Linking sounds to meanings: Infant statistical learning in a natural language

The processes of infant word segmentation and infant word learning have largely been studied separately. However, the ease with which potential word forms are segmented from fluent speech seems likely to influence subsequent mappings between words and their referents. To explore this process, we tested the link between the statistical coherence of sequences presented in fluent speech and infants’ subsequent use of those sequences as labels for novel objects. Notably, the materials were drawn from a natural language unfamiliar to the infants (Italian). The results of three experiments suggest that there is a close relationship between the statistics of the speech stream and subsequent mapping of labels to referents. Mapping was facilitated when the labels contained high transitional probabilities in the forward and/or backward direction (Experiment 1). When no transitional probability information was available (Experiment 2), or when the internal transitional probabilities of the labels were low in both directions (Experiment 3), infants failed to link the labels to their referents. Word learning appears to be strongly influenced by infants’ prior experience with the distribution of sounds that make up words in natural languages.     

Early Gesture Provides a Helping Hand to Spoken Vocabulary Development for Children with Autism,Down Syndrome,and Typical Development

Typically developing (TD) children refer to objects uniquely in gesture (e.g., point at a cat) before they produce verbal labels for these objects (“cat”). The onset of such gestures predicts the onset of similar spoken words, showing a strong positive relation between early gestures and early words. We asked whether gesture plays the same door-opening role in word learning for children with autism spectrum disorder (ASD) and Down syndrome (DS), who show delayed vocabulary development and who differ in the strength of gesture production. To answer this question, we observed 23 18-month-old TD children, 23 30-month-old children with ASD, and 23 30-month-old children with DS 5 times over a year during parent–child interactions. Children in all 3 groups initially expressed a greater proportion of referents uniquely in gesture than in speech. Many of these unique gestures subsequently entered children’s spoken vocabularies within a year—a pattern that was slightly less robust for children with DS, whose word production was the most markedly delayed. These results indicate that gesture is as fundamental to vocabulary development for children with developmental disorders as it is for TD children.     

Infants' reasoning about opaque and transparent occluders in an individuation task

Two experiments document that conceptual knowledge influences 3-year-olds' extension of novel words. In Experiment 1, when objects were described as having conceptual properties typical of artifacts, children extended novel labels for these objects on the basis of shape alone. When the very same objects were described as having conceptual properties typical of animate kinds, children extended novel labels for these objects on the basis of both shape and texture. Moreover, providing a salient perceptual cue (Experiment 2) did not interfere with children's reliance on conceptual information in extending novel words: when an object with eyes was labeled with a novel word in the context of a story describing the object as an artifact, children extended the label on the basis of shape alone (i.e. as though the object were an artifact). These results, which challenge directly the position that 'dumb attentional mechanisms' can account for word learning, stand as evidence for the central role of conceptual information in mapping words to meaning.     

English- and Chinese-learning infants map novel labels to objects and actions differently

Research based on naturalistic and checklist methods has revealed differences between English and Chinese monolingual children in their trajectories of learning nouns and verbs. However, studies based on controlled laboratory designs (e.g., Imai et al., 2008) have yielded a more mixed picture. Guided by a multidimensional view of word learning (in which different mechanisms are weighted and recruited to different extents over development), we examined English- and Mandarin-learning infants' (n = 128) ability to map novel labels to unfamiliar actions and objects. Findings reveal cross-linguistic variations in the mapping of words to actions versus objects that are consistent with those found previously with naturalistic and checklist methods. Specifically, English learners were able to map novel labels to both actions and objects at 18 months but to neither actions nor objects at 14 months. In an identical experimental paradigm, Mandarin learners at both 14 and 18 months of age were able to map novel labels to actions but not to objects. Similar patterns were found when infants were grouped based on their vocabulary size. Combined results lend support for a dynamic view of word learning that take into account multiple mechanisms interacting across developmental time with important cultural constraints.     

The emergence of words: attentional learning in form and meaning

Children improve at word learning during the 2nd year of life—sometimes dramatically. This fact has suggested a change in mechanism, from associative learning to a more referential form of learning. This article presents an associative exemplar-based model that accounts for the improvement without a change in mechanism. It provides a unified account of children's growing abilities to (a) learn a new word given only 1 or a few training trials ("fast mapping"); (b) acquire words that differ only slightly in phonological form; (c) generalize word meanings preferentially along particular dimensions, such as object shape (the "shape bias"); and (d) learn 2nd labels for already-named objects, despite a persisting resistance to doing so ("mutual exclusivity"). The model explains these improvements in terms of increased attention to relevant aspects of form and meaning, which reduces memory interference. The interaction of associations and reference in word learning is discussed.     

Pragmatics aid referent disambiguation and word learning in young children and adults

How do children succeed in learning a word? Research has shown robustly that, in ambiguous labeling situations, young children assume novel labels to refer to unfamiliar rather than familiar objects. However, ongoing debates center on the underlying mechanism: Is this behavior based on lexical constraints, guided by pragmatic reasoning, or simply driven by children's attraction to novelty? Additionally, recent research has questioned whether children's disambiguation leads to long-term learning or rather indicates an attentional shift in the moment of the conversation. Thus, we conducted a pre-registered online study with 2- and 3-year-olds and adults. Participants were presented with unknown objects as potential referents for a novel word. Across conditions, we manipulated whether the only difference between both objects was their relative novelty to the participant or whether, in addition, participants were provided with pragmatic information that indicated which object the speaker referred to. We tested participants’ immediate referent selection and their retention after 5 min. Results revealed that when given common ground information both age groups inferred the correct referent with high success and enhanced behavioral certainty. Without this information, object novelty alone did not guide their selection. After 5 min, adults remembered their previous selections above chance in both conditions, while children only showed reliable learning in the pragmatic condition. The pattern of results indicates how pragmatics may aid referent disambiguation and learning in both adults and young children. From early ontogeny on, children's social-cognitive understanding may guide their communicative interactions and support their language acquisition.

Research Highlights

• We tested how 2-3-year-olds and adults resolve referential ambiguity without any lexical cues.
• In the pragmatic context both age groups disambiguated novel word-object-mappings, while object novelty alone did not guide their referent selection.
• In the pragmatic context, children also showed increased certainty in disambiguation and retained new word-object-mappings over time.
• These findings contribute to the ongoing debate on whether children learn words on the basis of domain-specific constraints, lower-level associative mechanisms, or pragmatic inferences.

     

How parents introduce new words to young children: The influence of development and developmental disorders

This study documents how parents weave new words into on-going interactions with children who are just beginning to speak. Dyads with typically developing toddlers and with young children with autism spectrum disorder and Down syndrome (n = 56, 23, and 29) were observed using a Communication Play Protocol during which parents could use novel words to refer to novel objects. Parents readily introduced both labels and sound words even when their child did not respond expressively or produce the words. Results highlight both how parents act in ways that may facilitate their child's appreciation of the relation between a new word and its referent and how they subtly adjust their actions to suit their child's level of word learning and specific learning challenges.     

注意和记忆对孤独症儿童词汇发展滞后的影响

孤独症语言障碍的表现之一是词汇发展滞后, 可能与其注意和记忆损伤有关。当前研究结果表明, 孤独症儿童在学习词汇时难以利用社会注意提供的有效信息, 且其注意易受到无关刺激干扰, 这可能导致其形成的物体-词汇的联结不稳定, 影响其进一步将这种联结整合到心理词典并保存在记忆中。未来研究应探究联合注意影响孤独症儿童词汇学习的发展轨迹和机制, 儿童的词汇知识对其词汇记忆的影响, 并关注自然场景中孤独症儿童的词汇学习过程和个体差异。     

Statistical regularities in vocabulary guide language acquisition in connectionist models and 15-20-month-olds

This research tested the hypothesis that young children's bias to generalize names for solid objects by shape is the product of statistical regularities among nouns in the early productive vocabulary. Data from a 4-layer Hopfield network suggested that the statistical regularities in the early noun vocabulary are strong enough to create a shape bias, and that the shape bias is overgeneralized to nonsolid stimuli. A 2nd simulation suggested that this overgeneralization is due to the dominance of names for shape-based categories in the early noun vocabulary. Two subsequent longitudinal experiments tested whether it is possible to create word learning biases in children. Children 15-20 months old were given intensive naming experiences with 12 noun categories typical of the types of categories children learn to name early. The children developed a precocious shape bias that was overgeneralized to naming nonsolid substances; they also showed accelerated vocabulary development. Children taught an atypical set of nouns or no new nouns did not develop a shape bias and did not show accelerated vocabulary development.     

Intentions vs. resemblance: Understanding pictures in typical development and autism

Research has debated whether children reflect on artists’ intentions when comprehending pictures, or instead derive meaning entirely from resemblance. We explore these hypotheses by comparing how typically developing toddlers and low-functioning children with autism (a population impaired in intentional reasoning) interpret abstract pictures. In Experiment 1, both groups mapped familiar object names onto abstract pictures, however, they related the same representations to different 3-D referents. Toddlers linked abstract pictures with intended referents they did not resemble, while children with autism mapped picture-referent relations based on resemblance. Experiment 2 showed that toddlers do not rely upon linguistic cues to determine intended referential relations. Experiment 3 confirmed that the responding of children with autism was not due to perseveration or associative word learning, and also provided independent evidence of their intention-reading difficulties. We argue that typically developing children derive meaning from the social-communicative intentions underlying pictures when resemblance is an inadequate cue to meaning. By contrast, children with autism do not reflect on artists’ intentions and simply relate pictures to whatever they happen to resemble.     

Is this still called a dog? 18‐month‐olds' generalization of familiar labels to unusual objects

In two experiments the flexibility of 18‐month‐olds' extension of familiar object labels was investigated using the intermodal preferential looking paradigm. The first experiment tested whether infants consider intact and incomplete objects as equally acceptable referents for familiar labels. Infants looked equally long at the intact and incomplete objects whether or not a label was presented. In the second experiment, infants were requested to find the referent of a target word among an incomplete target and an intact distracter or an intact target and an incomplete distracter. The incomplete objects were missing a large or small part. Infants looked longer at the incomplete target, even when large or small parts were deleted. Taken together, these findings suggest that infants do not hold a strong shape bias when generalizing familiar words. Copyright © 2002 John Wiley & Sons, Ltd.     

Learn locally, think globally. Exemplar variability supports higher-order generalization and word learning

Research suggests that variability of exemplars supports successful object categorization; however, the scope of variability's support at the level of higher-order generalization remains unexplored. Using a longitudinal study, we examined the role of exemplar variability in first- and second-order generalization in the context of nominal-category learning at an early age. Sixteen 18-month-old children were taught 12 categories. Half of the children were taught with sets of highly similar exemplars; the other half were taught with sets of dissimilar, variable exemplars. Participants' learning and generalization of trained labels and their development of more general word-learning biases were tested. All children were found to have learned labels for trained exemplars, but children trained with variable exemplars generalized to novel exemplars of these categories, developed a discriminating word-learning bias generalizing labels of novel solid objects by shape and labels of nonsolid objects by material, and accelerated in vocabulary acquisition. These findings demonstrate that object variability leads to better abstraction of individual and global category organization, which increases learning outside the laboratory.     

Children construct novel word meaning ad-hoc based on known words: Computational model of shape and material biases

Taking the stance that two well-known word learning biases (shape and material bias) are formed through learning (learned bias account, LBA), we illustrated a concrete computational mechanism with “ad-hoc meaning substitution (AMS)” hypothesis, and verified it by two computer simulations. AMS represents that when given a novel word and a corresponding instance, children create novel word meaning by using the known word meaning and the instance as an ad-hoc template. The AMS function enables fast mapping and vocabulary spurt. To describe the AMS process computationally, we introduced “word distributional prototype (WDP),” which is the explicit representation of word meaning with an inductive learning function. Simulation 1 revealed that when a network with WDP and AMS was given a biased vocabulary reflecting young children, it demonstrated shape, material, and overgeneralized shape biases. This result suggested that a triad of word meaning induction, ad-hoc meaning substitution, and early biased vocabulary is essential for the emergence of biases. Simulation 2 introduced the notion of maturity that denoted a degree of learning convergence for each word meaning, and then the network showed neither shape nor material bias during an early small vocabulary. This result indicated that the period at which each bias emerges is decided by maturity. Though AMS consists of simpler and valider mechanisms than those proposed in previous studies, it could reproduce behavior of shape and material biases and explain their emergence process clearly. These results suggest that phenomena concerning shape and material biases are explicable with a simple ad-hoc learning instead of meta-learning among LBA or innate language-specific ones.     

How children name objects with shoes

Many studies report a shape bias in children's learning of object names. However, one previous study suggests that the shape bias is not the only perceptually based bias displayed by children learning count nouns. Specifically, children attended to texture as well as shape when extending a novel name to novel objects with eyes. Two experiments attempt to extend this finding, asking whether children will also attend to texture in the presence of another cue to animacy—shoes. In Experiment 1, 80 2- and 3-year-olds participated in either a Name generalization or Similarity judgment task. The novel objects were identical except that for half of the children the objects had shoes. In the Similarity condition, children made their judgments by overall similarity. In the Name condition, 2-year-olds extended the novel name by shape across objects both with and without shoes. In contrast, 3-year-olds generalized the novel name by shape when the objects had no shoes but by texture when the objects had shoes. Experiment 2 challenged this finding, using a forced choice procedure and objects that differed from the named exemplar more markedly in shape. Twenty 3-year-olds participated in a Name generalization task, half for objects with shoes, half for objects without shoes. Again, children attended reliably more to texture when the objects had shoes than when they had no shoes. The results are discussed in terms of the development of different perceptually based biases and the relation of such biases to a taxonomic bias in early word learning.     

Preschoolers' and adults' reliance on object shape and object function for lexical extension.

We investigated the developmental progression of reliance on object function versus object shape to extend novel words. In 3 experiments, 3-year-olds, 5-year-olds, and adults were presented with sets of objects consisting of a target, a same-shape/different-function match, a different-shape/same-function match, and a distracter. In Experiments 1 and 2, function was emphasized during the word learning phase and participants were given direct experience with the functions of target and test objects. In Experiment 3, function was emphasized both during the learning phase and when requesting a referent of the novel labels. Across all 3 experiments, 3- and 5-year-olds focused on shape while adults focused on function when extending the novel words. These results suggest a developmental change in the consideration of shape and function in lexical extension.     

Do 9-month-old infants expect distinct words to refer to kinds?

In 3 experiments, 9-month-old infants' expectations for what distinct count noun labels refer to were investigated. In Experiment 1, a box was opened to reveal 2 objects inside during familiarization: either 2 identical objects or 2 different objects. Test trials followed the same procedure, except before the box was opened, the contents were described using 2 distinct labels ("I see a wug! I see a dak!") or the same label twice ("I see a zav! I see a zav!"). Infants who heard a label repeated twice looked longer at 2 different objects versus 2 identical objects, whereas infants who heard 2 distinct labels showed a different pattern of looking. Experiments 2 and 3 presented infants with object pairs that only differed in shape or color, and it was found that infants expected the different-shaped (but not the different-colored) objects to be labeled by distinct count nouns. Because the property of shape is a cue to kind membership and the property of color is not, these results suggest that even at the beginning of word learning, infants may expect distinct labels to refer to distinct kinds of objects.     

Clarifying the role of shape in children's taxonomic assumption.

When asked to find a new referent of a novel label children tend to ignore thematic relations (e.g., the relation between a spider and its web) and focus instead on taxonomic relations (e.g., the relation between a spider and a snake). The precise nature of children's taxonomic assumption has not been clear, however. One possibility is that the taxonomic assumption reduces to a "similar-shape rule": perhaps children tend to select objects of the same taxonomic kind when asked to extend new labels simply because these objects are more similar in shape than objects which are only thematically related. Sixty children between 3 and 5 years of age participated in three studies which examined children's attention to thematic relations, similarity of shape, and taxonomic relations when extending novel object labels. The findings indicated that shape has some primacy in children's expectations about object label reference, yet when shape is not available as a guide, children also take taxonomic kind into consideration when searching for new referents of novel labels. Thus children make use of a relatively rich and somewhat varied set of expectations to guide their inferences about object label reference.     

Late talkers show no shape bias in a novel name extension task

By 2½ years of age, children typically show a shape bias in object naming – that is, they extend object names mostly to new instances with the same shape. The acquisition of a shape bias is related to a marked increase in the rate of object name learning. This study asks whether, conversely, children who do not readily acquire new object names lack a shape bias. Twelve 2- to 3-year-old ‘late talkers’– children whose total vocabularies rank below the 30th percentile for their age – were compared with age-matched children with larger vocabularies in a novel object name extension task. The controls extended novel names across novel objects with the same shape. The late talkers showed no group perceptual bias, but many individuals extended novel names across objects with the same surface texture. The implications of the results both for the role of attentional biases in object name learning and for the etiology of some late talking are discussed.      

Use of the mutual exclusivity assumption by young word learners

A critical question about early word learning is whether word learning constraints such as mutual exclusivity exist and foster early language acquisition. It is well established that children will map a novel label to a novel rather than a familiar object. Evidence for the role of mutual exclusivity in such indirect word learning has been questioned because: (1) it comes mostly from 2 and 3-year-olds and (2) the findings might be accounted for, not by children avoiding second labels, but by the novel object which creates a lexical gap children are motivated to fill. Three studies addressed these concerns by having only a familiar object visible. Fifteen to seventeen and 18-20-month-olds were selected to straddle the vocabulary spurt. In Study 1, babies saw a familiar object and an opaque bucket as a location to search. Study 2 handed babies the familiar object to play with. Study 3 eliminated an obvious location to search. On the whole, babies at both ages resisted second labels for objects and, with some qualifications, tended to search for a better referent for the novel label. Thus mutual exclusivity is in place before the onset of the naming explosion. The findings demonstrate that lexical constraints enable babies to learn words even under non-optimal conditions--when speakers are not clear and referents are not visible. The results are discussed in relation to an alternative social-pragmatic account.     

Cross-modal working memory binding and L1-L2 word learning

The ability to create temporary binding representations of information from different sources in working memory has recently been found to relate to the development of monolingual word recognition in children. The current study explored this possible relationship in an adult word-learning context. We assessed whether the relationship between cross-modal working memory binding and lexical development would be observed in the learning of associations between unfamiliar spoken words and their semantic referents, and whether it would vary across experimental conditions in first- and second-language word learning. A group of English monolinguals were recruited to learn 24 spoken disyllable Mandarin Chinese words in association with either familiar or novel objects as semantic referents. They also took a working memory task in which their ability to temporarily bind auditory-verbal and visual information was measured. Participants’ performance on this task was uniquely linked to their learning and retention of words for both novel objects and for familiar objects. This suggests that, at least for spoken language, cross-modal working memory binding might play a similar role in second language-like (i.e., learning new words for familiar objects) and in more native-like situations (i.e., learning new words for novel objects). Our findings provide new evidence for the role of cross-modal working memory binding in L1 word learning and further indicate that early stages of picture-based word learning in L2 might rely on similar cognitive processes as in L1.