Naming in young children: a dumb attentional mechanism?

The emergent executive: a dynamic field theory of the development of executive function

Executive function (EF) is a central aspect of cognition that undergoes significant changes in early childhood. Changes in EF in early childhood are robustly predictive of academic achievement and general quality of life measures later in adulthood. We present a dynamic neural field (DNF) model that provides a process-based account of behavior and developmental change in a key task used to probe the early development of executive function—the Dimensional Change Card Sort (DCCS) task. In the DCCS, children must flexibly switch from sorting cards either by shape or color to sorting by the other dimension. Typically, 3-year-olds, but not 5-year-olds, lack the flexibility to do so and perseverate on the first set of rules when instructed to switch. Using the DNF model, we demonstrate how rule-use and behavioral flexibility come about through a form of dimensional attention. Further, developmental change is captured by increasing the robustness and precision of dimensional attention. Note that although this enables the model to effectively switch tasks, the dimensional attention system does not “know” the details of task-specific performance. Rather, correct performance emerges as a property of system–wide interactions. We show how this captures children’s behavior in quantitative detail across 14 versions of the DCCS task. Moreover, we successfully test a set of novel predictions with 3-year-old children from a version of the task not explained by other theories.

The type, but not the amount, of information available influences toddlers' fast mapping and retention of new words

PURPOSE

The authors of this study examined whether the type and number of word-learning cues affect how children infer and retain word-meaning mappings and whether the use of these cues changes with age.

METHOD

Forty-eight 18- to 36-month-old children with typical language participated in a fast-mapping task in which 6 novel words were presented with 3 types of cues to the words' referents, either singly or in pairs. One day later, children were tested for retention of the novel words.

RESULTS

By 24 months of age, children correctly inferred the referents of the novel words at a significant level. Children retained the meanings of words at a significant rate by 30 months of age. Children retained the first 3 of the 6 word-meaning mappings by 24 months of age. For both fast mapping and retention, the efficacy of different cue types changed with development, but children were equally successful whether the novel words were presented with 1 or 2 cues.

CONCLUSION

The type of information available to children at fast mapping affects their ability to both form and retain word-meaning associations. Providing children with more information in the form of paired cues had no effect on either fast mapping or retention.

Development of adaptive tool-use in early childhood: sensorimotor, social, and conceptual factors

Tool-use is specialized in humans, and juvenile humans show much more prolific and prodigious tool-use than other juvenile primates. Nonhuman primates possess many of the basic motor and behavioral capacities needed for manual tool-use: perceptual-motor specialization, sociocultural practices and interactions, and abstract conceptualization of kinds of functions, both real and imagined. These traits jointly contribute to the human specialization for tool-using. In particular, from 2 to 5 years of age children develop: (i) more refined motor routines for interacting with a variety of objects, (ii) a deeper understanding and awareness of the cultural context of object-use practices, and (iii) a cognitive facility to represent potential dynamic human-object interactions. The last trait, which has received little attention in recent years, is defined as the ability to form abstract (i.e., generalizable to novel contexts) representations of kinds of functions, even with relatively little training or instruction. This trait might depend not only on extensive tool-using experience but also on developing cognitive abilities, including a variety of cognitive flexibility: specifically, imagistic memory for event sequences incorporating causal inferences about mechanical effects. Final speculations point to a possible network of neural systems that might contribute to the cognitive capacity that includes sensorimotor, sensory integration, and prefrontal cortical resources and interconnections.

Adjective semantics, world knowledge and visual context: comprehension of size terms by 2- to 7-year-old Dutch-speaking children

The interpretation of size terms involves constructing contextually-relevant reference points by combining visual cues with knowledge of typical object sizes. This study aims to establish at what age children learn to integrate these two sources of information in the interpretation process and tests comprehension of the Dutch adjectives groot 'big' and klein 'small' by 2- to 7-year-old children. The results demonstrate that there is a gradual increase in the ability to inhibit visual cues and to use world knowledge for interpreting size terms. 2- and 3-year-old children only used the extremes of the perceptual range as reference points. From age four onwards children, like adults, used a cut-off point in the mid-zone of a series. From age five on, children were able to integrate world knowledge and perceptual context. Although 7-year-olds could make subtle distinctions between sizes of various object classes, their performance on incongruent items was not yet adult-like.

Earlier development of analytical than holistic object recognition in adolescence

BACKGROUND

Previous research has shown that object recognition may develop well into late childhood and adolescence. The present study extends that research and reveals novel differences in holistic and analytic recognition performance in 7-12 year olds compared to that seen in adults. We interpret our data within a hybrid model of object recognition that proposes two parallel routes for recognition (analytic vs. holistic) modulated by attention.

METHODOLOGY/PRINCIPAL FINDINGS

Using a repetition-priming paradigm, we found in Experiment 1 that children showed no holistic priming, but only analytic priming. Given that holistic priming might be thought to be more 'primitive', we confirmed in Experiment 2 that our surprising finding was not because children's analytic recognition was merely a result of name repetition.

CONCLUSIONS/SIGNIFICANCE

Our results suggest a developmental primacy of analytic object recognition. By contrast, holistic object recognition skills appear to emerge with a much more protracted trajectory extending into late adolescence.

Interaction between language and vision: it's momentary, abstract, and it develops

In this paper, we present a case study that explores the nature and development of the mechanisms by which language interacts with and influences our ability to represent and retain information from one of our most important non-linguistic systems - vision. In previous work (Dessalegn & Landau, 2008), we showed that 4 year-olds remembered conjunctions of visual features better when the visual target was accompanied by a sentence containing an asymmetric spatial predicate (e.g., the yellow is to the left of the black) but not when the visual target was accompanied by a sentence containing a novel noun (e.g., look at the dax) or a symmetric spatial predicate (e.g., the yellow is touching the black). In this paper, we extend these findings. In three experiments, 3, 4 and 6 year-olds were shown square blocks split in half by color vertically, horizontally or diagonally (e.g., yellow-left, black-right) and were asked to perform a delayed-matching task. We found that sentences containing spatial asymmetric predicates (e.g., the yellow is to the left of the black) and non-spatial asymmetric predicates (e.g., the yellow is prettier than the black) helped 4 year-olds, although not to the same extent. By contrast, 3 year-olds did not benefit from different linguistic instructions at all while 6 year-olds performed at ceiling in the task with or without the relevant sentences. Our findings suggest by age 4, the effects of language on non-linguistic tasks depend on highly abstract representations of the linguistic instructions and are momentary, seen only in the context of the task. We further speculate that language becomes more automatically engaged in nonlinguistic tasks over development.

Distinct labels attenuate 15-month-olds' attention to shape in an inductive inference task

We examined the role of distinct labels on infants' inductive inferences. Thirty-six 15-month-old infants were presented with target objects that possessed a non-obvious property, followed by test objects that varied in shape similarity relative to the target. Infants were tested in one of two groups, a Same Label group in which target and test objects were labeled with the same noun, and a Distinct Label group in which target and test objects were labeled with different nouns. When target and test objects were labeled with the same count noun, infants generalized the non-obvious property to both test objects, regardless of similarity to the target. In contrast, labeling the target and test objects with different count nouns attenuated infants' generalization of the non-obvious property to both high and low-similarity test objects. Our results suggest that by 15 months, infants recognize that object labels provide information about underlying object kind and appreciate that distinct labels are used to designate members of different categories.

The Medium is the Message: Pictures and Objects Evoke Distinct Conceptual Relations in Parent-Child Conversations

An important developmental task is learning to organize experience by forming conceptual relations among entities (e.g., a lion and a snake can be linked because both are animals; a lion and a cage can be linked because the lion lives in the cage). We propose that representational medium (i.e., pictures vs. objects) plays an important role in influencing which relations children consider. Prior work has demonstrated that pictures more readily evoke broader categories, whereas objects more readily call attention to specific individuals. We therefore predicted that pictures would encourage taxonomic and shared-property relations, whereas objects would encourage thematic and slot-filler relations. We observed 32 mother-child dyads (M child ages = 2.9 and 4.3) playing with pictures and objects, and identified utterances in which they made taxonomic, thematic, shared-property, or slot-filler links between items. The results confirmed our predictions and thus support representational medium as an important factor that influences the conceptual relations expressed during dyadic conversations.

A Developmental Difference in Shape Processing and Word-Shape Associations between 4 and 6.5 Year Olds

In distinguishing individual shapes (defined by their contours), older children (6.5 years of age on average) performed better than younger children (4 years of age on average), and, although the task did not involve any categorization or generalization, the error pattern was qualitatively affected by shape differences that are generally common distinctions between objects belonging to different categories. The influence of these shape differences was also observed for unfamiliar shapes, demonstrating that the influence of categorization experience was not modulated by the retrieval of shape features from known categories but rather related to a different perception of shape by age. The results suggest a direct influence of categorization experience on more abstract shape processing. When children were distinguishing shapes, new words were paired with the target shapes, and in 2 additional tasks, the acquired name–shape associations were tested. The younger age group was able to remember more words correctly.

Developmental differences in the naming of contextually non-categorical objects

This study investigates the naming process of contextually non-categorical objects in children from 3 to 9 plus 13-year-olds. 112 children participated in the study. Children were asked to narrate a story individually while looking at Mercer Mayer's textless, picture book Frog, where are you? The narratives were audio recorded and transcribed. Texts were analyzed to find out how children at different ages name contextually non-categorical objects, tree and its parts in this case. Our findings revealed that increasing age in children is a positive factor in naming objects that are parts or extended forms of an object which itself constitutes a basic category in a certain context. Younger children used categorical names more frequently to refer to parts or disfigured forms of the object than older children and adults while older children and adults used specified names to refer to the parts or extended forms of the categorical names.

Do lions have manes? For children, generics are about kinds rather than quantities

Generic statements (e.g., "Lions have manes") make claims about kinds (e.g., lions as a category) and, for adults, are distinct from quantificational statements (e.g., "Most lions have manes"), which make claims about how many individuals have a given property. This article examined whether young children also understand that generics do not depend purely on quantitative information. Five-year-olds (n = 36) evaluated pairs of questions expressing properties that were matched in prevalence but varied in whether adults accept them as generically true (e.g., "Do lions have manes?" [true] vs. "Are lions boys?" [false]). Results demonstrated that children evaluate generics based on more than just quantitative information. Data suggest that even young children recognize that generics make claims about kinds.

Acquisition of generic noun phrases in Chinese: learning about lions without an '-s'

English-speaking children understand and produce generic expressions in the preschool years, but there are cross-linguistic differences in how generics are expressed. Three studies examined interpretation of generic noun phrases in three- to seven-year-old child (N=192) and adult speakers (N=163) of Mandarin Chinese. Contrary to suggestions by Bloom (1981), Chinese-speaking adults honor a clear distinction between generics (expressed as bare NPs) and other quantified expressions ('all'/suo3you3 and 'some'/you3de). Furthermore, Mandarin-speaking children begin to distinguish generics from 'all' or 'some' as early as five years, as shown in both confirmation (Study 2) and property-generation (Study 3) tasks. Nonetheless, the developmental trajectory for Chinese appears prolonged relative to English and this seems to reflect difficulty with 'all' and 'some' rather than difficulty with generics. Altogether these results suggest that generics are primary, and that the consistency of markings affects the rate at which non-generic NPs are distinguished from generics.

Preschoolers' novel noun extensions: shape in spite of knowing better

We examined the puzzling research findings that when extending novel nouns, preschoolers rely on shape similarity (rather than categorical relations) while in other task contexts (e.g., property induction) they rely on categorical relations. Taking into account research on children’s word learning, categorization, and inductive inference we assume that preschoolers have both a shape-based and a category-based word extension strategy available and can switch between these two depending on which information is easily available. To this end, we tested preschoolers on two versions of a novel-noun label extension task. First, we paralleled the standard extension task commonly used by previous research. In this case, as expected, preschoolers predominantly selected same-shape items. Second, we supported preschoolers’ retrieval of item-related information from memory by asking them simple questions about each item prior to the label extension task. Here, they switched to a category-based strategy, thus, predominantly selecting same-category items. Finally, we revealed that this shape-to-category shift is specific to the word learning context as we did not find it in a non-lexical classification task. These findings support our assumption that preschoolers’ decision about word extension change in accordance with the availability of information (from task context or by memory retrieval). We conclude by suggesting that preschoolers’ noun extensions can be conceptualized within the framework of heuristic decision-making. This provides an ecologically plausible processing account with respect to which information is selected and how this information is integrated to act as a guideline for decision-making when novel words have to be generalized.

Processing of perceptual information is more robust than processing of conceptual information in preschool-age children: evidence from costs of switching

Is processing of conceptual information as robust as processing of perceptual information early in development? Existing empirical evidence is insufficient to answer this question. To examine this issue, 3- to 5-year-old children were presented with a flexible categorization task, in which target items (e.g., an open red umbrella) shared category membership with one test item (e.g., a folded umbrella) and perceptual characteristics with another test item (e.g., a red mushroom). Participants were instructed to either categorize stimuli by the same dimension (i.e., perceptual similarity or category membership) in both phases of the task, or switch from categorizing by one dimension to categorizing by the other dimension. Results pointed to a strong asymmetry in switch costs: conceptual switch costs were higher than perceptual switch costs. These results suggest that processing of perceptual information remains more robust than processing of conceptual information at least until 5 years of age.

Rapid word learning in 13- and 17-month-olds in a naturalistic two-word procedure: looking versus reaching measures

This study investigated infants' rapid learning of two novel words using a preferential looking measure compared with a preferential reaching measure. In Experiment 1, 21 13-month-olds and 20 17-month-olds were given 12 novel label exposures (6 per trial) for each of two novel objects. Next, in the label comprehension tests, infants were shown both objects and were asked, "Where's the [label]?" (looking preference) and then told, "Put the [label] in the basket" (reaching preference). Only the 13-month-olds showed rapid word learning on the looking measure; neither age group showed rapid word learning on the reaching measure. In Experiment 2, the procedure was repeated 24h later with 10 participants per age group from Experiment 1. After a further 12 labels per object, both age groups now showed robust evidence of rapid word learning, but again only on the looking measure. This is the earliest looking-based evidence of rapid word learning in infants in a well-controlled (i.e., two-word) procedure; our failure to replicate previous reports of rapid word learning in 13-month-olds with a preferential reaching measure may be due to our use of more rigorous controls for object preferences. The superior performance of the younger infants on the looking measure in Experiment 1 was not straightforwardly predicted by existing theoretical accounts of word learning.

Object movement in preschool children's word learning

Two studies examined whether preschool children preferred to select a moving object over stationary objects when determining the referent of a novel word. In both studies three- and four-year-olds observed three novel objects, one moving object and two stationary objects. In Study 1, children (n=44) were asked to select the object that best matched a novel word. In Study 2, children (n=45) were asked to select the object that best matched a novel fact. Results across the two studies indicated that three- and four-year-olds showed a preference for selecting the moving object and that this preference was similar for both words and facts. These results suggest that preschool children are able to use movement to determine the referent of a novel word, especially when other cues are unavailable or unhelpful, but that movement may not be uniquely helpful for word learning.

Child categorization

Categorization is a process that spans all of development, beginning in earliest infancy yet changing as children's knowledge and cognitive skills develop. In this review article, we address three core issues regarding childhood categorization. First, we discuss the extent to which early categories are rooted in perceptual similarity versus knowledge-enriched theories. We argue for a composite perspective in which categories are steeped in commonsense theories from a young age but also are informed by low-level similarity and associative learning cues. Second, we examine the role of language in early categorization. We review evidence to suggest that language is a powerful means of expressing, communicating, shaping, and supporting category knowledge. Finally, we consider categories in context. We discuss sources of variability and flexibility in children's categories, as well as the ways in which children's categories are used within larger knowledge systems (e.g., to form analogies, make inferences, or construct theories). Categorization is a process that is intrinsically tied to nearly all aspects of cognition, and its study provides insight into cognitive development, broadly construed. WIREs Cogn Sci 2011 2 95-105 DOI: 10.1002/wcs.96 For further resources related to this article, please visit the WIREs website.

Determining that a label is kind-referring: factors that influence children's and adults' novel word extensions

The present studies examined factors that influence children's and adults' interpretation of a novel word. Four factors are hypothesized to emphasize that a label refers to a richly structured category (also known as a 'kind'): generic language, internal property attributions, familiar kind labels and absence of a target photograph. In Study 1, for college students (N=125), internal property attributions resulted in more taxonomic and fewer shape responses. In Study 2, for four-year-olds (N=126), the presence of generic language and familiar kind labels resulted in more taxonomic choices. Further, the presence of familiar kind labels resulted in fewer shape choices. The results suggest that, when learning new words, children and adults are sensitive to factors that imply kind reference.

From Perceptual Categories to Concepts: What Develops?

People are remarkably smart: they use language, possess complex motor skills, make non-trivial inferences, develop and use scientific theories, make laws, and adapt to complex dynamic environments. Much of this knowledge requires concepts and this paper focuses on how people acquire concepts. It is argued that conceptual development progresses from simple perceptual grouping to highly abstract scientific concepts. This proposal of conceptual development has four parts. First, it is argued that categories in the world have different structure. Second, there might be different learning systems (sub-served by different brain mechanisms) that evolved to learn categories of differing structures. Third, these systems exhibit differential maturational course, which affects how categories of different structures are learned in the course of development. And finally, an interaction of these components may result in the developmental transition from perceptual groupings to more abstract concepts. This paper reviews a large body of empirical evidence supporting this proposal.

From Perceptual Categories to Concepts: What Develops?

People are remarkably smart: they use language, possess complex motor skills, make non-trivial inferences, develop and use scientific theories, make laws, and adapt to complex dynamic environments. Much of this knowledge requires concepts and this paper focuses on how people acquire concepts. It is argued that conceptual development progresses from simple perceptual grouping to highly abstract scientific concepts. This proposal of conceptual development has four parts. First, it is argued that categories in the world have different structure. Second, there might be different learning systems (sub-served by different brain mechanisms) that evolved to learn categories of differing structures. Third, these systems exhibit differential maturational course, which affects how categories of different structures are learned in the course of development. And finally, an interaction of these components may result in the developmental transition from perceptual groupings to more abstract concepts. This paper reviews a large body of empirical evidence supporting this proposal.

Preschoolers' extension of novel words to animals and artifacts

We examined whether preschoolers' ontological knowledge would influence lexical extension. In Experiment 1, four-year-olds were presented with a novel label for either an object with eyes described as an animal, or the same object without eyes described as a tool. In the animal condition, children extended the label to similar-shaped objects, whereas in the tool condition, children extended the label to similar-function objects. In Experiment 2, when four-year-olds were presented with objects with eyes described as tools, they extended the label on the basis of shared function. These experiments suggest that preschoolers' conceptual knowledge guides their lexical extension.

Automatic shifts of attention in the Dimensional Change Card Sort task: subtle changes in task materials lead to flexible switching

Two experiments tested a hypothesis that reducing demands on executive control in a Dimensional Change Card Sort task will lead to improved performance in 3-year-olds. In Experiment 1, the shape dimension was represented by two dissimilar values (stars and flowers), and the color dimension was represented by two similar values (red and pink). This configuration of stimuli rendered shape more salient than color. In Experiment 2, attentional weights of each dimension value were manipulated by using two versus four values to represent the dimensions of shape and color. The results indicated that increasing saliency of the postswitch dimension (Experiment 1) and reducing attentional weights of individual dimension values (Experiment 2) lead to a marked improvement in the postswitch sorting accuracy in 3-year-olds.

Fast-mapping placeholders: Using words to talk about kinds

Fast-mapping is the ability to acquire a word rapidly on the basis of minimal information. As proposed by Carey (1978), we assume that children are able to achieve fast-mapping because their initial word meanings are skeletal placeholders that will be extended gradually over time. In this paper we propose that a notion of "kind" is fundamental to children's initial mappings for object labels. We illustrate this point by considering the acquisition of generic noun phrases, which are understood by children as kind-referring from very early on. We argue that the acquisition of generics has implications for mechanisms of word learning. Evidence suggests that generics cannot be acquired solely on the basis of associative learning mechanisms; rather, they are a default interpretation for young children.

Grounding Action Words in the Sensorimotor Interaction with the World: Experiments with a Simulated iCub Humanoid Robot

This paper presents a cognitive robotics model for the study of the embodied representation of action words. The present research will present how an iCub humanoid robot can learn the meaning of action words (i.e. words that represent dynamical events that happen in time) by physically interacting with the environment and linking the effects of its own actions with the behavior observed on the objects before and after the action. The control system of the robot is an artificial neural network trained to manipulate an object through a Back-Propagation-Through-Time algorithm. We will show that in the presented model the grounding of action words relies directly to the way in which an agent interacts with the environment and manipulates it.

Children's preference for HAS and LOCATED relations: a word learning bias for noun-noun compounds

The present study investigates children's bias when interpreting novel noun-noun compounds (e.g. kig donka) that refer to combinations of novel objects (kig and donka). More specifically, it investigates children's understanding of modifier-head relations of the compounds and their preference for HAS or LOCATED relations (e.g. a donka that HAS a kig or a donka that is LOCATED near a kig) rather than a FOR relation (e.g. a donka that is used FOR kigs). In a forced-choice paradigm, two- and three-year-olds preferred interpretations with HAS/LOCATED relations, while five-year-olds and adults showed no preference for either interpretation. We discuss possible explanations for this preference and its relation to another word learning bias that is based on perceptual features of the referent objects, i.e. the shape bias. We argue that children initially focus on a perceptual stability rather than a pure conceptual stability when interpreting the meaning of nouns.

Young children’s extension of novel labels to novel animate items in three testing conditions

The present research explores young children’s extension of novel labels to novel animate items. Three experiments were performed by means of the intermodal preferential looking (IPL) paradigm. In Experiment 1, after repeated exposure to novel word—object associations, 24- and 36-month-olds extend novel labels on the basis of shape similarity, in a task that pits a match in shape against a match in color. Experiment 2 finds 24-month-olds’ rapid reliance on shape, when introducing simplified trials that required identifying a match in shape or color separately. Experiment 3 reassesses young children’s ability to weigh up two perceptual cues, but in a condition in which the standard item remains visible, demonstrating 18- and 24-month-olds’ use of shape to extend novel labels. In contrast to previous research reporting an early shape bias mainly for inanimate items, this paper reveals that young children also consider shape to be a relevant cue to generalize novel labels to novel animate items. However, memory and processing demands appear to be crucial in the early ability to use shape information to extend novel labels to novel animate stimuli.

A developmental analysis of generic nouns in Southern Peruvian Quechua

Generic noun phrases (e.g., "Cats like to drink milk") are a primary means by which adults express generalizations to children, yet they pose a challenging induction puzzle for learners. Although prior research has established that English speakers understand and produce generic noun phrases by preschool age, little is known regarding the cross-cultural generality of generic acquisition. Southern Peruvian Quechua provides a valuable comparison because, unlike English, it is a highly inflected language in which generics are marked by the absence rather than the presence of any linguistic markers. Moreover, Quechua is spoken in a cultural context that differs markedly from the highly educated, middle-class contexts within which earlier research on generics was conducted. We presented participants from 5 age groups (3-6, 7-9, 10-12, 14-35, and 36-90 years of age) with two tasks that examined the ability to distinguish generic from non-generic utterances. In Study 1, even the youngest children understood generics as applying broadly to a category (like "all") and distinct from indefinite reference ("some"). However, there was a developmental lag before children understood that generics, unlike "all", can include exceptions. Study 2 revealed that generic interpretations are more frequent for utterances that (a) lack specifying markers and (b) are animate. Altogether, generic interpretations are found among the youngest participants, and may be a default mode of quantification. These data demonstrate the cross-cultural importance of generic information in linguistic expression.

Categorical structure among shared features in networks of early-learned nouns

The shared features that characterize the noun categories that young children learn first are a formative basis of the human category system. To investigate the potential categorical information contained in the features of early-learned nouns, we examine the graph-theoretic properties of noun-feature networks. The networks are built from the overlap of words normatively acquired by children prior to 2(1/2) years of age and perceptual and conceptual (functional) features acquired from adult feature generation norms. The resulting networks have small-world structure, indicative of a high degree of feature overlap in local clusters. However, perceptual features--due to their abundance and redundancy--generate networks more robust to feature omissions, while conceptual features are more discriminating and, per feature, offer more categorical information than perceptual features. Using a network specific cluster identification algorithm (the clique percolation method) we also show that shared features among these early-learned nouns create higher-order groupings common to adult taxonomic designations. Again, perceptual and conceptual features play distinct roles among different categories, typically with perceptual features being more inclusive and conceptual features being more exclusive of category memberships. The results offer new and testable hypotheses about the role of shared features in human category knowledge.

Generic language and judgements about category membership: Can generics highlight properties as central?

Many languages distinguish generic utterances (e.g., "Tigers are ferocious") from non-generic utterances (e.g., "Those tigers are ferocious"). Two studies examined how generic language specially links properties and categories. We used a novel-word extension task to ask if 4- to 5-year-old children and adults distinguish between generic and specific language, and judge that predicating a property of a depicted novel animal using generic language (e.g., "Bants have stripes"), rather than non-generic language (e.g., "This bant has stripes") implies a more kind-relevant connection between category and property. Participants were asked to endorse an extension of the label taught to a novel animal matching the target instance on either overall similarity or the mentioned property. Wording was found to have a significant effect on responses for both age groups. Altogether, the results of these studies suggest that the generic may be a default interpretation for young children, who need to learn the semantics of specific and set-theoretic expressions.

Learning from others: children's construction of concepts

Much of children's knowledge is derived not from their direct experiences with the environment but rather from the input of others. However, until recently, the focus in studies of concept development was primarily on children's knowledge, with relatively little attention paid to the nature of the input. The past 10 years have seen an important shift in focus. This article reviews this approach, by examining the nature of the input and the nature of the learner, to shed light on early conceptual learning. These findings argue against the simple notion that conceptual development is either supplied by the environment or innately specified, and instead demonstrate how the two work together. The implications for how children reconcile competing belief systems are also discussed.

Developmental changes in visual object recognition between 18 and 24 months of age

Two experiments examined developmental changes in children's visual recognition of common objects during the period of 18 to 24 months. Experiment 1 examined children's ability to recognize common category instances that presented three different kinds of information: (1) richly detailed and prototypical instances that presented both local and global shape information, color, textural and featural information, (2) the same rich and prototypical shapes but no color, texture or surface featural information, or (3) that presented only abstract and global representations of object shape in terms of geometric volumes. Significant developmental differences were observed only for the abstract shape representations in terms of geometric volumes, the kind of shape representation that has been hypothesized to underlie mature object recognition. Further, these differences were strongly linked in individual children to the number of object names in their productive vocabulary. Experiment 2 replicated these results and showed further that the less advanced children's object recognition was based on the piecemeal use of individual features and parts, rather than overall shape. The results provide further evidence for significant and rapid developmental changes in object recognition during the same period children first learn object names. The implications of the results for theories of visual object recognition, the relation of object recognition to category learning, and underlying developmental processes are discussed.

Rigid thinking about deformables: do children sometimes overgeneralize the shape bias?

Young children learning English are biased to attend to the shape of solid rigid objects when learning novel names. This study seeks further understanding of the processes that support this behavior by examining a previous finding that three-year-old children are also biased to generalize novel names for objects made from deformable materials by shape, even after the materials are made salient. In two experiments, we examined the noun generalizations of 72 two-, three- and four-year-old children with rigid and deformable stimuli. Data reveal that three-year-old, but not two- or four-year-old, children generalize names for deformable things by shape, and that this behavior is not due to the syntactic context of the task. We suggest this behavior is an overgeneralization of three-year-old children's knowledge of how rigid things are named and discuss the implications of this finding for a developmental account of the origins of the shape bias.