Why Dogs Have Puppies and Cats Have Kittens: The Role of Birth in Young Children's Understanding of Biological Origins

Abstract

Three studies examined young children's understanding of the biologically causal role of birth in determining animal properties and species kind identity. In Studies 1 and 2, 4- to 7-year-olds and adults were told stories in which a baby was born to an animal of one species (e.g., a horse) but was adopted and raised by an animal of another species (e.g., a cow). In Study 1, children were asked to judge which parent the baby would resemble on a set of physical properties and beliefs. The majority of children were unable to say that the baby would resemble the birth parent on physical properties but share the beliefs of the adoptive parent. These results indicate that children were not using domain-specific causal understandings to reason about the origins of these properties. In Study 2, however, when asked to explicitly predict the kind of the baby, even 5-year-olds were able to reliably judge that the baby would be of the same species kind as the birth parent rather than the adoptive parent. This result suggests that children do understand at some level that birth determines species kind. Study 3 examined further the extent to which knowledge about birth influenced children's inferences about properties. Five-year-olds were asked to judge whether a baby would share a set of physical and nonphysical properties with its mother or its father. The results showed that children who knew the factual information about where babies come from (i.e., inside mommies' tummies) were more likely to attribute the mother's properties to the baby than the father's, regardless of whether the properties were physical or nonphysical. But this finding was true only if the property of one of the parents was not inherently more desirable or true than that of the other parent. In sum, the results of these 3 studies indicate that knowledge of birth does play a role in children's inferential reasoning, even for 5-year-olds, but that that role is not domain-specific. The implications for children's understanding of biological inheritance are discussed.

Representation of Principled Connections: A Window Onto the Formal Aspect of Common Sense Conception

“…The results of the present experiments provide further support for this mode of explanation. They also further clarify the ways in which the formal mode of explanation differs from other modes of explanation that have been studied in previous research (e.g., Carey, 1985;Gelman, 1990;Gelman and Bloom, 2007;Gelman & Wellman, 1991;German & Johnson, 2002;German et al, 2004;Gergely et al, 1995;Gopnik & Meltzoff, 1997;Inagaki & Hatano, 2002;Johnson & Solomon, 1997;Keil, 1989Keil, , 1994Kelemen, 1999;Lombrozo & Carey, 2006;Opfer & Gelman, 2001;Springer & Keil, 1991, among many others). The results of Experiments 1-4 suggest that principled connections license formal explanations because we represent k-properties as aspects of being a given kind of thing and thus are able to use the part-whole principle to explain the presence of a k-property in an instance of the kind by reference to the kind of thing it is.…”

“…Previous research within this approach has found that our conceptual systems exploit causal-essential, teleological, and intentional modes of explanation (e.g., Carey, 1985;Gelman, 1990;Gelman & Bloom, 2007;Gelman & Wellman, 1991;German & Johnson, 2002;German, Niehaus, Roarty, Giesbrecht, & Miller, 2004;Gergely, Nadasdy, Csibra, & Biro, 1995;Gopnik & Meltzoff, 1997;Inagaki & Hatano, 2002;Johnson & Solomon, 1997;Keil, 1989Keil, , 1994Kelemen, 1999;Lombrozo & Carey, 2006;Opfer & Gelman, 2001;Springer & Keil, 1991; among many others). These modes of explanation differ with respect to both their explanatory principles as well as their domains of application (Keil, 1994).…”

Essentialism and Folkbiology: Evidence from Brazil

“…The adoption paradigm has been one of the main sources of evidence in the debate between these two opposing views (see, e.g., Astuti 2001, Block et al 2001, Solomon et al 1996Johnson & Solomon 1997, Springer 1996. This experimental task is a story about a baby reared exclusively by adoptive parents -i.e., without ever having any contact with its birth parents after the adoption -, and an inquiry whether the grow-up baby would resemble its birth parents or its adoptive parents.…”

“…According to one view, by ages 4 and 5, children have already acquired systematic folkbiological knowledge, which may be the result of an innate propensity to conceptualize living kinds in speci c ways (see Atran et al 2001;Atran 1987Atran , 1990Keil 1989;Gelman & Wellman 1991;Hatano & Inagaki 1994;Springer 1995Springer , 1996. The alternative view contends that only after age 7 do children start to elaborate a folk framework with a speci c conception of biological causality (see Carey 1985Carey , 1995Carey & Spelke 1994;Johnson & Solomon 1997;Johnson & Carey 1998, Solomon et al 1996.…”

Classification as diagnostic reasoning

“…However, unlike our underlying features, truly essential features are also viewed as immutable and having innate origins; indeed, essential properties are ones that are present in all category members that could exist (Gelman, 2003). And, although adults may have concrete beliefs about essences (e.g., DNA functions as the essence for biological kinds for many Western-educated adults), preschool children's knowledge about animals' essential properties is less specific, perhaps consisting of only a placeholder-that is, a commitment to the existence of internal biological mechanisms without any notion of what those mechanisms might be (Gelman & Wellman, 1991;Johnson & Solomon, 1997;Medin & Ortony, 1989). But despite these differences, we suggest that an underlying feature that is inferred from observable ones can affect classification regardless of whether it is defining, truly essential, or only strongly associated with the category.…”