Susan A. Gelman

The essential child : origins of essentialism in everyday thought

PART I: THE PHENOMENA PART II: MECHANISMS OF ACQUISITION PART III: IMPLICATIONS AND SPECULATIONS

Categories and induction in young children.

Abstract One of the primary functions of natural kind terms (e.g., tiger, gold) is to support inductive inferences. People expect members of such categories to share important, unforeseen properties, such as internal organs and genetic structure. Moreover, inductions can be made without perceptual support: even when an object does not look much like other members of its category, and even when a property is unobservable. The present work addresses how expectations about natural kinds originate. Young children, with their usual reliance on perceptual appearances and only rudimentary scientific knowledge, might not induce new information within natural kind categories. To test this possibility, category membership was pitted against perceptual similarity in an induction task. For example, children had to decide whether a shark is more likely to breathe as a tropical fish does because both are fish, or as a dolphin does because they look alike. By at least age 4, children can use categories to support inductive inferences even when category membership conflicts with appearances. Moreover, these young children have partially separated out properties that support induction within a category (e.g., means of breathing) from those that are in fact determined by perceptual appearances (such as weight). Since we examined only natural kind categories, we do not know to what extent children have differentiated natural kinds from other sorts of categories. Children may start out assuming that categories named by language have the structure of natural kinds and with development refine these expectations.

Insides and essences: Early understandings of the non-obvious

Insides and essences are both critical concepts for appreciating the importance of non-obvious entities: neither are observable, both contrast with external appearances, and both can be more important than external appearances. The present research examined understandings of insides and essences in 3- to 5-year-old children. In Study 1, children were asked questions requiring them to think about both the insides and the outer appearances of a series of objects. In Study 2, children were tested on their understanding that insides are typically more important than outer surfaces for an objects identity and functioning. In Studies 3, 4, and 5, children were tested on their understanding of innate potential, a concept that reflects understanding of an inborn essence. Contrary to the traditional view of children as externalists (cf. Piaget, 1951), these studies demonstrate that by age 4 children have a firm grasp of the importance of both insides and essences. Even by age 3 children reason clearly about the inside-outside distinction. These results suggest that preschool children attend to non-obvious features and realize their privileged status. They may also indicate a more basic predisposition toward psychological essentialism in young children.

Domain-specific knowledge and conceptual change

Overview We argue that human reasoning is guided by a collection of innate domain-specific systems of knowledge. Each system is characterized by a set of core principles that define the entities covered by the domain and support reasoning about those entities. Learning, on this view, consists of an enrichment of the core principles, plus their entrenchment, along with the entrenchment of the ontology they determine. In these domains, then, we would expect cross-cultural universality: cognitive universals akin to language universals. However, there is one crucial disanalogy to language. The history of science and mathematics demonstrates that conceptual change in cognitive domains is both possible and actual. Conceptual change involves overriding core principles, creating new principles, and creating new ontological types. We sketch one potential mechanism underlying conceptual change and motivate a central empirical problem for cognitive anthropology: To what extent is there cross-cultural universality in the domains covered by innate systems of knowledge? Domain-specific cognition The notion of domain-specific cognition to be pursued here is articulated most clearly by Chomsky (1980a). Humans are endowed with domainspecific systems of knowledge such as knowledge of language, knowledge of physical objects, and knowledge of number. Each system of knowledge applies to a distinct set of entities and phenomena. For example, knowledge of language applies to sentences and their constituents; knowledge of physical objects applies to macroscopic material bodies and their behavior; knowledge of number applies to sets and to mathematical operations such as addition. More deeply, each system of knowledge is organized around a distinct body of core principles.

The development of induction within natural kind and artifact categories

Abstract Recent studies have shown that children as young as age 3 1 2 use category membership as the basis of their inductive inferences. The present studies examine how children determine which category-based inductive inferences are warranted and which are unwarranted. Preschool and elementary school children learned various facts (e.g., “This apple has pectin inside”) and reported whether they thought the facts generalized to other items varying in similarity to the target (e.g., other apples, a banana, and a stereo). Categories included both natural kinds and artifacts and varied as to how similar category members were to one another (category homogeneity, as rated by adults). Results indicate that even the youngest children placed certain constraints on their inferences. However, the preschoolers made few principled distinctions among categories, basing their inferences primarily on category homogeneity. In contrast, older children made several distinctions that seemed based on domain-specific knowledge. Most importantly, they drew more inferences within natural kinds than within artifact categories, at times even overextending the distinction. Comparison with other research suggests that increasing scientific knowledge exerts powerful effects on patterns of induction within basic-level categories.

The Importance of Knowing a Dodo Is a Bird: Categories and Inferences in 2-Year-Old Children

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Are Ethnic Groups Biological “Species” to the Human Brain?: Essentialism in Our Cognition of Some Social Categories

If ethnic actors represent ethnic groups as essentialized natural groups despite the fact that ethnic essences do not exist, one must understand why. The A. presents a hypothesis and evidence that humans process ethnic groups (and a few other related social categories) as if they were species because their surface similarities to species make them inputs to the living-kinds mental module that initially evolved to process species-level categories. The main similarities responsible are (i) category-based endogamy and (2) descent-based membership. Evolution encouraged this because processing ethnic groups as species - at least in the ancestral environment - solved adaptive problems having to do with interactional discriminations and behavioral prediction. Coethnics (like conspecifics) share many strongly intercorrelated properties that are not obvious on first inspection. Since interaction with out-group members is costly because of coordination failure due to different norms between ethnic groups, thinking of ethnic groups as species adaptively promotes interactional discriminations towards the in-group (including endogamy). It also promotes inductive generalizations, which allow acquisition of reliable knowledge for behavioral prediction without too much costly interaction with out-group members. The relevant cognitive-science literature is reviewed, and cognitive field-experiment and ethnographic evidence from Mongolia is advanced to support the hypothesis.

PUTTING THE NOUN BIAS IN CONTEXT : A COMPARISON OF ENGLISH AND MANDARIN

Recently, researchers have been debating whether children exhibit a universal “noun bias” when learning a first language. The present study compares the proportions of nouns and verbs in the early vocabularies of 24 English- and 24 Mandarin-speaking toddlers ( M age 5 20 months) and their mothers. Three different methods were used to measure the proportion of noun types, relative to verb types: controlled observations in three contexts (book reading, mechanical toy play, regular toy play), identical across languages; a vocabulary checklist (MacArthur Communicative Development Inventory); and mothers’ reporting of their children’s “first words.” Across all measures, Mandarin-speaking children were found to have relatively fewer nouns and more verbs than English-speaking children. However, context itself played an important role in the proportions of nouns found in children’s vocabularies, such that, regardless of the language spoken, children’s vocabularies appeared dominated by nouns when they were engaged in book reading, but not when they were playing with toys. Mothers’ speech to children showed the same language differences (relatively more verbs in Mandarin), although both Mandarin- and English-speaking mothers produced relatively more verbs than their children. In sum, whether or not language-learning toddlers demonstrate a “noun bias” depends on a variety of factors, including the methods by which their vocabularies are sampled and the contexts in which observations occur.

Learning from others: children's construction of concepts.

Much of childrens 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 childrens 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.

Carrot-Eaters and Creature-Believers: The Effects of Lexicalization on Children's Inferences About Social Categories

This article examines how language affects childrens inferences about novel social categories. We hypothesized that lexicalization (using a noun label to refer to someone who possesses a certain property) would influence childrens inferences about other people. Specifically, we hypothesized that when a property is lexicalized, it is thought to be more stable over time and over contexts. One hundred fifteen children (5- and 7-year-olds) learned about a characteristic of a hypothetical person (e.g., “Rose eats a lot of carrots”). Half the children were told a noun label for each character (e.g., “She is a carrot-eater”), whereas half heard a verbal predicate (e.g., “She eats carrots whenever she can”). The children judged characteristics as significantly more stable over time and over contexts when the characteristics were referred to by a noun than when they were referred to by a verbal predicate. Lexicalization (in the form of a noun) provides important information to children regarding the stability of personal characteristics.