We examine the long-standing claim that understanding relational correspondence is a general component of representational understanding. Two experiments with 175 preschool children located in Norwich, United Kingdom, examined the use of a scale model comparing performances on a "copy" task, measuring abstract spatial arrangement…

Children display an early sensitivity to implicit proportions (e.g., 1 of 5 apples vs. 3 of 4 apples), but have considerable difficulty in learning the explicit, symbolic proportions denoted by fractions (e.g., "1/5" vs. "3/4"). Theoretically, reducing the gap between representations of implicit versus explicit proportions…

Defining developmental progressions can be an important step in identifying developmental precursors and mechanisms of change, within and across areas of reasoning. In one exploratory study, we examine whether the development of children's thinking about ownership follows a systematic progression wherein some components emerge reliably before…

Young children often struggle to answer the question "what would have happened?" particularly in cases where the adult-like "correct" answer has the same outcome as the event that actually occurred. Previous work has assumed that children fail because they cannot engage in accurate counterfactual simulations. Children have…

Moral pride is a key component of virtue development. This study provides developmental insight into children's moral pride across cultures, and the potential for moral pride to underlie prosocial behavior. Participants included children and adolescents ages 6, 9, and 12 years from Canada (n = 186; 50% girls; ethnically diverse sample), Japan (n =…

Two studies examined the process and aftermath of coming to disbelieve in the myth of Santa Claus. In Study 1, 48 children ages 6-15 answered questions about how they discovered Santa was not real and how the discovery made them feel, and 44 of their parents shared their perspectives and how they promoted Santa. In Study 2, 383 adults reflected on…

How does a person make decisions across perceptual boundaries? Here, we test the account that confidence constitutes a common currency for perceptual decisions even in childhood by examining whether confidence can be compared across distinct perceptual dimensions. We conducted a strict test of domain-generality in confidence reasoning by asking 6-…

Fractions are a challenging mathematics topic for many elementary and middle school students, and even for adults. However, a growing body of developmental research suggests that young children can reason about visually presented proportions, well before fraction instruction, providing insight into how fractions might be introduced to improve…

When faced with entities with potentially ambiguous category membership, adult category judgments are strongly biased toward dangerous and distinctive properties. For example, a cyanide-water mixture is categorized as cyanide. We used a developmental approach to better understand this cross-domain effect, which we term the asymmetric…

Upon hearing a novel label, listeners tend to assume that it refers to a novel, rather than a familiar object. While this disambiguation or mutual exclusivity (ME) effect has been robustly shown across development, it is unclear what it involves. Do listeners use their pragmatic and lexical knowledge to exclude the familiar object and thus select…

To examine whether children's acquisition of perspective-marking language supports development in their ability to reason about mental states, we conducted a longitudinal study testing whether proficiency with complement clauses around age 3 explained variance in false-belief reasoning 6 months later. Forty-five English-speaking 2- and 3-year-olds…

This study examined how children's and adolescents' beliefs about the distribution of wealth in society and the fairness of economic systems informed their behavior, judgments, and reasoning about access to opportunities among peers. The sample included 136 8- to 14-year-olds (47% girls, 60% White, majority middle- to higher-socioeconomic status…

To acquire social conventional knowledge, children must distinguish between behaviors that are practiced by groups of people versus those that are practiced by individuals. How do children infer the scope (i.e., level of generality) of social behavior? Prior work has addressed this question by focusing on the cues or instruction that adults…

Participants ranging in age from 3 to 98 years (N = 708; approximately 60% female; 49% Caucasian, 38% Asian; 12% Other ethnicities, 1% Indigenous; modal household income > $80,000) completed a battery of tasks involving verbal ability, executive function, and perspective-taking. Wherever possible, all participants completed the same version of…

We examined the influence of prior expectations on 4- to 10-year-olds' and adults' preferences and emotions following an undesirable outcome (N = 205; 49% female, 51% male; 6% Asian, 1% Black, 13% Hispanic/Latino [non-White], 57% White, 18% multiracial, and 5% another race/ethnicity; 75% with a college-educated parent). Participants attempted to…