Theories of emotion development propose that negative affect decreases over time as attention control and emotion regulation improve. Yet, research on infancy suggests that the first year of life can be characterised by a different developmental pattern: increased negative affect as infants age. Implementing an emotion-eliciting task, we measured infants' observed emotion reactivity and regulation, and physiological arousal (heart rate) during the challenge (toy retraction) and recovery (toy play) conditions at age 6months (n=82, 43 boys) and age 12months (n=68, 36 boys) continuously on a second-by-second basis. We first measured mean intensity of reactivity, regulation, and arousal by calculating within-person averages. Then, we measured three temporal dynamics: estimates of variability by calculating variance, lability by calculating root mean square of successive differences, and persistence of changes by calculating autocorrelation. Intensity, variability, and lability in negative reactivity increased from 6 to 12months with no change in persistence, indicating a larger and quicker negative reaction to toy retraction with age. Regulatory strategy use increased from 6 to 12months during challenge,whereas during recovery, it reduced and became more stable. Heart rate decreased from challenge to recovery at 12months but not at 6months. We then examined how the temporal associations between reactivity, regulation and arousal change over time. Cross-correlation analyses revealed stronger temporal associations between reactivity, regulation, and heart rate at 12 months, suggesting increased coherence between behavioural and physiological responses with age. We discuss these developmental changes in emotion dynamics and behaviour-physiology associations in the context of functionalist perspectives on emotion. SUMMARY: This study employs momentary recordings of emotional expressions, regulatory behaviours, and physiological arousal, focusing on two key aspects: within-task context and temporal dynamics. As they grow, infants show stronger negative reactions and greater regulatory efforts during stress but calmer reactions and reduced use of regulation once stressor ends. Temporal associations between emotional behaviours and physiology (heart rate) increased from 6 to 12months, suggesting stronger emotional coherence with age in infancy. Together, these patterns may reflect improved emotional flexibility, with older infants showing more context-appropriate emotion responses.

Early learning takes place within complex, multimodal environments where curiosity plays a critical role in guiding exploratory behaviors and supporting cognitive development. While trait curiosity shapes children's early learning experiences, state curiosity is context-dependent fostering early learning, in-part, through information seeking behaviors. Here, we explore whether state-induced curiosity can influence exploratory behaviors and facilitate word-learning within a multimodal search task that mirrors real-world learning environments. Children (2.5- to 4-year-olds) will be introduced to novel objects and labels via a storybook. After exposure to each novel object, participants will locate the target object (i.e., a sticker depicting the novel object), hidden within one of ten boxes uniformly distributed across a real-world space. Unbeknownst to participants, the target will only be hidden within a single hemispace. In the "High-Curiosity" condition, the storybook should elicit greater curiosity, whereas the "Low-Curiosity" condition will present novel words in a context that should invoke lower levels of curiosity. Following the search task, participants will complete a forced-choice word learning task. Findings will provide insights into whether and how curiosity facilitates word learning in rich, multimodal contexts and how this relationship can be impacted by children's explorative strategies, including their sensitivity to environmental statistics. SUMMARY: Curiosity drives early development, but the extent to which it facilitates learning within a multimodal environment remains underexplored. The study examines how high versus low induced curiosity states influence toddlers' exploratory behavior, including search efficiency and adaptation to spatial probability cues. The study assesses whether higher state-induced curiosity leads to stronger retention and recognition of novel word-object mappings compared to the lower curiosity condition. The study examines how curiosity-driven search strategies relate to novel word learning and whether learning is moderated by how children choose to search for information.

Trusting selectively is a crucial ability in successfully navigating social environments: trusting a trustworthy partner maximizes mutual benefits; withholding trust from an untrustworthy partner minimizes chances of being exploited. Here, we ask how children's trust expectations and experienced trustworthiness inform their own trust decisions. Using a child-friendly repeated Trust Game, we employ a computational modeling approach to examine how children learn about the trustworthiness of others through experience and adjust their own trust behaviors. We tested N = 96 children ages 6-11 years who played 40 trials of the game as trustors with a trustworthy and an untrustworthy trustee. Regression analyses showed that overall, children shared more with trustworthy than untrustworthy partners and older children shared overall more than younger children. Computational models provided a more fine-grained analysis of the learning pattern: a reinforcement learning model that included parameters for individual variation in prior trust expectations and a parameter quantifying the behavioral adjustment over time provided the best fit for the data. Using this computational approach, we could ascertain that children's behavioral adjustments became less responsive over time, suggesting a shift toward more stable patterns of trust once initial impressions were formed. Together, these findings shed light on the development of children's trust interaction with novel partners and highlight the opportunity that computational modeling provides in capturing developmental differences in trust behaviors. SUMMARY: Children aged 6-11 used experience to distinguish trustworthy from untrustworthy partners in a repeated Trust Game, sharing more with the trustworthy than the untrustworthy partner. Older children shared more than younger children, although they were not significantly differentiating between the trustworthy than the untrustworthy partner. Reinforcement learning modeling suggested that children updated trust expectations from experience, with age-related differences in the efficiency of impression updating. These findings highlight both children's capacity in flexibly adjusting their economic trust behaviors and the value of computational modeling in studying economic trust development.

Children's language development starts in utero, with language-relevant brain areas starting to develop and differentiate during the second trimester of pregnancy. Postnatal development in language-relevant brain areas such as the inferior frontal gyrus (IFG) and superior temporal gyrus (STG) has been shown to be related to language skills. In this study, as part of the Cambridge Human Imaging and Longitudinal Development (CHILD) project, prenatal structural characteristics of the IFG and STG (30th - 33rd GW) and their association with English children's language skills, obtained longitudinally at two postnatal assessment points (n = 24 and n = 25) was examined. Prenatal bilateral STG volume was found to be associated with expressive vocabulary 2-3 years after birth (M = 139.1 weeks), as measured by the Communicative Development Inventory (CDI). These results highlight the relevance of prenatal brain development for language acquisition after birth. SUMMARY: Postnatal structural characteristics of neural language network, including IFG and STG, are known to be related to language skills in children and adults Structural characteristics of IFG and STG were assessed prenatally in this study and related to language outcomes in early childhood Bilateral STG volume at birth predicts vocabulary scores 2-3 years later Findings support the importance of prenatal brain development for postnatal language acquisition.

COVID-19 has profoundly affected children's well-being. Resilience was often found to be negatively correlated with COVID-19 impacts. However, the role of resilience in directly shaping COVID-19 impacts on children remains unclear, as studies report conflicting evidence regarding the potential causal direction between COVID-19 impacts and resilience. Higher resilience could reduce COVID-19 impacts, while COVID-19 impacts may also disrupt or enhance resilience. Or it could be the case that the two are simply correlated due to shared underlying common factors. This preregistered study uses a twin-based Direction of Causation modeling approach with data from 1166 twins (age: M = 12.59; 50.78% male; 85.08% White) to explore the causal direction between COVID-19 impacts and resilience. Resilience was assessed using the Child and Youth Resilience Measure (CYRM)-Child Version, a child self-report questionnaire assessing resources available for children's resilience. Findings revealed a causal effect such that resilience resources explained 32% variance in overall COVID-19 impacts, consistently buffering negative outcomes across multiple domains (e.g., social connections, general stress, and COVID-related stress). A reciprocal causal effect was found for economic impacts, with resilience mitigating economic impacts and economic challenges enhancing resilience. SYMMARY: Resilience has been found to be negatively associated with negative impacts of COVID-19. Using a national twin sample, we adopted a twin-based Direction-Of-Causation Modeling approach to examine how COVID-19 impacts and resources for resilience influence each other. We found that resilience resources causally reduce COVID-19 impacts, explaining 32% of the variance in how children experienced the pandemic. Findings in this study inform clinical and educational practice, highlighting the value of resilience-building efforts to support children during and after crises.

ABSTRACTVocabulary knowledge is foundational to educational success, but significant gaps exist between students with reading disabilities or those from disadvantaged backgrounds and their peers. These gaps have cascading effects, as children with lower vocabulary knowledge are less likely to acquire new words through independent reading and are less responsive to vocabulary instruction methods like read‐alouds and explicit teaching. The effectiveness of explicit instruction relies on individualization, which typically places substantial demands on educators and thereby hinders the adoption of evidence‐based methods. A potential solution is using audiobooks supplemented by explicit and individualized remote instruction from paraprofessionals. We conducted a randomized controlled trial (RCT) intervention study in which children listened to text‐supplemented audiobooks, either alone or with scaffolded instructional support. Third and fourth‐grade students (N = 314, age: mean (SD) = 9.47(0.57) years) were randomly assigned to one of three conditions (Audiobooks‐Only, Audiobooks+Scaffold, or active control) for 8 weeks. Participants in the two audiobook intervention groups showed significant improvements in book‐specific vocabulary, while the active control group showed no improvement. The effectiveness of the intervention varied by reading ability and socioeconomic status (SES): poor readers benefited only when audiobooks were paired with one‐on‐one scaffolding, whereas children from lower‐SES backgrounds showed modest, nonsignificant gains from audiobook access alone and did not experience additional benefits from scaffolding. Additionally, the Audiobooks+Scaffold group spent more time listening to recommended audiobooks during the study. These findings suggest that text‐supplemented audiobooks, particularly when combined with personalized support, can be a valuable tool for supporting vocabulary development in struggling readers.SummaryChildren successfully learned new vocabulary words by engaging with text‐supplemented audiobooks.Vocabulary gains were largest amongst students who additionally received one‐on‐one remote scaffolding sessions throughout the intervention period.Poor readers only benefited when text‐supplemented audiobooks were paired with one‐on‐one instructional support.Students from lower socioeconomic backgrounds showed smaller, nonsignificant gains from either component, suggesting a need for additional support to achieve comparable vocabulary growth.

Canonical babbling, or the production of adult-like consonant-vowel syllables in infancy, represents a critical milestone in prelinguistic vocal development and predicts later speech and language outcomes. This systematic review and meta-analysis synthesized findings from 42 studies and 1277 infants aged 5-24 months across 16 language environments to examine how methodological and contextual factors influence the most common measure of canonical babbling: the canonical babbling ratio (CBR). Results confirmed a robust, linear increase in CBR with age, reinforcing its role as a consistent developmental marker. Different CBR measures yielded comparable developmental trajectories. Sampling method significantly affected CBR values, with interactive free-play sessions eliciting higher CBRs than naturalistic (LENA) home recordings, particularly in older infants. In contrast, the location of data collection had no effect. Ambient language complexity also shaped CBR: Infants acquiring languages with more complex syllable structures (e.g., English, Dutch) initially exhibited lower CBRs compared to infants acquiring languages with less complex syllable structures (e.g., Mandarin, Spanish). Despite these initial differences, babbling trajectories were predicted to converge by approximately 20 months as infants exposed to languages with more complex syllables demonstrated accelerated CBR growth. Publication bias was detected, with smaller samples more likely to report inflated CBRs. To address this issue, simulation-based analyses are reported to estimate sample size recommendations for improved precision in future research. Together, these results support CBR as a meaningful developmental marker while offering practical guidance for future research directions and continued clinicalapplications. SUMMARY: Meta-analysis of 42 studies with 1277 infants shows canonical babbling ratio (CBR) increases linearly from 0.12 at 5 months to 0.65 at 24 months across language environments. Ambient language syllable complexity significantly affects early CBR trajectories, with initial differences converging by 20 months. Interactive free-play sampling methods where caregivers are instructed to "act as they normally do," consistently elicits higher CBRs than naturalistic, home-based recordings. Publication bias revealed smaller studies report inflated CBR values; simulation analyses provide sample size recommendations for reliable measurement.

ABSTRACTLying about achievements is commonplace in reputation management, yet its social consequences may depend on cultural conventions. The present research examined how Chinese children aged 5–11 years (N = 173, 48% girls, Mage: 8.40 years) and adults (N = 98, 52% women, Mage: 20.76 years) evaluated truth‐tellers and lie‐tellers who described their achievements in ways that either violated or aligned with the Chinese cultural convention of modesty. When lying violated modesty conventions (Study 1A), both children and adults consistently preferred truth‐tellers over lie‐tellers in evaluations and behavioral preferences; these preferences were unrelated to individuals’ understanding of modesty. When lying aligned with modesty conventions (Study 1B and Study 2), children and adults overall still preferred truth‐tellers over lie‐tellers; however, among individuals who correctly identified the lie‐teller as more modest than the truth‐teller, preferences for truth‐tellers were attenuated. Moreover, when lying signaled modesty, children's age was positively associated with preferences for truth‐tellers only among those who incorrectly identified which protagonist was more modest, but not among children who correctly identified the lie‐teller as more modest. Together, these findings demonstrate that preferences for honesty emerge early and remain stable across development, but are flexibly shaped by modesty conventions and individuals’ understanding of those conventions.SummaryChildren and adults consistently preferred truth‐tellers over lie‐tellers when lying violated cultural modesty conventions.Preferences for honesty remained robust even when lying aligned with modesty conventions, but were attenuated among individuals recognizing modest intent.Individuals’ understanding of modesty moderated evaluations of honesty, indicating that cultural conventions shape social evaluations beyond simple truth‐lie distinctions.

Our hands rarely lie still while we talk. Some hand movements, like washing dishes or other household tasks, are often unrelated to what we express in speech. Other hand movements, known as gestures, are deeply integrated with verbal communication. Past research with adults has found strong temporal synchrony between speech and gesture, particularly as compared to speech and action. This evidence supports the claim that speech and gesture emerge from a single integrated system and suggests that gestures hold a unique status in communication compared to other kinds of hand movements. However, the developmental unfolding of this tight temporal integration is unknown. In this cross-sectional study, we directly measure the speech-gesture production system in childhood. In a within-subjects design, adults (N = 35; Mage = 19.94 years; range = 18-25 years) and children (N = 68; Mage = 8.38 years; range = 5-12 years) were asked to verbally describe how they use household objects while producing either gestures or communicative actions. Speech onset, action onset, and gesture onset were coded to determine the difference in onset between speech and movement (action or gesture). Results indicate that speech and gesture were produced in closer temporal synchrony than speech and action across all ages tested, showing remarkable stability in speech-gesture temporal relations over development. This lack of any notable developmental change in temporal synchrony between speech and gesture is consistent with the theory that speech and gesture emerged phylogenetically as an integrated cognitive system.

Parent-child interactions, particularly storytelling practices, play a critical role in children's language development, yet the influence of cultural variation in these practices remains underexplored. This quantitative study aims to examine differences between English and Zimbabwean storytelling practices and their impact on children's story recall. To address limitations in previous research, including the reliance on artificial settings and insufficient attention to cultural diversity, we will conduct a naturalistic study in participants' homes. Parent-child dyads will be observed in three contexts: playtime, story time using a storybook and oral narration. Data will be collected on verbal behaviour, hand gestures and visual attention, while children's recall will be measured following each type of storytelling. This study will address four key research questions: (1) How do cultural groups differ in their storytelling mode and pedagogic orientation? (2) How do multimodal dyadic behaviours differ across cultures during storytelling and play? (3) Are there cross-cultural differences in the frequency and types of hand gestures used in storytelling? (4) Is greater parental experience with oral narration associated with enhanced child recall? The study will involve English dyads in England and Zimbabwean dyads in Zimbabwe. By examining these interactions in participants' home environments and by including both Zimbabwean families in Zimbabwe and English families in England, this research will shed light on how culturally rooted storytelling practices influence cognitive and language development and inform our understanding of culturally responsive parenting approaches.