Naomi Havron

Early language is intricately related to the development of other skills. Motor skills, in particular, have been associated with language development, but the precise relations between these domains is a matter of ongoing research. Here we examined the longitudinal relations between fine- and gross-motor skills and language abilities in a large population cohort (N = 885, 49% female) from Singapore. Using a cross-lagged panel model with data from 9 to 48 months of age, we investigated both within-time associations and directional effects between motor and language domains. We found significant concurrent associations between motor and language skills. Fine-motor skills at 9 months predicted language development at 18 months, even after controlling for demographic factors. None of the other cross-domains paths was significant. In order to explain this discrepancy with past research, we therefore also explored without controlling for these factors. This latter analysis revealed more predictive paths from gross and fin- motor to language development, from the age of 9 months up to two years, suggesting that previous findings might be explained by confounding factors. Our findings highlight the importance of controlling for confounding factors when examining the relation between motor and language development.

Little is known about the dynamics of children’s conversations outside of urban Western contexts, where research focuses on one-on-one interactions with parents. Our study addresses this gap, aggregating naturalistic speech data gathered in 10 countries across multiple labs, and using novel speech diarization algorithms to extract and classify different types of conversation. We analyzed 23,000 hours of child-centered audio recordings taken from 844 children (mean age 23 months; 389 girls) across urban, agricultural, and foraging societies. We found that multiparty conversations, involving at least three speakers, are more frequent than any other type of conversation. Across settings, children’s relative exposure to conversation differed based on their age, number of siblings, and mother’s education. We conclude that the kinds of conversation most often studied differ from those children typically encounter. Greater focus on children’s conversations in multiparty contexts may provide a more representative picture of their daily experience with language.

Time is a fundamental component of our mental life because it structures our thinking and actions. However, time can mean several things, as it is a multifaceted concept (Le Poidevin, 2007; McTagga...

The ability to learn and apply rules lies at the heart of cognition. In a seminal study, Marcus et al. (1999) reported that 7‐month‐old infants learned abstract rules over syllable sequences and were able to generalize those rules to novel syllable sequences. Dozens of studies have since replicated that finding and extended it using different rules, modalities, stimuli, participants (human adults and non‐human animals) and experimental procedures. Yet questions remain about the generalizability of the core findings in Marcus et al., and sources of variation across these findings. In the current study, we address this issue by testing 839 infants (650 after exclusions) of a wide age range (5;0–12;0 months) in a multi‐laboratory (30 laboratories, [31 samples]) conceptual replication of the Marcus et al. study. This study and the analysis plan were submitted as a registered report. A mixed‐model analysis of the looking times at consistent versus inconsistent test trials indicated no significant effect. The current study therefore finds no evidence for rule‐learning; to the contrary, a Bayesian analysis of the data indicated strong evidence for a null effect. This was similarly the case for the moderating factors that were part of the design: mono‐ versus multilingualism, age, and experimental paradigm; none of these factors showed significant effects. Robustness analyses indicated that the results were not different in the case of different choices in the (pre‐)processing of the data. A follow‐up analysis for single labs indicated that there was no evidence of rule‐learning in 30 of the 31 contributed samples. The current finding raises fundamental issues about rule‐learning that are presented in the Discussion section.

Symbolic play supports crucial aspects of early childhood development, including language and social-cognitive skills. Parent-child dyadic play has been shown to facilitate symbolic play development, but less is known about the addition of siblings (triadic interactions), which may present both opportunities and challenges. We examined toddlers' symbolic play across dyadic (mother-child) and triadic (mother-child-sibling) free-play interactions recorded through videoconferencing. Twenty toddlers (aged 1.5–2.5 years, eight girls) were observed playing with their mothers and older siblings (aged 3.5–7.5 years, ten sisters) in two standardized 10-minute play sessions at their homes. We coded the frequency, duration, variety, toddler initiative, and complexity of symbolic play. Consistent with our hypothesis, toddlers demonstrated significantly higher levels of symbolic play in dyadic versus triadic interactions overall ( p < 0.0001, Cohen's d = 0.953) and across all measured dimensions ( p < 0.05 to p < 0.001, Cohen's d = 0.637–0.915). This suggests that dyadic play may optimize conditions for symbolic play development, and/or that the addition of siblings introduces competing demands that reduce opportunities for advanced symbolic play. The results have implications for understanding how family configuration influences early play experiences and may inform the design of interventions to support symbolic play development in different social contexts.

The ability to learn and apply rules lies at the heart of cognition. In a seminal study, Marcus et al.(1999) reported that 7-month-old infants learned abstract rules over syllable sequences and wereable to generalize those rules to novel syllable sequences. Dozens of studies have since replicatedthat finding and extended it using different rules, modalities, stimuli, participants (human adultsand non-human animals) and experimental procedures. Yet questions remain about thegeneralizability of Marcus et al.’s (1999) core findings, and sources of variation across thesefindings. In the current study, we address this issue by testing 839 infants of a wide age range(5;0-12;0 months) in a multi-laboratory (30 laboratories, [31 samples]) conceptual replication ofthe Marcus et al. (1999) study. This study and the analyses were submitted as a registered report.A mixed-model analysis of the looking times at consistent vs. inconsistent test trials indicated nosignificant effect. The current study therefore finds no evidence for rule-learning; to the contrary, aBayesian analysis of the data indicated strong evidence for a null effect. This was similarly thecase for the moderating factors that were part of the design: mono- vs. multilingualism, age, andexperimental paradigm; none of these factors showed significant effects. Robustness analysesindicated that the results were not different in the case of different choices in the (pre-)processingof the data. A follow-up analysis for single labs indicated that there was no evidence ofrule-learning in 30 of the 31 contributed samples. The current finding raises fundamental issuesabout rule-learning that are presented in Discussion.

Do toddlers and adults engage in spontaneous Theory of Mind? This multi-lab collaboration examined whether 18- to 27-month-olds’ and adults’ anticipatory looks distinguish between two basic forms of epistemic states: knowledge and ignorance. In adults (n = 703, 68% female), we found clear evidence that they do: they showed simple goal-based action anticipation and differentiated between knowledge and ignorance conditions. In toddlers (n = 521, 49% female), results were less conclusive. While demonstrating goal-based action anticipation, they did not differentiate between knowledge and ignorance as predicted. Future research can explore adults’ sensitivity to more complex epistemic states like true/false beliefs and clarify whether toddlers’ results reflect competence or performance limitations.

The current study aims to examine the developmental trajectory of word recognition in infants learning different languages across different ages, using an online adaptation of the traditional Looking-While-Listening paradigm. Specifically, we aim to examine whether children’s word recognition as indexed by speed and accuracy of their looking toward a named referent varies as a function of (1) age of the child, (2) whether their caregiver indicated that they understand the word, and (3) the language they are learning. Infants between 10-24-months from various countries and learning various languages will be recruited by research teams across the world to participate in the study, with the goal of 48 infants for each language. Children will be presented with two familiar objects on the screen while hearing the label of one of the objects embedded in a carrier phrase. Additionally, caregivers will also report children’s knowledge of the presented words through a questionnaire. We predict that infant word recognition accuracy and speed will improve as they grow older. However, given the mixed evidence for convergence between parent reports and children’s word recognition, and the possibility that there may be variation in the relationship between caregiver report and performance across languages due to linguistic differences, the nature of the association between parental report of word knowledge or language background on children’s word recognition remains an open empirical question. With our approach, we aim to build a more inclusive model of studying infant word recognition, and to develop more resource-friendly adaptations for cross-linguistic research.

Linguistic change often originates in the reanalysis of spoken language, that is, in a change in the underlying grammatical structure or semantic interpretation assigned to a form whose surface realization initially remains unchanged. If communication is viewed as faithful message transmission between sender and receiver, how can such mismatches arise? We argue that reanalysis is possible when truth conditions are preserved across the original and reanalysed representations, allowing mismatches between surface form and underlying grammar to be treated as noise and repaired in processing. We support this hypothesis with diachronic evidence from multiple languages showing shifts ingrammatical analysis alongside stable propositional content. We then present a sentence-repetition experiment in which participants were asked to repeat sentences verbatim. We find that participants reproduce a corrected form rather than the original stimulus when truth conditions remain stable, but accurately reproduce errors when these introduce semantic ambiguity. These findings indicate that repair is driven not by formal deviance alone, but by interpretive stability, and thus illuminate how real-time processing mechanisms can give rise to long-term language change.