sociocultural issues and public health crises prompted new investigative agendas, instigated conceptual and empirical innovations, and ultimately altered the course of social development research. Because numerous transformative issues and crises occurred, consideration is limited to three prominent exemplars, including research initiatives on childcare, bullying and peer victimization, and ethnic and political violence.
Childcare
Prompted by changing economic conditions and cultural mores (e.g., increase in dual‐earner families, feminism; Clarke‐Stewart & Parke, 2014), demand for childcare increased during the 1970s and accelerated thereafter. This movement toward nonparental care precipitated concerns, some of which had implications for children’s social development. Foremost among these concerns were questions about whether sustained nonparental care would disrupt parent–child relations (e.g., alter attachment security; Melhuish, 2001), help vs. hinder children’s self‐esteem, and enhance or impair children’s social competence (Phillips et al., 1987).
Accordingly, prominent research objectives included examining the effects of childcare on children’s emotions (e.g., stress), behaviors (e.g., externalizing behavior), and attachments to parents and teachers (McCartney et al., 2010; NICHD Early Child Care Research Network, 2005). Additionally, researchers sought to estimate childcare quality and identify dimensions associated with better‐quality care (Clarke‐Stewart & Allhusen, 2005; Melhuish, 2001).
The research that was undertaken to address these concerns spanned several decades (the 1980s–present) and, at its peak, included large‐scale, long‐term, government‐funded projects such as the NICHD Study for Early Child Care and Youth Development (NICHD Early Child Care Research Network, 2005). These investigations produced an extensive body of evidence that, collectively, characterized childcare as a context that – under certain conditions – could have positive as well as negative effects on children’s social development. Although findings implied that parent–child attachment typically was not altered by children’s participation in childcare, insecure attachments were evidenced when infants experienced both insensitive parenting and sustained poor‐quality childcare (NICHD Early Child Care Research Network, 2005). Time spent in childcare also emerged as a potential risk factor. Evidence indicated that children who attended childcare for longer intervals (i.e., per day, week, yearly, etc.) were more likely to exhibit disruptive, disobedient, and aggressive behavior (McCartney et al., 2010). High‐quality care, in contrast, was linked with many positive dimensions of children’s social development (e.g., sociability, self‐esteem, emotion regulation, prosocial behavior, compliance; Clarke‐Stuart & Allhusen, 2005; NICHD Early Child Care Research Network, 2005) as well as with children’s long‐term social and emotional adjustment (Vandell et al., 2010).
Bullying and peer victimization
Research on bullying and peer victimization began in Scandinavia during the late 1970s following a spate of suicides attributed to bullying (Olweus, 1978). By the late 1990s, bullying had become a worldwide public health crisis fueled by a series of highly publicized suicides (Greene, 1993) and violent acts (e.g., 1999 Columbine shootings) committed by previously bullied children. In response to this crisis, scientists from many countries established research and policy initiatives (European Association of Developmental Psychology, 2007 UNESCO, n.d.) and searched for ways to eliminate bullying. Thereafter, evidence began to accrue about the determinants of bullying, the characteristics of bullies and victims, the effects of bullying on victims, the impact of cultures and cohorts, and the results of prevention programs.
Theory and research on the causes of bullying implicated genetic as well as environmental determinants (Ball et al., 2008). Definitional, measurement, and taxonomic innovations led to the identification of different types of bullies (e.g., bullies, bully‐victims), victims (e.g., passive, aggressive victims), and bystanders (e.g., defenders, reinforcers, assistants; Huitsing & Veenstra, 2012). Characteristics ascribed to bullies included aggressiveness, impulsiveness, physical strength, positive self‐concept, and, depending on the subtype, social intelligence (Pabian & Vandebosch, 2016). Passive victims were characterized as shy, anxious, physically weak, isolated, low in self‐esteem, and submissive toward bullies (Olweus, 1978; Perry et al., 1988). In contrast, aggressive, or provocative victims were described as angry, impulsive, emotionally dysregulated, and vengeful (Schwartz, 2000).
The victims of bullying, it was found, often developed multiple and enduring psychological and health problems including internalizing and externalizing problems (Reijntjes et al., 2010, 2011). Many of these maladies were found to be chronic, even following the termination of abuse (Kochenderfer‐Ladd & Wardrop, 2001; Wolke & Lereya, 2015).
Bullying venues and tactics were found to vary by culture and cohort. International surveys (Elgar et al., 2009), although complicated by cultural, definitional, and translational issues (Smith et al., 2016), revealed cross‐national differences in bullying rates (e.g., lower in wealthier countries) and tactics (e.g., harassing familiar vs. unfamiliar peers). As recent cohorts of children accessed cell phones and the internet (Livingstone & Haddon, 2009), bullying venues and tactics shifted, and incidents of “cyberbullying” increased (Wolak et al., 2006). By the mid‐2000s, cyberbullying was a top research priority, and accruing evidence linked it with both internalizing and externalizing problems (Menesini & Spiel, 2012).
Antibullying programs were initially implemented in Scandinavia (Olweus Bully Prevention Program [OBPP]; Olweus & Limber, 2010) and were designed to reduce bullying via adult‐mediated environmental management (e.g., rules, limit setting, establishing consequences). Findings showed that, after 20 months, the OBPP achieved a nearly 50% reduction in bully‐victim problems. Newer programs (e.g., KiVa; Salmivalli & Poskiparta, 2012) incorporated peer‐mediated intervention strategies (e.g., empowering peer defenders) and proved effective particularly with preadolescents. Currently, antibullying efforts are widespread. Investigators in many countries have devised and tested a myriad of antibullying programs, and meta‐analyses of the results suggest that many produce modest but significant reductions in bullying and victimization (Jiménez‐Barbero et al., 2016).
Ethnic and political violence
Although ethnic and political violence likely has harmed children for centuries, the scope, prominence, and severity of contemporary hostilities (e.g., racially motivated genocide, refugee crises, Intifada, repression‐driven internal displacements, World Trade Center bombing) brought this issue to the fore. From the mid‐1980s to the mid‐1990s, it was estimated that approximately 10 million children have been traumatized by war, 1.5 million children have died in armed conflicts, and an additional 4 million have been disabled, maimed, blinded, or suffered brain damage (Benjamin, 1994). Today, it is estimated that approximately 250 million children reside in politically volatile, conflict‐ridden locales (Dubow et al., 2019).
The scientists who studied ethnic and political violence found that the consequences of growing up amid violence, chaos, and deprivation were frequently harmful and often severe. Evidence gathered in many of the world’s trouble spots (e.g., Bosnia, Iraq, Lebanon Palestine, Rwanda; Dubow et al., 2009; Ladd & Cairns, 1996), consistently showed that children exposed to violence exhibited dysfunctions (e.g., PTSD) and often developed enduring adjustment problems (i.e., internalizing and externalizing problems; Dubow et al., 2009, 2019). Given the current level of political tensions, ethnic strife, and terrorist activity throughout the world, this issue will undoubtedly remain a pressing sociocultural concern for the foreseeable future.
Advances in research methodology and analytic strategies
Knowledge about social development expanded at an unprecedented rate during modern and near‐contemporary eras and this accomplishment largely was attributable to changes in scientific practice. Two progressive research
