Infancy最新文献

The progression from crawling to walking in infancy is associated with changes in infant language development. One possible explanation for such change is the infant's language environment. Prior research indicates that caregivers use more action directives with walking infants compared to crawling infants, but the relations of such parental speech with infant vocabulary is unknown. Here, we present findings from day-long home audio recordings (Study 1) and laboratory observations (Study 2) of same-aged crawling and walking infants to explore how caregiver language, specifically action directives, were associated with parent reported infant vocabulary size. Findings in both studies indicated that caregiver action directives were associated with crawling, but not walking infants' receptive vocabulary sizes. Specifically, action directives about objects occurring when the infant and caregiver were not jointly engaged were associated with higher receptive vocabulary scores for crawling infants, but no such pattern was found for walking infants. The replication of results in distinct samples with different research methodologies strengthens the findings. Taken together, these studies demonstrate that caregiver social engagement specific to infant motoric development is related with infant language learning.

Free play is a natural activity in toddlerhood, depending on environmental conditions like available objects and the social environment. The COVID-19 pandemic and its consequences for parents’ mental health held the potential to change toddlers’ play environment. This cross-sectional study investigated 2-year-olds’ (N = 97) free play with objects, and aspects of caregiver mental well-being in three cohorts during the pandemic in Germany. Caregivers reported their positive mental health (PMH), threat perception, perception of current family situation from negative to positive, and workload. We categorized toddlers’ behavior in free play sessions in their homes with a fixed set of objects through behavioral coding. Play behavior did not differ between cohorts and did not correlate with caregivers’ positive mental health, threat perception, and perception of family situation. A MANOVA revealed a significant main effect of cohort on PMH, threat perception and perception of family situation, qualified by two discriminant functions. Full sample analyses revealed that toddlers of caregivers perceiving a workload increase compared to the time before the pandemic showed less pretend play, and less functional and nonfunctional play. The results provide insights into 2-year-olds’ play behavior during a global pandemic and highlight the role of caregiver availability for children’s play.

We investigated the temporal impact of multisensory settings on children's learning of word-object and action-object associations at 1- and 2-years of age. Specifically, we examined whether the temporal alignment of words and actions influenced the acquisition of novel word-action-object associations. We used a preferential looking and violation of expectation task in which infants and young children were first presented with two distinct word-object and action-object pairings either in a synchronous (overlapping in time) or sequential manner (one after the other). Findings revealed that 2-year-olds recognized both, action-object and word-object associations when they first saw the word-action-object combinations synchronously, but not sequentially, as evidenced by looking behavior. 1-year-olds did not show evidence for recognition for either of the word-object and action-object pairs, regardless of the initial temporal alignment of these cues. To control for individual differences, we explored factors that might influence associative learning based on parental reports of 1- and 2-year-olds development, however, developmental measures did not explain word-action-object associative learning in either group. We discuss that while young children may benefit from the temporal alignment of multisensory cues as it enables them to actively engage with the multisensory content in real-time, infants may have been overwhelmed by the complexity of this input.

Understanding the factors contributing to sensitive parenting is crucial to optimize infant social and emotional functioning. Research has supported the association between parents' personality and parenting quality, but findings are inconsistent when examining various global personality measures. Further, it is likely that the interaction between parent-level (e.g., personality) and infant-level characteristics (e.g., temperament) are more strongly associated with caregiving quality. Most studies examining predictors of parenting quality have only included mothers, compared to fathers. The current study examined the interaction between parental personality and infant temperament and associations with parental sensitivity and intrusiveness with mothers and fathers. The participants included families (n = 102) when the infants were 4, 6, and 8 months old. Using parent report measures and a face-to-face play task, significant main effects of maternal behavioral inhibition on parenting behaviors were observed for mothers. A Behavioral Activation X Infant Negative Reactivity interaction predicted both maternal sensitivity and intrusiveness, whereas a Behavioral Inhibition X Infant Surgency predicted paternal intrusiveness. In summary, the results revealed support for the goodness-of-fit perspective between parents' personality and infant temperament.

Early environments can have significant and lasting effects on brain, body, and behavior across the lifecourse. Here, we address current research efforts to understand how experiences impact neurodevelopment with a new perspective integrating two well-known conceptual frameworks – the Developmental Origins of Health and Disease (DOHaD) and sensitive/critical period frameworks. Specifically, we consider how prenatal experiences characterized in the DOHaD model impact two key neurobiological mechanisms of sensitive/critical periods for adapting to and learning from the postnatal environment. We draw from both animal and human research to summarize the current state of knowledge on how particular prenatal substance exposures (psychoactive substances and heavy metals) and nutritional profiles (protein-energy malnutrition and iron deficiency) each differentially impact brain circuits' excitation/GABAergic inhibition balance and myelination. Finally, we highlight new research directions that emerge from this integrated framework, including testing how prenatal environments alter sensitive/critical period timing and learning and identifying potential promotional/buffering prenatal exposures to impact postnatal sensitive/critical periods. We hope this integrative framework considering prenatal influences on postnatal neuroplasticity will stimulate new research to understand how early environments have lasting consequences on our brains, behavior, and health.

To efficiently recognize words, children learning an intonational language like English should avoid interpreting pitch-contour variation as signaling lexical contrast, despite the relevance of pitch at other levels of structure. Thus far, the developmental time-course with which English-learning children rule out pitch as a contrastive feature has been incompletely characterized. Prior studies have tested diverse lexical contrasts and have not tested beyond 30 months. To specify the developmental trajectory over a broader age range, we extended a prior study (Quam & Swingley, 2010), in which 30-month-olds and adults disregarded pitch changes, but attended to vowel changes, in newly learned words. Using the same phonological contrasts, we tested 3- to 5-year-olds, 24-month-olds, and 18-month-olds. The older two groups were tested using the language-guided-looking method. The oldest group attended to vowels but not pitch. Surprisingly, 24-month-olds ignored not just pitch but sometimes vowels as well—conflicting with prior findings of phonological constraint at 24 months. The youngest group was tested using the Switch habituation method, half with additional phonetic variability in training. Eighteen-month-olds learned both pitch-contrasted and vowel-contrasted words, whether or not additional variability was present. Thus, native-language phonological constraint was not evidenced prior to 30 months (Quam & Swingley, 2010). We contextualize our findings within other recent work in this area.

Research in the U.S. and other Western countries shows that children’s early gesture use, which starts prior to verbal communication, is an important predictor of children’s later language development. Despite increasing efforts to study gesture use in diverse contexts, most of our knowledge on the role of gesture is largely based on populations of Western countries. In this study, we add to the growing body of international research by examining gesture use by 31 mothers and their 14-month-old infants (12 girls) in South Korea and investigate the gestures used during interaction, and whether early gesture use at 14 months predicts Korean children’s later language skills at 36 months. The results showed that in addition to using gestures observed in other cultural contexts, Korean mother-child dyads used culturally specific gesture (i.e., bowing), showing an early sign of socialization that starts with preverbal children. In addition, Korean infants’ index-finger pointing, but not showing and giving, predicted their later receptive and expressive vocabulary skills at 36 months, providing additional support for the importance of pointing in early language development.

Efficiently processing information from faces in infancy is foundational for nonverbal communication. We studied individual differences in 5-month-old infants' (N = 517) sustained attention to faces and preference for emotional faces. We assessed the contribution of genetic and environmental influences to individual differences in these gaze behaviors, and the association between these traits and other concurrent and later phenotypes. We found an association between the mean duration of looking at a face (before looking away from it) at 5 months and socio-communicative abilities at 14 months (β = 0.17, 95% CI: 0.08; 0.26, p < 0.001). Sustained attention to faces predicted socio-communicative abilities over and above variance captured by mean fixation duration. We also found a statistically significant but weak tendency to prefer looking at smiling faces (relative to neutral faces), but no indication that variability in this behavior was explained by genetic effects. Moderate heritability was found for sustained attention to faces (A = 0.23, CI: 0.06; 0.38), while shared environmental influences were non-significant for both phenotypes. These findings suggest that sustained looking at individual faces before looking away is a developmentally significant ‘social attention’ phenotype in infancy, characterized by moderate heritability and a specific relation to later socio-communicative abilities.

Elevated psychological distress, experienced by pregnant women and parents, has been well-documented during the COVID-19 pandemic. Most research focuses on the first 6-months postpartum, with single or limited repeated measures of perinatal distress. The present longitudinal study examined how perinatal distress, experienced over nearly 2 years of the COVID-19 pandemic, impacted toddler socioemotional development. A sample of 304 participants participated during pregnancy, 6-weeks, 6-months, and 15-months postpartum. Mothers reported their depressive, anxiety, and stress symptoms, at each timepoint. Mother-reported toddler socioemotional functioning (using the Brief Infant–Toddler Social and Emotional Assessment) was measured at 15-months. Results of structural equation mediation models indicated that (1) higher prenatal distress was associated with elevated postpartum distress, from 6-weeks to 15-months postpartum; (2) associations between prenatal distress and toddler socioemotional problems became nonsignificant after accounting for postpartum distress; and (3) higher prenatal distress was indirectly associated with greater socioemotional problems, and specifically elevated externalizing problems, through higher maternal distress at 6 weeks and 15 months postpartum. Findings suggest that the continued experience of distress during the postpartum period plays an important role in child socioemotional development during the COVID-19 pandemic.

For pregnant women, the COVID-19 pandemic has resulted in unprecedented stressors, including uncertainty regarding prenatal care and the long-term consequences of perinatal infection. However, few studies have examined the role of this adverse event on maternal wellbeing and infant socioemotional development following the initial wave of the pandemic when less stringent public health restrictions were in place. The current study addressed these gaps in the literature by first comparing prenatal internalizing symptoms and infant temperament collected after the first wave of the pandemic to equivalent measures in a pre-pandemic sample. Second, associations between prenatal pandemic-related stress and infant temperament were examined. Women who were pregnant during the COVID-19 pandemic endorsed higher pregnancy-specific anxiety relative to the pre-pandemic sample. They also reported greater infant negative emotionality and lower positive affectivity and regulatory capacity at 2 months postpartum. Prenatal infection stress directly predicted infant negative affect. Both prenatal infection and preparedness stress were indirectly related to infant negative emotionality through depression symptoms during pregnancy and at 2 months postpartum. These results have implications for prenatal mental health screening procedures during the pandemic and the development of early intervention programs for infants born to mothers during this adverse event.