Developmental Science最新文献

Research has shown that infants are curious and actively seek situations from which they can learn. For instance, a recent eye-tracking study demonstrates that babies tend to allocate their attention to stimuli that offer opportunities for learning new information. Interestingly, however, the degree to which attention is guided by information gain varies among individual infants. This longitudinal study provides the first empirical evidence suggesting that these early individual differences in infants’ sensitivity to information gain are linked to later cognitive development. Specifically, we found that the extent to which infants’ attention was guided by information gain at 8 months was related to their IQ scores at 3.5 years of age (n = 60, 50% female): especially children who displayed the greatest curiosity as infants tended to have a more favourable cognitive development. These findings demonstrate the lasting consequences of early existing differences in curiosity-driven exploration for later childhood cognitive development.

Summary

Emotion and language are very common in young children's everyday lives. Hour by hour, they play, listen, vocalize, react, and emote. Despite the centrality of emotion and language to toddlers’ local environments, the dynamic interplay of these communicative signals is practically unexplored. Here, we investigated how fluctuations in caregiver and child affect are linked to caregiver–child communication and children's emerging knowledge of words. Multiday household audio recordings and densely-sampled ratings of affect revealed that, in a US-based sample, children (24–30 months) were more likely to know words that they heard frequently in moments with more positive valence or higher arousal. These moments were also associated with denser communication, suggesting that moments of higher valence or arousal facilitate word knowledge in part by supporting mutually engaging communication. This investigation underscores the importance of natural affective states for understanding how children learn language.

Summary

Toddlers better retain novel object-label mappings from taxonomic categories they have more knowledge of. Separately, words for concepts with more perceptual features are learned earlier than words for concepts with fewer perceptual features. Because these factors have only been examined separately, it is unclear whether the effects of taxonomic density stem from differences in structured taxonomic knowledge or simply reflect lower-level differences in perceptual similarity among concepts. We asked how taxonomic structure and perceptual information jointly contribute to word learning at 24 months old in an ostensive word learning task. We found that semantic category knowledge facilitated word learning. We also found that the availability of perceptual features served as additional supports for word learning by children with smaller expressive vocabularies. This indicates that structured taxonomic knowledge is a better predictor of word learning compared to lower-level perceptual features at 24 months old. However, perceptual cues may provide additional support for vocabulary growth at the start of development.

Summary

A critical aspect of spoken language development is learning to categorize the sounds of the child's language(s). This process was thought to develop early during infancy to set the stage for the later development of higher-level aspects of language (e.g., vocabulary, syntax). However, many recent studies have shown that speech categorization continues to develop through adolescence. This work, which uses more sophisticated forced-choice tasks and stimuli that span speech continua (e.g., /b/ to /p/ in small steps) suggests that children show increasingly sharp category boundaries over development. However, this contrasts with the consensus view in adult speech perception that speech categories are graded and this may help listeners be more flexible. Here, our longitudinal study revisited these results using a new Visual Analogue Scaling (VAS) task, which employs a continuous rating scale to potentially unpack the underlying cause of a shallower or more gradient boundary. We tested 225 school-aged children (in grades 1–3) over 4 years (through grades 4–6). A Bayesian Hierarchical psychometric model was fit to extract the Slope of the categorization function and Response Consistency (the trial-by-trial variance). Results show that as children age, they show shallower (more gradient) slopes. It also highlighted a new variable, suggesting that older children exhibit greater trial-by-trial categorization consistency. These findings suggest that sound categorization continues to develop through early school age. These findings also suggest that children become increasingly sensitive to fine-grained gradient detail in the signal. The dramatic changes in consistency represent a challenge to current theoretical models that focus primarily on underlying category representation.

Summary

Although exploratory play is considered a hallmark of cognitive development and learning, relatively few studies have been able to quantitatively characterize the shifts that may occur in children's approach to exploration. One reason for this gap is due to challenges coding and analyzing children's exploratory play behavior. In our paper, we employ a novel computational modeling approach to understand whether and how children's exploratory play patterns shift in early childhood (3- to 11-years-old). We analyze data from children (N = 432) across five different experiments that varied in the type of exploration task (including novel toys, novel topics, and novel envelopes). Children's behaviors were coded action-by-action according to whether children repeated an action on the same type of target, switched to a novel target, or terminated play. Our computational Markov model searches over the space of possible “stay,” “switch,” and “end” parameters to quantify child-specific transition probabilities. We find that overall, older children are less likely to perseverate, more likely to switch, and more likely to end the task earlier. Our approach provides a demonstration of how Markov models can be used to map the process of play, providing insight into theories of developmental changes in exploration.

Summary

A basic question about bilingual development is how the acquisition of one language affects the acquisition of the other. Previous findings are few and mixed. The present study addressed this question with longitudinal data on the dual-language vocabulary growth of 149 US-born children from Spanish-speaking immigrant families, who were followed from the age of 2.5 to 12 years. Expressive and receptive vocabulary skills in English and Spanish were assessed with standardized tests, and primary caregivers provided estimates of the relative quantity of the children's English and Spanish exposure at home. The relations between English and Spanish skill levels and growth rates were assessed with concurrent correlations at each age and longitudinal bivariate structural equation models. The relations of skill levels in each language to the relative quantity of home exposure were assessed with concurrent correlations at each age. Findings indicated a tradeoff between English and Spanish expressive vocabulary growth through age 4 only and no competitive relation between English and Spanish in receptive vocabulary development at any age. English vocabularies were related to relative exposure quantity at home only through age 6; Spanish vocabularies were related to home exposure through age 12. The findings thus suggest that bilingual development is subtractive only in the first years of development when both languages compete for the same limited resource—home exposure, and that bilingual receptive language development is additive from an earlier age than is expressive language development.

Summary

Children often say that possible events are impossible, and only gradually come to see these events as possible. For instance, they often deny that people could do unusual things, like own a pet peacock, or immoral things, like stealing or lying. These possibility denials are surprising. For instance, children have first-hand experience with the very moral violations they say are impossible. In two experiments (total N = 220), we provide evidence that children's possibility denials can nonetheless be taken at face value and do not merely arise from quirks in how children understand questions about possibility. We do this by showing that these denials also arise in children's judgments of actuality—their judgments about what has actually happened and about which assertions of actual events could be true. In Experiment 1, children aged 4–7 judged whether ordinary, immoral, and improbable events could happen or had ever happened. With both judgments, children mostly responded affirmatively to ordinary events, often responded negatively for immoral events, and mostly responded negatively to improbable ones. In Experiment 2, children aged 5–7 judged if assertions of the three kinds of events could be true, and the same pattern emerged again. Together, these findings show that children's denials of immoral and conceptually improbable events extend beyond their judgments about what is possible and match their inferences about what is actual. These correspondences across judgments suggest that children drew on a single procedure, or set of procedures, for assessing possibility.

Summary

Parental language input is a key predictor of child language achievement. Parentese is a widely used style of child-directed speech (CDS) distinguished by a higher pitch and larger pitch range. A recent parent coaching randomized control trial (Parentese-RCT) demonstrated that English-speaking US parents who were coached to use parentese with their 6- to 18-month-olds increased the frequency of its use; their children showed enhanced language outcomes at 18 months. While these results are exciting, a roadblock in scaling this intervention is the fact that parentese has to be manually identified from daylong LENA recordings. Here we demonstrate that a newly developed CDS classifier captures the effect of this Parentese-RCT without human annotation, through a new variable: Proportion of CDS relative to all adult speech (CDS-Proportion). Two daylong recordings per child (N = 70) per timepoint (child age: 6, 10, 14, and 18 months) from the Parentese-RCT were re-analyzed by removing periods of sleep and estimating CDS-Proportion through the classifier. As was the case for parentese in the Parentese-RCT, CDS-Proportion was significantly enhanced in the intervention group. Moreover, the change over time in CDS-Proportion was significantly and positively correlated with infants’ word use at 18 months. We emphasize that the classifier does not “recognize parentese.” Likewise, CDS-Proportion is not a proxy for parentese, but rather, a variable related to parentese in complex ways. The present findings suggest a promising future for scalability of interventions using daylong recordings in combination with novel technologies.

Summary

Collaboration, the process by which individuals work together toward mutual benefits, is a core feature of human sociality. Capacities for collaboration emerge early in development and represent an important social competence. Yet, collaborative commitments can conflict with commitments to societal norms such as honesty and rule compliance, and little is known about whether the development of collaborative proclivities can promote dishonesty in young children. In this study, we tested pairs of 6- to 8-year-old Kazakh-speaking and Russian-speaking children in Kazakhstan (N = 192), a Central Asian post-Soviet society characterized by relatively high social interdependence compared to European and North American, post-industrialized samples commonly recruited in developmental research. Children participated in a die-rolling game in which they could misreport the frequency of a specific outcome to win rewards. We found that children were more likely to cheat when they benefited together with a partner (collaboration condition) than when they benefited individually (solo condition). Additionally, across both conditions, children in Kazakh-speaking classes overreported winning outcomes more frequently than children in Russian-speaking classes. These findings demonstrate that collaborative motives and socio-cultural contexts can influence honesty from an early stage in development.

Summary

Children's ability to recognize emotions in the facial expressions of others is critical for their social functioning and self-regulation. Children exposed to adversity often show differences in their ability to recognize emotions. However, most prior research has relied on clinical or high-risk samples and focused on exposure to extreme forms of adversity, such as child maltreatment or serious deprivation. The present study utilized data from the Environmental Risk (E-Risk) Longitudinal Twin Study, an epidemiological cohort of 2232 British twins, to test whether (1) children growing up in households with lower versus higher socioeconomic status (SES) are less sensitive in their identification of emotions, controlling for child intelligence quotient (IQ) and sex, and, if so, (2) differences in parenting and household environment (maternal warmth, negative parenting, orderly homes, polyvictimization, or maternal depression) across lower versus higher SES households explains these differences. Results indicated that children living in higher versus lower-income households were more sensitive in identifying a range of facial emotions, even after accounting for child IQ and sex. Maternal warmth and the state of the children's homes, but not other factors, mediated this association. Additional within-family analyses showed that children whose mothers expressed more warmth when describing them, as compared to their same-sex twin, were also more sensitive to the recognition of negative emotions. Future research is needed to test whether enhanced maternal warmth or home environments can lead to improved emotion recognition among children.

Summary