Taxonomic Knowledge: What Kind and When?

Taxonomic knowledge may be distinguished into several forms: horizontal , representing links between items at the same level of a taxonomic hierarchy (e.g., dog-cow), and vertical , representing links between items at different hierarchical levels (e.g., dog-animal). Horizontal relations include 3 category types: slot-filler (based on constrained function, i.e., shared function within an event), conventional subcategory (based on constrained, but not event-based, function and/or on arbitrary cultural groupings), and conventional superordinate (based on unconstrained function). 3 experiments–category production, word association, and forced-picture-choice–explored taxonomic and thematic/ schematic knowledge in 4- and 7-year-old children and adults. Results showed preschooler taxonomic knowledge to be restricted to slot-filler categories. Conventional horizontal relations and vertical taxonomic knowledge emerged with age. Slot-fillers played a role in these developments of taxonomic knowledge. Also developing was' task/context sensitive responding, with 7-, but not 4-year-olds, relying on distinct forms of knowledge across tasks.     

The Development of Children's Beliefs about Social and Biological Aspects of Gender Differences

2 studies examined children's beliefs about the origins of gender differences and addressed 2 main questions: (a) What age-related changes are there in children's beliefs about the contributions of nature and nurture to the development of gender roles? and (b) Do children differentiate between aspects of gender roles that adults believe to be more biologically determined and those they believe to be more socially influenced? 160 4- to 10-year-olds and 32 adults participated in Study 1. Participants were told about a child raised with only opposite-sex individuals and were asked whether the child would grow up to possess a series of gender-stereotyped, biological, and control properties. Until age 9 or 10, children believed that gender-stereotyped properties would develop in an infant regardless of the social context of upbringing. Study 2 provides evidence that children were not merely reporting stereotypical category associations. These studies suggest that young children may have an early bias to view gender categories as predictive of essential, underlying similarities between members, but later come to acknowledge the role of other causal mechanisms (e.g., the social environment) in shaping how category members develop.     

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.     

The Development of Category-based Induction

In a category-based induction, knowing that a property is true of some category members leads one to conclude that the property is true of other category members. An example is: Cardinals have ulnar arteries. Therefore hawks have ulnar arteries. Recently, Osherson et al. (1990) demonstrated a number of phenomena involving category-based inductions, and proposed that these phenomena can be explained by variations in 2 processes: (a) the similarity between the premise category (cardinals in the above example) and the conclusion category (hawks in the above example), and (b) the degree to which the premise category "covers" (roughly, is similar to) instances of the lowest-level category that includes both the premise and conclusion categories (birds in the above example). The present paper traces the developmental course of the relevant phenomena and of the similarity and coverage processes that presumably underlie them. Studies 1 and 2 demonstrated that the inductions made by kindergartners are sensitive only to the similarity between the premise and conclusion categories. Studies 3 and 4 showed that second graders' inductions are sensitive to both premise-conclusion similarity and coverage, as long as there is no need actually to use a generated category that includes both the premise and conclusion categories. These developmental findings reveal an orderly process in the growth of category-based inductions, and also decompose the Osherson et al. model into 3 basic components that have not previously been explicitly distinguished.     

Basic level object categories support the acquisition of novel adjectives: evidence from preschool-aged children

Two experiments examined 3- and 4-year-old children's ability to map novel adjectives to object properties. Sixty-four children were introduced to a target (e.g., a bumpy object), and asked to choose between (1) a matching test object (e.g., a different bumpy object), and (2) a contrasting test object (e.g., a smooth object). Four-year-olds successfully extended novel adjectives from the target to the matching test object whether these objects were drawn from the same, or different, basic level categories. In contrast, 3-year-olds' extensions were more restricted. They successfully extended novel adjectives if the target and test objects were drawn from the same basic level category but failed to do so if the objects were drawn from different basic level categories (Experiment 1). However, if 3-year-olds (n = 20) were first permitted to extend a novel adjective to objects within the same basic level category, they were subsequently able to extend that novel adjective broadly to objects from different basic level categories (Experiment 2). Thus, basic level object categories serve as an initial foundation in the process of mapping novel adjectives to object properties.     

Children's inductive inferences within superordinate categories: the role of language and category structure

One important function of categories is to allow inferences that extend beyond surface appearances. In 2 studies, preschool and second-grade children were tested on their understanding that members of a category have similar internal parts. In 1 study, children were taught new information about the internal structure of various objects (e.g., an apple), then were probed to determine how far they generalized the new information (e.g., to another apple, to other fruit, to an unrelated object). In a second study, children participated in an open-ended interview that probed whether various types of objects had "the same kinds of stuff inside." Children at both ages and in both studies drew many inferences concerning the internal children to report that members of a basic-level category had the same internal parts. Older children drew more inferences at the superordinate level than did younger children. Older children were also more sensitive to differences in category domain (natural kind vs. artifact) at both basic and superordinate levels. Altogether, these results suggest that preschool children assume that basic-level categories share internal parts. They need to refine this belief at the basic level and to extend it to superordinate-level categories.     

Asking Children to “Be Helpers” Can Backfire After Setbacks

Describing behaviors as reflecting categories (e.g., asking children to “be helpers”) has been found to increase pro-social behavior. The present studies (N = 139, ages 4–5) tested whether such effects backfire if children experience setbacks while performing category-relevant actions. In Study 1, children were asked either to “be helpers” or “to help,” and then pretended to complete a series of successful scenarios (e.g., pouring milk) and unsuccessful scenarios (e.g., spilling milk while trying to pour). After the unsuccessful trials, children asked to “be helpers” had more negative attitudes. In Study 2, asking children to “be helpers” impeded children's helping behavior after they experienced difficulties while trying to help. Implications for how category labels shape beliefs and behavior are discussed.     

The role of language, appearance, and culture in children's social category-based induction

Four studies examined whether Israeli 5-year-olds (N = 88) and adults (N = 48) drew inferences about psychological properties based on a character's social category, personality trait, or physical appearance trait. Study 1 revealed that while children drew inferences mostly by social category, adults did it by personality trait. Study 2 showed that the children's pattern was not due to how the categorical information was conveyed. Studies 3 and 4 demonstrated that for kindergarteners, labels, not appearances, are determinant of the inductive potential of social categories. Studies indicated that "Jew" and "Arab" were the most inductively powerful social categories for both children and adults. The results carry implications for the roles of language, appearances, and culture in the conceptualization of "human kinds."     

Mother-child conversations about pictures and objects: referring to categories and individuals

The distinction between individuals (e.g., Rin-Tin-Tin) and categories (e.g., dogs) is fundamental in human thought. Two studies examined factors that influence when 2- to 3-year-old children and adults focus on individuals versus categories. Mother-child dyads were presented with pictures and toys (e.g., a picture of a boat or a toy boat). Conversations were coded for references to generic categories ("Dogs are furry"), ostensive labels ("This is a dog"), or specific individuals ("Lassie"). Overall, pictures generated more talk about categories; objects generated more talk about individuals. However, when objects could not be manipulated, speakers expressed relatively more category references. These results suggest that representations (in the form of pictures or objects-on-display) encourage young children and parents alike to think about categories.     

One Cow Does Not an Animal Make: Young Children Can Extend Novel Words at the Superordinate Level

Six match-to-sample picture/object selection experiments were designed to explore children's knowledge about superordinate words (e.g., "food") and how they acquire this knowledge. Three factors were found to influence the learning and extension of superordinate words in 3- to 5-year-old children (N = 230): The number of standards (one versus two), the type of standards presented (from different basic-level categories versus from the same basic-level category), and the nature of the object representations used (pictures versus objects). A different pattern of superordinate word acquisition was found between 3-year-olds and 4- and 5-year-olds. Although 4- and 5-year-olds could learn and extend novel words to superordinate categories in the presence of two picture exemplars from different categories or a single three-dimensional (3-D) exemplar, 3-year-olds could do so only in the presence of two 3-D exemplars. These findings indicate that young children's acquisition of superordinate words is influenced by multiple factors and that there is a developmental progression from multiple exemplars to single exemplars in superordinate word learning.     

Understanding Natural Cause: Children''s Explanations of How Objects and Their Properties Originate

An understanding of natural cause includes the realization that events can occur independently of human activity or intentions. It also often entails realizing that causal mechanisms can be nonobservable or nonobvious. The present research investigated to what extent children ages 4-7 have developed a concept of natural cause. Study 1 examined children's understandings of object origins (e.g., how the sun began); Study 2 probed children's causal understandings of object behaviors and properties (e.g., why rabbits hop and have long ears). In both studies, children by age 4 were sensitive to the natural kind-artifact distinction in their explanations. They mentioned human intervention for human-made artifacts but rarely for naturally occurring things. Moreover, subjects at all ages were able to identify specific kinds of natural cause, including intrinsic causes (such as growth) and inborn nature. Finally, subjects understood the link between nonobvious, internal parts and self-generated activity (e.g., that bones are important for the flight of a bird). Altogether, these results suggest that even preschool children realize that natural causes exist. They contradict Piaget's characterization of young children as artificialistic (believing that naturally occurring things are created by people) and as focused on observable properties.     

Development of orthographic skills in Chinese children

This study investigates possible developmental trends in children's invented spelling (or spelling errors) in Chinese elementary schools. The entire study consists of two substudies, Study A and Study B. Study A analyzes over 7000 invented spellings collected from the writing samples of 1200 children. Study B analyzes 3995 invented spellings that were collected from the spelling tests of 300 children. These invented spellings are sorted initially according to emerging patterns according to the way the invented spellings deviate from standard spellings; they are then further subsumed into three general categories according to the linguistic principles of Chinese characters - phonologically based spelling errors, graphemic spelling errors, and semantic spelling errors. Qualitative analysis of the invented spellings of these three categories indicates that children's spelling errors are not random; rather they reflect the development of children's orthographic knowledge. Regression analysis for linear trend shows that a developmental trend in the use of spelling strategies exists: at the lower elementary level, phonological strategies predominate; as grade level advances, the use of graphemic and semantic strategies increases.     

Perceptual development and category generalization.

This work is concerned with developmental changes in the structure of classifications. The central claim is that young children's undifferentiated perceptions of complex stimuli are highly structured by wholistic similarity whereas older children's perceptions are structured by component dimensions. It is shown in 2 experiments that young children systematically and spontaneously generalize a category if it is well organized by overall similarity but not if it is organized by a criterial dimension. Older children, on the other hand, spontaneously apprehend and extend a category by its dimensional structure. The third experiment was designed to test the hypothesis that criterial property categories are preferred in classification tasks requiring the explicit discovery of a general rule. It was found that younger children's attention to the dimensional relations within a category increases under rule-discovery instructions, although they still have difficulty ignoring wholistic similarity relations. The trend from similarity to dimensional classification is discussed in the context of Piagetian classification tasks and family-resemblance accounts of natural categories.     

The Mind's "I": Children's Conception of the Mind as an Active Agent

1 hypothesis about children's developing conception of the mind is that preschoolers are limited to an understanding that persons have internal, mental contents like thoughts and beliefs, whereas older children and adults conceive of the mind itself as an independent, active structure or processor. Adults' conception of the mind in this independent active fashion seems evident in their use of personified mental metaphor (e.g., "My mind tricked me"). 3 studies examined the development and consolidation of this active, personified view. Study 1 provided an analysis of natural language data regarding 1 child's uses of vision words such as see and look from age 2 1/2 to 8 years. We examined the child's use of such words to refer literally to perception (e.g., "I see the TV") and also to refer nonliterally to active mental processes such as comprehension and inference (e.g., "I see what you mean"). Studies 2 and 3 examined 6-, 8-, and 10-year-olds' comprehension and production of mental metaphors. In a metaphor comprehension task, we asked children to interpret personified metaphoric statements about the mind (e.g., "My mind wandered") and 3 comparison domains, mechanics (e.g., "The car is dead"), nature (e.g., "The wind is howling"), and emotion (e.g., "Her heart was smiling"). In an explanation task, we asked children to explain the processes underlying the making of both instant photos and mental images. The findings reveal a developing ability to interpret and produce statements personifying the mind and provide considerable evidence about children's movement toward a conception of the mind as an independent entity deserving reference and conceptualization in its own right.     

Categories influence predictions about individual consistency

Predicting how people will behave in the future is a critical social-cognitive task. In four studies (N = 150, ages preschool to adult), young children (ages 4-5) used category information to guide their expectations about individual consistency. They predicted that psychological properties (preferences and fears) would remain consistent over time after hearing one example in which properties followed a category-linked distribution (e.g., children of different genders had different properties) but not when properties varied within a category (e.g., children of the same gender had different properties). The developmental course of these findings is examined. Results suggest the importance of considering how children's emerging theories of behavior and of social groups operate together to inform their expectations about the social world.     

External and internal sources of variation in the creation of false reports in children

In this article, we describe several “families” of variables that may account for reliable variation in children's suggestibility. Specifically, we begin by discussing factors that are external to the organism (e.g., various forms of biased interviewing such as visualization inductions, accusatory tone, repeated yes/no questioning) that could explain why at any age studied, large suggestibility effects are produced in some situations but not in others. Following this, we discuss research on factors that are internal to the organism that may be at the source of individual differences in suggestibility-proneness (e.g., IQ, memory strength, relevant content knowledge). We conclude by postulating a framework in which multiple and complex interactions among cognitive, social, personality, and biological factors converge to make some children and some situations more or less suggestible than others.     

What is "high"? The development of reference points for "high" and "low"

Young children have been characterized as interpreting relative adjectives as if they were nominal or categorical terms. The categorical interpretation of relative terms, however, may be quite complex. Indeed, the mature understanding of relative terms would seem to include a complex system of reference points for the terms' categorical usages. In 5 experiments we examined the complexity of 3-5-year-old children's and adults' categorical interpretations. We specifically examined how reference points for the categorical interpretation of high and low are defined. The definition of reference points relative to the object judged, the vertical position of the observer, and the extent of vertical variation were assessed. 3 major developmental trends were observed: a trend from the application of the terms to only extreme values to their application to broader categories; a trend from nominal-like categories to ones defined flexibly relative to context (e.g., nature of object judged, and extent of vertical variation); and a trend from reference points functioning as focal points to their operating as directional category boundaries. In brief, the results suggest that the categorical usage of relative terms involves a rich and intricate knowledge system and that it takes children considerable time to acquire and organize the relevant pieces of knowledge.     

Categories of Environmental Print: All Logos are Not Created Equal

The purpose of this research was to investigate whether different kinds of environmental print logos were known more frequently by young children than other kinds. Sixty-one 3-, 4-, and 5-year-olds were assessed on 20 full-context color pictures of environmental print logos. These 20 logos were divided into three categories: community (signs prevalent in the local community; e.g., McDonald’s, Kroger), household (items found in many American homes: e.g., Doritos, Crest), and child (items associated with children rather than adults; e.g., Toy Story 2, Lego). Chi-squares were run to determine whether, as hypothesized, the child logos would be better known than the community and household logos within: (1) the whole sample, (2) each of the three age groups, and (3) both genders. As expected, child logos were the best known by all age groups and both boys and girls. However, the differences between the three categories were not significant for the 3-year-olds. This paper concludes with advice to teachers of young children on how to use child related environmental print logos in their classrooms.