ABSTRACT

Metacognitive reasoning is central to decision-making. For every decision, we can also judge our trust in that decision, or our level of confidence. The mechanisms and representations underlying reasoning about confidence remain debated. We test whether children rely on processing fluency to infer their own confidence: do decisions that come quickly and easily lead to high confidence, while decisions that are slow and effortful result in low confidence? Using children's verbal disfluency—fillers (e.g., “umm,” “uhh”), hedges (e.g., “I think,” “maybe”), and pauses in speech—as an observable index of processing fluency, we assess whether children's reports of confidence are a read-out of their verbal disfluency. Five-to-eight-year-olds answered semantic questions about animals and performed perceptual comparisons, then reported their confidence in their answers in a two-alternative forced-choice confidence judgment task. Verbal disfluency predicted both answer accuracy and children's reports of confidence: children produced more fillers, more hedges, and longer speech onsets during incorrect trials and during low confidence trials. But we also found a dissociation between fluency and confidence. When examining trials where accuracy and confidence diverge (i.e., correct but low confidence or incorrect but high confidence trials), we observe no reliable relationship between confidence and fillers and hedges, and children take longer to begin answering on high confidence trials. We conclude that—in 5–8-year-old-children—fluency is a reliable tracker of accuracy but not confidence, and that fluency is only predictive of metacognitive judgments in children when confidence and accuracy are aligned.

Developmental Science, Volume 28, Issue 3, May 2025.

Developmental Science, Volume 28, Issue 3, May 2025.

ABSTRACT

Children are more likely than adults to explore new options, but is this due to a top-down epistemic-uncertainty-driven process or a bottom-up novelty-driven process? Given immature cognitive control, children may choose a new option because they are more susceptible to the automatic attraction of perceptual novelty and have difficulty disengaging from it. This hypothesis is difficult to test because perceptual novelty is intertwined with epistemic uncertainty. To address this problem, we designed a new n-armed bandit task to fully decouple novelty and epistemic uncertainty. By having adults and 4- to 6-year-olds perform the task, we found that perceptual novelty predominated 4-year-olds’ (but not adults’ or older children's) decisions even when it had no epistemic uncertainty and had the lowest reward value. Additionally, 4-year-olds showed such a novelty preference only when the option's novelty was directly observable, but not when it could only be anticipated, providing new evidence that perceptual novelty alone can drive elevated exploration in early development in a bottom-up manner.

ABSTRACT

Numbers and letters are culturally created symbols that acquire meaning through extensive training, significantly influencing brain function. The distinct hemispheric specialization of cortical regions for these categories has been hypothesized to relate to the co-activated brain networks: the left language regions for letters, and the right intra-parietal sulcus for numbers. However, the potential influence of deafness and sign language on hemispheric specialization for letters and numbers remains unclear. The present study aims to explore this issue by using a FPVS-EEG approach with an oddball paradigm. Deaf and hearing children aged 8–13 were exposed to rapid streams of visual stimuli (6 Hz), with a deviant category introduced periodically (every 5 items; at 1.2 Hz) and eliciting a neural response in the frequency domain if discriminated from the base category. Here, digits are served as base stimuli and letters as oddball stimuli, and vice-versa. Our results suggest disparities in hemispheric lateralization for letters between deaf and hearing children, while neural responses to digits did not significantly vary between the two groups. Both groups exhibited right-lateralized responses to digits, which were stronger compared to responses to letters. Importantly, in deaf children, the neural response to letters was stronger in the right hemisphere, whereas hearing children displayed a bilateral response with a nonsignificant trend toward left lateralization. The important implications of these exploratory results, suggesting an early impact of sensory deprivation and/or sign language on the organization of the brain, are discussed.

Developmental Science, Volume 28, Issue 3, May 2025.

Developmental Science, Volume 28, Issue 2, March 2025.

ABSTRACT

Executive control (EC) emerges in the first year of life, with the ability to inhibit prepotent responses (inhibitory control [IC]) and to flexibly readapt (cognitive flexibility [CF]) steadily improving. Simultaneously, electrophysiological brain activity undergoes profound reconfiguration, which has been linked to individual variability in EC. However, most studies exploring this relationship have used relative/absolute power and tasks that combine different executive processes. In addition, brain activity conflates aperiodic and oscillatory activity, which hinders the interpretation of the relationship between power and cognition. In the current study, we used the Early Childhood Inhibitory Touchscreen Task (ECITT) to examine the development of EC skills from 9 to 16 months in a longitudinal sample, and related performance of the task to resting-state EEG (rs-EEG) power, separating oscillatory and aperiodic activity. Our results showed improvement in IC but not in CF with age. In addition, alpha and theta oscillatory activity were concurrent (9-mo.) and longitudinal predictors of CF in toddlerhood, whereas the aperiodic exponent of the EEG signal did not contribute to EC. These findings demonstrate the relevance of oscillatory brain activity for cognitive development and provide an early brain marker for the early development of EC.

We examined the development of resolution and vernier acuity in children with dense congenital cataracts who gained sight late in life as part of Project Prakash. Our data reveal marked longitudinal improvements in both acuity measures. Like the normally-sighted, late-sighted individuals’ vernier acuity also exceeds their resolution acuity, albeit to a lesser extent. Despite some postsurgical limitations, these findings point to the feasibility of forming integrative circuits in the visual cortex even when inputs are severely compromised for many years.

ABSTRACT

We possess a remarkably acute ability to detect even small misalignments between extended line segments. This “vernier acuity” significantly exceeds our “resolution acuity”—the ability to resolve closely separated stimuli—and is generally considered a “hyperacuity,” since the detectable misalignments are markedly finer than the diameter of single retinal cones. Vernier acuity has, thus, often been proposed to reflect spatial organization and multi-unit cortical processing, rendering it an important index of visual function. Notably, vernier acuity exhibits a characteristic developmental signature: it is inferior to resolution acuity early in life but eventually exceeds it by up to one order of magnitude. However, vernier acuity may be disproportionately sensitive to developmental disruptions. Here, we examined the resilience of acquiring this visual proficiency to early-onset, prolonged deprivation by longitudinally tracking vernier and resolution acuities in children with dense congenital cataracts who gained sight late in life as part of Project Prakash. Our data reveal marked longitudinal improvements in both acuity measures and also demonstrate that, like the normally-sighted, late-sighted individuals’ vernier acuity exceeds their resolution acuity, thereby rendering it a hyperacuity. However, the extent of this hyperacuity is weaker than observed in normally-sighted controls, pointing to partial limitations in postsurgical skill acquisition. Despite these constraints, our findings point to the feasibility of forming some integrative circuits in the visual system even when inputs are severely compromised, and to the availability of some residual plasticity late in childhood, with implications for the rehabilitation prospects of children following treatment for congenital cataracts.

ABSTRACT

Nonverbal behavior is a ubiquitous, everyday cue that is often used as a basis for social evaluation. Numerous studies indicate that children are sensitive to these signals and form evaluative judgments after viewing positive or negative nonverbal cues directed toward a target. Furthermore, they generalize these judgments to other members of a targets’ social group, indicating that nonverbal behavior displays can influence intergroup bias. However, no studies thus far have directly examined whether exposure to positive nonverbal behavior cues can reduce children's implicit and explicit racial bias. In the current study, we exposed White and Asian children ages 9–11 to positive nonverbal behavior displayed by a White expresser toward a Black target, drawn from children's television shows. Children demonstrated a pro-White/anti-Black bias implicitly, but explicitly preferred Black over White characters. Additionally, children judged Black characters from the clips and novel Black characters positively. We found that there was no difference in implicit or explicit racial bias between children who viewed positive nonverbal behavior demonstrated by a White expresser to a Black target as compared to children who were only exposed to a Black target (and no nonverbal cues) or unrelated video clips. Future research examining the influence of positive nonverbal behavior on children's racial bias should consider using more overt or prolonged demonstrations of positive nonverbal behavior or increasing children's familiarity with the characters presented.

ABSTRACT

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 typically developing preschool-aged children (36–72 months old) during two conditions—a book reading condition, in which children listened to a story read by a live experimenter while viewing words and pictures in a book, and a screen time condition, in which children listened to a story that was played via an audio recording while viewing words and pictures on a screen. Analyses revealed significant activation in the right temporal parietal junction (TPJ) during the book reading condition only. Across regions of interest (ROIs), including the inferior and middle frontal gyrus (IMFG), the superior and middle temporal gyrus (SMTG), and the TPJ, brain response during the book reading condition was greater in right-lateralized ROIs than left-lateralized ROIs, while brain response during the screen time condition was similar across left and right ROIs. Findings suggest that the lateralization of preschool-aged children's brain function within these ROIs differs during book reading and screen time, which provides a possible neurobiological explanation for why book reading and screen time impact language development in such different ways. Findings provide important insights into how children's brains function during different types of activities (dyadic vs. solitary) and when using different types of media (print vs. digital).

ABSTRACT

Addressing racial bias in early childhood is crucial for fostering inclusivity and reducing social inequalities. This study examined the effectiveness of individuation training in reducing racial bias among Canadian preschool-aged children and explored how interracial contact might influence changes in children's implicit anti-Black bias. A total of 113 preschool-age children (60 females, M _age = 5.31 years) were trained to individuate Black or White faces. Results showed a significant reduction in implicit anti-Black bias following Black individuation training, whereas no significant change was observed in the White individuation training group. Additionally, factors such as interracial friendships were found to influence the reduction of bias. These findings contribute to the understanding of developmental interventions for diverse cultural contexts, with implications for early childhood education and efforts to promote social inclusivity. A video abstract of this article can be viewed at https://www.powtoon.com/c/enBEKBMdMXR/1/m

ABSTRACT

Several studies suggest that children's learning and engagement with the content of play activities is affected by the ways parents and children interact. In particular, when parents are overly directive and set more goals during play with their children, their children tend to play less or are less engaged by subsequent challenges with the activity on their own. A concern, however, is that this directed interaction style is only compared with other styles of parent–child interaction, not with a baseline measure of engagement or learning. The present study incorporates such a baseline measure, comparing it with previously-collected data on children's engagement and learning in a set of circuit-building challenges. Regarding engagement, children were less engaged by the challenges when their parents were more directed during a free play setting (tested in Sobel et al. 2021) than when children had no prior experience playing with the circuit components. Regarding learning, children were better able to complete the circuit challenges and provided more causal explanations for how the completed challenges worked when they had experience playing with the circuit blocks with their parent. Overall, these data suggest that parent–child interaction during a STEM activity relates to both children's engagement and performance on challenges related to that activity.

ABSTRACT

Contagious crying in infants has been considered an early marker of their sensitivity to others’ emotions, a form of emotional contagion, and an early basis for empathy. However, it remains unclear whether infant distress in response to peer distress is due to the emotional content of crying or acoustically aversive properties of crying. Additionally, research remains severely biased towards samples from Europe and North America. In this study, we address both aspects by employing the novel and non-invasive method of infrared thermal imaging, in combination with behavioural markers of emotional contagion, to measure emotional arousal during a contagious crying paradigm in a cross-cultural sample of 10- to 11-month-old infants from rural and urban Uganda and the United Kingdom (N = 313). Infants heard social stimuli of positive, negative, and neutral emotional valence (infant laughing, crying, and babbling, respectively) and a non-social, acoustically matched artificial aversive sound. Results revealed that overall changes (as opposed to positive or negative) in infant nasal temperature were larger in response to crying and laughing compared to the artificial aversive sound and larger for crying than for babbling. Infants showed stronger behavioural responses for crying than for the artificial stimulus, as well as for crying than for laughing. Overall, our results support the view that infants within the first year of life experience emotional contagion in response to peer distress, an effect that is not just explained by the aversive nature of the stimuli. Sensitivity to others’ emotional signals in the first year of life may provide the core building blocks for empathy. A video abstract of this article can be viewed at https://youtu.be/JbwL3BHkKlU.

ABSTRACT

The classical view is that perceptual attunement to the native language, which emerges by 6–10 months, developmentally precedes phonological feature abstraction abilities. That assumption is challenged by findings from adults adopted into a new language environment at 3–5 months that imply they had already formed phonological feature abstractions about their birth language prior to 6 months. As phonological feature abstraction had not been directly tested in infants, we examined 4–6-month-olds’ amodal abstraction of the labial versus coronal place of articulation distinction between consonants. In the training phase, infants heard a series of labial non-words paired with an animal image and a series of coronal non-words (multisyllabic) paired with another image. At test, they viewed a silent video of a talker producing coronal and labial words, paired with either the familiarised image or the contrary image. The infants looked significantly longer on matching trials than mismatching trials, suggesting amodal abstraction of this consonantal place of articulation distinction by 4–6 months. These findings provide direct evidence for the inference from the adoptee findings that phonological feature abstraction emerges prior to perceptual attunement.

ABSTRACT

Newborns are able to neurally discriminate between speech and nonspeech right after birth. To date it remains unknown whether this early speech discrimination and the underlying neural language network is associated with later language development. Preterm-born children are an interesting cohort to investigate this relationship, as previous studies have shown that preterm-born neonates exhibit alterations of speech processing and have a greater risk of later language deficits. This investigation also holds clinical importance, as differences in neonatal speech discrimination and its functional networks may serve as predictors of later language outcomes. We therefore investigated neural speech discrimination using functional near-infrared spectroscopy in 92 preterm- and term-born neonates and its predictive value for language development in 45 of them. Three to five years later, preterm-born and term-born children did not significantly differ in language comprehension, sentence production, the use of morphological rules, or phonological short-term memory. In addition, the gestational age at birth was not a significant predictor of language development. Neural speech discrimination, in contrast, was strongly correlated with later phonological short-term memory. However, not the extent of speech discrimination, but rather its lateralization, was a predictor of language development. Children with less right hemisphere involvement—and therefore more left-lateralized speech discrimination at birth—showed better development of phonological short-term memory three to five years later. These findings suggest that the ability of fetuses to form memory traces is reflected by neonatal abilities to neurally discriminate speech, which in turn is a predictor for later phonological short-term memory.

ABSTRACT

Before they even talk, infants become sensitive to the speech sounds of their native language and recognize the auditory form of an increasing number of words. Traditionally, these early perceptual changes are attributed to an emerging knowledge of linguistic categories such as phonemes or words. However, there is growing skepticism surrounding this interpretation due to limited evidence of category knowledge in infants. Previous modeling work has shown that a distributional learning algorithm could reproduce perceptual changes in infants' early phonetic learning without acquiring phonetic categories. Taking this inquiry further, we propose that linguistic categories may not be needed for early word learning. We introduce STELA, a predictive coding algorithm designed to extract statistical patterns from continuous raw speech data. Our findings demonstrate that STELA can reproduce some developmental patterns of phonetic and word form learning without relying on linguistic categories such as phonemes or words nor requiring explicit word segmentation. Through an analysis of the learned representations, we show evidence that linguistic categories may emerge as an end product of learning rather than being prerequisites during early language acquisition.

Developmental Science, Volume 28, Issue 2, March 2025.

ABSTRACT

Previous research indicates that both adults and newborns show enhanced electrophysiological and behavioral responses to schematic face-like configurations (FCs—three dots composing a downward-pointing triangle), as compared to the inverted configurations (ICs). Even fetuses, when exposed to light stimuli projected through the uterine wall, preferentially orient their heads toward FCs rather than ICs. However, when this effect emerges along the third trimester of pregnancy and in relation to the maturation of which brain structures is still unknown. Here, to provide a sensitive measure of fetal preference for FCs along the whole third trimester, fetal lens movements in response to FCs and ICs was monitored with 2D-ultrasound. In a series of three experiments, fetuses were recruited at 26, 31, and 37 weeks of gestational age and were presented with both flashing and continuous light stimuli. Our results showed that significantly more lens movements were observed in response to continuous as compared to flashing light stimuli. Furthermore, lens movements linearly increased within the third trimester and, regardless of the time-point, significantly more lens movements were observed in response to FCs versus ICs. We also found a significant correlation in the first time-point, wherein the greater the FCs versus ICs differential response the larger the thalamic nuclei dimension. These findings suggest that FC preference is already present at the beginning of the third trimester, as soon as thalamocortical projections are established.

ABSTRACT

Immigration is among the most pressing issues of our time. Important questions concern the psychological mechanisms that contribute to attitudes about immigration. Whereas much is known about adults’ immigration attitudes, the developmental antecedents of these attitudes are not well understood. Across three studies (N = 616), we examined US children's attitudes toward migrants by introducing them to two novel groups of people: one native to an island and the other migrants to the island. The migrants varied by (1) Migrant Status: migrants came from a resource-poor island (fleers) or a resource-rich island (pursuers); and (2) Acculturation Style: migrants assimilated to the native culture (assimilated) or retained their original cultural identity (separated). We studied a range of children's immigration attitudes: children's preferences, resource allocations, and perceptions of solidarity between groups (Experiment 1), children's conferral of voting power (Experiment 2a) and political representation (Experiment 2b), and children's beliefs about political representation when an equal government was not possible (Experiment 3). Overall, children showed a bias toward natives, but the degree of their bias depended on the type of migrant they were evaluating. Children generally favored Pursuers over Fleers, and Assimilated migrants over Separated migrants. In some cases, the intersection of these factors mattered: children expressed a specific preference for Separated Pursuers and a specific penalization of Separated Fleers. These studies reveal the early developmental roots of immigration attitudes, particularly as they relate to political power and the intersecting forces of migrant status and acculturation.