Susan Gelman

Three studies examined the co‐existence of natural and supernatural explanations for illness and disease transmission, from a developmental perspective. The participants (5‐, 7‐, 11‐, and 15‐year‐olds and adults; N = 366) were drawn from 2 Sesotho‐speaking South African communities, where Western biomedical and traditional healing frameworks were both available. Results indicated that, although biological explanations for illness were endorsed at high levels, witchcraft was also often endorsed. More important, bewitchment explanations were neither the result of ignorance nor replaced by biological explanations. Instead, both natural and supernatural explanations were used to explain the same phenomena, and bewitchment explanations were highest among adults. Taken together, these data provide insight into how diverse, culturally constructed belief systems about illness co‐exist across development.

This chapter examines associationist models of cognitive development, focusing on the development of naming in young children — the process by which young children learn of construct the meanings of words and concepts. It presents two early-emerging insights that children possess about the nature of naming. These insights are: essentialism: certain words map onto nonobvious, underlying causal features, and genericity: certain expressions map onto generic kinds as opposed to particular instances. The chapter discusses empirical studies with preschool children to support the contention that essentialism and genericity emerge early in development and that neither insight is directly taught. It also explores the question of whether these insights can be derived wholly from a direct reading of cues that are ‘out there’in the world, and concludes that they cannot. The implications of these findings for innateness are then considered. It is argued that both essentialism and genericity provide cues regarding plausible candidates for innate conceptual knowledge in children.

Much evidence suggests that, from a young age, humans are able to generalize information learned about a subset of a category to the category itself. Here, we propose that—beyond simply being able to perform such generalizations—people are biased to generalize to categories, such that they routinely make spontaneous, implicit category generalizations from information that licenses such generalizations. To demonstrate the existence of this bias, we asked participants to perform a task in which category generalizations would distract from the main goal of the task, leading to a characteristic pattern of errors. Specifically, participants were asked to memorize two types of novel facts: quantified facts about sets of kind members and generic facts about entire kinds. Moreover, half of the facts concerned properties that are typically generalizable to an animal kind, and half concerned properties that are typically more idiosyncratic. We predicted that—because of the hypothesized bias—participants would spontaneously generalize the quantified facts to the corresponding kinds, and would do so more frequently for the facts about generalizable properties. In turn, these generalizations would lead to a higher rate of quantified-to-generic memory errors for the generalizable properties. The results of four experiments supported this prediction. Moreover, the same generalizable-versus-idiosyncratic difference in memory errors occurred even under cognitive load, which suggests that the hypothesized bias operates unnoticed in the background, requiring few cognitive resources. In sum, this evidence suggests the presence of a powerful bias to draw generalizations about kinds

Generic statements (e.g., “Birds lay eggs”) express generalizations about categories. In this paper, we hypothesized that there is a paradoxical asymmetry at the core of generic meaning, such that these sentences have extremely strong implications but require little evidence to be judged true. Four experiments confirmed the hypothesized asymmetry: Participants interpreted novel generics such as “Lorches have purple feathers” as referring to nearly all lorches, but they judged the same novel generics to be true given a wide range of prevalence levels (e.g., even when only 10% or 30% of lorches had purple feathers). A second hypothesis, also confirmed by the results, was that novel generic sentences about dangerous or distinctive properties would be more acceptable than generic sentences that were similar but did not have these connotations. In addition to clarifying important aspects of generics’ meaning, these findings are applicable to a range of real-world processes such as stereotyping and political discourse.