Views regarding children's influence on their environment and their own development have undergone considerable changes over the years. Following Bell's (1968) seminal paper, the notion of children's influence and the view of socialization as a bidirectional process have gradually gained wide acceptance. However, empirical research implementing this theoretical advancement has lagged behind. This Special Section compiles a collection of new empirical works addressing multiple forms of influential child processes, with special attention to their consequences for children's and others’ positive functioning, risk and resilience. By addressing a wide variety of child influences, this Special Section seeks to advance integration of influential child processes into myriad future studies on development and psychopathology and to promote the translation of such work into preventive interventions.

We examined whether a maximum threshold of time spent in nonmaternal care exists, beyond which infants have an increased risk of forming a disorganized infant–mother attachment. The hours per week infants spent in nonmaternal care at 7–8 months were examined as a continuous measure and as a dichotomous threshold (over 40, 50 and 60 hr/week) to predict infant disorganization at 12–15 months. Two different samples (Austin and NICHD) were used to replicate findings and control for critical covariates: mothers' unresolved status and frightening behavior (assessed in the Austin sample, N = 125), quality of nonmaternal caregiving (assessed in the NICHD sample, N = 1,135), and family income and infant temperament (assessed in both samples). Only very extensive hours of nonmaternal care (over 60 hr/week) and mothers' frightening behavior independently predicted attachment disorganization. A polynomial logistic regression performed on the larger NICHD sample indicated that the risk of disorganized attachment exponentially increased after exceeding 60 hr/week. In addition, very extensive hours of nonmaternal care only predicted attachment disorganization after age 6 months (not prior). Findings suggest that during a sensitive period of attachment formation, infants who spend more than 60 hr/week in nonmaternal care may be at an increased risk of forming a disorganized attachment.

At approximately 30, 42, and 54 months of age (N = 231), the relations among children's externalizing symptoms, intrusive maternal parenting, and children's effortful control (EC) were examined. Both intrusive parenting and low EC have been related to psychopathology, but children's externalizing problems and low EC might affect the quality of parenting and one another. Mothers’ intrusive behavior with their children was assessed with observations, children's EC was measured with mothers’ and caregivers’ reports, and children's externalizing symptoms were assessed with mothers’, fathers’, and caregivers’ reports. In a structural equation panel model, bidirectional relations between intrusive parenting and EC were found: EC at 30 and 42 months predicted low levels of intrusive parenting a year later, controlling for prior levels of parenting and vice versa. Moreover, high levels of children's externalizing problems at both 30 and 42 months negatively predicted EC a year later, controlling for prior levels of EC. Although externalizing problems positively predicted high EC over time, this appeared to be a suppression effect because these variables had a strong negative pattern in the zero-order correlations. Moreover, when controlling for the stability of intrusive parenting, EC, and externalizing (all exhibited significant stability across time) and the aforementioned cross-lagged predictive paths, EC and externalizing problems were still negatively related within the 54-month assessment. The findings are consistent with the view that children's externalizing behavior undermines their EC and contributes to intrusive mothering and that relations between intrusive parenting and EC are bidirectional across time. Thus, interventions that focus on modifying children's externalizing problems (as well as the quality of parenting) might affect the quality of parenting they receive and, hence, subsequent problems with adjustment.

In the present investigation, we examined the developmental viability of the externalizing behavior construct spanning the period from 8 to 24 months of age. A sample of 274 psychologically aggressive couples was recruited from hospital maternity wards and followed from childbirth through 24 months of age. Mothers and fathers completed questionnaire measures of infant physical aggression, defiance, activity level, and distress to limitations at 8, 15, and 24 months. The developmental viability of externalizing behavior at each age studied was suggested by several results. Physical aggression, defiance, activity level, and distress to limitations reflected the operation of a single underlying externalizing behavior factor. In some cases, these individual facets of externalizing behavior became more strongly associated with one another over time. The externalizing construct exhibited remarkable longitudinal stability, with the stability of physical aggression and defiance increasing with age. The externalizing behavior construct was concurrently and prospectively associated with several factors in its nomological network (e.g., interparental conflict and poor parental bond with the infant). Our findings suggest that externalizing behaviors coalesce into a psychologically meaningful construct by 8 months of infant life. Researchers who seek to chart the emergence of the externalizing behavior construct may now need to look to earlier months.

Recent research in the field of child maltreatment has begun to shed new light on the emergence of health problems in children by emphasizing the responsiveness of developmental processes to children's environmental and biological contexts. Here, I highlight recent trends in the field with an emphasis on the effects of early life stress across multiple levels of developmental domains.

We examined caregiver report of externalizing behavior from 12 to 54 months of age in 102 children randomized to care as usual in institutions or to newly created high-quality foster care. At baseline no differences by group or genotype in externalizing were found. However, changes in externalizing from baseline to 42 months of age were moderated by the serotonin transporter linked polymorphic region genotype and intervention group, where the slope for short–short (S/S) individuals differed as a function of intervention group. The slope for individuals carrying the long allele did not significantly differ between groups. At 54 months of age, S/S children in the foster care group had the lowest levels of externalizing behavior, while children with the S/S genotype in the care as usual group demonstrated the highest rates of externalizing behavior. No intervention group differences were found in externalizing behavior among children who carried the long allele. These findings, within a randomized controlled trial of foster care compared to continued care as usual, indicate that the serotonin transporter linked polymorphic region genotype moderates the relation between early caregiving environments to predict externalizing behavior in children exposed to early institutional care in a manner most consistent with differential susceptibility.

Research on neurobiological development is providing insight into the nature and mechanisms of human neural plasticity. These mechanisms appear to support two different forms of developmental learning. One form of learning could be described as externalizing, in which neural representations are highly responsive to environmental influences, as the child typically operates under a mode of hedonic approach. A second form of learning supports internalizing, in which motive control separates attention and self-regulation from the immediate influences of the context, particularly when the child faces conditions of avoidance and threat. The dorsal cortical networks of externalizing are organized around dorsal limbic (cingulate, septal, lateral hypothalamic, hippocampal, and ventral striatal) circuits. In contrast, the ventral cortical networks of internalizing are organized around ventral limbic (anterior temporal and orbital cortex, extended amygdala, dorsal striatal, and mediodorsal thalamic) circuits. These dual divisions of the limbic system in turn self-regulate their arousal levels through different brain stem and forebrain neuromodulator projection systems, with dorsal corticolimbic networks regulated strongly by locus coeruleus norepinephrine and brain stem raphe nucleus serotonin projection systems, and ventral corticolimbic networks regulated by ventral tegmental dopamine and forebrain acetylcholine projections. Because the arousal control systems appear to regulate specific properties of neural plasticity in development, an analysis of these systems explains differences between externalizing and internalizing at multiple levels of neural and psychological self-regulation. In neuroscience, the concept of critical periods has been applied to times when experience is essential for the maturation of sensory systems. In a more general neuropsychological analysis, certain periods of the child's development require successful self-regulation through the differential capacities for externalizing and internalizing.

This paper presents multilevel findings on adolescents' victimization exposure from a large longitudinal cohort of twins. Data were obtained from the Environmental Risk (E-Risk) Longitudinal Twin Study, an epidemiological study of 2,232 children (1,116 twin pairs) followed to 18 years of age (with 93% retention). To assess adolescent victimization, we combined best practices in survey research on victimization with optimal approaches to measuring life stress and traumatic experiences, and introduce a reliable system for coding severity of victimization. One in three children experienced at least one type of severe victimization during adolescence (crime victimization, peer/sibling victimization, Internet/mobile phone victimization, sexual victimization, family violence, maltreatment, or neglect), and most types of victimization were more prevalent among children from low socioeconomic backgrounds. Exposure to multiple victimization types was common, as was revictimization; over half of those physically maltreated in childhood were also exposed to severe physical violence in adolescence. Biometric twin analyses revealed that environmental factors had the greatest influence on most types of victimization, while severe physical maltreatment from caregivers during adolescence was predominantly influenced by heritable factors. The findings from this study showcase how distinct levels of victimization measurement can be harmonized in large-scale studies of health and development.

Most theoretical models of developmental psychopathology involve a transactional, bidirectional relation between parenting and children's behavior problems. The present study utilized a cross-lagged panel, multiple interval design to model change in bidirectional relations between child and parent behavior across successive developmental periods. Two major categories of child behavior problems, internalizing and externalizing, and two aspects of parenting, positive (use of support and structure) and harsh discipline (use of physical punishment), were modeled across three time points spaced 3 years apart. Two successive developmental intervals, from approximately age 7.5 to 10.5 and from 10.5 to 13.5, were included. Mother–child dyads (N = 138; 65 boys) from a lower income longitudinal sample of families participated, with standardized measures of mothers rating their own parenting behavior and teachers reporting on child's behavior. Results revealed different types of reciprocal relations between specific aspects of child and parent behavior, with internalizing problems predicting an increase in positive parenting over time, which subsequently led to a reduction in internalizing problems across the successive 3-year interval. In contrast, externalizing predicted reduced levels of positive parenting in a reciprocal sequence that extended across two successive intervals and predicted increased levels of externalizing over time. Implications for prevention and early intervention are discussed.

Building upon the transactional model of brain development, we explore the impact of early maternal deprivation on neural development and plasticity in three neural systems: hyperactivity/impulsivity, executive function, and hypothalamic–pituitary–adrenal axis functioning across rodent, nonhuman primate, and human studies. Recognizing the complexity of early maternal–infant interactions, we limit our cross-species comparisons to data from rodent models of artificial rearing, nonhuman primate studies of peer rearing, and the relations between these two experimental approaches and human studies of children exposed to the early severe psychosocial deprivation associated with institutional care. In addition to discussing the strengths and limitations of these paradigms, we present the current state of research on the neurobiological impact of early maternal deprivation and the evidence of sensitive periods, noting methodological challenges. Integrating data across preclinical animal models and human studies, we speculate about the underlying biological mechanisms; the differential impact of deprivation due to temporal factors including onset, offset, and duration of the exposure; and the possibility and consequences of reopening of sensitive periods during adolescence.

Genetic moderation of interpersonal psychotherapy (IPT) efficacy for economically disadvantaged women with major depressive disorder was examined. Specifically, we investigated whether genotypic variation in corticotropin releasing hormone receptor 1 (CRHR1) and the linked polymorphic region of the serotonin transporter gene (5-HTTLPR) moderated effects of IPT on depressive symptoms over time. We also tested genotype moderation of IPT mechanisms on social adjustment and perceived stress. Non-treatment-seeking urban women at or below the poverty level with infants were recruited from the community (N = 126; M age = 25.33 years, SD = 4.99; 54.0% African American, 22.2% Caucasian, and 23.8% Hispanic/biracial) and randomized to individual IPT or Enhanced Community Standard groups. The results revealed that changes in depressive symptoms over time depended on both intervention group and genotypes (5-HTTLPR and CRHR1). Moreover, multiple-group path analysis indicated that IPT improved depressive symptoms, increased social adjustment, and decreased perceived stress at posttreatment among women with the 0 copies of the CRHR1 TAT haplotype only. Finally, improved social adjustment at postintervention significantly mediated the effect of IPT on reduced depressive symptoms at 8 months postintervention for women with 0 copies of the TAT haplotype only. Post hoc analyses of 5-HTTLPR were indicative of differential susceptibility, albeit among African American women only.

A sample of 356 children recruited from Head Start (58% European American, 25% African American, and 17% Hispanic; 54% girls; Mage = 4.59 years) were followed longitudinally from prekindergarten through fifth grade. Latent profile analyses of teacher-rated inattention from kindergarten through third grade identified four developmental trajectories: stable low (53% of the sample), stable high (11.3%), rising over time (16.4%), and declining over time (19.3%). Children with stable low inattention had the best academic outcomes in fifth grade, and children exhibiting stable high inattention had the worst, with the others in between. Self-regulation difficulties in preschool (poor executive function skills and elevated opposition–aggression) differentiated children with rising versus stable low inattention. Elementary schools characterized by higher achievement differentiated children with declining versus stable high inattention. Boys and children from single-parent families were more likely to remain high or rise in inattention, whereas girls and children from dual-parent families were more likely to remain low or decline in inattention.

In a change from the once-dominant view of children as passive in the parent-led process of socialization, children are now seen as active agents who can considerably influence that process. However, these newer perspectives typically focus on the child's antagonistic influence, due either to a difficult temperament or aversive, resistant, negative behaviors that elicit adversarial responses from the parent and lead to future coercive cascades in the relationship. Children's capacity to act as receptive, willing, even enthusiastic, active socialization agents is largely overlooked. Informed by attachment theory and other relational perspectives, we depict children as able to adopt an active willing stance and to exert robust positive influence in the mutually cooperative socialization enterprise. A longitudinal study of 100 community families (mothers, fathers, and children) demonstrates that willing stance (a) is a latent construct, observable in diverse parent–child contexts, parallel at 38, 52, and 67 months and longitudinally stable; (b) originates within an early secure parent–child relationship at 25 months; and (c) promotes a positive future cascade toward adaptive outcomes at age 10. The outcomes include the parent's observed and child-reported positive, responsive behavior, as well as child-reported internal obligation to obey the parent and parent-reported low level of child behavior problems. The construct of willing stance has implications for basic research in typical socialization and in developmental psychopathology as well as for prevention and intervention.

The following prospective longitudinal study considers the ways that protracted exposure to verbal and physical aggression between parents may take a substantial toll on emotional adjustment for 1,025 children followed from 6 to 58 months of age. Exposure to chronic poverty from infancy to early childhood as well as multiple measures of household chaos were also included as predictors of children's ability to recognize and modulate negative emotions in order to disentangle the role of interparental conflict from the socioeconomic forces that sometimes accompany it. Analyses revealed that exposure to greater levels of interparental conflict, more chaos in the household, and a higher number of years in poverty can be empirically distinguished as key contributors to 58-month-olds' ability to recognize and modulate negative emotion. Implications for models of experiential canalization of emotional processes within the context of adversity are discussed.

Sensitive periods (SP) in behavioral development appeared in the biological sciences during the first decade of the 20th century, and research in animal models beginning in the 1950s provide terminology and evidence for SP effects. This paper proposes a rigorous program for human SP research and argues that the complexity of the human brain and variability of the human ecology necessitate that SP effects must be studied in humans, employ longitudinal designs starting at birth, test mechanism-based hypotheses based on animal studies that manipulate early environments, and utilize high-risk conditions as “natural experiments.” In light of research on the molecular basis of critical periods and their sequential cascades, it is proposed that the oxytocin (OT) system, an ancient and integrative system that cross-talks with the stress, reward, immune, and brain stem mediated homeostatic systems and supports mammalian sociality, plays a unique role in experience-dependent plasticity that buttresses SP effects due to its (a) dendritic mode of release leading to autoregulated functioning primed by early experience, (b) pulsatile pattern of activity, and (c) special role in neural plasticity at the molecular and network assembly levels. Synchrony, the coordination of biology and behavior during social contact, is suggested as a mechanism by which SP exert their effect on OT functionality, the social brain, and adult sociality. Findings from four high-risk birth cohorts, each followed repeatedly from birth to 10 years, provide unique “natural experiments” for human SP research based on specific programs in animal models. These include prematurity (maternal proximity), multiple birth (peer rearing), postpartum depression (low licking and grooming), and chronic unpredictable trauma (maternal rotation, variable foraging demands). In each cohort, hypotheses are based on the missing environmental component during SP, and findings on social synchrony, OT functionality, stress response, emotion regulation, and mental health accord with the multilevel and dynamic principles of developmental psychopathology. The results on the potential for reparation versus chronicity following early deprivation highlight a flexible conceptualization of resilience based on human SP research. Consideration of SP effects at the molecular, endocrine, brain, and behavioral levels and in relation to the neural plasticity and multifinality of human social functions may assist in fine-tuning early detection and the construction of targeted individualized interventions.

This study advances understanding of predictors of child abuse and neglect at multiple levels of influence. Mothers, fathers, and children (N = 1,418 families, M age of children = 8.29 years) were interviewed annually in three waves in 13 cultural groups in nine countries (China, Colombia, Italy, Jordan, Kenya, Philippines, Sweden, Thailand, and the United States). Multilevel models were estimated to examine predictors of (a) within-family differences across the three time points, (b) between-family within-culture differences, and (c) between-cultural group differences in mothers' and fathers' reports of corporal punishment and children's reports of their parents' neglect. These analyses addressed to what extent mothers' and fathers' use of corporal punishment and children's perceptions of their parents' neglect were predicted by parents' belief in the necessity of using corporal punishment, parents' perception of the normativeness of corporal punishment in their community, parents' progressive parenting attitudes, parents' endorsement of aggression, parents' education, children's externalizing problems, and children's internalizing problems at each of the three levels. Individual-level predictors (especially child externalizing behaviors) as well as cultural-level predictors (especially normativeness of corporal punishment in the community) predicted corporal punishment and neglect. Findings are framed in an international context that considers how abuse and neglect are defined by the global community and how countries have attempted to prevent abuse and neglect.

This study was designed to investigate a genetic moderation effect of dopamine receptor 4 gene (DRD4) alleles that have seven or more repeats (long alleles) on an intervention to deter drug use among rural African American adolescents in high-risk families. Adolescents (N = 291, M age = 17) were assigned randomly to the Adults in the Making (AIM) program or to a control condition and were followed for 27.5 months. Adolescents provided data on drug use and vulnerability cognitions three times after pretest. Pretest assessments of caregiver depressive symptoms, disruption in the home, and support toward the adolescent were used to construct a family risk index. Adolescents living in high-risk families who carried at least one DRD4 long allele and were assigned to the control condition evinced greater escalations in drug use than did (a) adolescents who lived in high-risk families, carried the DRD4 long allele, and were assigned to AIM, or (b) adolescents assigned to either condition who carried no DRD4 long alleles. AIM-induced reductions in vulnerability cognitions were responsible for the Family Risk × AIM × DRD4 status drug use prevention effects. These findings support differential susceptibility predictions and imply that prevention effects on genetically susceptible individuals may be underestimated.