A child\'s social world is complex and rich, but has traditionally been assessed with conventional experiments where children are presented with repeated stimuli on a screen. These assessments are impoverished relative to the dynamics of social interactions in real life, and can be challenging to implement with preschoolers, who struggle to comply with strict lab rules. The current work meets the need to develop new platforms to assess preschoolers\' social development, by presenting a unique virtual-reality set-up combined with wearable functional near-infrared spectroscopy (fNIRS). As a proof-of-principle, we validated this platform by measuring brain activity during self-guided social interaction in 3-to-5-year-olds, which is under-investigated, yet crucial to understand the basis of social interactions in preschoolers. 37 preschoolers chose an interaction partner from one of 4 human-like avatars of different gender and age. We recorded spontaneous brain fluctuations from the frontal and temporoparietal regions (notably engaged in social-categorization and preference) while children played a bubble-popping game with a preferred and an assigned avatar. 60% of the participants chose to play with the same-gender and same-age avatar. However, this result was driven by females (>80% vs. 50% in males). Different fronto-temporoparietal connectivity patterns when playing with the two avatars were observed, especially in females. We showed the feasibility of using a novel set-up to naturalistically assess social preference in preschoolers, which was assessed at the behavioural and functional connectivity level. This work provides a first proof-of-principle for using cutting-edge technologies and naturalistic experiments to study social development, opening new avenues of research.

During the second year of life, children\'s need for autonomy grows, and their behaviors become increasingly complex. Parental sensitivity to children\'s different cues is important in supporting adaptive psycho-emotional development. The present study assumes that mothers and fathers may respond with varying levels of sensitivity to the child\'s different cues, with particular attention to requests for greater autonomy. The study also examines the possible role played by interactive contexts (ie., play and feeding) and children\'s and parents\' individual factors. The sample comprised N = 91 families with children aged between 12 and 24 months. Mother-toddler and father-toddler interactions were assessed during feeding and play. Parents completed questionnaires assessing children\'s temperament, psychopathological risk, and parenting stress. RESULTS: showed that toddlers\' demands for autonomy were the most frequent cues in both play and feeding contexts, both with mothers and fathers. Furthermore, parents were more sensitive to toddlers\' requests for cooperation than their requests for autonomy, in both interactive contexts. Moreover, mothers and fathers showed higher sensitivity to toddlers\' demands for greater autonomy in the play context rather than in the feeding context. Mothers were more sensitive than fathers to toddlers\' cues of resistance to parents\' actions and to toddlers\' requests for cooperation. Results showed differences and specificities in mother-toddler and father-toddler interactions in the two interactive contexts, showing associations between child negative emotionality, parental psychopathological risk and parenting stress, and maternal and paternal sensitivity to toddlers\' demands for greater autonomy during play and feeding, respectively. These results confirm the initial hypotheses regarding parental sensitivity and its differential expression according to child cues. Implications are discussed.

UNASSIGNED: This study aimed to investigate the effect of rapid weight gain (RWG) on the incidence of central precocious puberty (CPP) using nationwide population-based data.
UNASSIGNED: A total of 253,967 children (101,841 boys and 152,126 girls) who underwent regular health consultations under the National Health Insurance Service from 2007 to 2010 were followed up until the age of 10 years for boys and 9 years for girls. We calculated differences in the weight Z-scores from 4-6 months to 9-12 months (infancy) and from 9-12 months to 18-24 months or 30-36 months (toddlerhood) using the lambda-mu-sigma method. The population was subdivided into four groups: RWGinf/tod (infancy > + 0.67 standard deviation score [SDS], toddlerhood > 0 SDS), RWGinf (infancy > + 0.67 SDS, toddlerhood < 0 SDS), RWGtod (toddlerhood > + 0.67 SDS), and control (no RWG). The diagnosis of CPP was based on the diagnostic codes of the International Classification of Diseases 10th revision and the prescription of gonadotropin-releasing hormone agonists. The cumulative risk of CPP based on age was analyzed using Kaplan-Meier survival curves, and the association between the RWG groups and CPP was assessed using multivariate logistic regression analysis.
UNASSIGNED: CPP was diagnosed in 268 boys and 9,225 girls. For the girls, the CPP-free probability was the highest in the control group, followed by the RWGtod, RWGinf, and RWGinf/tod groups (log-rank p < 0.001). However, the incidence of CPP did not vary significantly for the boys. Compared to the control group, the other groups had a higher risk of CPP in girls (RWGinf/tod: adjusted odds ratio [aOR] 1.35, 95%, confidence interval [95% CI] 1.13-1.62; RWGinf: aOR 1.25, 95% CI 1.13-1.38; and RWGtod: aOR 1.18, 95% CI 1.09-1.28).
UNASSIGNED: This nationwide population-based study demonstrated that any RWG from birth to 3 years of age contributed to an increased risk of CPP in girls but not in boys. Girls who experienced RWG during both infancy and toddlerhood had the highest risk of developing CPP. These findings suggest that early detection and appropriate management of excessive weight gain in early life may be important for preventing CPP in girls.

Little is known about the direction, ordering, and uniqueness of longitudinal associations between behavior problems and cognitive ability, from toddlerhood to middle childhood. A developmental cascade model was tested in the present study to examine the transactional processes in 103 Chinese children at the ages of 1, 2, 7, and 9 years. Behavior problems were assessed using the maternal reported Infant-Toddler Social and Emotional Assessment at the ages of 1, 2 and parental reported Children Behavior Checklist at the ages of 7, 9. Cognitive ability was measured using Bayley Scales of Infant and Toddler Development at the ages of 1, 2 and Wechsler Intelligence Scale for Children at the ages of 7, 9. The results revealed the stability of behavior problems and cognitive ability from age 1 to age 9 years and concurrent associations between externalizing and internalizing problems. Unique longitudinal associations were identified between (1) age 1 cognitive ability and age 2 internalizing problems, (2) age 2 externalizing problems and age 7 internalizing problems, (3) age 2 externalizing problems and age 7 cognitive ability, (4) age 7 cognitive ability and age 9 externalizing problems. The results indicated essential targets for future interventions aimed at reducing children\'s behavior problems at 2 years old and promoting cognitive ability at 1 year old and 7 years old.

Parent relationship satisfaction and parental reflective functioning (PRF) are significant factors in the transition to first-time parenting and are likely to affect a child\'s later wellbeing. However, little is known about their joint longitudinal effects from pregnancy onward. Starting in the prenatal period, this follow-up study of 1016 Finnish first-time parents (358 fathers and 658 mothers at baseline) examined the stability and the reciprocal associations between relationship satisfaction and PRF in predicting child behavioral problems (CBCL) at age 2. First, the results of the random-intercept cross-lagged panel models showed that both relationship satisfaction and PRF were stable from pregnancy onward for both mothers and fathers, with the exception of mothers\' prenatal PRF. Second, there were significant reciprocal associations between low prenatal PRF and low relationship satisfaction at age 1, and vice versa. Third, for both mothers and fathers, a low level of relationship satisfaction, but not PRF, predicted consistently higher levels of child behavioral problems at age 2. These results suggest that parent relationship satisfaction and PRF are stable but largely independent parental factors during the transition to parenthood. In addition, our results highlight the significant role of parent relationship satisfaction in predicting toddler behavior problems, which indicates the relevance of early relationship-orientated help for first-time parents.

Firstborn children have higher rates of obesity compared to secondborns, perhaps due, in part, to differential feeding practices. Despite the centrality of siblings in family life and potential for influence, almost nothing is known about the role of siblings in parent feeding practices in early childhood.
Participants (n = 117) were mothers of consecutively born siblings. Firstborns participated in an RCT that compared a responsive parenting intervention designed for primary prevention of obesity against a safety control. Secondborns participated in an observational cohort. Multilevel models tested whether and how firstborn characteristics (temperament, appetite, rapid weight gain) at 16 weeks and 1 year were associated maternal feeding practices of secondborns in infancy at 16 weeks, 28 weeks, and 1 year (food to soothe) and at ages 1, 2, and 3 years (structure-and control-based feeding practices). A purposive subsample (n = 30) of mothers also participated in semi-structured interviews to further illuminate potential sibling influences on maternal feeding practices during infancy and toddlerhood.
Firstborn characteristics did not predict secondborn feeding in infancy (all ps > 0.05). Firstborn negative affect, however, predicted mothers\' less consistent mealtime routines (b (SE) = - 0.27 (0.09); p = 0.005) and more pressure (b (SE) = 0.38 (0.12); p = 0.001). Firstborn appetite predicted mothers\' less frequent use of food to soothe (b (SE) = - 0.16 (0.07); p = 0.02) when secondborns were toddlers. Firstborn surgency, regulation, and rapid weight gain, however, did not predict secondborn feeding practices during toddlerhood (all ps > 0.05). Interviews with mothers revealed three ways that maternal experiences with firstborns informed feeding practices of secondborns: 1) Use of feeding practices with secondborn that worked for the firstborn; 2) Confidence came from firstborn feeding experiences making secondborn feeding less anxiety-provoking; and 3) Additional experiences with firstborn and other factors that contributed to secondborn feeding practices.
Some firstborn characteristics and maternal experiences with firstborns as well as maternal psychosocial factors may have implications for mothers\' feeding practices with secondborns. Together, these mixed methods findings may inform future research and family-based interventions focused on maternal feeding of siblings in early childhood.

Contact with water, even from birth, may be an important experience for child development. In this work, we aimed to investigate if baby swimming might influence infant development in motor and cognitive domains. We assigned infants to either a 10-week baby swimming intervention (n = 12; M age = 13 months (SD) = 7) or a control group (n = 15; M age = 22 months (SD) = 6). We assessed motor development with the Peabody Developmental Motor Scales (2nd edition, PDMS-2) and cognitive development with core tests of executive functions: delayed response for working memory, object retrieval for inhibition, and A-not-B for response shifting. Non-parametric analyses revealed that infants in the baby-swimming group improved in gross, fine, and total motor skills, and showed marginally better inhibition speed and shifting accuracy, with associated gains of shifting accuracy and fine and total motor skills. Even with in this small-sized convenience sample, this pilot study revealed promising benefits from baby swimming on motor development that warrant further study. This preliminary work paves the way for replication and illustrates what effect sizes may be expected in sufficiently powered well-designed follow-up research targeted to aid the joint development of motor and cognitive skills as early as infancy.

Executive functioning (EF) is one of the building blocks in parental caregiving behavior, and contextual variables have been reported to moderate the link between EF and caregiving behavior. Although psychological distress due to various factors is prevalent during early parenthood and is negatively associated with adult EF, it is not known whether psychological distress influences the maternal EF/caregiving link. This study explored the association between maternal EF and caregiving behavior (more specifically, Emotional Availability/EA), and whether single and cumulative maternal psychological distress domains moderated the EF/EA association in a general population sample of 137 Finnish birth cohort mothers with 2.5-year-old children. EF was measured with a composite of five computerized Cogstate tasks, EA with the Emotional Availability Scales, and three psychological distress domains with self-report questionnaires (depression: EPDS, anxiety: SCL-90, insomnia: AIS). Better EF was significantly associated with more positive, sensitive caregiving, but this association was no longer significant when controlling for education level. Neither individual nor cumulative distress domains moderated the EF/EA association significantly, although the observed moderation effects were in the expected direction. These findings suggest that EF should be recognized alongside socioemotional factors as variables that are associated with parental caregiving behavior during toddlerhood. Furthermore, if the non-significant moderation results are replicated, they indicate that mothers in community samples are not at great risk for psychological distress that would compromise their capacity to utilize their EF while caring for their child. Further studies are needed to confirm these findings, as well as to examine these associations among fathers and in samples that have higher levels of chronic stressors. Studies with more diverse samples in terms of distress levels and EF performance would provide further insight into early childhood parenting and its risk factors.

This study is one of a very few prospective long-term studies in autism spectrum disorder (ASD). The study compared outcome trajectories in three adolescent groups (T2): \"best outcome\" (BO, n = 11) did not meet cut-off points for ASD and IQ scores ≥85; high functioning (HF-ASD, n = 14); and lower functioning (LF-ASD, n = 43). Additionally, the study searched for characteristics at toddlerhood (T1) that may predict belonging to the above groups. The study included 68 adolescents (63 males) diagnosed with ASD at toddlerhood (mean age: 13:10 years), mean follow-up time was 11:7 years. Participants underwent comprehensive assessments at T1 and T2. Different trajectories were found for the three defined groups. The BO group improved significantly in cognitive ability, autism severity, and adaptive skills in comparison to no improvement for the LF-ASD group or partial progress for the HF-ASD group. At toddlerhood, better cognition and less severe autism social affect symptoms were generally associated with a better outcome. Early social behaviors including better \"pointing,\" \"facial expression directed to others,\" \"showing,\" and \"response to joint attention\" were associated with membership in the BO group. In addition, the BO group had the lowest prevalence of significant T2 inattention and anxiety symptoms. No significant differences between the three outcome groups were noted in the birth and prevalence of medical problems. Higher cognitive ability and better T1 showing and pointing behaviors predicted better outcome. The study points to the change in autism severity over time and to the prognostic value of early developmental abilities, social engagement behaviors, and the existence of comorbidities. Autism Res 2020, 13: 1130-1143. © 2020 International Society for Autism Research and Wiley Periodicals LLC. LAY SUMMARY: This long-term study compared characteristics of toddlers diagnosed with autism spectrum disorder (ASD) in three outcome groups in adolescence: best outcome (BO-average IQ/not meeting criteria for ASD), high-functioning ASD, and low-functioning ASD (LF-ASD). At toddlerhood, the BO group displayed less severe autism symptoms, mostly in sharing interests, compared to the LF-ASD group. The BO group had fewer inattention and anxiety symptoms than the two ASD groups. Additionally, early cognitive level and social engagement behaviors predicted outcome in ASD.

Active play is regarded as physical activity during early childhood. Physical activity has many benefits for children\'s physical and psychosocial health and wellbeing, as well as for their cognitive development. The aim of this study was to investigate associations between the preference for active play and neurological development in toddlers. The study was conducted as a register-based study, and the data were collected from a public-health clinic\'s electronic health records. The register data about active play used in this study were originally assessed by parents at home and by early years teachers at nurseries. Neurological development was assessed by the public health nurses in public child-health clinics. The data eligible for this study were available from 717 toddlers aged 2.5-3.0 years old (mean: 2.5 years ± 2 months). The majority of toddlers (85%) showed a preference for active play, both at home and at the nursery. The prevalence of delays in the neurological development of toddlers varied in different developmental areas (by 1-15%). Delays in gross motor competence, auditory perception, and self-help skills were associated with a lower preference for active play in nursery settings, but none of the neurodevelopmental items were found to be associated with toddlers\' preference for active play at home. Nurseries need to encourage children to actively play and support their gross motor competence and self-help skills.