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.      

Children's reliance on creator's intent in extending names for artifacts

When children learn a name for a novel artifact, they tend to extend the name to other artifacts that share the same shape—a phenomenon known as the shape bias. The present studies investigated an intentional account of this bias. In Study 1, 3-year-olds were shown two objects of the same shape, and were given an explanation for why the objects were the same shape even though they were intended to be different kinds. The shape bias disappeared in children provided with this explanation. In Study2, 3-year-olds were shown triads of objects, and were either given no information about the function of a named target object, told the function that object could fulfill, or told the functions all three objects were intended to fulfill. Only in the third condition did children overcome a shape bias in favor of a function bias when extending the name of the target object. These findings indicate that 3-year-olds' shape bias results from intuitions about what artifacts were intended to be.     

What's in a shape? Children represent shape variability differently than adults when naming objects

Children and adults often generalize a word to objects of the same shape. However, the shape properties on which generalization is based are unknown. We investigated the degree to which two shape dimensions were represented categorically by children and adults when learning names for objects. Multidimensional scaling techniques were used to establish the perceptual similarity of two sets of objects in Experiment 1. In Experiments 2 and 3, children (from 2;8 to 4;5 years of age) and adults participated in two tasks in which they learned a novel name for an exemplar. We then examined how often the novel name was generalized to different objects and to line drawings of the objects. In one task, participants generalized the names from memory; in a second task the exemplar was in front of the participant during generalization. Adults accepted names more often to objects that fell "within" the proposed shape boundaries than to objects that fell "across" the boundaries. Children, however, were just as likely to generalize names to novel objects that fell within as to objects that crossed the boundaries.     

Word learning and phonetic processing in preschool-age children

Consonants and vowels have been shown to play different relative roles in different processes, including retrieving known words from pseudowords during adulthood or simultaneously learning two phonetically similar pseudowords during infancy or toddlerhood. The current study explores the extent to which French-speaking 3- to 5-year-olds exhibit a so-called “consonant bias” in a task simulating word acquisition, that is, when learning new words for unfamiliar objects. In Experiment 1, the to-be-learned words differed both by a consonant and a vowel (e.g., /byf/-/duf/), and children needed to choose which of the two objects to associate with a third one whose name differed from both objects by either a consonant or a vowel (e.g., /dyf/). In such a conflict condition, children needed to favor (or neglect) either consonant information or vowel information. The results show that only 3-year-olds preferentially chose the consonant identity, thereby neglecting the vowel change. The older children (and adults) did not exhibit any response bias. In Experiment 2, children needed to pick up one of two objects whose names differed on either consonant information or vowel information. Whereas 3-year-olds performed better with pairs of pseudowords contrasting on consonants, the pattern of asymmetry was reversed in 4-year-olds, and 5-year-olds did not exhibit any significant response bias. Interestingly, girls showed overall better performance and exhibited earlier changes in performance than boys. The changes in consonant/vowel asymmetry in preschoolers are discussed in relation with developments in linguistic (lexical and morphosyntactic) and cognitive processing.     

The importance of shape in early lexical learning

We ask if certain dimensions of perceptual similarity are weighted more heavily than others in determining word extension. The specific dimensions examined were shape, size, and texture. In four experiments, subjects were asked either to extend a novel count noun to new instances or, in a nonword classification task, to put together objects that go together. The subjects were 2-year-olds, 3-year-olds, and adults. The results of all four experiments indicate that 2- and 3-year-olds and adults all weight shape more heavily than they do size or texture. This observed emphasis on shape, however, depends on the age of the subject and the task. First, there is a developmental trend. The shape bias increases in strength and generality from 2 to 3 years of age and more markedly from early childhood to adulthood. Second, in young children, the shape bias is much stronger in word extension than in nonword classification tasks. These results suggest that the development of the shape bias originates in language learning—it reflects a fact about language—and does not stem from general perceptual processes.     

How Do Opportunities to View Objects Together in Time Influence Children's Memory for Location?

We conducted three experiments to investigate how opportunities to view objects together in time influence memory for location. Children and adults learned the locations of 20 objects marked by dots on the floor of an open, square box. During learning, participants viewed the objects either simultaneously or in isolation. At test, participants replaced the objects without the aid of the dots. Experiment 1 showed that when the box was divided into quadrants and the objects in each quadrant were categorically related, 7-, 9-, and 11-year-olds and adults in the simultaneous viewing condition exhibited categorical bias, but only 11-year-olds and adults in the isolated viewing condition exhibited categorical bias. Experiment 2 showed that when the objects were categorically related but no boundaries were present, 11-year-olds and adults in the simultaneous viewing condition exhibited categorical bias, but only adults showed bias in the isolated viewing condition. Experiment 3 revealed that adults exhibited bias in both simultaneous and isolated viewing conditions when boundaries were present but the objects were not related. These findings suggest that opportunities to see objects together in time interact with cues available for grouping objects to help children form spatial groups.     

A Mutually Facilitative Relationship Between Learning Names and Learning Concepts in Preschool Children: The Case of Artifacts

Two studies investigated the relationship between learning names and learning concepts in preschool children. More specifically, we focused on the relationship between learning the names and learning the intended functions of artifacts, given that the intended function of an artifact is generally thought to constitute core conceptual information about an artifact's category. We asked whether learning the intended function of a novel artifact facilitates retention of its name and whether learning the name of a novel artifact prompts the search for information about its intended function. In Experiment 1, 3- and 4-year-old children better retained the names of novel artifacts when the intended functions of these artifacts were revealed. The comparison condition involved providing perceptually relevant and conceptually irrelevant information about the objects. In Experiment 2, 4-year-old children who were provided with the names of novel artifacts were more likely to seek out information about the objects' functions than children provided with conceptually irrelevant information about the artifacts. Together, the studies demonstrate the intimate and mutually facilitative relationship between names and concepts in young children.     

Atypical shape bias and categorization in autism: Evidence from children and computational simulations

The shape bias, a preference for mapping new word labels onto the shape rather than the color or texture of referents, has been postulated as a word‐learning mechanism. Previous research has shown deficits in the shape bias in children with autism even though they acquire sizeable lexicons. While previous explanations have suggested the atypical use of color for label extension in individuals with autism, we hypothesize an atypical mapping of novel labels to novel objects, regardless of the physical properties of the objects. In Experiment 1, we demonstrate this phenomenon in some individuals with autism, but the novelty of objects only partially explains their lack of shape bias. In a second experiment, we present a computational model that provides a developmental account of the shape bias in typically developing children and in those with autism. This model is based on theories of neurological dysfunctions in autism, and it integrates theoretical and empirical findings in the literature of categorization, word learning, and the shape bias. The model replicates the pattern of results of our first experiment and shows how individuals with autism are more likely to categorize experimental objects together on the basis of their novelty. It also provides insights into possible mechanisms by which children with autism learn new words, and why their word referents may be idiosyncratic. Our model highlights a developmental approach to autism that emphasizes deficient representations of categories underlying an impaired shape bias.     

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.     

A One-to-One Bias and Fast Mapping Support Preschoolers' Learning About Faces and Voices

A multimodal person representation contains information about what a person looks like and what a person sounds like. However, little is known about how children form these face-voice mappings. Here, we explored the possibility that two cognitive tools that guide word learning, a one-to-one mapping bias and fast mapping, also guide children's learning about faces and voices. We taught 4- and 5-year-olds mappings between three individual faces and voices, then presented them with new faces and voices. In Experiment 1, we found that children rapidly learned face-voice mappings from just a few exposures, and furthermore spontaneously mapped novel faces to novel voices using a one-to-one mapping bias (that each face can produce only one voice). In Experiment 2, we found that children's face-voice representations are abstract, generalizing to novel tokens of a person. In Experiment 3, we found that children retained in memory the face-voice mappings that they had generated via inference (i.e., they showed evidence of fast mapping), and used these newly formed representations to generate further mappings between new faces and voices. These findings suggest that preschoolers' rapid learning about faces and voices may be aided by biases that are similar to those that support word learning.     

They call it like they see it: spontaneous naming and attention to shape

Two experiments explore children's spontaneous labeling of novel objects as a method to study early lexical access. The experiments also provide new evidence on children's attention to object shape when labeling objects. In Experiment 1, the spontaneous productions of 21 23- to 28-month-olds (mean 26;28) shown a set of novel, unnamed objects were analyzed both in terms of the specific words said and, via adult judgments, their likely perceptual basis. We found that children's spontaneous names were cued by the perceptual feature of shape. Experiment 2 examines the relation between spontaneous productions, name generalizations in a structured task, and vocabulary development in a group of children between 17 and 24 months of age (mean 21;6). Results indicate that object shape plays an important role in both spontaneous productions and novel noun generalization, but contrary to current hypotheses, children may name objects by shape from the earliest points of productive vocabulary development and this tendency may not be lexically specific.     

Young children's use of functional information to categorize artifacts: three factors that matter

Three experiments addressed factors that might influence whether or not young children take into account function, as opposed to overall appearance or shape, when they extend the names of novel artifacts. Experiment 1 showed that 4-year-olds more often extend a name on the basis of a demonstrated function when that function provides a plausible causal account of perceptible object structure. Experiment 2 showed that they more often extend a name by function when they respond slowly, and hence thoughtfully. Experiment 3 demonstrated that they are more likely to take function into account when they extend names than when they judge similarities. Comparisons of lexical and non-lexical conditions in younger children failed to show any differences. Overall, the findings suggest that by 4 years of age, children may learn names as labels for novel artifact kinds rather than perceptual classes, and that the processes by which they categorize may be mindful and reflective, as in adults.     

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.     

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.     

The role of comparison in preschoolers’ novel object categorization

We examined the role of the comparison process and shared names on preschoolers’ categorization of novel objects. In our studies, 4-year-olds were presented with novel object sets consisting of either one or two standards and two test objects: a shape match and a texture match. When children were presented with one standard, they extended the category based on shape regardless of whether the objects were named. When children were presented with two standards that shared the same texture and the objects were named with the same noun, they extended the category based on texture. The opportunity to compare two standards, in the absence of shared names, led to an attenuation of the effect of shape. These findings demonstrate that comparison plays a critical role in the categorization of novel objects and that shared names enhance this process.     

How special are objects? Children's reasoning about objects, parts, and holes

Discrete physical objects have a special status in cognitive and linguistic development. Infants track and enumerate objects, young children are biased to construe novel words as referring to objects, and, when asked to count an array of items, preschool children tend to count the discrete objects, even if explicitly asked to do otherwise. We address here the question of whether discrete physical objects are the only entities that have this special status, or whether other individuals are salient as well. In two experiments, we found that 3-year-olds are just as good at identifying, tracking, and counting certain nonobject entities (holes in Experiment 1; holes and parts in Experiment 2) as they are with objects. These results are discussed in light of different theories of the nature and development of children's object bias.     

Causal Clarity Prevents the Emergence of Social Biases in Children’s Excusing of Mistakes

In two studies, we examined how 5-­year-­olds weigh similarity against other factors in deciding from whom to learn. Specifically, we examined the factors of history of and reasons for inaccuracy in Experiment 1 (n = 64) and of competence and authority in Experiment 2 (n = 32). In the 1st phase of Experiments 1 and 2, children’s social biases were tested: 5-year-olds met both a similar informant (SI) and a dissimilar informant (DI). These informants were puppets (Experiment 1) or human teachers (Experiment 2). Children could select either informant as a source of object names. Across experiments children systematically preferred learning from the SI over DI. In the 2nd phase of Experiment 1, both informants first provided accurate information and then 1 of them became inaccurate during an event that clearly explained (being blindfolded) or did not explain (wearing a scarf) the inaccuracy. For half the children, the SI was accurate and the DI was inaccurate. Only after inaccuracy events that were causally unclear did children showcase similarity biases in their subsequent learning preferences. Experiment 2 showed that identifying a DI as a teacher (a profession associated with positive attributes) failed to counter children’s similarity bias. These findings provide important insights on contextual factors that contribute to children’s favoring of socially meaningful others.     

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.