these results and those of a previous study of phrase frequency effects in recognition memory (Jacobs et al., 2016) by assuming that the language processing system provides features that are linked to episodic contexts. Recall tasks map from these contexts to linguistic elements, and recognition maps from linguistic elements to contexts. Word and phrase frequency effects in both memory tasks emerge both within the language processing system and from multiple stored episodes, and the fact that the representations of phrases are tied to knowledge of their component words, rather than being representational islands.
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Early bilinguals often show as much sensitivity to L2-specific contrasts as monolingual speakers of the L2, but most work on cross-language speech perception has focused on isolated segments, and typically only on neighboring vowels or stop contrasts. In tasks that include sounds in context, listeners' success is more variable, so segment discrimination in isolation may not adequately represent the phonetic detail in stored representations. The current study explores the relationship between language experience and sensitivity to segmental cues in context by comparing the categorization patterns of monolingual English listeners and early and late Spanish-English bilinguals. Participants categorized nonce words containing different classes of English- and Spanish-specific sounds as being more English-like or more Spanish-like; target segments included phonemic cues, cues for which there is no analogous sound in the other language, or phonetic cues, cues for which English and Spanish share the category but for which each language varies in its phonetic implementation. Listeners' language categorization accuracy and reaction times were analyzed. Our results reveal a largely uniform categorization pattern across listener groups: Spanish cues were categorized more accurately than English cues, and phonemic cues were easier for listeners to categorize than phonetic cues. There were no differences in the sensitivity of monolinguals and early bilinguals to language-specific cues, suggesting that the early bilinguals' exposure to Spanish did not fundamentally change their representations of English phonology. However, neither did the early bilinguals show more sensitivity than the monolinguals to Spanish sounds. The late bilinguals however, were significantly more accurate than either of the other groups. These findings indicate that listeners with varying exposure to English and Spanish are able to use language-specific cues in a nonce-word language categorization task. Differences in how, and not only when, a language was acquired may influence listener sensitivity to more difficult cues, and the advantage for phonemic cues may reflect the greater salience of categories unique to each language. Implications for foreign-accent categorization and cross-language speech perception are discussed, and future directions are outlined to better understand how salience varies across language-specific phonemic and phonetic cues.
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Children with Autism Spectrum Disorder (ASD) aged 11-13 (N = 16) and an IQ-matched typically developing (TD) group aged 7-12 (N = 16) completed a graded grammaticality judgment task, as well as a standardized test of cognitive function. In a departure from previous studies, the judgment task involved verb argument structure overgeneralization errors (e.g., *Lisa fell the cup off the shelf) of the type sometimes observed amongst typically developing children, as well as grammatical control sentences with the same verbs (e.g., The cup fell off the shelf). The ASD group showed a smaller dispreference for ungrammatical sentences (relative to the control sentences) than did the TD group. These findings are indicative of a subtle grammatical impairment in even relatively high-functioning children with ASD.
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Transtorno do Espectro Autista/psicologia , Desenvolvimento da Linguagem , Adolescente , Transtorno do Espectro Autista/fisiopatologia , Criança , Feminino , Generalização Psicológica , Humanos , Julgamento , Linguística , MasculinoRESUMO
In 3 studies we explored when 3-year-olds would imitate novel words in utterances produced by adult speakers. Child and experimenter took turns in requesting objects from a game master. The experimenter always went first and always preceded the object's familiar name with a novel adjective (e.g., "the dilsige duck"). In the first 2 experiments, we found that children were more likely to reproduce the adjective when there were 2 different instances of the same object present in the situation than when there was only 1 or when there were 2 objects of different types present. Thus, children seemed to be sensitive to the descriptive and contrastive function of the adjectives in determining which parts of the utterances to reproduce. Nonetheless, replication of even redundant material was over 50%, suggesting a strategy of somewhat blind copying. In the 3rd experiment, we found that children were less likely to reproduce a redundant adjective when the speaker indicated gesturally that he did not intend to produce it than when he clearly produced it intentionally. We distinguish insightful imitation (the copying of a speaker's goal and means when motivated by insight into why those particular means were chosen) and blind imitation (the copying of a speaker's goal and means with no awareness of why those specific means were chosen) from mimicry. We explore the roles that these modes of imitation might play in language development.
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Comportamento Imitativo/fisiologia , Desenvolvimento da Linguagem , Psicolinguística , Aprendizagem Verbal/fisiologia , Pré-Escolar , Feminino , Humanos , Masculino , Análise de Regressão , VocabulárioRESUMO
We compared 24-month-old children's learning when their exposure to words came either in an interactive (coupled) context or in a nonsocial (decoupled) context. We measured the children's learning with two different methods: one in which they were asked to point to the referent for the experimenter, and the other a preferential looking task in which they were encouraged to look to the referent. In the pointing test, children chose the correct referents for words encountered in the coupled condition but not in the decoupled condition. In the looking time test, however, they looked to the targets regardless of condition. We explore the explanations for this and propose that the different response measures are reflecting two different kinds of learning.