Preschoolers acquire general knowledge by sharing in pretense

Children acquire general knowledge about many kinds of things, but there are few known means by which this knowledge is acquired. In this article, it is proposed that children acquire generic knowledge by sharing in pretend play. In Experiment 1, twenty-two 3- to 4-year-olds watched pretense in which a puppet represented a "nerp" (an unfamiliar kind of animal). For instance, in one scenario, the nerp ate and disliked a carrot. When subsequently asked generic questions about real nerps, children's responses suggested that they had learned general facts (e.g., nerps dislike carrots). In Experiment 2, thirty-two 4- to 5-year-olds learned from scenarios lacking pretend speech or sound effects. The findings reveal a long overlooked means by which children can acquire generic knowledge.     

Children's Causal Explanations of Animate and Inanimate Motion

Adults frequently refer to nonobvious, internal, or immanent causal mechanisms when explaining certain kinds of movement— such as the movement of animals (e.g., a rabbit hops because of its brain and muscles) and the self-sustained movement of artifacts (e.g., a toy moves on its own because of batteries or gears). This series of studies examined whether and when preschool children are willing to attribute internal and immanent causes to motion. In 3 studies, preschool children and adults viewed animals and artifacts (wind-up toys and transparent objects) either moving independently or being transported by a person. Children explained animal and artifact events differently, even with the kind of movement controlled: They were more likely to attribute immanent cause to animals than to artifacts and more likely to attribute human cause to artifacts than animals. Internal causes were less frequently endorsed overall; however, when asked to describe the insides of artifacts, children who saw them moving alone more often described internal mechanisms (e.g., batteries, electricity) than children who did not see them moving alone. Altogether, the studies suggest that children as young as 3 or 4 years of age honor two principles: For animals more than for artifacts, movement is caused by an immanent source, and across domains, movements without an observable agent have an internal or immanent source.     

Sensing the Coherence of Biology in Contrast to Psychology: Young Children's Use of Causal Relations to Distinguish Two Foundational Domains

To what extent do children understand that biological processes fall into 1 coherent domain unified by distinct causal principles? In Experiments 1 and 2 ( N  =   125) kindergartners are given triads of biological and psychological processes and asked to identify which 2 members of the triad belong together. Results show that 5-year-olds correctly cluster biological processes and separate them from psychological ones. Experiments 3 and 4 ( N  =   64) examine whether or not children make this distinction because they understand that biological and psychological processes operate according to fundamentally different causal mechanisms. The results suggest that 5-year-olds do possess this understanding, and furthermore, they have intuitions about the nature of these different mechanisms.     

The nature of preschoolers' concept of living and artificial objects

This study investigated preschoolers' living kinds conceptualization by employing an extensive stimulus set and alternate indices of understanding. Thirty-four 3- to 5-year-olds and 36 adult undergraduates completed 3 testing phases involving 4 object classes: plants, animals, mobile, and immobile artifacts. The phases involved inquiries participants generated, what biological properties they attributed and their assignment of "alive" to the 4 classes. The study also focused on preschoolers' conceptual coherence by examining their responding across indices. Results revealed both competence and confusion in preschoolers' living kinds conceptualization relative to adults'. In addition, demonstrations of coherence across testing situations suggest that the beginnings of an abstract, biologically organized framework for understanding of living and nonliving kinds are in place in the preschool period.     

Robots and rodents: children's inferences about living and nonliving kinds

This study tests the firm distinction children are said to make between living and nonliving kinds. Three, 4-, and 5-year-old children and adults reasoned about whether items that varied on 3 dimensions (alive, face, behavior) had a range of properties (biological, psychological, perceptual, artifact, novel, proper names). Findings demonstrate that by 4 years of age, children make clear distinctions between prototypical living and nonliving kinds regardless of the property under consideration. Even 3-year-olds distinguish prototypical living and nonliving kinds when asked about biological properties. When reasoning about nonbiological properties for the full range of items, however, even 5-year-olds and adults occasionally rely on facial features. Thus, the living/nonliving distinction may have more narrow consequences than previously acknowledged.     

Priorities in children's expectations about object label reference: form over color

Young children show considerable interest in color similarity; thus we might expect them to use color as a basis for generalizing object labels. However, natural language observations suggest they do not: children tend to overextend labels based on form similarity and rarely, if ever, overextend labels to objects that share only color. Perhaps, then, children give form priority over color in their expectations about object-label reference. This hypothesis was investigated in 2 studies. In a first study, 40 2- and 3-year-olds sorted 10 sets of 3 pictures that contrasted form with color. Children participated in 1 of 2 conditions: half of the children were shown a target object and asked to "find another one" from among the two choice objects, while the other children heard a novel label for the target (e.g., "See this zom?") and were asked to extend the label (e.g., "Can you find another zom?"). 3-year-olds sorted almost exclusively on the basis of form in both conditions, while 2-year-olds performed differently in the 2 conditions: they frequently chose the color match when labels were absent, but selected by form rather than color when asked to extend a novel label. A second study replicated these findings with novel objects that were real rather than pictured. This study also suggested that 3-year-olds grant color some role in their decisions about object-label reference as long as form differences are reduced to a tolerable level. In sum, young children expect form to be more important than color for guiding object-label reference, even though they may find color interesting when not asked to extend labels. This expectation helps explain the speed and relative ease with which children acquire object labels.     

Children''s and Adults'' Models for Predicting Teleological Action: The Development of a Biology-Based Model

Understanding that only living things must act to gain self-beneficial goals is important for developing a theory-like understanding of the living world. This research studied the models that preschoolers, fifth graders, and adults use to guide their predictions of self-beneficial, goal-directed (i.e., teleological) action. Four possible models have been suggested: finalist, complexity based, biology based, and animal based. In Study 1, participants (N = 104) were assigned to one of two conditions that differed in whether a beneficial or neutral object was pictured; they were asked to predict whether animals, plants, machines, and simple artifacts would modify their movement in the direction of that object. Preschoolers' predictions were consistent with an animal-based model, fifth graders' predictions were consistent with biology-based and complexity-based models, and adults' predictions were consistent with a biology-based model. Analysis of both individual response patterns and explanations supported these findings, but also showed that a significant number of preschoolers and fifth graders were finalist, and that very few individual fifth graders followed a complexity-based teleology. In Study 2, participants (N = 84) reported whether the animals, plants, machines, and simple artifacts in Study 1 had psychological capacities. All age groups attributed psychological capacities to animals at levels higher than other domains and at above-chance levels. The evidence from these two studies suggests that preschoolers, unlike fifth graders and adults, predict teleological action for plants and animals on the basis of these entities' inferred psychological capacities.     

How specific is the shape bias?

Children tend to extend object names on the basis of sameness of shape, rather than size, color, or material-a tendency that has been dubbed the "shape bias." Is the shape bias the result of well-learned associations between words and objects? Or does it exist because of a general belief that shape is a good indicator of object category membership? The present three studies addressed this debate by exploring whether the shape bias is specific to naming. In Study 1, 3-year-olds showed the shape bias both when asked to extend a novel name and when asked to select an object of the same kind as a target object. Study 2 found the same shape bias when children were asked to generalize properties relevant to category membership. Study 3 replicated the findings from Study 1 with 2-year-olds. These findings suggest that the shape bias derives from children's beliefs about object kinds and is not the product of associative learning.     

Preschoolers are sensitive to the speaker's knowledge when learning proper names

Unobservable properties that are specific to individuals, such as their proper names, can only be known by people who are familiar with those individuals. Do young children utilize this “familiarity principle” when learning language? Experiment 1 tested whether forty-eight 2- to 4-year-old children were able to determine the referent of a proper name such as “Jessie” based on the knowledge that the speaker was familiar with one individual but unfamiliar with the other. Even 2-year-olds successfully identified Jessie as the individual with whom the speaker was familiar. Experiment 2 examined whether children appreciate this principle at a general level, as do adults, or whether this knowledge may be specific to certain word-learning situations. To test this, forty-eight 3- to 5-year-old children were given the converse of the task in Experiment 1—they were asked to determine the individual with whom the speaker was familiar based on the speaker’s knowledge of an individual’s proper name. Only 5-year-olds reliably succeeded at this task, suggesting that a general understanding of the familiarity principle is a relatively late developmental accomplishment.     

Young children's knowledge about visual perception: projective size and shape

Although recent research indicates that an increased sensitivity to visual appearances develops around 4 or 5 years of age, evidence from perceptual studies suggests that certain types of appearances, that is, projective size and shape, are not noticed or understood until at least 7. 4 experiments investigated preschool children's knowledge of the projective size--distance and projective shape--orientation relationships. In Experiment 1, 3- and 4-year-olds were asked whether an object should be moved farther or nearer in order to increase or decrease its apparent size. 4-year-olds performed significantly better than chance, but 3-year-olds did not. Experiment 2 showed that 3-year-olds are able to perceive projective size changes, indicating that although they do not fully understand the projective size-distance relationship, the necessary perceptual information is potentially available to them. In Experiment 3, 3- and 4-year-olds were asked to indicate how a circular object should be rotated to make it appear either circular or elliptical. Again, 4-year-olds performed significantly better than chance, but 3-year-olds did not. Again also, the results of Experiment 4 indicate that although 3-year-olds are not aware of the projective shape-orientation relationship, they are capable of attending to changes in projective shape. Thus, the constraints on children's knowledge of the projective size-distance and projective shape-orientation relationships seem to be at least partly cognitive rather than wholly perceptual. These results are interpreted as further evidence for the acquisition of level 2 percept knowledge during early childhood.     

Knowledge, Concepts, and Inferences in Childhood

The role of knowledge in children's inferences was investigated in 3 experiments. Experiment 1 examined developmental changes in the role of categorical membership, perceptual appearance, and item complexity in inferences for natural kind and artifact concepts. Preschoolers (5-year-olds), second graders (8-year-olds), and fourth graders (10-year-olds) were taught novel properties about target concepts and asked whether each of 4 probes had those properties. Probes varied in category membership and perceptual appearance relative to the target item. Item complexity also varied. Experiments 2 and 3 examined inferences with known and unknown concepts for familiar and unfamiliar properties. Older children's knowledge led to differential weighting of categorical information over appearance but only for known concepts and/or familiar properties. Preschoolers made no distinction between category and appearance for either known or unknown concepts. Additionally, as target item complexity increased, older children made more inferences than preschoolers. No differences between inferences about natural kind and artifact concepts were found. The role of theories and knowledge in children's drawing of inferences is discussed.     

Young children's learning and transfer of biological information from picture books to real animals

Preschool children (N = 104) read a book that described and illustrated color camouflage in animals (frogs and lizards). Children were then asked to indicate and explain which of 2 novel animals would be more likely to fall prey to a predatory bird. In Experiment 1, 3- and 4-year-olds were tested with pictures depicting animals in camouflage and noncamouflage settings; in Experiment 2, 4-year-olds were tested with real animals. The results show that by 4 years of age, children can learn new biological facts from a picture book. Of particular importance, transfer from books to real animals was found. These findings point to the importance that early book exposure can play in framing and increasing children's knowledge about the world.     

Young Children's Conceptualization of Pretense: Action or Mental Representational State?

A growing body of research indicates that children do not understand mental representation until around age 4. However, children engage in pretend play by age 2, and pretending seems to require understanding mental representation. This apparent contradiction has been reconciled by the claim that in pretense there is precocious understanding of mental representation. 4 studies tested this claim by presenting children with protagonists who were not mentally representing something (i.e., an animal), either because they did not know about the animal or simply because they were not thinking about being the animal. However, the protagonists were acting in ways that could be consistent with pretending to be that animal. Children were then asked whether the protagonists were pretending to be that animal, and children tended to answer in the affirmative. The results suggest that 4-year-olds do not understand that pretending requires mental representation. Children appear to misconstrue pretense as its common external manifestations, such as actions, until at least the sixth year.     

Three-Year-Olds'' Problems with False Belief: Conceptual Deficit or Linguistic Artifact?

Researchers are divided over whether young children understand other people's minds. This study reexamines the main technique used to show a basic inability in 3-year-olds to make judgments about a person's thoughts when that person's knowledge happens to be false. 131 children, aged 3, 3 1/2, and 4, were shown the real, unexpected contents of a chocolate box and were required to say what a friend would think was in it and what their own previous expectations had been. Success in this task was compared between the 3 age groups and also according to the specificity of questions asked. It was found, in contrast to previous findings, that test questions that are temporally specific and syntactically straightforward enable most 3-year-olds to attribute false beliefs to others. These results suggest that 3-year-olds' access to information about others' mental states is bounded by the linguistic demands placed upon them, but long before their fourth birthday children have some understanding of others' mind.     

Object Properties and Knowledge in Early Lexical Learning

The ease with which young children learn object nouns suggests that they possess strategies to identify properties critical to lexical category membership. In previous work, young children used a same-shape criterion to extend new count nouns. The present research tested the generality of this shape bias. 2- and 3-year-olds were asked either to extend a novel count noun to new instances, or to choose unnamed objects to go together. The objects varied in shape, size, and texture. For half of the subjects, the objects had eyes--a property strongly associated with certain material kinds. If young children know this association, they should attend to texture as well as shape in classifying objects with eyes. With named objects only, both 2- and 3-year-old children classified eyeless objects by shape and objects with eyes by both shape and texture. The results suggest that very young children possess considerable knowledge about conditional relations between kinds of perceptual properties. Knowledge of such conditional relations may aid children in forming new categories and thus in discovering new word meanings.     

Young children's inductions from natural kinds: the role of categories and appearances

Recent analyses of natural kind terms (e.g., dog, gold) suggest that people expect members of a kind to share unforeseen properties. The present study investigated the development of this expectation by studying children's inductive inferences. On each of a series of problems, 3- and 4-year-old children were taught a new fact about an object and then were asked whether it would generalize to: an object that looked like the original, that had the same label as the original, that looked like the original and had the same label, or that differed from the original in both respects. The results indicate that 3- and 4-year-olds drew more inferences based on category membership than on perceptual appearances, when both were available. Furthermore, children often based their inferences on category membership even when no label was provided. Thus even 3-year-olds assumed that natural kind categories include more than superficial features.