Unraveling the complex interplay between statistical learning and working memory in Chinese children with and without dyslexia across different ages.

The relation between statistical learning and working memory in children with developmental dyslexia (DD) remains unclear. This study employed a distributional and a conditional statistical learning experiment and a working memory task to examine this relation in 651 Chinese 6- to 12-year-olds with and without DD (NDD = 199, 101 females; NwoDD = 452, 227 females; participated 2014-2019). Results showed working memory positively associated with recognizing high-predictable and familiar items in both groups, but negatively associated with recognizing unfamiliar items in the DD group only. These findings uncovered the complex interplay between statistical learning and working memory, demonstrating how different working memory abilities in children with and without DD relate to various statistical learning mechanisms at the item level.

Testing mechanisms underlying children's reading development: The power of learning lexical representations.

Prominent theories of reading development have separately emphasized the relevance of children's skill in learning (Share, 2008) and lexical representations (Perfetti & Hart, 2002). Integrating these ideas, we examined whether skill in learning lexical representations is a mechanism that might explain children's reading development. To do so we conducted a longitudinal study, following 139 children from Grades 3 to 5. In Grade 3, children completed measures of word reading and reading comprehension and again at Grade 5. In Grade 4, children read short stories containing novel words; they were later tested on their memory for the spellings and meanings of these new words, capturing orthographic and semantic learning, respectively. Using multiple-mediation path analysis, we tested whether children's skill in learning orthographic and semantic dimensions of new words was a mediator of individual differences in each of word reading and reading comprehension. In models controlling for nonverbal ability, working memory, vocabulary, and phonological awareness, we found two clear effects: individual differences in orthographic learning at Grade 4 mediated the gains that children made in word reading between Grades 3 and 5 and individual differences in semantic learning at Grade 4 mediated gains in reading comprehension over the same time period. These findings suggest that children's ability to learn lexical representations is a mechanism in reading development, with orthographic effects on word reading and semantic effects on reading comprehension. These findings show the power and the specificity of children's capacity to learn in determining their progress in learning to read. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The Intensity of Formal Child-Care Attendance Decreases the Shared Environment Contribution to School Readiness: A Twin Study.

The purpose of this study was to explore if child-care intensity (hours/weeks) and age of onset could moderate genetic and environmental contributions to school readiness. A sample of 648 (85% Whites; 50% Females) pairs of twins was used to compute a GxE, CxE and ExE interaction analyses. The moderation model showed that shared environment explains 48% of individual differences in school readiness for children not attending formal child-care, and decreased gradually to a mere 3% for children attending formal child-care full time, e.g., 40 h per week. Age of onset exerted no moderation effect. The results support the hypothesis that child-care acts as a normalizing environment, possibly buffering negative effects from low-quality home environments on school readiness.

From preschool language skills to writing in adolescence: Evidence of genetic continuity.

Given the importance of writing for academic achievement, this study aimed to understand how early oral language contributes to later writing skills. The first objective was to determine if preschool language skills were associated with high school writing, and if so, whether they contributed directly or indirectly through school age language. The second aim was to explore the extent to which genetic and environmental factors explained these potential associations. The sample was drawn from the Quebec Newborn Twin Study, a longitudinal follow-up of twins born in the greater Montreal area, Quebec, Canada. Language skills were assessed when children were 1.5, 2.5, 6, 7, 10, and 12 years old. Writing skills were measured at 15 years old. Participants who completed the writing task in French were included in the study (n = 316 twin pairs: 46% males). Mothers of these participants self-identified mostly as White. About 74% of them had a postsecondary diploma or certificate, and 27% further had a university degree. Most families had an income higher than 30,000 CND. Results indicate that preschool language was modestly associated with high school writing (r = .25) and that school age language fully mediated this association. Genes explained 53% of the association between preschool language and school age language and 64% of the association between school age language and high school writing. These results highlight the developmental continuity from oral to written language from preschool to high school and show that genetic factors largely account for this continuity. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Children With Persistent Versus Transient Early Language Delay: Language, Academic, and Psychosocial Outcomes in Elementary School.

Purpose The objective of this study was to compare children with persistent versus transient preschool language delay on language, academic, and psychosocial outcomes in elementary school. Method Children with persistent language delay (n = 30), transient language delay (n = 29), and no language delay (controls; n = 163) were identified from a population-based sample of twins. They were compared on language skills, academic achievement, and psychosocial adjustment in kindergarten and Grades 1, 3, 4, and 6. Results Children with persistent language delay continued to show language difficulties throughout elementary school. Furthermore, they had academic difficulties, in numeracy, and psychosocial difficulties (attention-deficit/hyperactivity disorder behaviors, externalizing behaviors, peer difficulties) from Grade 1 to Grade 6. Children with transient language delay did not differ from controls on language and academic performance. However, they showed more externalizing behaviors in kindergarten and peer difficulties in Grade 1 than controls. Conclusion Difficulties at school age are widespread and enduring in those with persistent early language delay but appear specific to psychosocial adjustment in those with transient language delay.

The bidirectional association between maternal speech and child characteristics.

Our aim was to assess whether infants influence the quantity and quality of their mothers' speech to them and, in turn, whether this maternal speech influences children's later language. As 189 mothers interacted with each of their twins at age 0;5, we calculated the number of utterances, the proportion of sensitive utterances, and the proportion of self-repeated utterances they produced. We later assessed the twins' language comprehension and production when they were 1;6, 2;6, and 5;2. Quantity of maternal speech predicted child language at 5;2, whereas sensitivity predicted child language at 2;6 and 5;2 and partial self-repetition predicted child language at 1;6. Conversely, sensitivity and partial self-repetition in maternal speech at 0;5 were associated with genetic factors from the child, indicating that infant characteristics influence the quality of maternal speech. Overall, our findings stress the importance of considering both directions in the association between maternal speech and child characteristics.

Young readers' skill in learning spellings and meanings of words during independent reading.

Independent reading offers children opportunities to learn the spellings and meanings of words. Evidence to date shows that older children take advantage of these orthographic and semantic learning opportunities. We provided a much-needed test of whether young readers can acquire spellings and meanings of novel words through independent reading as well as of whether each of these skills explains individual differences in word reading and reading comprehension. To test theory stringently, we assessed whether these effects are separable from those of decoding. A sample of 66 English-speaking children in Grades 1 and 2 independently read stories containing novel words referring to new inventions (e.g., a veap used to clean fish tanks). We scored accuracy in reading the novel words in the stories to assess target decoding. Children completed choice measures evaluating their learning of the novel words' spellings and meanings along with word reading and reading comprehension and controls for age, short-term memory, vocabulary, and phonological awareness. Scores for both the orthographic and semantic learning measures were higher with successful decoding than without it. At both grade levels, children were above chance in choosing correct spellings and meanings even when they had not accurately decoded the target a single time. In terms of individual differences, after accounting for controls including target decoding, orthographic learning was related to word reading and semantic learning was related to reading comprehension. Young children have powerful skill in learning spellings and meanings through their independent reading, with highly specific impacts of such learning on reading outcomes.