Rising divorce rates spurred research on the effects of marital discord and divorce on children’s development. Studies of family conflict revealed that interparental hostility – particularly when severe, unresolved, and witnessed by children – elevated children’s distress and foreshadowed chronic adjustment problems (Cummings & Davies, 2010). Likewise, divorce and family dissolution were linked with children’s adjustment difficulties. Evidence indicated that children from divorced families were less well‐adjusted than their counterparts in intact families and more likely to develop emotional and behavioral problems. Age, as well as other child characteristics (e.g., gender, temperament, intelligence, and pre‐divorce adjustment), were implicated as moderators of children’s post‐divorce adjustment (Clarke‐Stewart & Brentano, 2006).
Research on parents’ mental health during the 1980s focused attention on maternal depression. It was discovered, for example, that children of manic‐depressive parents not only had more difficulty maintaining social interactions and controlling aggressive behavior but also exhibited lower levels of prosocial behavior (Zahn‐Waxler et al., 1984). Subsequent studies revealed that these and other child impairments (e.g., poor emotion regulation) stemmed from a combination of genetic influences (Cicchetti & Toth, 2006) and depressed parents’ disorganized parenting and dysfunctional thinking and behavior (e.g., insensitivity, negative attributions, poor spousal relationships; Hammen, 2009).
Attachment theory’s growing influence prompted longitudinal studies of the consequences of insecure versus secure parent–child attachments. In general, investigators worked from the hypothesis that children with a history of insecure attachment would evidence more adjustment difficulties as they matured. Findings attested to the stability of attachment status (Waters et al., 2000) and showed that insecurely attached children were more likely than their secure counterparts to develop adjustment problems, particularly if their subsequent caregiving relationships were not consistently sensitive and supportive (Thompson, 2013).
Impoverished rearing conditions
Early studies of infants raised in orphanages implied that impoverished environments, particularly institutionalization and inconsistent caretaking, adversely impacted children’s social development. Subsequent research clarified the nature of institutionalized children’s social deficits and uncovered underlying causes or contributing factors. For example, findings showed that institutionally reared children tended to develop emotional and behavior problems, exhibit indiscriminate friendliness, and form poor‐quality friendships (Roy et al., 2004). These deficits were attributed to neurodevelopmental problems, which often were expressed as attentional deficits and over‐active behavior (Rutter et al., 2001). Additional evidence, comparing institutionalized children with their adopted or home‐reared counterparts, suggested that impoverished rearing conditions anteceded a variety of social difficulties (Maclean, 2003), including behavior problems, peer difficulties, and attachment disorders.
Also studied were the effects of adoption or foster‐care placement on the social development of formerly institutionalized children. Results from these studies, most of which were conducted with children reared in Romanian orphanages, constituted the one bright spot in an otherwise bleak body of findings. In general, these data indicated that removing children from deprived rearing environments and placing them in better‐quality care (e.g., via adoption, foster placement) lessened the likelihood that they would develop social impairments. The best outcomes were achieved when children’s exposure to deprivation was brief rather than prolonged (i.e., adoption before six months of age; Fox et al., 2013; Kennedy et al., 2016).
Problems in the peer system
Extensive research was undertaken to elucidate the developmental consequences of adverse peer relations during childhood. The impetus, in large part, stemmed from early longitudinal findings (Ladd, 2005) indicating that poor peer relations in childhood were one of the best predictors of adult social and mental health difficulties. Three peer “adversities” received the most empirical scrutiny: peer group rejection, peer exclusion, and peer victimization.
Research on peer rejection focused on children who were disliked by the majority of members of their peer group. Longitudinal findings revealed that rejection by one’s peers, especially when chronic, increased children’s risk for adverse interpersonal and developmental outcomes (Ladd, 2005). Peer exclusion was investigated by identifying and following children who were marginalized by peers (e.g., actively ignored, isolated from interactions and activities). Like rejection, peer exclusion during childhood was linked with unfavorable social and developmental consequences (Buhs et al., 2006). Evidence gathered on peer victimization (e.g., peer maltreatment) revealed that it often had detrimental and, in some instances, life‐threatening consequences. Evidence related to this peer adversity is reviewed in a subsequent section.
Risky child characteristics
Also investigated were child attributes that were conceptualized as risk factors, that is, characteristics that were hypothesized to increase the likelihood of adverse developmental outcomes. Prominent among those investigated were particular behavioral propensities (e.g., aggressive, withdrawn behavior), habitual reaction patterns (e.g., difficult temperament), and enduring maladies (e.g., childhood depression).
Early investigators established that aggressive behavior was quite stable, especially in boys (Olweus, 1979), and follow‐back longitudinal studies showed that delinquent adolescents often were aggressive during childhood (Mulligan et al., 1963). Subsequent longitudinal studies further clarified potential outcomes by showing that early aggressiveness not only predicted later misconduct but also diverse social dysfunctions. To illustrate, researchers followed assaultive fourth‐graders and a sample of matched controls over many years and found that the aggressive children were more likely to develop a range of dysfunctions in adolescence and adulthood, including criminal arrests, teenage motherhood, and psychiatric care (Cairns & Cairns, 1994). Researchers also drew distinctions between direct and indirect aggression (Lagerspetz et al., 1988) and found that both direct and indirect forms of aggression were predictive of maladjustment (Crick, 1996).
Initial research on withdrawn behavior failed to make clear whether it was a stable child characteristic and one that predicted adjustment difficulties (Morris et al., 1954). Later theory and evidence led to the identification of solitary subtypes that were differentiated by children’s propensities to engage in solitary‐anxious, unsociable, or socially avoidant behaviors (Coplan et al., 2013). Longitudinal findings revealed that some forms of withdrawn behavior became increasingly stable as children matured and were predictive of adjustment problems (Ladd, 2006). Conclusions remain tentative, but extant evidence implied that solitary‐anxious behavior, in particular, anteceded the development of interpersonal and internalizing problems (Gazelle & Ladd, 2003).
Certain configurations of child temperament were investigated as risk factors, particularly those characterized as low in extroversion‐surgency (e.g., shy, inhibited) and low in effortful control or high in negative affectivity (e.g., under controlled, “difficult”). Findings suggested that, whereas inhibited children were likely to develop internalizing problems, those deficient in regulation abilities, such as effortful control, tended to develop externalizing problems (Rothbart et al., 2011). Children disposed toward negative affectivity had a higher probability of developing aggressive behavior or conduct problems (Mathiesen & Prior, 2006). Overall, evidence suggested that temperaments skewed toward characteristics such as emotionality, impulsiveness, and irritability increased children’s risk for adjustment difficulties