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…

Behavioral research demonstrates a critical transition in preschooler's mental-state understanding (i.e., theory of mind; ToM), revealed most starkly in performance on tasks about a character's false belief (e.g., about an object's location). Questions remain regarding the neural and cognitive processes differentiating children who pass versus…

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 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…

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…

Studies of hemispheric specialization have traditionally cast the left hemisphere as specialized for language and the right hemisphere for spatial function. Much of the supporting evidence for this separation of function comes from studies of healthy adults and those who have sustained lesions to the right or left hemisphere. However, we know…

We introduce a novel method to test a classic idea in developmental science that children's attention to a stimulus is driven by how much they can learn from it. Preschoolers (4-6 years, M=4.6) watched a video where a distracting animation accompanied static, page-by-page illustrations of a storybook. The audio narration for each storybook page…

There are long-held concerns regarding the impact of screen media on children's cognitive development. In particular, fast pace and fantastical events have been theorized to deplete children's cognitive resources, leading to reductions in their attention and executive functions (EF). To date, however, empirical tests of short-term effects of media…

Symbolic numeracy first emerges as children learn the meanings of number words and how to use them to precisely count sets of objects. This development starts before children enter school and forms a foundation for lifelong mathematics achievement. Despite its importance, exactly how children acquire this basic knowledge is unclear. Here we test…

Although exploratory play is considered a hallmark of cognitive development and learning, relatively few studies have been able to quantitatively characterize the shifts that may occur in children's approach to exploration. One reason for this gap is due to challenges coding and analyzing children's exploratory play behavior. In our paper, we…

Reading disorders are common in children and can impact academic success, mental health, and career prospects. Reading is supported by network of interconnected left hemisphere brain regions, including temporo-parietal, occipito-temporal, and inferior-frontal circuits. Poor readers often show hypoactivation and reduced gray matter volumes in this…

Increased focus on resting-state functional connectivity (rsFC) and the use and accessibility of functional near-infrared spectroscopy (fNIRS) have advanced knowledge on the interconnected nature of neural substrates underlying executive function (EF) development in adults and clinical populations. Less is known about the relationship between rsFC…

Although most U. S. children can accurately count sets by 4 years of age, many fail to understand the structural analogy between counting and number -- that adding 1 to a set corresponds to counting up 1 word in the count list. While children are theorized to establish this Structure Mapping coincident with learning how counting is used to…

In uncertain situations, individuals rely on prior experiences of successes and failures to guide future decisions. Research has shown that children exposed to early adversity, such as abuse, can exhibit atypical behaviours in probabilistic learning tasks compared to peers without such experiences, which may have long-term behavioural…

The neural representation of visual-spatial functions has traditionally been ascribed to the right hemisphere, but little is known about these representations in children, including whether and how lateralization of function changes over the course of development. Some studies suggest bilateral activation early in life that develops toward…