Learning What to Remember: Vocabulary Knowledge and Children's Memory for Object Names and Features

Although young children can map a novel name to a novel object, it remains unclear what they actually remember about objects when they initially make such a name–object association. In the current study we investigated (1) what children remembered after they were initially introduced to name–object associations and (2) how their vocabulary size and vocabulary structure influenced what they remembered. As a group, children had difficulty remembering each of the features of the original novel objects. Further analyses revealed that differences in vocabulary structure predicted children's ability to remember object features. Specifically, children who produced many names for categories organized by similarity in shape (e.g. ball, cup) had the best memory for newly‐learned objects' features—especially their shapes. In addition, the more features children remembered, the more likely they were to retain the newly learned name–object associations. Vocabulary size, however, was not predictive of children's feature memory or retention. Taken together, these findings demonstrate that children's existing vocabulary structure, rather than simply vocabulary size, influences what they attend to when encountering a new object and subsequently their ability to remember new name–object associations. Copyright © 2015 John Wiley & Sons, Ltd.     

The effects of type of instruction,animacy cues,and dimensionality of objects on the shape bias in 3‐ to 6‐year‐old children

Robust evidence exists for the shape bias, or children's tendency to extend novel names and categorize objects more readily on the basis of shape than on other object features. However, issues remain about the conditions that affect the shape bias and its importance as a linguistic device. In this research, we examined how type of instruction (common noun naming, proper noun naming, same kind, and goes with), animacy of objects (animate, inanimate), and dimensionality of objects (two‐dimensional, three‐dimensional) affect the shape bias in 3‐ to 6‐year‐old children. Overall, all children showed strong use of the shape bias with categorization (same kind, goes with) instructions, the former in line with the shape‐as‐cue theory. Additionally, the shape bias was quite robust in the inanimate condition, regardless of type of instruction or dimensionality of objects. However, in the animate condition, a proper noun naming instruction coupled with an animate object cue reduced the shape bias across both two‐ and three‐dimensional objects. Implications of these findings are presented.

Highlights

• This study assessed the “shape bias,” a linguistic strategy young children routinely use when confronted with the task of extending a novel name from one object to another.
• Novel name extension and categorization tasks were used in this study.
• Shape bias was affected by the type of instructions, animacy of objects, and dimensionality of objects.

     

The shape of thought

When children learn the name of a novel object, they tend to extend that name to other objects similar in shape – a phenomenon referred to as the shape bias. Does the shape bias stem from learned associations between names and categories of objects, or does it derive from more general properties of children's understanding of language and the world? We argue here for the second alternative, presenting evidence that the shape bias emerges early in development, is not limited to names, and is intimately related to how children make sense of categories.     

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.     

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.     

From the lexicon to expectations about kinds: a role for associative learning

In the novel noun generalization task, 2 1/2-year-old children display generalized expectations about how solid and nonsolid things are named, extending names for never-before-encountered solids by shape and for never-before-encountered nonsolids by material. This distinction between solids and nonsolids has been interpreted in terms of an ontological distinction between objects and substances. Nine simulations and behavioral experiments tested the hypothesis that these expectations arise from the correlations characterizing early learned noun categories. In the simulation studies, connectionist networks were trained on noun vocabularies modeled after those of children. These networks formed generalized expectations about solids and nonsolids that match children's performances in the novel noun generalization task in the very different languages of English and Japanese. The simulations also generate new predictions supported by new experiments with children. Implications are discussed in terms of children's development of distinctions between kinds of categories and in terms of the nature of this knowledge.     

Novel Labels Increase Category Coherence,But Only When People Have the Goal to Coordinate

From infancy, we recognize that labels denote category membership and help us to identify the critical features that objects within a category share. Labels not only reflect how we categorize, but also allow us to communicate and share categories with others. Given the special status of labels as markers of category membership, do novel labels (i.e., non‐words) affect the way in which adults select dimensions for categorization in unsupervised settings? Additionally, is the purpose of this effect primarily coordinative (i.e., do labels promote shared understanding of how we categorize objects)? To address this, we conducted two experiments in which participants individually categorized images of mountains with or without novel labels, and with or without a goal of coordination, within a non‐communicative paradigm. People who sorted items with novel labels had more similar categories than people who sorted without labels only when they were told that their categories should make sense to other people, and not otherwise. We argue that sorters' goals determine whether novel labels promote the development of socially coherent categories.     

Children learn words easier when they are interested in the category to which the word belongs

The overall pattern of vocabulary development is relatively similar across children learning different languages. However, there are considerable differences in the words known to individual children. Historically, this variability has been explained in terms of differences in the input. Here, we examine the alternate possibility that children's individual interest in specific natural categories shapes the words they are likely to learn – a child who is more interested in animals will learn a new animal name easier relative to a new vehicle name. Two‐year‐old German‐learning children (N = 39) were exposed to four novel word–object associations for objects from four different categories. Prior to the word learning task, we measured their interest in the categories that the objects belonged to. Our measure was pupillary change following exposure to familiar objects from these four categories, with increased pupillary change interpreted as increased interest in that category. Children showed more robust learning of word–object associations from categories they were more interested in relative to categories they were less interested in. We further found that interest in the novel objects themselves influenced learning, with distinct influences of both category interest and object interest on learning. These results suggest that children's interest in different natural categories shapes their word learning. This provides evidence for the strikingly intuitive possibility that a child who is more interested in animals will learn novel animal names easier than a child who is more interested in vehicles.     

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.     

Visual variability affects early verb learning

Research demonstrates that within‐category visual variability facilitates noun learning; however, the effect of visual variability on verb learning is unknown. We habituated 24‐month‐old children to a novel verb paired with an animated star‐shaped actor. Across multiple trials, children saw either a single action from an action category (identical actions condition, for example, travelling while repeatedly changing into a circle shape) or multiple actions from that action category (variable actions condition, for example, travelling while changing into a circle shape, then a square shape, then a triangle shape). Four test trials followed habituation. One paired the habituated verb with a new action from the habituated category (e.g., ‘dacking’ + pentagon shape) and one with a completely novel action (e.g., ‘dacking’ + leg movement). The others paired a new verb with a new same‐category action (e.g., ‘keefing’ + pentagon shape), or a completely novel category action (e.g., ‘keefing’ + leg movement). Although all children discriminated novel verb/action pairs, children in the identical actions condition discriminated trials that included the completely novel verb, while children in the variable actions condition discriminated the out‐of‐category action. These data suggest that – as in noun learning – visual variability affects verb learning and children's ability to form action categories.     

Fifteen-month-old infants attend to shape over other perceptual properties in an induction task

This study examined whether infants privilege shape over other perceptual properties when making inferences about the shared properties of novel objects. Forty-six 15-month-olds were presented with novel target objects that possessed a nonobvious property, followed by test objects that varied in shape, color, or texture relative to the target. Infants generalized the nonobvious property to test objects that were highly similar in shape, but not to objects that shared the same color or texture. These results demonstrate that infants’ attention to shape is not specific to lexical contexts and is present at the early stages of productive language development. The implications of these findings for debates about children's shape bias, in particular, and the nature of infants’ categories more generally, are discussed.     

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.     

Context and Perceptual Salience Influence the Formation of Novel Stereotypes via Cumulative Cultural Evolution

We use a transmission chain method to establish how context and category salience influence the formation of novel stereotypes through cumulative cultural evolution. We created novel alien targets by combining features from three category dimensions—color, movement, and shape—thereby creating social targets that were individually unique but that also shared category membership with other aliens (e.g., two aliens might be the same color and shape but move differently). At the start of the transmission chains each alien was randomly assigned attributes that described it (e.g., arrogant, caring, confident). Participants were given training on the alien‐attribute assignments and were then tested on their memory for these. The alien‐attribute assignments participants produced during test were used as the training materials for the next participant in the transmission chain. As information was repeatedly transmitted an increasingly simplified, learnable stereotype‐like structure emerged for targets who shared the same color, such that by the end of the chains targets who shared the same color were more likely to share the same attributes (a reanalysis of data from Martin et al., 2014 which we term Experiment 1). The apparent bias toward the formation of novel stereotypes around the color category dimension was also found for objects (Experiment 2). However, when the category dimension of color was made less salient, it no longer dominated the formation of novel stereotypes (Experiment 3). The current findings suggest that context and category salience influence category dimension salience, which in turn influences the cumulative cultural evolution of information.     

Inductive Inferences Across Time and Identity: Are Category Members More Alike Than Single Individuals?

Young children tend to expect that 2 members of the same category will share properties, yet they frequently deny that an individual's properties will remain stable across time and context. Two experiments, involving 72 four- to five-year-olds, 72 seven- to eight-year-olds, and 76 undergraduates, explored the factors that lead children to generalize properties across and within individuals. Results suggest that adults' and older children's judgments are consistent with the principle of homogeneity—within-individual projections are more secure than across. In contrast, young children showed distinct patterns of reasoning across and within individuals, suggesting that for young children, the 2 contexts may present distinct inductive problems. This discussion focuses on how features of each problem contribute to young children's willingness to make inductive generalizations.     

To the letter: Early readers trust print‐based over oral instructions to guide their actions

Children have many opportunities to learn from others through oral and written sources. Recent evidence suggests that early readers place more trust in written over oral testimony when learning names for unfamiliar objects. Across three studies, we examined whether the authority of print extends beyond mere naming to guide children's actions in the physical world. In Study 1, 3‐ to 6‐year‐olds received conflicting oral and print‐based advice from two puppets about how to operate a novel apparatus. Whereas pre‐readers were indiscriminate in their trust, early readers preferred to follow the print‐based advice. In Study 2, we replicated this finding, controlling for the amount of corroborating evidence presented by both sources, and the location of the print. In Study 3, we explored whether readers' preference for print‐based information was due to a global preference for external representations, or a more specific preference for text. Children were presented with conflicting instructions based on text versus a coloured circle. Whereas pre‐readers preferred to follow the colour circle, readers preferred to follow the text. Together, the results suggest that when children learn to read, they rapidly come to regard the written word as a particularly authoritative source of information about how to act in the world.     

Parallels Between Action‐Object Mapping and Word‐Object Mapping in Young Children

Across a series of four experiments with 3‐ to 4‐year‐olds we demonstrate how cognitive mechanisms supporting noun learning extend to the mapping of actions to objects. In Experiment 1 (n = 61) the demonstration of a novel action led children to select a novel, rather than a familiar object. In Experiment 2 (n = 78) children exhibited long‐term retention of novel action‐object mappings and extended these actions to other category members. In Experiment 3 (n = 60) we showed that children formed an accurate sensorimotor record of the novel action. In Experiment 4 (n = 54) we demonstrate limits on the types of actions mapped to novel objects. Overall these data suggest that certain aspects of noun mapping share common processing with action mapping and support a domain‐general account of word learning.     

The moment‐to‐moment pitch dynamics of child‐directed speech shape toddlers’ attention and learning

Young children have an overall preference for child‐directed speech (CDS) over adult‐directed speech (ADS), and its structural features are thought to facilitate language learning. Many studies have supported these findings, but less is known about processing of CDS at short, sub‐second timescales. How do the moment‐to‐moment dynamics of CDS influence young children's attention and learning? In Study 1, we used hierarchical clustering to characterize patterns of pitch variability in a natural CDS corpus, which uncovered four main word‐level contour shapes: ‘fall’, ‘rise’, ‘hill’, and ‘valley’. In Study 2, we adapted a measure from adult attention research—pupil size synchrony—to quantify real‐time attention to speech across participants, and found that toddlers showed higher synchrony to the dynamics of CDS than to ADS. Importantly, there were consistent differences in toddlers’ attention when listening to the four word‐level contour types. In Study 3, we found that pupil size synchrony during exposure to novel words predicted toddlers’ learning at test. This suggests that the dynamics of pitch in CDS not only shape toddlers’ attention but guide their learning of new words. By revealing a physiological response to the real‐time dynamics of CDS, this investigation yields a new sub‐second framework for understanding young children's engagement with one of the most important signals in their environment.     

What Is the Buzz About Iconicity? How Iconicity in Caregiver Speech Supports Children's Word Learning

One cue that may facilitate children's word learning is iconicity, or the correspondence between a word's form and meaning. Some have even proposed that iconicity in the early lexicon may serve to help children learn how to learn words, supporting the acquisition of even noniconic, or arbitrary, word–referent associations. However, this proposal remains untested. Here, we investigate the iconicity of caregivers’ speech to young children during a naturalistic free-play session with novel stimuli and ask whether the iconicity of caregivers’ speech facilitates children's learning of the noniconic novel names of those stimuli. Thirty-four 1.5-2-year-olds (19 girls; half monolingual English learners and half bilingual English-Spanish learners) participated in a naturalistic free-play task with their caregivers followed by a test of word-referent retention. We found that caregivers’ use of iconicity, particularly in utterances in which they named the novel stimuli, was associated with the likelihood that children learned that novel name. This result held even when controlling for other factors associated with word learning, such as the concreteness and frequency of words in caregiver speech. Together, the results demonstrate that iconicity not only can serve to help children identify the referent of novel words (as in previous research) but can also support their ability to retain even noniconic word-referent mappings.     

Children's Explanations as a Window Into Their Intuitive Theories of the Social World

Social categorization is an early emerging and robust component of social cognition, yet the role that social categories play in children's understanding of the social world has remained unclear. The present studies examined children's (N = 52 four‐ and five‐year olds) explanations of social behavior to provide a window into their intuitive theories of how social categories constrain human action. Children systematically referenced category memberships and social relationships as causal‐explanatory factors for specific types of social interactions: harm among members of different categories more than harm among members of the same category. In contrast, they systematically referred to agents' mental states to explain the reverse patterns of behaviors: harm among members of the same category more than harm among members of different categories. These data suggest that children view social category memberships as playing a causal‐explanatory role in constraining social interactions.