the foremost overarching theoretical innovation was the progressive transformation that occurred in scientists’ conceptions of the causes of development (i.e., bio‐psycho‐social determinants) and the dynamics of development (i.e., processes that shape growth and outcomes). Previously in the discipline’s history, research on development cycled through epochs during which either naturist or nurturist perspectives dominated scientific inquiry. As a result, when “development” was inferred from findings, it was typically attributed to maturational or environmental determinants, but not both. This state of affairs, in turn, fueled the nature versus nurture controversy.
Across the past several decades, the roles of nature and nurture as determinants of development were reconceptualized in ways that gave rise to novel, integrated perspectives. Behavioral geneticists, for example, postulated that environments influenced genetic expression (e.g., milieus amplify vs. canalize gene influence; Plomin, 1995) and, conversely, that genes shaped the developing organism's environment (Scarr & McCartney, 1983). In the latter paradigm, three modes of influence, or gene by environment interactions, were proposed (i.e., passive, evocative, active), each of which depicted distinct avenues through which children’s genotypes affected the form, quality, or responses of their rearing environments. These models broadened preexisting premises about the causes of development by postulating that biological and environmental determinants not only influenced each other but also worked conjointly to foster development.
Interactionist perspectives emerged alongside behavioral genetic frameworks and evolved into what were eventually termed person‐by‐environment models or, in the context of developmental research, child‐by‐environment models (Magnusson & Stattin, 1998). A central premise of child‐by‐environment models was that the determinants of development originate not only within the child but also in the child’s social environment. Guided by this premise, researchers often focused on stable, organismic characteristics of the child (e.g., temperament, behavioral dispositions) and pertinent features of the child’s social environment (e.g., quality of caregiver or peer relationships) and examined both factors as antecedents of children’s development. Over time, multiple categories of child‐by‐environment frameworks (e.g., additive, moderator, and mediator models; Ladd, 2003) were proposed and utilized to investigate how particular child and environmental characteristics operated together (e.g., combined) to influence development. Thus, similar to the innovations in behavioral genetic theory, child‐by‐environment frameworks encouraged scientists to conceptualize development as a product of organismic and environmental forces, and investigate these determinants as conjoint rather than singular influences.
In time, some of the assumptions within behavior genetic and child‐by‐environment perspectives (e.g., the primacy of biological influences; a static conception of environments) were criticized because they failed to sufficiently characterize development as an ongoing, dynamic process. For example, it was argued that environments, like their biological or organismic counterparts, should be conceptualized as dynamic rather than static entities – determinants whose influence changed across time in response to children’s growth or maturation (Wachs, 1983).
Criticisms such as these, coupled with the ascendance of dynamic perspectives (e.g., transactional, systems theories; Sameroff & Chandler, 1975; Thelen, 1989) and advances in longitudinal research design and analyses, encouraged scientists to formulate more complex, process‐oriented frameworks. In many instances, these frameworks took the form of multivariate longitudinal process models. Unlike prior perspectives, these models were better suited to theorizing about the dynamic nature of development because they afforded scientists the ability to specify: (a) multiple constructs (i.e., hypothesized causes and consequences); (b) complex patterns of relations among postulated causes and consequences, both concurrently and prospectively (e.g., directions of effect, mediation, moderation, reciprocation of effects, continuities, discontinuities, trajectories, transactions, cascades); and (c) timeframes during which developmental processes (i.e., relations among determinants and outcomes) were postulated to emerge, play out, strengthen or weaken, etc. (e.g., ages, stages, sensitive periods, constant vs. time‐varying intervals, distal vs. proximal lags).
The exact structure of these longitudinal process models often was specific to the facet of social development that was under investigation. However, throughout this era, four overarching classes of multivariate longitudinal process models (i.e., continuity, discontinuity, transactional, and cascade) rose to prominence and played a significant role in theory development and testing.
Continuity models were influential in the formulation and testing of hypotheses about developmental continuities, such as the stability of early‐emerging characteristics (e.g., temperament; specific behavioral dispositions) or the lasting impact of early experiences or relationships (e.g., parent–child attachment). As one illustration, Caspi et al. (1987) postulated that children’s early behavioral dispositions derive from constitutional factors (e.g., temperament) and that, throughout development, these dispositions perpetually orient children toward social contexts (e.g., caregiver, peer relations) that sustain these dispositions via dynamic processes termed interactional and cumulative continuity.
Discontinuity models, in contrast, were formulated to test premises about bio‐organismic and environmental factors that, when activated or experienced, caused shifts (i.e., discontinuities) in previously established developmental trajectories, thereby redirecting children toward more or less adaptive pathways. Frameworks of this type were utilized in research on many aspects of social development. To illustrate, researchers hypothesized that adolescent transitions constituted a “turning point” because the juncture between childhood and adolescence was marked by a confluence of biological, psychological, and social disruptions that altered youths’ previously established adjustment trajectories (Rutter, 1996). Findings consistent with this model’s premises – linking transition‐related disruptions or instabilities with discontinuities in adolescents’ adjustment trajectories – were reported in many investigations (Petersen & Hamburg, 1986).
Transactional models were introduced during the 1970s within the context of infant research (Sameroff & Chandler, 1975) and held, as a principal tenet, that development occurred through a continuous process of dynamic interactions in which infants and caregivers mutually influenced each other (i.e., bidirectional, reciprocal patterns of influence, interdependent effects; Sameroff, 2009). Over time, this conception of development was incorporated into the mainstream of developmental theory and was widely utilized as a framework for research on social development (Sameroff, 2009). In research on marital relations, for example, researchers discovered that parental conflict predicted negative child behavior which, in turn, forecasted higher levels of marital discord (Schermerhorn et al., 2010). Bidirectional or reciprocal patterns of influence also were documented in gene‐environment research, with evidence suggesting that children’s genes shaped their environments which, in turn, influenced their genes (Rutter, 2006).
Cascade models represent a recent innovation in developmental theory. The cascade concept has been defined and applied in various ways in the natural and physical sciences, but in developmental research, it has denoted the process through which different facets of the child’s development (e.g., social, emotional, psychological) mutually or sequentially influence each other to engender diverse developmental outcomes (i.e., broader rather than narrower bands or sequences of effects; spreading, snowballing of consequences; Masten & Cicchetti, 2010). These models principally have been utilized in research on psychopathology and have yielded important discoveries. Findings, for example, have shown that children disposed toward externalizing problems in childhood also were likely to develop academic difficulties, and this combination of problems not only endured but also forecasted the emergence of a third dysfunction later in development (i.e., internalizing problems; Masten et al., 2005). Effects consistent with cascade models also have been reported for children who were exposed to institutional deprivation (Golm et al., 2020) and children who exhibited early‐emerging social difficulties (Van Lier & Koot, 2010).
The emergence of pressing sociocultural issues and public health crises
