Childhood multiple risk factor exposure exceeds the adverse developmental impacts of singular exposures. Multiple risk factor exposure may also explain why sociodemographic variables (e.g., poverty) can have adverse consequences. Most research on multiple risk factor exposure has relied upon cumulative risk (CR) as the measure of multiple risk. CR is constructed by dichotomizing each risk factor exposure (0 = no risk; 1 = risk) and then summing the dichotomous scores. Despite its widespread use in developmental psychology and elsewhere, CR has several shortcomings: Risk is designated arbitrarily; data on risk intensity are lost; and the index is additive, precluding the possibility of statistical interactions between risk factors. On the other hand, theoretically more compelling multiple risk metrics prove untenable because of low statistical power, extreme higher order interaction terms, low robustness, and collinearity among risk factors. CR multiple risk metrics are parsimonious, are statistically sensitive even with small samples, and make no assumptions about the relative strengths of multiple risk factors or their collinearity. CR also fits well with underlying theoretical models (e.g., Bronfenbrenner's, 1979, bioecological model; McEwen's, 1998, allostasis model of chronic stress; and Ellis, Figueredo, Brumbach, & Schlomer's, 2009, developmental evolutionary theory) concerning why multiple risk factor exposure is more harmful than singular risk exposure. We review the child CR literature, comparing CR to alternative multiple risk measurement models. We also discuss strengths and weaknesses of developmental CR research, offering analytic and theoretical suggestions to strengthen this growing area of scholarship. Finally, we highlight intervention and policy implications of CR and child development research and theory.

The utility of different theoretical models of restorative experience was explored in a quasi-experimental field study and a true experiment. The former included wilderness backpacking and nonwilderness vacation conditions, as well as a control condition in which participants continued with their daily routines. The latter had urban environment, natural environment, and passive relaxation conditions. Multimethod assessments of restoration consisted of self-reports of affective states, cognitive performance, and, in the latter study, physiological measures. Convergent self-report and performance results obtained in both studies offer evidence of greater restorative effects arising from experiences in nature. Implications for theory, methodology, and design are discussed.

The one in five children growing up in poverty in America have elevated risk for socioemotional difficulties. One contributing factor to their elevated risk may be exposure to multiple physical and psychosocial stressors. This study demonstrated that 8- to 10-year-old, low-income, rural children (N = 287) confront a wider array of multiple physical (substandard housing, noise, crowding) and psychosocial (family turmoil, early childhood separation, community violence) stressors than do their middle-income counterparts. Prior research on self-reported distress among inner-city minority children is replicated and extended among low-income, rural White children with evidence of higher levels of self- and parent-reported psychological distress, greater difficulties in self-regulatory behavior (delayed gratification), and elevated psychophysiological stress (resting blood pressure, overnight neuroendocrine hormones). Preliminary mediational analyses with cross-sectional data suggest that cumulative stressor exposure may partially account for the well-documented, elevated risk of socioemotional difficulties accompanying poverty.

Characteristics of the physical environment that influence child development are discussed. Topics include behavioral toxicology, noise, crowding, housing and neighborhood quality, natural settings, schools, and day care settings. Socioemotional, cognitive, motivation, and psychophysiological outcomes in children and youths are reviewed. Necessary methodological and conceptual advances are introduced as well.

There are growing levels of chaos in the lives of American children, youth, and families. Increasingly, children grow up in households lacking in structure and routine, inundated by background stimulation from noise and crowding, and forced to contend with the frenetic pace of modern life. Although widespread, chaos does not occur randomly in the population. We document that low-income adolescents face higher levels of chaos than their more affluent counterparts and provide longitudinal evidence that some of the adverse effects of poverty on socioemotional adjustment are mediated by exposure to chaotic living conditions.

The income-achievement gap is a formidable societal problem, but little is known about either neurocognitive or biological mechanisms that might account for income-related deficits in academic achievement. We show that childhood poverty is inversely related to working memory in young adults. Furthermore, this prospective relationship is mediated by elevated chronic stress during childhood. Chronic stress is measured by allostatic load, a biological marker of cumulative wear and tear on the body that is caused by the mobilization of multiple physiological systems in response to chronic environmental demands.

Childhood socioeconomic status (SES) predicts executive function (EF), but fundamental aspects of this relation remain unknown: the developmental course of the SES disparity, its continued sensitivity to SES changes during that course, and the features of childhood experience responsible for the SES-EF relation. Regarding course, early disparities would be expected to grow during development if caused by accumulating stressors at a given constant level of SES. Alternatively, they would narrow if schooling partly compensates for the effects of earlier deprivation, allowing lower-SES children to 'catch up'. The potential for later childhood SES change to affect EF is also unknown. Regarding mediating factors, previous analyses produced mixed answers, possibly due to correlation amongst candidate mediators. We address these issues with measures of SES, working memory and planning, along with multiple candidate mediators, from the NICHD Study of Early Childcare (n = 1009). Early family income-to-needs and maternal education predicted planning by first grade, and income-to-needs predicted working memory performance at 54 months. Effects of early SES remained consistent through middle childhood, indicating that the relation between early indicators of SES and EF emerges in childhood and persists without narrowing or widening across early and middle childhood. Changes in family income-to-needs were associated with significant changes in planning and trend-level changes in working memory. Mediation analyses supported the role of early childhood home characteristics in explaining the association between SES and EF, while early childhood maternal sensitivity was specifically implicated in the association between maternal education and planning. Early emerging and persistent SES-related differences in EF, partially explained by characteristics of the home and family environment, are thus a potential source of socioeconomic disparities in achievement and health across development.

No abstract