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Scientific research can be categorized into: a) descriptive research, with the main goal to summarize characteristics of a group (or person); b) predictive research, with the main goal to forecast future outcomes that can be used for screening, selection, or monitoring; and c) explanatory research, with the main goal to understand the underlying causal mechanism, which can then be used to develop interventions. Since each goal requires different research methods in terms of design, operationalization, model building and evaluation, it should form an important basis for decisions on how to set up and execute a study. To determine the extent to which developmental research is motivated by each goal and how this aligns with the research designs that are used, we evaluated 100 publications from the Consortium on Individual Development (CID). This analysis shows that the match between research goal and research design is not always optimal. We discuss alternative techniques, which are not yet part of the developmental scientist's standard toolbox, but that may help bridge some of the lurking gaps that developmental scientists encounter between their research design and their research goal. These include unsupervised and supervised machine learning, directed acyclical graphs, Mendelian randomization, and target trials., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Mapuche represents the largest indigenous group in Chile amounting to nearly 10% of the total population. In a longitudinal cohort of 12,398 children, we analyzed the role of ethnicity in physical and psychosocial development of Mapuche and nonindigenous Chilean toddlers (age 2.5 years), taking into account sociodemographic and caregiver characteristics. As indicated by our univariate analysis, the Mapuche developmental niche was characterized by lower income, lower maternal education, poorer quality of the home environment, longer breastfeeding, and higher parental stress. Physical development showed higher body mass index. Mapuche children showed less externalizing problems. We then analyzed the incremental contribution of ethnicity in a series of hierarchical regressions with the second wave of developmental measurements (age 4.5 years) as outcome variables, showing a significant but modest incremental contribution of ethnicity to the prediction of children's development between 2.5 and 4.5 years of age. Controlling for environmental variables, Mapuche showed less externalizing and internalizing, behavior problems. Socioeconomic status, quality of the home environment, and parenting stress were stronger predictors of socioemotional development than ethnicity per se.

This study examined whether the association between age and amygdala-medial prefrontal cortex (mPFC) connectivity in typically developing 6- to 10-year-old children is correlated with parental care. Resting-state functional magnetic resonance imaging scans were acquired from 124 children of the Generation R Study who at 4 years old had been observed interacting with their parents to assess maternal and paternal sensitivity. Amygdala functional connectivity was assessed using a general linear model with the amygdalae time series as explanatory variables. Higher level analyses assessing Sensitivity × Age as well as exploratory Sensitivity × Age × Gender interaction effects were performed restricted to voxels in the mPFC. We found significant Sensitivity × Age interaction effects on amygdala-mPFC connectivity. Age was related to stronger amygdala-mPFC connectivity in children with a lower combined parental sensitivity score (b = 0.11, p = .004, b = 0.06, p = .06, right and left amygdala, respectively), but not in children with a higher parental sensitivity score, (b = -0.07, p = .12, b = -0.06, p = .12, right and left amygdala, respectively). A similar effect was found for maternal sensitivity, with stronger amygdala-mPFC connectivity in children with less sensitive mothers. Exploratory (parental, maternal, paternal) Sensitivity × Age × Gender interaction analyses suggested that this effect was especially pronounced in girls. Amygdala-mPFC resting-state functional connectivity has been shown to increase from age 10.5 years onward, implying that the positive association between age and amygdala-mPFC connectivity in 6- to 10-year-old children of less sensitive parents represents accelerated development of the amygdala-mPFC circuit.

We investigated the association between mothers' and fathers' harsh parenting and sensitive parenting practices and child's executive functions (EF) in early childhood in 607 families. We focused on three broad dimensions of child EF: Emergent metacognition, inhibitory self-control, and flexibility measured with the parent-reported Behavior Rating Inventory of Executive Function-Preschool Version. Less sensitive parenting of the mother and harsher parenting of the father were related to lower scores of emergent metacognition and inhibitory self-control. Parenting was not associated with child flexibility. This study extends previous research on the association between parenting and EF by the focus on the role of the father and demonstrates independent effects of mother and father on child EF., (© 2015 The British Psychological Society.)

Objective: Early caregiving can have an impact on brain structure and function in children. The influence of extreme caregiving experiences has been demonstrated, but studies on the influence of normal variation in parenting quality are scarce. Moreover, no studies to date have included the role of both maternal and paternal sensitivity in child brain maturation. This study examined the prospective relation between mothers' and fathers' sensitive caregiving in early childhood and brain structure later in childhood., Method: Participants were enrolled in a population-based prenatal cohort. For 191 families, maternal and paternal sensitivity was repeatedly observed when the child was between 1 year and 4 years of age. Head circumference was assessed at 6 weeks, and brain structure was assessed using magnetic resonance imaging (MRI) measurements at 8 years of age., Results: Higher levels of parental sensitivity in early childhood were associated with larger total brain volume (adjusted β = 0.15, p = .01) and gray matter volume (adjusted β = 0.16, p = .01) at 8 years, controlling for infant head size. Higher levels of maternal sensitivity in early childhood were associated with a larger gray matter volume (adjusted β = 0.13, p = .04) at 8 years, independent of infant head circumference. Associations with maternal versus paternal sensitivity were not significantly different., Conclusion: Normal variation in caregiving quality is related to markers of more optimal brain development in children. The results illustrate the important role of both mothers and fathers in child brain development., (Copyright © 2015 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.)

A large volume of behavioral research has explored the variable number of tandem repeat (VNTR) polymorphism on the dopamine receptor D4 gene (DRD4). However, findings are inconsistent and there is no agreement about what constitutes "functional" and "less functional" variants at this locus. First, we systematically review studies exploring biological differences between DRD4 VNTRs (k=21). Second, we systematically review studies relating DRD4 variation to behavioral traits in population-based, non-clinical samples of children and adolescents (k=46; N=13,195), highlighting the various genotypic classifications previously used. Third, we use meta-analyses to examine associations of DRD4 VNTRs with five broadly-defined behavioral outcomes (externalizing and attention problems, executive function, social/emotional development, and "reactive" temperament). We identify a significant association of "longer" DRD4 variants with lower levels of executive function and social/emotional development, but not independent of the choice of genotypic classification. We suggest that until the functionality of DRD4 VNTRs is established, researchers should report all genotypic classifications to ensure full transparency and allow for further meta-analytic work., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

To investigate potential infant-related antecedents characterizing later attachment security, this study tested whether attention to facial expressions, assessed with an eye-tracking paradigm at 7 months of age (N = 73), predicted infant-mother attachment in the Strange Situation Procedure at 14 months. Attention to fearful faces at 7 months predicted attachment security, with a smaller attentional bias to fearful expressions associated with insecure attachment. Attachment disorganization in particular was linked to an absence of the age-typical attentional bias to fear. These data provide the first evidence linking infants' attentional bias to negative facial expressions with attachment formation and suggest reduced sensitivity to facial expressions of negative emotion as a testable trait that could link attachment disorganization with later behavioral outcomes., (© 2015 The Authors. Child Development published by Wiley Periodicals, Inc. on behalf of Society for Research in Child Development.)

Objective: A number of studies have established an association between antenatal maternal depression and infant sleep. One key question is whether all infants are equally susceptible to environmental influences, including the intrauterine environment. Reactive temperament has been examined as a plasticity factor, with accumulating evidence suggesting that infants with reactive temperament may be more susceptible to both positive and negative environmental influences. This study examines whether infant reactivity moderates any association between antenatal depression and infant sleep in 2 longitudinal studies: the Avon Longitudinal Study of Parents and Children (ALSPAC) and Generation R cohorts., Methods: Maternal depression scores were assessed during pregnancy using Edinburgh Postnatal Depression Scale and Brief Symptom Inventory. Infant sleep duration and awakenings, in ALSPAC (N = 8318) and Generation R (N = 2241), were assessed at 18 and 24 months of age, respectively. Infant reactivity was assessed by temperament questionnaire at 6 months of age., Results: Hierarchical linear regression models indicated a 3-way interaction between reactivity and gender moderating the effect of antenatal depression on infant sleep, on sleep duration in Generation R at 24 months (β = .085, p < .001) in the whole sample and when limited to the Dutch/European group (β = .055, p = .030), and on night awakenings at 18 months in ALSPAC (β = -.085, p = .013). Boys with more reactive temperament exhibited shorter sleep duration and a higher number of awakenings when previously exposed to maternal symptoms of antenatal depression., Conclusion: For the first time, these findings highlight, in 2 large cohorts, that children with temperamental reactivity may be more vulnerable to antenatal depression, raising the possibility of targeted interventions to improve infant outcomes.

We examined whether differences in adult attachment representations could be predicted from early and later maternal sensitivity, controlling for early and later assessments of attachment. In this longitudinal study on 190 adoptees, attachment at 23 years was measured with the Attachment Script Assessment. Maternal sensitivity was observed in infancy and at seven and 14 years. Attachment was also measured in infancy and at 14 years. Higher maternal sensitivity in infancy predicted more secure attachment in infancy and more secure attachment representations in young adulthood. Higher maternal sensitivity in middle childhood also predicted more secure attachment representations in young adulthood. There was no continuity of attachment from infancy to young adulthood, but attachment in adolescence and young adulthood were significantly related. Even in genetically unrelated families, maternal sensitivity in early and middle childhood predicts attachment representations in young adults, confirming the importance of sensitive parenting for human development.

The immediate and short-term consequences of adult HIV for affected children are well documented. Little research has examined the long-term implications of childhood adversity stemming from caregiver HIV infection. Through overviews provided by experts in the field, together with an iterative process of consultation and refinement, we have extracted insights from the broader field of child development of relevance to predicting the long-term consequences to children affected by HIV and AIDS. We focus on what is known about the impact of adversities similar to those experienced by HIV-affected children, and for which there is longitudinal evidence. Cautioning that findings are not directly transferable across children or contexts, we examine findings from the study of parental death, divorce, poor parental mental health, institutionalization, undernutrition, and exposure to violence. Regardless of the type of adversity, the majority of children manifest resilience and do not experience any long-term negative consequences. However, a significant minority do and these children experience not one, but multiple problems, which frequently endure over time in the absence of support and opportunities for recovery. As a result, they are highly likely to suffer numerous and enduring impacts. These insights suggest a new strategic approach to interventions for children affected by HIV and AIDS, one that effectively combines a universal lattice of protection with intensive intervention targeted to selected children and families.

The goal of this study is to clarify the relation between maternal sensitivity and internalizing problems during the preschool period. For this purpose, a longitudinal, bidirectional model was tested in two large prospective, population-based cohorts, the Generation R Study and the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (NICHD SECCYD), including over 1,800 mother-child dyads in total. Maternal sensitivity was repeatedly observed in mother-child interaction tasks and information on child internalizing problems was obtained from maternal reports. Modest but consistent associations between maternal sensitivity and internalizing problems were found in both cohorts, confirming the importance of sensitive parenting for positive development in the preschool years. Pathways from maternal sensitivity to child internalizing problems were consistently observed but child-to-mother pathways were only found in the NICHD SECCYD sample.

The neuropeptide oxytocin has been implicated in a variety of social processes. However, recent studies indicate that oxytocin does not enhance prosocial behavior in all people in all circumstances. Here, we investigate effects of intranasal oxytocin administration on intrinsic functional brain connectivity with resting state functional magnetic resonance imaging. Participants were 42 women who received a nasal spray containing either 16 IU of oxytocin or a placebo and reported how often their mother used love withdrawal as a disciplinary strategy involving withholding love and affection after a failure or misbehavior. We found that oxytocin changes functional connectivity between the posterior cingulate cortex (PCC) and the brainstem. In the oxytocin group there was a positive connectivity between these regions, whereas the placebo group showed negative connectivity. In addition, oxytocin induced functional connectivity changes between the PCC, the cerebellum and the postcentral gyrus, but only for those participants who experienced low levels of maternal love withdrawal. We speculate that oxytocin enhances prosocial behavior by influencing complex brain networks involved in self-referential processing and affectionate touch, most prominently in individuals with supportive family backgrounds., (Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.)

Objective: First, we give an overview of child psychiatric research in the Generation R Study, a population-based cohort from fetal life forward. Second, we examine within Generation R whether the functional polymorphism (5-HTTLPR) in the promoter of the serotonin transporter gene interacts with prenatal maternal chronic difficulties, prenatal maternal anxiety or postnatal maternal anxiety to influence child emotional development., Method: A total of 2,136 northern European children were genotyped for 5-HTTLPR and rs25531. Mothers reported chronic difficulties and anxiety symptoms at 20 weeks' pregnancy and when the child was 3 years old. Child emotion recognition was observed at 3 years, and child emotional problems were assessed with the CBCL/1½-5 at 5 years., Results: There were consistent main effects of maternal difficulties and anxiety on child emotional problems, but no main effect of 5-HTTLPR. Moreover, children with the s allele were at increased risk for emotional problems if their mothers reported prenatal anxiety symptoms (β = 2.02, p < .001) or postnatal anxiety symptoms (β = 1.64, p < 0.001). Also, in children of mothers with prenatal anxiety symptoms, the s allele was associated with less accurate emotion-matching (β = -0.11, p = .004)., Conclusions: This population-based study shows that vulnerability due to 5-HTTLPR is not specific for certain adverse exposures or severe events, but suggests that the small effects of gene-environment interaction on emotional development become manifest early in life., (Copyright © 2012 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.)

Two extant evolutionary models, biological sensitivity to context theory (BSCT) and differential susceptibility theory (DST), converge on the hypothesis that some individuals are more susceptible than others to both negative (risk-promoting) and positive (development-enhancing) environmental conditions. These models contrast with the currently dominant perspective on personal vulnerability and environmental risk: diathesis stress/dual risk. We review challenges to this perspective based on emerging theory and data from the evolutionary, developmental, and health sciences. These challenges signify the need for a paradigm shift in conceptualizing Person x Environment interactions in development. In this context we advance an evolutionary--neurodevelopmental theory, based on DST and BSCT, of the role of neurobiological susceptibility to the environment in regulating environmental effects on adaptation, development, and health. We then outline current thinking about neurogenomic and endophenotypic mechanisms that may underpin neurobiological susceptibility, summarize extant empirical research on differential susceptibility, and evaluate the evolutionary bases and implications of BSCT and DST. Finally, we discuss applied issues including methodological and statistical considerations in conducting differential susceptibility research; issues of ecological, cultural, and racial--ethnic variation in neurobiological susceptibility; and implications of differential susceptibility for designing social programs. We conclude that the differential susceptibility paradigm has far-reaching implications for understanding whether and how much child and adult development responds, for better and for worse, to the gamut of species-typical environmental conditions.

Background: The rearing environment of human immunodeficiency virus (HIV)-infected children is often compromised, putting these children at additional risks. Positive caregiving may ameliorate the impact of adverse circumstances and promote attachment security. The goal of the present study was to examine the attachment relationships of HIV-infected children in biological families and institutions; to examine the effects of HIV infection and institutional rearing on attachment security and indiscriminate friendliness; and to assess the role of caregiving in the face of HIV-related adversities., Methods: We studied 64 Ukrainian uninfected and HIV-infected children reared in families and institutions (mean age 50.9 months). Physical and cognitive development of children as well as attachment-related domains and indiscriminate friendliness were assessed., Results: Institutional care but not the presence of HIV was associated with lower levels of attachment security and higher levels of indiscriminate friendliness. On average, the level of indiscriminate friendliness among institution-reared children was more than twice as high as among family-reared children. Only 24% of institution-reared children had clearly developed attachment patterns, as opposed to 97% among family-reared children. Controlling for physical and cognitive development, type of care (institution or family), and HIV status, positive caregiving was associated with higher levels of attachment security. Indiscriminate friendliness was associated with lower levels of attachment security among family-reared children, but with higher levels of positive caregiving among institution-reared children., Conclusions: Etiology and function of indiscriminate friendliness may differ for family-reared versus institution-reared children. The findings of this study suggest the necessity of early interventions improving the quality of care for HIV-infected children., (© 2010 The Authors. Journal of Child Psychology and Psychiatry. © 2010 Association for Child and Adolescent Mental Health.)

Objective: To compare the physical, cognitive, and motor development of infants adopted from foster care with infants adopted from institutions., Method: Forty-two formerly fostered and 50 post-institutionalized girls adopted from China, aged between 11 and 16 months on arrival, were visited 2 and 6 months after adoption. Children's height, weight, and head circumference were measured. Stress regulation was assessed by diurnal salivary cortisol levels, and cognitive and motor development were assessed using the Bayley Scales of Infant Development-second edition., Results: At both assessments, the (modest) physical growth delays were similar for formerly fostered and post-institutionalized children. For weight and head circumference (but not for height) a catch-up over time was found, with a significant interaction between time and age at arrival, showing a more rapid catch-up for earlier adopted children. The daily cortisol curves of the formerly fostered and post-institutionalized children were similar and did not change over time. At both assessments, the former foster children outperformed the post-institutionalized children on mental and motor skills. Both groups showed a similar catch-up for mental development. For motor development, no catch-up was found., Conclusions: The influence of pre-adoption foster versus institutional rearing seems more pronounced for cognitive and motor development than for physical development and hormonal stress regulation. Our outcomes suggest that pre-adoption foster care is less detrimental to children's cognitive and motor development than institutional rearing.

To study the effects of perinatal HIV-1 infection and early institutional rearing on the physical and cognitive development of children, 64 Ukrainian uninfected and HIV-infected institutionalized and family-reared children were examined (mean age = 50.9 months). Both HIV infection and institutional care were related to delays in physical and cognitive development, with a larger effect of the rearing environment. Family care, even of compromised quality, was found to be more favorable for children's physical and cognitive development than institutional care. The impact of the quality of child care on physical and cognitive development is discussed in light of future interventions.

To study the effect of institutional rearing on physical growth and stress regulation we examined 16 institution-reared children (3-6 years old) in Ukraine and compared them with 18 native family-reared children pair-matched on age and gender. Physical growth trajectories were examined on the basis of archival medical records and current measurements of height, weight, and head circumference. Stress regulation was studied on the basis of diurnal salivary cortisol sampled six times during 1 day. 31% of institution-reared children were stunted at 48 months whereas none of the family-reared children were. Substantial delays in physical growth were observed in institution-reared children especially during the first year of life. From 24 months onwards a tendency for improvement in physical growth was evident among the temporarily stunted institution-reared children, with complete catch-up in weight and partial catch-up in height by the time of assessment. Chronically stunted institution-reared children demonstrated persistent severe growth delays. Institution-reared and family-reared children showed similar patterns of diurnal cortisol production with decreases over the day. However, temporarily stunted institution-reared children had a significantly higher total daily cortisol production than both chronically stunted institution-reared children and family-reared children. These data confirm previous findings regarding physical growth delays and stress dysregulation associated with institutional care, but also point to differences in cortisol production between stunted and non-stunted institution-reared children.

Objective: To examine infant attachment and developmental functioning shortly after international adoption., Methods: At 14 months, infant-mother attachment and mental (MDI) and psychomotor (PDI) development were assessed in 70 internationally adopted children. Mean age at arrival was 5.5 months, mean stay in the adoptive family 8.7 months., Results: Adopted children's MDI and PDI did not deviate from normative scores. Also, their secure-insecure attachment distribution was comparable with that of normative groups. However, more adoptees were disorganized attached (36 vs. 15% in normative groups). Temporary residence in a foster home in the country of origin before adoption was related to higher MDI and PDI, whereas disorganized attachment in the adoptive family was related to lower MDI and PDI scores., Conclusions: The majority of internationally adopted children form secure attachment relationships and function at normative developmental levels shortly after adoption. Residence in a foster family before adoption may partly prevent developmental delays.

Are serious growth delays caused by malnutrition and neglect permanent or reversible? The effects of institutionalization and international adoption on children's physical growth are estimated with meta-analysis. Studies with sufficient data to compute differences between adoptees and the reference population (33 papers with 122 study outcomes) were collected through Web of Science, ERIC (Education Resource Information Center), PsycINFO (Psychological Literature), and Medline (U.S. National Library of Medicine) (1956-2006). The influence of pre- and postadoption care on height, weight, and head circumference was tested. Effect sizes (d) and confidence intervals (CIs) around the point estimate for the growth lag indices were computed. The more time spent in institutional care, the more the children lagged behind in physical growth (d = 1.71, 95% CI: 0.82-2.60, n = 893). At adoptive placement, the children showed large delays in height, weight, and head circumference (d = -2.39 to -2.60; n = 1331-3753). Although after adoption, they showed almost complete catch-up of height (d = -0.57, 95% CI: -0.87 to -0.27, n = 3437 adoptees) and weight (d = -0.72, 95% CI: -1.04 to -0,39, n = 3259 adoptees), catch-up of head circumference seemed slower and remained incomplete (d = -1.56, 95% CI: -2.27 to -0.85, n = 527). Later age at arrival was related to less complete catch-up of height and weight. International adoption leads to substantial catch-up of height and weight but not of head circumference, demonstrating differential plasticity of children's physical growth.

Background: Research suggests that institutional care has long-lasting effects on children. However, no study has longitudinally studied infants in an institution and their subsequent development at age four., Methods: Sixty-one adopted children aged four years who had spent their first two years of life in an institution were compared to 39 children reared in their own two-parent families. Cognitive development, security of attachment, shyness, children's emotional understanding and behavioural problems were examined in both groups. Parental health and stress were also assessed., Results: At four years adopted children still had lower scores on cognitive development, were less secure, and less able to understand emotions than family-reared children. Children with a secure attachment type in infancy were found to be less secure at age four, compared with those who were classified in infancy as having an insecure attachment type. Their physical development had recovered, they were less shy, had no behavioural problems and no problems in the relationship with their teacher., Conclusions: Early residential group care has long-lasting effects on important socio-emotional and cognitive aspects of preschool children's development.

In the present longitudinal study, early adopted children (N = 160) were followed from infancy to adolescence to assess the influence of previous and concurrent factors on the children's social development. This study allowed for more conclusive evidence of the influence of early and concurrent rearing experiences and temperament on adolescents' social development, independent of shared genetic factors between children and parents. Results showed that social development and temperament were stable over time and that both previous and current parental sensitivity were important in predicting social development in adolescence. Quality of the early parent-child relationship was indirectly associated with social development in adolescence through the influence on social development in middle childhood. Maternal sensitivity in middle childhood and in adolescence partly buffered the negative effects of difficult temperament on social development in adolescence. Adaptation emerged as the product of both developmental history and current circumstances.

Grandmothers are important in Chinese families. This study explored the early emerging mother-grandmother-infant network and its association with child's socioemotional development in multigenerational families in a non-WEIRD country. The analytic sample included 60 children (T1: M[subscript age] = 6.5 months) and their caregivers residing in Beijing. Measures used were the Strange Situation Procedure (SSP), the Lausanne Trilogue Play (LTP), the Maternal Behavior Q-Sort (MBQS), and the Infant-Toddler Social and Emotional Assessment. Structural equation and path modeling revealed that (1) more grandmaternal neutral/watching coparenting behaviors at the first assessment were related to more secure infant-mother attachment relationships at the second assessment (T2: M[subscript age] = 1 year); (2) maternal sensitivity at T2 was a partial mediator between earlier undermining and neutral/watching coparenting behaviors and young children's externalizing problems at the final assessment (T3: M[subscript age] = 2 years). Findings are discussed in terms of the roles played by mother-grandmother coparenting network in the children's socioemotional development.

Clear associations of sleep, cognitive performance, and behavioral problems have been demonstrated in meta-analyses of studies in adults. This meta-analysis is the first to systematically summarize all relevant studies reporting on sleep, cognition, and behavioral problems in healthy school-age children (5-12 years old) and incorporates 86 studies on 35,936 children. Sleep duration shows a significant positive relation with cognitive performance (r = 0.08, confidence interval [CI] [0.06, 0.10]). Subsequent analyses on cognitive subdomains indicate specific associations of sleep duration with executive functioning (r = 0.07, CI [0.02, 0.13]), with performance on tasks that address multiple cognitive domains (r = 0.10, CI = [0.05, 0.16]), and with school performance (r = 0.09, CI [0.06, 0.12]), but not with intelligence. Quite unlike typical findings in adults, sleep duration was not associated with sustained attention and memory. Methodological issues and brain developmental immaturities are proposed to underlie the marked differences. Shorter sleep duration is associated with more behavioral problems (r = 0.09, CI [0.07, 0.11]). Subsequent analyses on subdomains of behavioral problems showed that the relation holds for both internalizing (r = 0.09, CI [0.06, 0.12]) and externalizing behavioral problems (r = 0.08, CI [0.06, 0.11]). Ancillary moderator analyses identified practices recommended to increase sensitivity of assessments and designs in future studies. In practical terms, the findings suggest that insufficient sleep in children is associated with deficits in higher-order and complex cognitive functions and an increase in behavioral problems. This is particularly relevant given society's tendency towards sleep curtailment. (Contains 5 figures and 5 tables.)

This study addresses the extent to which insecure and disorganized attachments increase risk for externalizing problems using meta-analysis. From 69 samples (N = 5,947), the association between insecurity and externalizing problems was significant, d = 0.31 (95% CI: 0.23, 0.40). Larger effects were found for boys (d = 0.35), clinical samples (d = 0.49), and from observation-based outcome assessments (d = 0.58). Larger effects were found for attachment assessments other than the Strange Situation. Overall, disorganized children appeared at elevated risk (d = 0.34, 95% CI: 0.18, 0.50), with weaker effects for avoidance (d = 0.12, 95% CI: 0.03, 0.21) and resistance (d = 0.11, 95% CI: -0.04, 0.26). The results are discussed in terms of the potential significance of attachment for mental health.

In an intriguing account, the hypothesis is proposed that elevating effects of quantity of childcare on aggression might not, as other research has suggested, be dissipating over time, but instead be diffusing across groups of children. Paradoxically, this diffusion may also affect children with little or no experience with non-maternal care. If supported, this hypothesis may cause great concern about the increasing childcare use in western countries. In this commentary, we take a closer look at this hypothesis, focusing on limitations in ethnic and cultural diversity of the available data, on the inconclusive role of temperament, on the causal nature of some conclusions, and on the role of the father as a non-maternal caregiver.

Gene-environment interactions interpreted in terms of differential susceptibility may play a large part in the explanation of individual differences in human development. Reviewing studies on the behavioral and molecular genetics of attachment, we present evidence for interactions between genetic and environmental factors explaining individual differences in attachment security and disorganization. In particular, the DRD4 7-repeat polymorphism seems associated with an increased risk for disorganized attachment, but only when combined with environmental risk. Gene-environment (G x E) interactions may be interpreted as genetic vulnerability "or" differential susceptibility. We found support for the differential susceptibility hypothesis predicting not only more "negative" outcomes for susceptible children in unfavorable environments, but also "positive" outcomes for susceptible children in "favorable" environments.

The current article presents results from a twin study of genetic and environmental components of maternal sensitivity and infant attachment and their association. The sample consisted of 136 twin pairs from 2 sites: Leiden, the Netherlands, and London, UK. Maternal sensitivity was assessed in the home at 9-10 months, and infant attachment security was observed in the laboratory at 12 months. The study yielded little evidence that genetic factors are involved in variations between twins in maternal sensitivity ratings but did find that shared variance in maternal sensitivity was able to account for some of the similarity between twins in attachment security. Weak nonshared associations between sensitivity and attachment appeared to suppress the magnitude of the correlation between attachment and sensitivity in twin children. The results could indicate that the attachment security of one twin may depend on the relationship the parent has with the other twin. The results are brought to bear on the validity of attachment theory as a theory of primarily shared environmental effects in children's development and the continuing challenge posed to attachment theory by within-family differences in socioemotional processes.

The validity of the Adult Attachment Interview (AAI), and its relation to toddlers' social and emotional adaptation, were investigated. The AAI and the Parental Bonding Instrument were related, but only the AAI yielded classifications that corresponded to the quality of infant-parent attachment. (Author/LB)

To investigate the effectiveness of interventions aiming to improve hot and cold executive functions (EFs) in children and adolescents with acquired brain injury (ABI) and to examine whether characteristics of the intervention, participants, etiology of ABI (Traumatic-brain-injury [TBI] or non-TBI), time of assessment, or study quality moderate intervention effects. Whereas cold EFs refer to purely cognitive EFs, hot EFs refer to the affective aspects of these cognitive skills. A total of 970 participants from 23 randomized-controlled-trial studies (112 effect sizes [ES]) were included. A three-level random effects approach (studies, ES, individual participants) was used. Moderation analyses were conducted through meta-regressions. The three-level random effects model showed a better fit than the two-level model. Almost all individual studies showed non-significant ES across outcomes but in combination interventions were effective (Cohen's d = 0.38, CI 0.16 ~ 0.61). Lower methodological quality, inclusion of participants with non-TBI, and parental participation predicted larger ES. Participants' age, time of assessment, number of sessions, and focus on hot or cold EFs were not related to ES. We found no evidence of publication bias. Interventions are effective with small to medium ES according to conventional criteria. Intervention effects do not seem to fade away with time. Parent participation in the intervention is important to improve EFs. The efficacy of interventions seems larger when non-TBI is part of the etiology of ABI. Variation between studies is relevant for tracing the effective intervention characteristics. Most studies are conducted in adolescence, and studies in early childhood are needed. [ABSTRACT FROM AUTHOR]