Developmental Science最新文献

Caregivers play an outsized role in shaping early life experiences and development, but we often lack mechanistic insight into how exactly caregiver behavior scaffolds the neurodevelopment of specific learning processes. Here, we capitalized on the fact that caregivers differ in how predictable their behavior is to ask if infants' early environmental input shapes their brains' later ability to learn about predictable information. As part of an ongoing longitudinal study in South Africa, we recorded naturalistic, dyadic interactions between 103 (46 females and 57 males) infants and their primary caregivers at 3-6 months of age, from which we calculated the predictability of caregivers' behavior, following caregiver vocalization and overall. When the same infants were 6-12-months-old they participated in an auditory statistical learning task during EEG. We found evidence of learning-related change in infants' neural responses to predictable information during the statistical learning task. The magnitude of statistical learning-related change in infants' EEG responses was associated with the predictability of their caregiver's vocalizations several months earlier, such that infants with more predictable caregiver vocalization patterns showed more evidence of statistical learning later in the first year of life. These results suggest that early experiences with caregiver predictability influence learning, providing support for the hypothesis that the neurodevelopment of core learning and memory systems is closely tied to infants' experiences during key developmental windows.

Sensory features are included in the diagnostic criteria of autism and atypical sensory responsiveness may produce "cascading effects" on later development. Similarly, autistic individuals often struggle with motor coordination and early delays in the motor domain appear to be linked to later development. However, the longitudinal interrelation between early sensory profiles and motor features on later socio-communicative skills remains to be defined. This study aimed to investigate whether sensory sensitivity impacts fine motor abilities and vice versa from 12 to 18 months of age and to examine how sensory-motor interplay would be associated with later autistic traits at 24-36 months of age. The sample included 118 infant siblings of autistic children recruited at 12 months of age. Sensory sensitivity and eye-hand coordination were assessed at 12 and 18 months of age and autistic traits were evaluated at 24-36 months of age. Cross-lagged panel analysis revealed significant within-domain effects for sensory sensitivity and eye-hand coordination from 12 to 18 months. Furthermore, a significant association between these two domains on later autistic traits was found. In analyzing the longitudinal bidirectional relationship, we found that lower eye-hand coordination skills at 12 months predicted later sensory sensitivity at 18 months, and in turn, social communication skills at 24-36 months. The present study offers new empirical evidence supporting the potential clinical value of including sensory and motor measures besides social communication skills within early autism surveillance programs.

Language learning is influenced by both neural development and environmental experiences. This work investigates the influence of early bilingual experience on the neural mechanisms underlying speech processing in 4-month-old infants. We study how an early environmental factor such as bilingualism interacts with neural development by comparing monolingual and bilingual infants' brain responses to speech. We used functional near-infrared spectroscopy (fNIRS) to measure 4-month-old Spanish-Basque bilingual and Spanish monolingual infants' brain responses while they listened to forward (FW) and backward (BW) speech stimuli in Spanish. We reveal distinct neural signatures associated with bilingual adaptations, including increased engagement of bilateral inferior frontal and temporal regions during speech processing in bilingual infants, as opposed to left hemispheric functional specialization observed in monolingual infants. This study provides compelling evidence of bilingualism-induced brain adaptations during speech processing in infants as young as 4 months. These findings emphasize the role of early language experience in shaping neural plasticity during infancy suggesting that bilingual exposure at this young age profoundly influences the neural mechanisms underlying speech processing.

Moral decisions often involve dilemmas: cases of conflict between competing obligations. In two studies (N = 204), we ask whether children appreciate that reasoning through dilemmas involves acknowledging that there is no single, simple solution. In Study 1, 5- to 8-year-old US children were randomly assigned to a Moral Dilemma condition, in which story characters face dilemmas between two prosocial actions, or a Personal Cost control, in which story characters face decisions between a matched prosocial action and a self-interested action. Children were then presented with two reasoners who made the same judgment, but one confidently endorsed one moral action, and the other hesitantly acknowledged both actions. As they aged, children became more likely to prefer the uncertain reasoner's "way of thinking" in the Moral Dilemma compared to the Personal Cost condition. They also inferred that the uncertain reasoner was nicer and more trustworthy than the confident one. In Study 2, when both reasoners acknowledged the dilemma and differed only in their level of uncertainty, 5-year-olds preferred the acknowledgment to be accompanied by a confident decision, 6- and 7-year-olds preferred it be accompanied by uncertainty, and 8-year-olds showed no preference. These results show that, before the age at which children can resolve dilemmas successfully on their own, they recognize and value others who approach dilemmas with appropriate humility.

Longitudinal research can assess how diverging development of multiple cognitive skills during infancy, as well as familial background, are related to the emergence of neurodevelopmental conditions. Sensorimotor and effortful control difficulties are seen in infants later diagnosed with autism; this study explored the relationships between these skills and autism characteristics in 340 infants (240 with elevated familial autism likelihood) assessed at 4-7, 8-10, 12-15, 24, and 36 months. We tested: (1) the relationship between parent-reported effortful control (Rothbart's temperament questionnaires) and sensorimotor skills (Mullen Scales of Early Learning), using random intercept cross-lagged panel modelling; (2) whether household income and maternal education predicted stable individual differences in cognition; (3) sensorimotor and effortful control skills as individual and interactive predictors of parent-reported autism characteristics (Social Responsiveness Scale) at 3 years, using multiple regression; and (4) moderation of interactions by familial likelihood. Sensorimotor skills were longitudinally associated with effortful control at the subsequent measurement point from 12-15 months. Socioeconomic status indicators did not predict stable between-infant differences in sensorimotor or effortful control skills. Effortful control skills were longitudinally related to 3-year autism characteristics from the first year of life, with evidence for an interaction with sensorimotor skills at 24 months. Effects of effortful control increased with age and were particularly important for infants with family histories of autism. Results are discussed in relation to different theoretical frameworks: Developmental Cascades and Anterior Modifiers in the Emergence of Neurodevelopmental Disorders. We suggest a role for 24-month effortful control in explaining the emergent autism phenotype. RESEARCH HIGHLIGHTS: Sensorimotor skills longitudinally predicted effortful control from 12-15 months onward but effortful control did not longitudinally predict sensorimotor skills during infancy. Measures of effortful control skills taken before the age of 1 predicted continuous variation in autism characteristics at 36 months, with associations increasing in strength with age. Effortful control (measured at 12-15 and 24 months) was a stronger predictor of 36-month autism characteristics in infants with elevated familial likelihood for autism. The relationship between 24-month sensorimotor skills and 36-month autism characteristics was stronger in infants with weaker effortful control skills.

Previous research has shown that when domain-general transitional probability (TP) cues to word segmentation are in conflict with language-specific stress cues, English-learning 5- and 7-month-olds rely on TP, whereas 9-month-olds rely on stress. In two artificial languages, we evaluated English-learning infants' sensitivity to TP cues to word segmentation vis-a-vis language-specific vowel phonotactic (VP) cues-English words do not end in lax vowels. These cues were either consistent or conflicting. When these cues were in conflict, 10-month-olds relied on the VP cues, whereas 5-month-olds relied on TP. These findings align with statistical bootstrapping accounts, where infants initially use domain-general distributional information for word segmentation, and subsequently discover language-specific patterns based on segmented words. RESEARCH HIGHLIGHTS: Research indicates that when transitional probability (TP) conflicts with stress cues for word segmentation, English-learning 9-month-olds rely on stress, whereas younger infants rely on TP. In two artificial languages, we evaluated English-learning infants' sensitivity to TP versus vowel phonotactic (VP) cues for word segmentation. When these cues conflicted, 10-month-olds relied on VPs, whereas 5-month-olds relied on TP. These findings align with statistical bootstrapping accounts, where infants first utilize domain-general distributional information for word segmentation, and then identify language-specific patterns from segmented words.

To navigate their environment, infants rely on intersensory facilitation when unisensory perceptual demand is high, a principle known as inverse effectiveness. Given that this principle was mainly documented in the context of audiovisual stimulations, here we aim to determine whether it applies to olfactory-to-visual facilitation. We build on previous evidence that the mother's body odor facilitates face categorization in the 4-month-old brain, and investigate whether this effect depends on visual demand. Scalp electroencephalogram (EEG) was recorded in two groups of 4-month-old infants while they watched 6-Hz streams of visual stimuli with faces displayed every 6th stimulus to tag a face-selective response at 1 Hz. We used variable natural stimuli in one group (Nat Group), while stimuli were simplified in the other group (Simp Group) to reduce perceptual categorization demand. During visual stimulation, infants were alternatively exposed to their mother's versus a baseline odor. For both groups, we found an occipito-temporal face-selective response, but with a larger amplitude for the simplified stimuli, reflecting less demanding visual categorization. Importantly, the mother's body odor enhances the response to natural, but not to simplified, face stimuli, indicating that maternal odor improves face categorization when it is most demanding for the 4-month-old brain. Overall, this study demonstrates that the inverse effectiveness of intersensory facilitation applies to the sense of smell during early perceptual development. RESEARCH HIGHLIGHTS: Intersensory facilitation is a function of unisensory perceptual demand in infants (inverse effectiveness). This inverse relation between multisensory and unisensory perception has been mainly documented using audiovisual stimulations. Here we show that olfactory-to-visual facilitation depends on visual demand in 4-month-old infants. The inverse effectiveness of intersensory facilitation during early perceptual development applies to the sense of smell.

Intra-individual response time variability (IIRTV) during cognitive performance is increasingly recognized as an important indicator of attentional control (AC) and related brain region function. However, what determinants contribute to preschoolers' IIRTV received little attention. The present study explored the interaction of dopaminergic polygenic composite score (DPCS) and the parent-child relationship in relation to preschoolers' IIRTV. In the initial sample, 452 preschoolers (M age = 5.17, SD = 0.92) participated in the study. The modified Flanker task was used to evaluate children's IIRTV and their parents were requested to complete the Parent-Child Relationship Scale to assess the parent-child relationship (closeness/conflict). DNA data were extracted from children's saliva samples, and a DPCS was created by the number of COMT, DAT1, and DRD2 alleles associated with lower dopamine levels. Results showed that DPCS significantly interacted with the parent-child closeness to impact preschoolers' IIRTV. Specifically, preschoolers with higher DPCS exhibited lower IIRTV under higher levels of the parent-child closeness, and greater IIRTV under lower levels of the parent-child closeness compared to those with lower DPCS, which supported the differential susceptibility theory (DST). A direct replication attempt with 280 preschoolers (M age = 4.80, SD = 0.86) was conducted to investigate whether the results were in accordance with our exploratory outcomes. The interactive effect of DPCS and the parent-child closeness on IIRTV was confirmed. Additionally, the significant interactive effect of DPCS and the parent-child conflict on IIRTV was found in the replication study. The findings indicate that preschoolers' IIRTV, as an indicator of AC and related brain region function, is influenced by the interactions of dopaminergic genotypes and the parent-child relationship. RESEARCH HIGHLIGHTS: We investigated the Gene × Environment mechanism to underline the intra-individual response time variability as an indicator of attentional control (AC) in Chinese preschoolers. Dopaminergic polygenic composite score (COMT, DAT1, and DRD2) interacted with the parent-child relationship to predict preschoolers' intra-individual reaction time variability. A direct replication attempt has been conducted, and the results were in accordance with our exploratory outcomes, which increased the credibility of the present findings. The findings highlight the importance of considering precursors, including polygenic and environmental factors, which contribute to the development of early cognitive performance such as AC.