Discover the most talked about and latest scientific content & concepts.

Journal: Child development


Although most studies of language learning take place in quiet laboratory settings, everyday language learning occurs under noisy conditions. The current research investigated the effects of background speech on word learning. Both younger (22- to 24-month-olds; n = 40) and older (28- to 30-month-olds; n = 40) toddlers successfully learned novel label-object pairings when target speech was 10 dB louder than background speech but not when the signal-to-noise ratio (SNR) was 5 dB. Toddlers (28- to 30-month-olds; n = 26) successfully learned novel words with a 5-dB SNR when they initially heard the labels embedded in fluent speech without background noise, before they were mapped to objects. The results point to both challenges and protective factors that may impact language learning in complex auditory environments.

Concepts: Language, Word, Acoustics, Learning, Microsoft Word, Noise, Signal-to-noise ratio, Eb/N0


The social and historical contexts may influence the speed of development. In seven large, nationally representative surveys of U.S. adolescents 1976-2016 (N = 8.44 million, ages 13-19), fewer adolescents in recent years engaged in adult activities such as having sex, dating, drinking alcohol, working for pay, going out without their parents, and driving, suggesting a slow life strategy. Adult activities were less common when median income, life expectancy, college enrollment, and age at first birth were higher and family size and pathogen prevalence were lower, consistent with life history theory. The trends are unlikely to be due to homework and extracurricular time, which stayed steady or declined, and may or may not be linked to increased Internet use.

Concepts: Family, Marriage, Biology, Life expectancy, Mother, Human development, Vagina, Wine


This study tracked the long-term effect of perceptual individuation training on reducing 5-year-old Chinese children’s (N = 95, Mage  = 5.64 years) implicit pro-Asian/anti-Black racial bias. Initial training to individuate other-race Black faces, followed by supplementary training occurring 1 week later, resulted in a long-term reduction of pro-Asian/anti-Black bias (70 days). In contrast, training Chinese children to recognize White or Asian faces had no effect on pro-Asian/anti-Black bias. Theoretically, the finding that individuation training can have a long-term effect on reducing implicit racial bias in preschoolers suggests that a developmentally early causal linkage between perceptual and social processing of faces is not a transitory phenomenon. Practically, the data point to an effective intervention method for reducing implicit racism in young children.

Concepts: Redox, Effectiveness, Black people, Race, Ethnic group, White people, Racism, Preschool education


Middle adolescents' close friendship strength and the degree to which their broader peer group expressed a preference to affiliate with them were examined as predictors of relative change in depressive symptoms, self-worth, and social anxiety symptoms from ages 15 to 25 using multimethod, longitudinal data from 169 adolescents. Close friendship strength in midadolescence predicted relative increases in self-worth and decreases in anxiety and depressive symptoms by early adulthood. Affiliation preference by the broader peer group, in contrast, predicted higher social anxiety by early adulthood. Results are interpreted as suggesting that adolescents who prioritize forming close friendships are better situated to manage key social developmental tasks going forward than adolescents who prioritize attaining preference with many others in their peer milieu.

Concepts: Anxiety, Psychology, Sociology, Adolescence, Adult, Friendship, Adulthood, 2000 albums


This meta-analysis, spanning 5 decades of Draw-A-Scientist studies, examined U.S. children’s gender-science stereotypes linking science with men. These stereotypes should have weakened over time because women’s representation in science has risen substantially in the United States, and mass media increasingly depict female scientists. Based on 78 studies (N = 20,860; grades K-12), children’s drawings of scientists depicted female scientists more often in later decades, but less often among older children. Children’s depictions of scientists therefore have become more gender diverse over time, but children still associate science with men as they grow older. These results may reflect that children observe more male than female scientists in their environments, even though women’s representation in science has increased over time.

Concepts: Male, Female, United States, Gender, U.S. state, Woman, Latin, Kindergarten


Pseudomature behavior-ranging from minor delinquency to precocious romantic involvement-is widely viewed as a nearly normative feature of adolescence. When such behavior occurs early in adolescence, however, it was hypothesized to reflect a misguided overemphasis upon impressing peers and was considered likely to predict long-term adjustment problems. In a multimethod, multireporter study following a community sample of 184 adolescents from ages 13 to 23, early adolescent pseudomature behavior was linked cross-sectionally to a heightened desire for peer popularity and to short-term success with peers. Longitudinal results, however, supported the study’s central hypothesis: Early adolescent pseudomature behavior predicted long-term difficulties in close relationships, as well as significant problems with alcohol and substance use, and elevated levels of criminal behavior.

Concepts: Scientific method, Prediction, Economics, Hypothesis, Adolescence, Term, Thought experiment, Peer group


The development of self-regulation has been studied primarily in Western middle-class contexts and has, therefore, neglected what is known about culturally varying self-concepts and socialization strategies. The research reported here compared the self-regulatory competencies of German middle-class (N = 125) and rural Cameroonian Nso preschoolers (N = 76) using the Marshmallow test (Mischel, 2014). Study 1 revealed that 4-year-old Nso children showed better delay-of-gratification performance than their German peers. Study 2 revealed that culture-specific maternal socialization goals and interaction behaviors were related to delay-of-gratification performance. Nso mothers' focus on hierarchical relational socialization goals and responsive control seems to support children’s delay-of-gratification performance more than German middle-class mothers' emphasis on psychological autonomous socialization goals and sensitive, child-centered parenting.

Concepts: Psychology, Sociology, Educational psychology, Developmental psychology, Cultural studies, Motivation, Mother


Evidence from twin studies points to substantial environmental influences on intelligence, but the specifics of this influence are unclear. This study examined one developmental process that potentially causes intelligence differences: learning to read. In 1,890 twin pairs tested at 7, 9, 10, 12, and 16 years, a cross-lagged monozygotic-differences design was used to test for associations of earlier within-pair reading ability differences with subsequent intelligence differences. The results showed several such associations, which were not explained by differences in reading exposure and were not restricted to verbal cognitive domains. The study highlights the potentially important influence of reading ability, driven by the nonshared environment, on intellectual development and raises theoretical questions about the mechanism of this influence.

Concepts: Psychology, Educational psychology, Learning, Developmental psychology, Twin, Intelligence, Twins


Heavy parent digital technology use has been associated with suboptimal parent-child interactions, but no studies examine associations with child behavior. This study investigates whether parental problematic technology use is associated with technology-based interruptions in parent-child interactions, termed “technoference,” and whether technoference is associated with child behavior problems. Parent reports from 170 U.S. families (child Mage  = 3.04 years) and actor-partner interdependence modeling showed that maternal and paternal problematic digital technology use predicted greater technoference in mother-child and father-child interactions; then, maternal technoference predicted both mothers' and fathers' reports of child externalizing and internalizing behaviors. Results suggest that technological interruptions are associated with child problem behaviors, but directionality and transactional processes should be examined in future longitudinal studies.

Concepts: Family, Parent, Sociology, Human behavior, Mother, Father, Technology, Fatherhood


Amid growing controversy about the oft-cited “30-million-word gap,” this investigation uses language data from five American communities across the socioeconomic spectrum to test, for the first time, Hart and Risley’s (1995) claim that poor children hear 30 million fewer words than their middle-class counterparts during the early years of life. The five studies combined ethnographic fieldwork with longitudinal home observations of 42 children (18-48 months) interacting with family members in everyday life contexts. Results do not support Hart and Risley’s claim, reveal substantial variation in vocabulary environments within each socioeconomic stratum, and suggest that definitions of verbal environments that exclude multiple caregivers and bystander talk disproportionately underestimate the number of words to which low-income children are exposed.