Young children tend to deny the possibility of events that violate their expectations, including events that are merely improbable, like making onion-flavored ice cream or owning a crocodile as a pet. Could this tendency be countered by teaching children more valid strategies for judging possibility? We explored this question by training children…

Friends are a vital source of social relations throughout the lifespan and across developmental stages. Our knowledge of how friendships develop over time, especially from childhood through adulthood, is limited. Furthermore, it is now recognized that this specific type of relationship influences health across the life course in unique ways. Using…

Learning requires effort, but children cannot try hard at everything. Here, we evaluated whether children use their improvement over time to decide whether to stick with a challenge. To eliminate the effect of individual differences in ability or prior knowledge, we created a novel paradigm that allowed us to surreptitiously control children's…

Humans appear to intuitively grasp definitions foundational to formal geometry, like definitions that describe points as infinitely small and lines as infinitely long. Nevertheless, previous studies exploring human's intuitive natural geometry have consistently focused on geometric principles in planar Euclidean contexts and thus may not…

People who are in close relationships tend to do and like the same things, a phenomenon termed the "homophily principle." The present research probed for evidence of the homophily principle in 4- to 6-year-old children. Across two experiments, participants (N = 327; 166 girls, 161 boys; located in the Midwestern United States) were asked…

Gender-stereotyped beliefs develop early in childhood and are thought to increase with age based on prior research that was primarily carried out in Western cultures. Little research, however, has examined cross-cultural (in)consistencies in the developmental trajectory of gender-stereotyped beliefs. The present study examined implicit gender-toy…

The study investigated age-related trends in moral identity goal characteristics, as proposed in previous research (Krettenauer, 2022a), by modifying the Self-Importance of Moral Identity Questionnaire (Aquino & Reed, 2002). Internally and externally motivated moral identity was assessed on varying levels of abstractness for promotion…

Proactive interference (PI) occurs when previously learned memories compete with currently relevant information. Despite extensive literature investigating the effect in adults, little work has been done in young children. In three preregistered studies (N = 38, 35, 172; convenience samples from the Northeastern United States), first, we showed…

Children show less positivity toward gender-nonconforming (GN) than gender-conforming (GC) peers. Yet, little is known about children's reasoning about peers of varying gender expressions, including age-, gender-, and culture-related influences. We investigated how children aged 4- to 5- and 8- to 9-years-old in Hong Kong and Canada (N = 678)…

Gender and age are salient social categories from early in development. However, whether children's beliefs about gender and age intersect, such that gender stereotypes might be expressed differently when asked about children (compared to adults) has not been investigated. Here, in a preregistered study (N = 297), we examined if young children…

Third-party punishment has been regarded as an important mechanism to promote fairness. Although previous research has shown that children aged 6 and older punish unfair behaviors at a personal cost, it is unknown whether they actually intend to establish equality or whether equality is a mere byproduct of punishment. In this preregistered study,…

Existing research focused on social role destabilization (historical increases in role instability) and destandardization (historical increases in variability of role instability) has primarily focused on discrete social roles during discrete periods of development. Building on this work, we applied a macro approach to elucidate the extent to…

In pursuing goals, people seek favorable odds. We investigated whether young children use this fact to infer goals from people's actions across two experiments on Canadian 3- to 7-year-old children (N = 316; 167 girls, 149 boys). Participants' demographic information was not formally collected, but the region is predominantly middle-class and…

This study examined age-related patterns in exposure and affective reactivity to daily stressors across a 20-year time span among adults who were between 22 and 77 years old at their baseline interview. Longitudinal data from the National Study of Daily Experiences (NSDE) consisted of three bursts of eight consecutive nightly interviews of stress…

Sensitivity to auditory rhythmic structures in music and language is evident as early as infancy, but performance on beat perception tasks is often well below adult levels and improves gradually with age. While some research has suggested the ability to perceive musical beat develops early, even in infancy, it remains unclear whether adult-like…