Categories convey prescriptive information across domains and development

Testimony and observation of statistical evidence interact in adults' and children's category-based induction

Hearing generic or other kind-relevant claims can influence the use of information from direct observations in category learning. In the current study, we ask how both adults and children integrate their observations with testimony when learning about the causal property of a novel category. Participants were randomly assigned to hear one of four types of testimony: generic, quantified "all", specific, or only labels. In Study 1, adults (N = 1249) then observed that some proportion of objects (10%-100%) possessed a causal property. In Study 2, children (N = 123, Mage = 5.06 years, SD = 0.61 years, range 4.01-5.99 years) observed a sample where 30% of the objects had the causal property. Generic and quantified "all" claims led both adults and children to generalize the causal property beyond what was observed. Adults and children diverged, however, in their overall trust in testimony that could be verified by observations: adults were more skeptical of inaccurate quantified claims, whereas children were more accepting. Additional memory probes suggest that children's trust in unverified claims may have been due to misremembering what they saw in favor of what they heard. The current findings demonstrate that both child and adult learners integrate information from both sources, offering insights into the mechanisms by which language frames first-hand experience.

Norm Dynamics: Interdisciplinary Perspectives on Social Norm Emergence, Persistence, and Change

Social norms are the glue that holds society together, yet our knowledge of them remains heavily intellectually siloed. This article provides an interdisciplinary review of the emerging field of norm dynamics by integrating research across the social sciences through a cultural-evolutionary lens. After reviewing key distinctions in theory and method, we discuss research on norm psychology-the neural and cognitive underpinnings of social norm learning and acquisition. We then overview how norms emerge and spread through intergenerational transmission, social networks, and group-level ecological and historical factors. Next, we discuss multilevel factors that lead norms to persist, change, or erode over time. We also consider cultural mismatches that can arise when a changing environment leads once-beneficial norms to become maladaptive. Finally, we discuss potential future research directions and the implications of norm dynamics for theory and policy.

Rethinking Norm Psychology

Norms permeate human life. Most of people's activities can be characterized by rules about what is appropriate, allowed, required, or forbidden-rules that are crucial in making people hyper-cooperative animals. In this article, I examine the current cognitive-evolutionary account of "norm psychology" and propose an alternative that is better supported by evidence and better placed to promote interdisciplinary dialogue. The incumbent theory focuses on rules and claims that humans genetically inherit cognitive and motivational mechanisms specialized for processing these rules. The cultural-evolutionary alternative defines normativity in relation to behavior-compliance, enforcement, and commentary-and suggests that it depends on implicit and explicit processes. The implicit processes are genetically inherited and domain-general; rather than being specialized for normativity, they do many jobs in many species. The explicit processes are culturally inherited and domain-specific; they are constructed from mentalizing and reasoning by social interaction in childhood. The cultural-evolutionary, or "cognitive gadget," perspective suggests that people alive today-parents, educators, elders, politicians, lawyers-have more responsibility for sustaining normativity than the nativist view implies. People's actions not only shape and transmit the rules, but they also create in each new generation mental processes that can grasp the rules and put them into action.

Speaking of Kinds: How Correcting Generic Statements can Shape Children's Concepts

Generic language (e.g., "tigers have stripes") leads children to assume that the referenced category (e.g., tigers) is inductively informative and provides a causal explanation for the behavior of individual members. In two preregistered studies with 4- to 7-year-old children (N = 497), we considered the mechanisms underlying these effects by testing how correcting generics might affect the development of these beliefs about novel social and animal kinds (Study 1) and about gender (Study 2). Correcting generics by narrowing their scope to a single individual limited beliefs that the referenced categories could explain what their members would be like while broadening the scope to a superordinate category (Study 2) uniquely limited endorsement of gender norms. Across both studies, correcting generics did not alter beliefs about feature heritability and had mixed effects on inductive inferences, suggesting that additional mechanisms (e.g., causal reasoning about shared features) contribute to the development of full-blown essentialist beliefs. These results help illuminate the mechanisms by which generics lead children to view categories as having rich inductive and causal potential; in particular, they suggest that children interpret generics as signals that speakers in their community view the referenced categories as meaningful kinds that support generalization. The findings also point the way to concrete suggestions for how adults can effectively correct problematic generics (e.g., gender stereotypes) that children may hear in daily life.

How "is" shapes "ought" for folk-biological concepts

Knowing which features are frequent among a biological kind (e.g., that most zebras have stripes) shapes people's representations of what category members are like (e.g., that typical zebras have stripes) and normative judgments about what they ought to be like (e.g., that zebras should have stripes). In the current work, we ask if people's inclination to explain why features are frequent is a key mechanism through which what "is" shapes beliefs about what "ought" to be. Across four studies (N = 591), we find that frequent features are often explained by appeal to feature function (e.g., that stripes are for camouflage), that functional explanations in turn shape judgments of typicality, and that functional explanations and typicality both predict normative judgments that category members ought to have functional features. We also identify the causal assumptions that license inferences from feature frequency and function, as well as the nature of the normative inferences that are drawn: by specifying an instrumental goal (e.g., camouflage), functional explanations establish a basis for normative evaluation. These findings shed light on how and why our representations of how the natural world is shape our judgments of how it ought to be.

Stereotypes as prototypes in children's gender concepts

How do gender stereotypes shape prototypes across development? In the current pre-registered study with children ages 3- to 10-years-old and adults (N = 257), participants made judgements about which members of gender categories (boys and girls) and animal categories (for comparison) were the most representative and informative about their kinds, using simplified scales of five category members varying on a stereotypical feature (e.g., girls wearing more or less pink). Young children chose boys and girls with extreme stereotypical features (e.g., the girl in head-to-toe pink) as both representative and informative of their categories and this tendency declined with age, similar to developmental patterns in prototypes of animal categories. Controlling for age, children whose parents reported more conservative social-political views also held more extreme gender (but not animal) prototypes. Thus, stereotypes play a central role in children's gender prototypes, especially young children and those living in socially-conservative households. RESEARCH HIGHLIGHTS: Stereotypes play a central role in children's gender prototypes, especially young children and those in socially-conservative households. Children ages 3-10 and adults chose which girls, boys, and animals were most representative and informative. Younger children chose category members with more extreme stereotypical features (e.g., the girl in head-to-toe pink) than older children and adults. Children with more conservative parents also held more extreme gender prototypes.

How cues to social categorization impact children's inferences about social categories

Social categorization involves two crucial processes: First, children seek properties on which they can categorize individuals, i.e., they learn to form social categories; then children make inferences based on social category membership and might develop affective responses toward social categories. Over the last decade, a growing number of research in developmental psychology started to use novel social categories to investigate how children learn and reason about social categories. To date, three types of cues have been put forward as means to form social categories, namely linguistic, visual, and behavioral cues. Based on social category membership, children draw inferences about the shared properties of social category members and about how social category members ought to behave and interact with each other. With additional input, children might apply essentialist beliefs to social categories and develop affective responses toward social categories. This article aims to provide key insights on the development of stereotypes and intergroup biases by reviewing recent works that investigated how children learn to form novel social categories and the kind of inferences they make about these novel social categories.