Infancy最新文献

Infants' emerging sense of agency is thought to be supported by caregivers' contingent responsiveness. However, it remains unclear which types of responses are most relevant to this process. Here, we examined the role of contingent vocal imitation, defined as the prompt repetition of an infant's vocalization by an interaction partner. To tease apart the contribution of contingent vocal imitation from other elements of social interactions, we developed a novel vocal contingency paradigm. First, we investigated whether 5- to 6-month-old infants could rapidly learn the contingency between their own vocalizing and a novel imitative response. Then, we examined whether infants tested this newly learned contingency when it was suddenly discontinued. Novel audio-visual imitative responses were delivered and manipulated by an artificial agent. Infants' vocalizations were recorded while they experienced the novel contingency (connect phase) and its discontinuation (disconnect phase). Time-course analyses indicated a significant linear increase in vocalization frequency over time in the connect phase, supporting the hypothesis that contingent vocal imitation enables rapid vocal contingency learning. Descriptively, data suggested a quadratic trend consistent with a vocal extinction burst during the disconnect phase. However, this trend did not reach statistical significance. Therefore, there was only partial support for the role of contingent vocal imitation in the emerging sense of agency (i.e., young infants quickly learned this contingency, but there was no evidence that they tested it upon discontinuation). Overall, our paradigm provided proof of concept that vocal contingency learning can be studied in the absence of a human interaction partner.

Most studies on child language acquisition occur in the minority world (countries which make up the minority of the world's population). Their findings are not generalizable to majority-world contexts, where the majority of the world's population lives. The limited research in the latter contexts reveals the presence of differing child language socialization practices, not generalizable across Global South contexts, and that socio-economic status (SES) and geographic location (rural/urban) can affect these practices. This study examined the language input to 5-month-olds in a low-SES, Afrikaans-speaking community in South Africa. Half of the 10 participating households were urban-situated and half rural-situated. Each home had a 1-h video recording of household members interacting naturally with and around the infant; these recordings were transcribed and coded in ELAN. The amount of child-directed speech (CDS) and number of (a) different utterance types, and (b) instances of contingent speech were determined. CDS comprised 76% of all utterances. Although there were no significant differences between urban and rural households when all CDS was considered collectively, more questions were directed at rural than urban infants, and more instances of speaking on behalf of the child occurred in the case of rural infants: in each recording, caregivers used "typical" CDS features (higher pitch, repetition, etc.) to speak in the first person but on behalf of infants, an infrequently reported phenomenon in CDS research. The types and number of utterances and the amount of CDS used did not pattern as reported by scholars for other low-SES, majority-world communities.

Social odor plays an important role for various facets of early development, including communication and social processing. Previous research focusing on maternal odor has shown that smelling the mother can influence face processing in general as well as emotion processing more specifically. However, it is unclear to what extent these effects are specific to maternal odor or can also be found for other familiar social odors. To address this question, we investigated the impact of the father's odor on emotional face processing in 7-month-old infants (age at appointment 1: 209 ± 6 days [mean ± SD], range: 199-225 days; age at appointment 2: 217 ± 6 days, range: 206-231 days; gender: 15 girls and 15 boys). We recorded the infant's EEG response to female and male happy and fearful faces while infants were exposed to either their father's odor or the odor of a different infant's father. Analysis of the frontocentral Nc amplitude revealed an enhanced response to fearful compared to happy male faces only when infants smelled their own father but not when they smelled an unfamiliar father. In contrast, emotion processing at the occipital N290 was not affected by the presence of paternal odor, suggesting an impact of social odor on attention allocation rather than structural face processing. Interestingly, all effects were specific to male faces, pointing to a gender-specific impact of social odor. Our findings therefore provide first evidence for an influence of the father's odor on face processing, specifically male faces, in infancy.

Media has the potential to hinder children's language development if it disrupts or displaces parent-child interactions. However, little research has examined the wider family media ecology and how this might relate to the home language environment during infancy and early childhood. The current research utilized a longitudinal study to examine associations between the family media ecology (joint media engagement, technoference, and child television screen time) and children's quantity of child talk and parent/child conversational turns. Participants included 250 families with children (Wave 1 M age = 15.85 months) who completed a number of questionnaires and observations around media and language at two time points approximately one year apart. Higher technoference was related to lower quantity of child talk at the first wave only, but children who had higher television screen time demonstrated lower quantity of child talk and experienced fewer conversational turns 1 year later. However, there was no significant association between joint media engagement or parental technoference on quantity of child talk or conversational turns over time. Reducing television screen time in early childhood may be one strategy to encourage quantity of child talk and to enhance the home language environment.

Children readily respond to others' bids for communicative interactions from early childhood and actively initiate these themselves. However, the extent and variety of early child-initiated communicative intentions is poorly understood, with theoretically derived intentions lacking systematic empirical support from naturalistic observations. This study, using a cross-sectional data set, provides a fine-grained characterization of communicative behaviors across three time points in the second year of life (13, 18, and 23 months, N = 47). We coded one-hour-long video recordings of home observations using a novel coding scheme to document the type of interactions toddlers initiated using four deictic gestures (reach, point, give, hold out) to meet a range of communicative goals, such as sharing interest, attention, or emotion, requesting an object or an action, seeking information or help, and giving information. Expressive interactions accounted for 49.9% of events, followed by requestive (40%), information/help seeking (8.3%), and information giving intentions (1.7%). These findings characterize early communicative toddler-caregiver interactions and provide insights into the age-related patterns of toddlers' propensity to seek and transmit information which emerge increasingly as part of toddlers' communicative repertoire.

YouTube is the most popular video-sharing platform for young children and is largely characterized by low content quality. This study examined associations between YouTube viewing in toddlers, family demographics, child executive functioning (EF) and YouTube content quality. Participants include 361 largely white/non-Hispanic (72%) parents and their 24-to 26-month-olds (50% female) in a community-based cohort study; data from the baseline wave is used in this analysis. Parents completed surveys and children completed three EF tasks (Snack Delay, Shape Stroop, Reverse Categorization task). Parents reported whether their child watched YouTube or YouTube Kids, and links to the last 10 videos viewed were collected. A total of 1032 videos were coded for 6 different features, and a total quality score was calculated for each video. YouTube viewing was very common: 258 (71.5%) toddlers watched YouTube or YouTube Kids versus 103 (28.5%) toddlers who never watched YouTube. YouTube viewing was associated with parent minoritized race/ethnicity, unemployment, single parenting, and higher child daily screen time. Videos had high levels of attention-capturing "bedazzling" features (39.1%) and vicarious pleasure (48.6%), but fewer had high levels of educational content (16.7%) or positive role modeling (15.4%). Child EF scores were not associated with the content of YouTube videos viewed. Predictors of higher-quality YouTube content viewing included higher income and children not attending childcare. These results have implications for both YouTube platform design and parent decision-making about content.

Bilinguals show differences in face processing compared to monolinguals, automatically orienting more rapidly to faces and dwelling longer on faces and mouths than monolinguals. However, it is difficult to identify specific visual strategies from average-level data. This pre-registered study uses growth curve analysis within trials to explore individual differences in monolingual and bilingual children's dynamic allocation of visual attention to static faces ("Face Pop-Out") and dynamic mouths ("50 Faces"). Participants were from Greater London in two age groups: 7- to 18-month-olds (n = 131) collected at the Birkbeck Babylab, and 18- to 34-month-olds (n = 745) whose data was publicly available from the Developing Human Connectome Project. Results show that children's attentional trajectories for viewing faces and mouths are sensitive to age and early language environment. Specifically, young bilinguals showed stronger systematic disengagement than monolinguals from faces and mouths after initial orientation. Older bilinguals prioritized the mouth more than monolinguals, driven by a steeper increase in mouth-looking over stimulus time. Age-dependent shifts in attentional allocation over stimulus time were evident within both age groups, particularly in static face viewing. In infants, younger children showed earlier re-fixations to static faces than older children. In toddlers, attention to faces was more stable over stimulus time in older than younger children. Overall, results suggest that age and early exposure to two languages modulates the temporal structure of children's social attention from 7- to 34-months of age.

Research on face-selectivity in infants under 4 months has shown mixed results, especially with rapid stimulus presentations. Here we tested whether increasing face saliency would promote face-selective responses even with brief presentation times in infants aged 4-to-6 months and younger. Using frequency-tagging EEG, we presented face and nonface stimuli at a rapid 6-Hz rate (i.e., 167 ms/stimulus), with faces appearing once per second as every 6th stimulus, therefore isolating face-selectivity at 1 Hz in the EEG spectrum. Two sets of images were presented in separate conditions: a “classic” set from previous studies and a “new” more salient set with increased luminance and size of the depicted items as well as a smoother background intending to facilitate figure-ground segregation. In Experiment 1, we validated the use of the new set to elicit high-level face-selectivity in adults (N = 19). Crucially, Experiment 2 demonstrated benefits from the new set for 2-to-6-month old infants (N = 46), with the youngest ones (2-to-4-month-olds) featuring face-selective responses only to this new set. Thus, adapting stimuli to the visual capabilities of infants uncovered earlier developmental emergence of face-selectivity to rapid visual stimulation than previously thought.

As young children's digital media use increases, more research on parents' decisions, such as preferred digital content and mediation strategies, is necessary, particularly with underrepresented populations. The present study analyzed survey data on Arab parents' decisions regarding digital media use of their children under 3 years in the United Arab Emirates. Most children did not use digital media, and those who did predominantly engaged in “watching” activities. Media content focused on early learning activities and Arabic-language videos. Most parents engaged in digital media together with their child, and joint engagement was linked to less digital media use. The results suggest Arab parents' media decisions included consideration of content and an emphasis on co-using media with their children. Implications are suggested for policymakers, media developers, and parental guidelines.