Unlike adults, young children think that many weird and unlikely events are impossible. Existing theories have argued that this developmental shift is driven primarily by age-related changes in knowledge as well as an increasing ability to reflect on one's modal intuitions. However, this intuition + reflection model fails to explain…

The standard view on Theory of Mind (ToM) is that the mastery of the false belief (FB) task around age 4 marks the ontogenetic emergence of full-fledged meta-representational ToM. Recently, a puzzling finding has emerged: Once children master the FB task, they begin to fail true belief (TB) control tasks. This finding threatens the validity of FB…

Children often say that possible events are impossible, and only gradually come to see these events as possible. For instance, they often deny that people could do unusual things, like own a pet peacock, or immoral things, like stealing or lying. These possibility denials are surprising. For instance, children have first-hand experience with the…

Previous research on children's knowledge about the mind has primarily focused on their comprehension of false beliefs, leaving the conceptualization of thoughts and thinking less explored. To address this gap, we developed a new assessment tool, the interview about the mind (IaM), to assess children's understanding of the mind. Two studies…

Theory of mind (ToM) is the ability to attribute mental states and feelings to others, and to understand that those mental states and feelings affect their behaviour. It is one of three core developmental tasks for children in preschool years, along with emotion self-regulation and relationships with parents and family members. Given there are…

Previous research suggests that book reading and screen time have contrasting effects on language and brain development. However, few studies have explicitly investigated whether children's brains function differently during these two activities. The present study used functional near-infrared spectroscopy (fNIRS) to measure brain response in 28…

The host of the internationally popular early childhood podcast "That Early Childhood Nerd" provides a framework for understanding the importance of free play. Free play is disappearing from the lives of too many young children, leaving them vulnerable to negative effects on their physical and mental health, social and emotional growth,…

Trajectories of cognitive and neural development suggest that, despite early emergence, the ability to extract environmental patterns changes across childhood. Here, 5- to 9-year-olds and adults (N = 211, 110 females, in a large Canadian city) completed a memory test assessing what they remembered after watching a stream of shape triplets: the…

The human capacity for rational decisions hinges on modal judgment: the discernment of what could, has to, or cannot happen. This ability was proposed to be a late outcome of human cognitive development, contingent on the mastery of linguistic structures. Here, we show that preschool-age children are capable of sophisticated forms of modal…

This study examined children's emotion attributions and moral judgements to hypothetical procedural justice outcomes when the candidates were equal in merit but different in need. Children (7 to 11 years old, N = 88) were presented with four vignettes depicting resource-rich and resource-poor candidates losing educational materials and…

Counterfactual emotions such as regret may aid future decision-making by encouraging people to focus on controllable features of personal past events. However, it remains unclear when children begin to preferentially focus on controllable features of such events. Across two studies, Australian 4-9-year-olds (N = 336, 168 females; data collected…

Aperiodic electroencephalography (EEG) activity is hypothesized to index biological mechanisms that underpin brain functioning. This longitudinal study characterized the developmental trajectories of the aperiodic slope (i.e., aperiodic exponent) and offset from infancy to 7 years of age in a US community sample (N = 391, 46.5% female,…

Working memory (WM) is a critical cognitive system that supports processing a variety of information. Remembering different types of objects may impose different levels of cognitive demands on WM performance. In the present study, we examined 205 children's WM in representing different types of content and its developmental trajectories in early…

Executive functions (EF) are crucial to regulating learning and are predictors of emerging mathematics. However, interventions that leverage EF to improve mathematics remain poorly understood. 193 four-year-olds (mean age = 3 years; 11 months pre-intervention; 111 female, 69% White) were assessed 5 months apart, with 103 children randomised to an…

Conversational turns are an important predictor of cognitive and language development, but little is known about their relationship with socioemotional development. In a previous study using LENA technology, Gómez and Strasser (2021) found that conversational turns assessed with 43 infants at 18 months predicted socioemotional competencies at 30…