How does social contingency facilitate vocabulary development?

Previous research shows that infants of parents who are more likely to engage in socially contingent interactions with them tend to have larger vocabularies. An open question is how social contingency facilitates vocabulary growth. One possibility is that parents who speak in response to their infants more often produce larger amount of language input, which accelerates vocabulary growth. Another possibility is that the simplicity of contingent language input is especially suitable to support early word learning. A third possibility is that more evidence of the communicative nature of language, achieved through frequent contingent responses, helps infants build a link between their own words or vocalizations and others' behaviors. This link may lead to a better understanding of the communicative nature of language and further language advances, including vocabulary growth. To distinguish between these hypotheses, we analyzed the relations between parent-infant interactions when infants were 9 months and their vocabulary size at 12 months, using a naturalistic corpus. Our findings show that the frequency of parents' verbal contingent responses predicts receptive vocabulary size at 12 months and this predictive relation is unlikely to be due to the amount of language input or the simplicity of language within socially contingent interactions. RESEARCH HIGHLIGHTS: Infants of parents who respond to their vocalizations more often during the first year of life tend to have larger vocabularies in the second year. It is an open question what drives the predictive relation between parents' responsiveness and infants' vocabulary; we tested three hypotheses that offer competing explanations. More responsive parents might provide (1) more language input, (2) simpler language input, (3) more evidence of the communicative nature of language (via frequent responses). We find support for the third hypothesis; the frequency of parents' responses predicts infants' vocabularies above and beyond the amount and simplicity of language input.

Talking About the Absent and the Abstract: Referential Communication in Language and Gesture.

Human language permits us to call to mind objects, events, and ideas that we cannot witness directly, either because they are absent or because they have no physical form (e.g., people we have not met, concepts like justice). What enables language to transmit such knowledge? We propose that a referential link between words, referents, and mental representations of those referents is key. This link enables us to form, access, and modify mental representations even when the referents themselves are absent ("absent reference"). In this review we consider the developmental and evolutionary origins of absent reference, integrating previously disparate literatures on absent reference in language and gesture in very young humans and gesture in nonhuman primates. We first evaluate when and how infants acquire absent reference during the process of language acquisition. With this as a foundation, we consider the evidence for absent reference in gesture in infants and in nonhuman primates. Finally, having woven these literatures together, we highlight new lines of research that promise to sharpen our understanding of the development of reference and its role in learning about the absent and the abstract.

From social contingency to verbal reference: A constructivist hypothesis.

In the first year of life, infants' word learning is slow, laborious, and requires repeated exposure to word-referent co-occurrences. In contrast, by 14-18 months, infants learn words from just a few labeling events, use joint attention and eye gaze to decipher word meaning, and begin to use speech to communicate about absent things. We propose that this remarkable advancement in word learning results from attaining a referential understanding of words-that words are linked to mental representations and used intentionally to communicate about real-world entities. We suggest that verbal reference is supported by codeveloping conceptual, social, representational, and statistical learning capacities. We also propose that infants' recognition of this tri-directional link between words, referents, and mental representations is enabled by their experience participating in and observing socially contingent interactions. Understanding verbal reference signals a qualitative shift in infants' word learning. This shift enables infants to bootstrap word meanings from syntax and semantics, learn novel words and facts from nonostensive communication, and make inferences about speakers' epistemic competence based on their language production. In this paper, we review empirical findings across multiple facets of infant cognition and propose a novel developmental theory of verbal reference. Finally, we suggest new directions of empirical research that may provide stronger and more direct evidence for our theory and contribute to our understanding of the development of verbal reference and language-mediated learning in infancy and beyond. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Acquiring verbal reference: The interplay of cognitive, linguistic, and general learning capacities.

Verbal reference is the ability to use language to communicate about objects, events, or ideas, even if they are not witnessed directly, such as past events or faraway places. It rests on a three-way link between words, their referents, and mental representations of those referents. A foundational human capacity, verbal reference extends the communicative power of language beyond the here-and-now, enabling access to language-mediated learning and thus fueling cognitive development. In the current review, we consider how and when verbal reference develops. The existing literature suggests that verbal reference emerges around infants' first birthdays and becomes increasingly robust by their second. In discussing the powerful developmental advantages of acquiring verbal reference we propose that this achievement requires a dynamic interplay among infants' cognitive and language development, fueled by general learning capacities. We close by describing new research directions, aimed at advancing our understanding of how verbal reference emerges.

Semantic priming supports infants' ability to learn names of unseen objects.

Human language permits us to call to mind objects, events, and ideas that we cannot witness directly. This capacity rests upon abstract verbal reference: the appreciation that words are linked to mental representations that can be established, retrieved and modified, even when the entities to which a word refers is perceptually unavailable. Although establishing verbal reference is a pivotal achievement, questions concerning its developmental origins remain. To address this gap, we investigate infants' ability to establish a representation of an object, hidden from view, from language input alone. In two experiments, 15-month-olds (N = 72) and 12-month-olds (N = 72) watch as an actor names three familiar, visible objects; she then provides a novel name for a fourth, hidden fully from infants' view. In the Semantic Priming condition, the visible familiar objects all belong to the same semantic neighborhood (e.g., apple, banana, orange). In the No Priming condition, the objects are drawn from different semantic neighborhoods (e.g., apple, shoe, car). At test infants view two objects. If infants can use the naming information alone to identify the likely referent, then infants in the Semantic Priming, but not in the No Priming condition, will successfully infer the referent of the fourth (hidden) object. Brief summary of results here. Implications for the development of abstract verbal reference will be discussed.

Questions Can Answer Questions About Mechanisms of Preschoolers' Selective Word Learning.

This study examined how inferences about epistemic competence and generalized labeling errors influence children's selective word learning. Three- to 4-year-olds (N = 128) learned words from informants who asked questions about objects, mentioning either correct or incorrect labels. Such questions do not convey stark differences in informants' epistemic competence. Inaccurate labels, however, generate error signals that can lead to weaker encoding of novel information. Preschoolers retained novel labels from both informants but were slower to respond in the Inaccurate Labeler condition. When the test procedure was not sensitive to the strength of information encoding, children performed above chance in both conditions and their response times did not differ. These results suggest that epistemic-level inferences and error generalizations influence preschoolers' selective word learning concurrently.

I don't believe what you said before: Preschoolers retrospectively discount information from inaccurate speakers.

Children use speakers' past accuracy to make inferences about novel word meanings those individuals provide in the future. An open question is whether children can retrospectively reevaluate information after learning that the source was inaccurate. We addressed this question in two experiments where a speaker first introduced labels for novel objects and then revealed that she is either accurate or inaccurate in naming familiar objects. Experiment 1 showed that 3.5- to 6.5-year-olds displayed enhanced performance on a word knowledge test when they had learned novel words from a speaker who then showed herself to be an accurate labeler as opposed to an inaccurate labeler. Experiment 2 replicated this procedure but had a different speaker provide inaccurate label information. This manipulation did not affect learning, suggesting that children discount speakers and are not simply influenced by the demands of processing inaccurate information. Together, these results indicate that 3.5- to 6.5-year-olds continue to monitor the speakers' accuracy after learning new words from them, update their beliefs as accuracy data become available, and selectively retain words learned from speakers who they deem to be epistemically competent.

Eighteen-month-olds selectively generalize words from accurate speakers to novel contexts.

The present studies examine whether and how 18-month-olds use informants' accuracy to acquire novel labels for novel objects and generalize them to a new context. In Experiment 1, two speakers made statements about the labels of familiar objects. One used accurate labels and the other used inaccurate labels. One of these speakers then introduced novel labels for two novel objects. At test, toddlers saw those two novel objects and heard an unfamiliar voice say one of the labels provided by the speaker. Only toddlers who had heard the novel labels introduced by the accurate speaker looked at the appropriate novel object above chance. Experiment 2 explored possible mechanisms underlying this difference in generalization. Rather than making statements about familiar objects' labels, both speakers asked questions about the objects' labels, with one speaker using accurate labels and the other using inaccurate labels. Toddlers' generalization of novel labels for novel objects was at chance for both speakers, suggesting that toddlers do not simply associate hearing the accurate label with the reliability of the speaker. We discuss these results in terms of potential mechanisms by which children learn and generalize novel labels across contexts from speaker reliability.

Cross-linguistic gestures reflect typological universals: a subject-initial, verb-final bias in speakers of diverse languages.

In communicating events by gesture, participants create codes that recapitulate the patterns of word order in the world's vocal languages (Gibson et al., 2013; Goldin-Meadow, So, Ozyurek, & Mylander, 2008; Hall, Mayberry, & Ferreria, 2013; Hall, Ferreira, & Mayberry, 2014; Langus & Nespor, 2010; and others). Participants most often convey simple transitive events using gestures in the order Subject-Object-Verb (SOV), the most common word order in human languages. When there is a possibility of confusion between subject and object, participants use the order Subject-Verb-Object (SVO). This overall pattern has been explained by positing an underlying cognitive preference for subject-initial, verb-final orders, with the verb-medial order SVO order emerging to facilitate robust communication in a noisy channel (Gibson et al., 2013). However, whether the subject-initial and verb-final biases are innate or the result of languages that the participants already know has been unclear, because participants in previous studies all spoke either SVO or SOV languages, which could induce a subject-initial, verb-late bias. Furthermore, the exact manner in which known languages influence gestural orders has been unclear. In this paper we demonstrate that there is a subject-initial and verb-final gesturing bias cross-linguistically by comparing gestures of speakers of SVO languages English and Russian to those of speakers of VSO languages Irish and Tagalog. The findings show that subject-initial and verb-final order emerges even in speakers of verb-initial languages, and that interference from these languages takes the form of occasionally gesturing in VSO order, without an additional bias toward other orders. The results provides further support for the idea that improvised gesture is a window into the pressures shaping language formation, independently of the languages that participants already know.