Introduction to the special section on the effects of early experience on development

Allostatic load in children: The cost of empathic concern

Early-life adversity affects long-term health outcomes but there is considerable interindividual variability in susceptibility to environmental influences. We proposed that positive psychological characteristics that reflect engagement with context, such as being concerned about people or performance on tasks (i.e., empathic concern), could moderate the interindividual variation in sensitivity to the quality of the early environment. We studied 526 children of various Asian nationalities in Singapore (46.6% female, 13.4% below the poverty line) with longitudinal data on perinatal and childhood experiences, maternal report on empathic concern of the child, and a comprehensive set of physiological measures reflecting pediatric allostatic load assessed at 6 y of age. The perinatal and childhood experiences included adversities and positive experiences. We found that cumulative adverse childhood experience was positively associated with allostatic load of children at 6 y of age at higher levels of empathic concern but not significantly associated at lower levels of empathic concern. This finding reveals evidence for the importance of empathic concern as a psychological characteristic that moderates the developmental impact of environmental influences, serving as a source for vulnerability to adversities in children.

Longitudinal study of infants receiving extra motor stimulation, full‐term control infants, and infants born preterm: High‐density EEG analyses of cortical activity in response to visual motion

Electroencephalography was used to investigate the effects of extrastimulation and preterm birth on the development of visual motion perception during early infancy. Infants receiving extra motor stimulation in the form of baby swimming, a traditionally raised control group, and preterm born infants were presented with an optic flow pattern simulating forward and reversed self‐motion and unstructured random visual motion before and after they achieved self‐produced locomotion. Extrastimulated infants started crawling earlier and displayed significantly shorter N2 latencies in response to visual motion than their full‐term and preterm peers. Preterm infants could not differentiate between visual motion conditions, nor did they significantly decrease their latencies with age and locomotor experience. Differences in induced activities were also observed with desynchronized theta‐band activity in all infants, but with more mature synchronized alpha–beta band activity only in extrastimulated infants after they had become mobile. Compared with the other infants, preterm infants showed more widespread desynchronized oscillatory activities at lower frequencies at the age of 1 year (corrected for prematurity). The overall advanced performance of extrastimulated infants was attributed to their enriched motor stimulation. The poorer responses in the preterm infants could be related to impairment of the dorsal visual stream that is specialized in the processing of visual motion.

Developmental Consequences of Early Life Stress on Risk for Psychopathology: Longitudinal Associations with Children's Multisystem Physiological Regulation and Executive Functioning

The etiology of psychopathology is multifaceted and warrants consideration of factors at multiple levels and across developmental time. Although experiences of adversity in early life have been associated with increased risk of developing psychopathology, pathways toward maladaptation or resilience are complex and depend upon a variety of factors, including individuals' physiological regulation and cognitive functioning. Therefore, in a longitudinal cohort of 113 mother-child dyads, we explored associations from early adverse experiences to physiological co-regulation across multiple systems and subsequent variations in executive functioning. Latent profile analysis derived multisystem profiles based on children's heart rate, respiratory sinus arrhythmia, pre-ejection period, and cortisol measured during periods of rest and reactivity throughout a developmentally challenging protocol. Three distinct profiles of multisystem regulation emerged: heightened multisystem baseline activity (Anticipatory Arousal/ANS Responder), typically adaptive patterns across all systems (Active Copers/Mobilizers) and heightened HPA axis activity (HPA Axis Responders). Path models revealed that children exposed to adversity before 18-months were more likely to evidence an Anticipatory Arousal/ANS Responders response at 36-months, and children in this profile had lower executive functioning scores than the Active Copers/Mobilizers. In sum, these findings provide important information about potential physiological associations linking early adversity to variations in children's task-based executive functioning.

Infant negative affect moderates longitudinal associations between maternal gatekeeping and toddlers’ social–emotional difficulties

Maternal gatekeeping is characterized by the extent to which mothers engage in behaviors that ultimately serve to inhibit (i.e., gate close) or encourage (i.e., gate open) father involvement in childrearing. This study considered direct and indirect associations between observed and reported maternal gatekeeping and children’s social–emotional difficulties. Data come from a sample of 182 parents who transitioned to parenthood in 2008–2010 and their young children. Results of longitudinal path analyses indicated mothers’ perceptions of maternal gate closing at 3-months postpartum were associated with greater dysregulation (β = .21, 95% CI [.08, .35], p = .002) and externalizing (β = .25, 95% CI [.10, .41], p = .001) in 26-month-old toddlers. Observed maternal gate opening at 3-months postpartum predicted lower dysregulation (β = −.18, 95% CI [−.32, −.05], p = .008) in 26-month-old toddlers. Observed fathers’ parenting quality did not mediate associations between maternal gatekeeping and child social–emotional difficulties. However, a statistically significant interaction between infant negative affect and observed maternal gate opening emerged as a predictor of toddler dysregulation, such that the adjusted negative effect of observed maternal gate opening on toddler dysregulation was strongest when infant negative affect was low. Statistically significant interactions between fathers’ perceptions of gate closing and infant negative affect also emerged as predictors of toddler dysregulation and externalizing. Infants high in negative affect exposed to maternal gate closing were at the greatest risk for externalizing and dysregulation difficulties. Implications for maternal gatekeeping theory and research are discussed.

Affectionate Touch in the Context of Breastfeeding and Maternal Depression Influences Infant Neurodevelopmental and Temperamental Substrates

BACKGROUND

While numerous studies have demonstrated maternal depression's influence on infant brain development, few studies have examined the changes that occur as a consequence of co-occurring experiential factors that affect quality of mother and infant affectionate touch as well as infant temperament and neurophysiological systems. The aim of the study was to examine the interactive effects of maternal depression and breastfeeding on mother and infant affectionate touch and infant temperament and cortical maturation patterns across early development.

METHODS

113 mothers and their infants participated when infants were 1 and 3 months of age. Questionnaires to assess maternal depressive symptoms, feeding, and temperament were completed. Tonic EEG patterns (asymmetry and left and right activity) were collected and the dyads were video-recorded during feeding to assess mother and infant affectionate touch patterns.

RESULTS

Data analysis showed that EEG activity and mother-infant affectionate touch differed as a function of mood and feeding method. Notably, only infants of depressed mothers that bottle-fed showed right frontal EEG asymmetry and attenuated change in the left frontal region across 3 months. Breastfeeding positively impacted affectionate touch behaviors and was associated with increased left and decreased right frontal EEG activation even for depressed groups. Furthermore, a model incorporating physiology, maternal depression, touch, temperament, and feeding indicated significant prediction for infant affectionate touch (with breastfeeding and affectively positive temperament demonstrating the strongest prediction). Con-clusion: The findings suggest that breastfeeding and the infant's positive temperament influence mother-infant affectionate touch patterns and result in neuroprotective outcomes for infants, even those exposed to maternal depression within early development.

The Effects of Adverse Childhood Experiences on Internalizing and Externalizing Behaviors among Black Children and Youth

There is limited research on the short-term effects of ACEs on Black children and youth. Black children and youth are disproportionately exposed to abuse, neglect, and other victimizations (Drake et al. 2009; Wade et al. Journal of Family Issues, 17(3), 283-316, 2014). Investigating ACEs will provide a broader understanding of childhood trauma on developmental processes. The current study investigates how ACES impacts psychological distress, substance use, and delinquency among Black children and youth. Hypotheses were tested using a subsample of longitudinal data from 265 participants who were recruited from six school districts in Southeast Michigan. ACEs at T1 significantly predicted depressive symptoms at T2 (β = .19, p < .05), which in turn predicted substance use (β = .20, p < .05), and delinquency (β = .19, p < .05). Psychological distress also mediated the associations between ACEs and substance use, and delinquency. To engage youth in prevention/interventions and practice, it is important to understand the contexts in which they develop i.e. having knowledge on the specific type of victimization instances that Black youth may experience more than their peers as well as the social factors. Therefore, taking a trauma-informed approach that will acknowledge the adverse childhood experiences that youth went through and to understand how these experiences shape their development through adolescence may be efficacious.

Emotional Experiences During Childhood of Iranian Women with Compulsive Sexual Behaviour: A Qualitative Study

Compulsive sexual behaviour is a disorder causing substantial social damage. Understanding the experiences of individuals with this disorder can help prevent and mitigate its consequences. Researchers conducted an independent content analysis of the data obtained through qualitative methods in the cities of Shiraz and Tehran in Iran. A total of 19 women aged 20–35 years receiving treatment for their sexual compulsivity as well as a therapist were interviewed. Five main categories emerged from the data, including the resentful emotional duality (having contradictory or paradoxical emotions simultaneously, such as love versus hate and rage versus fear) felt towards their father and men in general, an early aberrant social experience (premature exposure to sexual relations) and an abnormal perception of love. It appears that the weak cultural and educational structures in place and interpersonal communication disorders contribute significantly to the formation of hyper-sexuality.

Environmental Forces that Shape Early Development: What We Know and Still Need to Know

Understanding health requires more than knowledge of the genome. Environmental factors regulate gene function through epigenetics. Collectively, environmental exposures have been called the "exposome." Caregivers are instrumental in shaping exposures in a child's initial years. Maternal dietary patterns, physical activity, degree of weight gain, and body composition while pregnant will influence not only fetal growth, but also the infant's metabolic response to nutrients and energy. Maternal over- or underweight, excess caloric intake, nutrient imbalances, glucose dysregulation, and presence of chronic inflammatory states have been shown to establish risk for many later chronic diseases. During the period from birth to age 3 y, when the infant's metabolic rate is high and synaptogenesis and myelination of the brain are occurring extremely rapidly, the infant is especially prone to damaging effects from nutrient imbalances. During this period, the infant changes from a purely milk-based diet to one including a wide variety of foods. The process, timing, quality, and ultimate dietary pattern acquired are a direct outcome of the caregiver-infant feeding relationship, with potentially lifelong consequences. More research on how meal time interactions shape food acceptance is needed to avoid eating patterns that augment existing disease risk. Traditional clinical trials in nutrition, meant to isolate single factors for study, are inadequate to study the highly interconnected realm of environment-gene interactions in early life. Novel technologies are being used to gather broad exposure data on disparate populations, employing pioneering statistical approaches and correlations applied specifically to the individual, based on their genetic make-up and unique environmental experiences.

Adverse Environmental Exposures During Gestation and Childhood: Predictors of Adolescent Drinking

Adverse conditions, including exposures to drugs and other environmental influences during early development, may affect behaviors later in life. This study examined the role of environmental influences from the gestation and childhood on adolescent drinking behavior. 917 mother/offspring dyads were followed prospectively from pregnancy to a 16-year follow-up assessment. Interim assessments occurred at delivery, 6, 10, and 14 years. Prenatal exposures to alcohol, tobacco, and marijuana were measured during gestation. Data were collected at each phase on childhood environment, including parenting practices, quality of the home environment, maternal depression and hostility, and lifetime exposure to child maltreatment and community violence. Alcohol outcomes were offspring age of drinking initiation and level of drinking at age 16 years. Cox Proportional Hazards ratios were used to model offspring age of drinking initiation. Logistic regression analyses were used to evaluate significant predictors of drinking level. Childhood environment, including less parental strictness, greater exposure to violence and childhood maltreatment, significantly predicted earlier age of alcohol initiation. Level of drinking among the adolescent offspring was significantly predicted by prenatal exposure to alcohol, less parental strictness, and exposures to maltreatment and violence during childhood. Whites and offspring with older mothers were more likely to initiate alcohol use early and drink at higher levels. Early and heavier alcohol use was associated with early exposures to adversity such as prenatal alcohol exposure, and child exposures to maltreatment and violence. These results highlight the importance of environmental adversity and less effective parenting practices on the development of adolescent drinking behavior.

Prenatal alcohol and other early childhood adverse exposures: Direct and indirect pathways to adolescent drinking

We examined direct and indirect pathways between adverse environmental exposures during gestation and childhood and drinking in mid-adolescence. Mothers and their offspring (n=917 mother/child dyads) were followed prospectively from second trimester to a 16-year follow-up assessment. Interim assessments occurred at delivery, 6, 10, and 14years. Adverse environmental factors included gestational exposures to alcohol, tobacco, and marijuana, exposures to childhood maltreatment and violence, maternal psychological symptoms, parenting practices, economic and home environments, and demographic characteristics of the mother and child. Indirect effects of early child behavioral characteristics including externalizing, internalizing activity, attention, and impulsivity were also examined. Polytomous logistic regression analyses were used to evaluate direct effects of adverse environmental exposures with level of adolescent drinking. Structural equation modeling (SEM) was applied to simultaneously estimate the relation between early adversity variables, childhood characteristics, and drinking level at age 16 while controlling for significant covariates. Level of drinking among the adolescent offspring was directly predicted by prenatal exposure to alcohol, less parental strictness, and exposures to maltreatment and violence during childhood. Whites and offspring with older mothers were more likely to drink at higher levels. There was a significant indirect effect between childhood exposure to violence and adolescent drinking via childhood externalizing behavior problems. All other hypothesized indirect pathways were not significant. Thus most of the early adversity measures directly predicted adolescent drinking and did not operate via childhood behavioral dysregulation characteristics. These results highlight the importance of adverse environmental exposures on pathways to adolescent drinking.

Language Problems Among Abused and Neglected Children: A Meta-Analytic Review

Research data show that exposure to abuse and neglect has detrimental effects on a child's language development. In this meta-analysis, we analyze studies (k = 23), to compare the language skills (receptive language, expressive language, pragmatics) of children who have experienced abuse and/or neglect with the language skills of children who have not experienced abuse and/or neglect and to examine whether age or type of maltreatment moderate the relationship between maltreatment and language skills. Results confirm that the language skills of children who have experienced abuse and/or neglect are delayed when compared to children who have not experienced abuse and/or neglect. Compared to older children, young children seem particularly vulnerable to abuse and neglect. No significant differences were demonstrated concerning the type of maltreatment suffered by the child. These findings support the necessity of early detection of language problems in abused and neglected children as well as early intervention in order to implement interventions that will positively stimulate their development.

Toddlers' Differential Susceptibility to the Effects of Coparenting on Social-Emotional Adjustment

The present study tested whether infants high in negative affectivity are differentially susceptible to observed coparenting behavior in relation to their subsequent social-emotional development. Data came from a longitudinal study of 182 U.S. dual-earner, primiparous couples and their infant children. At 9-months postpartum, child negative affectivity was reported by mothers and fathers and supportive and undermining coparenting behavior were assessed from mother-father-infant observations. At 27-months mothers reported on toddlers' externalizing behavior and dysregulation using a clinical assessment tool designed to identify competencies and areas of concern in toddlers' social-emotional development. Hierarchical regression analyses revealed partial support for the differential susceptibility hypothesis. Specifically, infants high in negative affectivity had lower levels of dysregulation when embedded in a more supportive coparenting context, and higher levels of dysregulation when embedded in a less supportive coparenting context. In contrast, supportive coparenting behavior was not relevant for the dysregulation of infants initially low in negative affectivity.

Adversity Across the Life Course of Incarcerated Parents: Gender Differences

More than half of the 1.6 million adults in U.S. prions are parents. Despite growing knowledge regarding the life course adversities of corrections-involved populations, less is known regarding incarcerated parents per se and the implications of cumulative adversities both on their needs and those of their children. Using a gender-balanced (41% minority) sample of incarcerated parents (N=357) from a randomized controlled trial of an in-prison parent training program, this study examines differences between incarcerated mothers and fathers in their exposures to adversities across the life course. Mothers and fathers shared similar patterns of adversity exposure in their families of origin, but differed in their experiences of juvenile justice and child welfare systems involvement, as well as in their adult experiences of victimization and related adult social and mental health outcomes. Implications for gender-responsive parent support and prevention programs for their children of incarcerated mothers and fathers are discussed.

Parenting dimensions in relation to pre-schoolers’ behaviour problems in Latvia and Lithuania

The aim of the present study was to examine associations between parenting and child behaviour problems in two neighbouring countries with subtle, yet apparent cultural differences. Participants were mothers and fathers of preschool-age children from Latvia and Lithuania. Parents completed a measure of child-rearing attitudes and reported on their child’s internalizing and externalizing behaviours. In both countries, parental warmth was negatively associated with child behaviour problems, and punishment orientation was positively associated. There were differences by country in the association of paternal psychological control and behaviour problems, and in the interactions of parenting dimensions, specifically maternal warmth and punishment orientation. Possible differences in the meaning attributed to parenting practices imply considerations for parent training programs.

Four decades of leading-edge research in the reproductive and developmental sciences: the Infant Primate Research Laboratory at the University of Washington National Primate Research Center

The Infant Primate Research Laboratory (IPRL) was established in 1970 at the University of Washington as a visionary project of Dr. Gene (Jim) P. Sackett. Supported by a collaboration between the Washington National Primate Research Center and the Center on Human Development and Disability, the IPRL operates under the principle that learning more about the causes of abnormal development in macaque monkeys will provide important insights into the origins and treatment of childhood neurodevelopmental disabilities. Over the past 40 years, a broad range of research projects have been conducted at the IPRL. Some have described the expression of normative behaviors in nursery-reared macaques while others have focused on important biomedical themes in child health and development. This article details the unique scientific history of the IPRL and the contributions produced by research conducted in the laboratory. Past and present investigations have explored the topics of early rearing effects, low-birth-weight, prematurity, birth injury, epilepsy, prenatal neurotoxicant exposure, viral infection (pediatric HIV), diarrheal disease, vaccine safety, and assisted reproductive technologies. Data from these studies have helped advance our understanding of both risk and resiliency in primate development. New directions of research at the IPRL include the production of transgenic primate models using our embryonic stem cell-based technology to better understand and treat heritable forms of human intellectual disabilities such as fragile X.

The science of early life toxic stress for pediatric practice and advocacy

Young children who experience toxic stress are at high risk for a number of health outcomes in adulthood, including cardiovascular disease, cancers, asthma, and depression. The American Academy of Pediatrics has recently called on pediatricians, informed by research from molecular biology, genomics, immunology, and neuroscience, to become leaders in science-based strategies to build strong foundations for children's life-long health. In this report, we provide an overview of the science of toxic stress. We summarize the development of the neuroendocrine-immune network, how its function is altered by early life adversity, and how these alterations then increase vulnerability to disease. The fact that early environments shape and calibrate the functioning of biological systems very early in life is both a cautionary tale about overlooking critical periods in development and reason for optimism about the promise of intervention. Even in the most extreme cases of adversity, well-timed changes to children's environments can improve outcomes. Pediatricians are in a unique position to contribute to the public discourse on health and social welfare by explaining how factors that seem distal to child health may be the key to some of the most intractable public health problems of our generation. We consider the challenges and opportunities for preventing toxic stress in the context of contemporary pediatric practice.

Attention to the neglected: prospects for research on child neglect for the next decade

In 1997, the National Institutes of Health within the United States Department of Health and Human Services reviewed the state of its research on child abuse and neglect (US Department of Health and Human Services, National Institutes of Health, 1997). The findings suggested that although neglect was the most frequent type of child maltreatment, research studies were lacking. Through an unprecedented partnership across federal funding agencies for research on child neglect, research was encouraged in several areas. Over the past fifteen years, consortia of researchers have continued to increase our knowledge of child neglect and to shape the field. Nonetheless, challenges for research on child neglect remain, including the changing demographics of the nation and health disparities. Evidenced-based early interventions and treatments may be an opportunity for prevention of child neglect and improving child welfare services, particularly in an era of health care reform. Developmental researchers across the translational pipeline are encouraged to integrate child neglect research in future studies to inform prevention, treatment and policy efforts for the improved health and well-being of children, families and communities.

Parents' education, mothers' vocabulary, and cognitive development in early childhood: longitudinal evidence from Ecuador

OBJECTIVES

I estimated the association between parents' education, mothers' vocabulary, and early child cognitive development in a sample of poor children in rural Ecuador.

METHODS

I used regression analysis to estimate the association between parents' education, mothers' vocabulary, and the vocabulary, memory, and visual integration skills of children at early ages, controlling for possible confounders. The study is based on a longitudinal cohort of children in rural Ecuador (n = 2118).

RESULTS

The schooling and vocabulary levels of mothers were strong predictors of the cognitive development of young children. Household wealth and child's height, weight, and hemoglobin levels explained only a modest fraction of the observed associations. The vocabulary levels of mothers and children were more strongly correlated among older children in the sample, suggesting that the effects of a richer maternal vocabulary are cumulative.

CONCLUSIONS

Differences in children's cognitive outcomes start very early, which has important implications for the intergenerational transmission of poverty and inequality. Programs that seek to increase early stimulation for disadvantaged children, perhaps through parenting programs or high-quality center-based care, hold promise.

The role of the sociotype in managing chronic disease: integrating bio-psycho-sociology with systems biology

THE PROBLEM

Attempts have been made to replace the bio-medical approach with that of systems biology, which considers dynamic human behavior (internal factors) for chronic (rather than acute) disease management. They have not yet incorporated the Bio-psycho-social (BPS) model of Engel which adds patients' background and cultural beliefs (external factors) contributing to their susceptibility to, and coping strategies for, non-communicable diseases (NCDs) the increasing domain of global Public Health. The problem is how to include the social determinants of disease in a comprehensive model of care, especially in the management of chronic disease.

THE SOLUTION HYPOTHESIS

The concept of "sociotype" is proposed as a framework for understanding the interactions between the social, cultural and environmental inputs that influence the growth, development and life-long behavior of a person, including relationships, lifestyle and coping strategies. Pre-/peri-natal influences on development and subsequent susceptibility to chronic disease are examples of interactions between the sociotype, genotype and phenotype. Disorders of the sociotype, encompassing social determinants (e.g. poverty, education, networking), of disease are major contributors to the increase in NCDs, as well as for mental illness and absenteeism. Thus, people are the product of a threefold cord--genotype, phenotype and sociotype. WHAT NEXT?: Holistic management of patients through the BPS model have to be aligned with the relevant elements of systems biology--context, space, time and robustness--that pertain to the sociotype. Medical curricula should balance basic sciences with disciplines such as psychology, sociology, anthropology and public health that attempt to explain human behavior and the social determinants of disease. This requires methodologies combining qualitative and quantitative research to study simultaneous interactions (and their possible mechanisms) between systems biology and the BPS model. The neologism "sociotype" highlights the importance of the social dimension of the BPS model in a novel and useful way. The sociotype, with its effects on genotype and phenotype, will bring psychosocial variables into a paradigm of medical practice to promote health and improve the management of chronic illness.

Individual differences in biological stress responses moderate the contribution of early peer victimization to subsequent depressive symptoms

RATIONALE

Some children who are exposed to early peer victimization become depressed, whereas others are resilient. Understanding individual differences in responses to early adversity, such as victimization, is critical for developing both comprehensive theoretical models and effective interventions.

OBJECTIVES

This study examined whether individual differences in biological stress responses (i.e., activation of the hypothalamic-pituitary-adrenal axis and autonomic nervous system) moderated the contribution of peer victimization to depressive symptoms across a 1-year period.

METHODS

Children (N = 132; M age = 9.46 years, SD = 0.33) completed measures of peer victimization and depressive symptoms, and rated their ruminative responses (i.e., persistent thoughts about negative task-related emotion and experiences) to a laboratory-based social challenge task involving two conflict-of-interests situations with an unfamiliar peer. Children's saliva was collected prior to, and following, participation in the task, and was later assayed for cortisol and alpha amylase [sAA].

RESULTS

Victimization interacted with levels of cortisol measured in anticipation of the task to predict task-related rumination and depressive symptoms 1 year later, adjusting for initial symptoms. Specifically, victimization served as a risk factor for rumination and depressive symptoms in children with heightened but not dampened anticipatory cortisol; yet, heightened anticipatory cortisol was protective against rumination and depressive symptoms in low-victimized children. Victimization also predicted subsequent depressive symptoms in girls with high sAA reactivity across the task.

CONCLUSIONS

This study advances contemporary theory and research by implicating individual variation in biological stress responses as one determinant of sensitivity to the mental health effects of early adversity.