Adolescence spans the second decade of life, a phase social scientists describe as beginning in biology and ending in society. Adolescence may be defined as the life-span period in which most of a person’s biological, cognitive, psychological, and social characteristics are changing in an interrelated manner from what is considered childlike to what is considered adultlike. When most of a person’s characteristics are in this state of change the person is an adolescent.
CHANGING MODELS OF ADOLESCENCE
Since the founding of the scientific study of adolescent development at the beginning of the twentieth century the predominant conceptual frame for the study of this age period has been one of storm and stress, or of an onto-genetic time of normative developmental disturbance (Freud 1969). Typically, these deficit models of the characteristics of adolescence were predicated on biologically reductionist models of genetic or maturational determination (Erikson 1959, 1968) and resulted in descriptions of youth as broken or in danger of becoming broken (Benson, Scales, Hamilton, and Sesma 2006), as both dangerous and endangered (Anthony 1970), or as problems to be managed (Roth, Brooks-Gunn, Murray, and Foster 1998). In fact, if positive development was discussed in the adolescent development literature—at least prior to the 1990s—it was implicitly or explicitly regarded as the absence of negative or undesirable behaviors. A youth who was seen as manifesting behavior indicative of positive development was depicted as someone who was not taking drugs or using alcohol, not engaging in unsafe sex, and not participating in crime or violence.
Beginning in the early 1990s, and burgeoning in the first half decade of the twenty-first century, a new vision and vocabulary for discussing young people emerged. Propelled by the increasingly more collaborative contributions of scholars (Benson et al. 2006; Damon 2004; Roth & Brooks-Gunn 2003), practitioners (Floyd & McKenna 2003; Little 1993; Pittman, Irby, and Ferber 2001), and policy makers (Cummings 2003; Gore 2003), youth are viewed as resources to be developed. The new vocabulary emphasizes the strengths present within all young people and involves concepts such as developmental assets, moral development, civic engagement, well-being, and thriving. These concepts are predicated on the ideas that every young person has the potential for positive youth development (PYD).
This vision for and vocabulary about youth has evolved in the context of the growth of developmental systems, theoretical models that stress that human development derives from dynamic and systemic (and therefore bidirectional and mutually influential) relations among the multiple levels of organization that comprise the human development system. Developmental systems theory eschews the reduction of an individual to fixed genetic influences and, in fact, contends that such a hereditarian conception of behavior is counterfactual. Instead, developmental systems theory stresses the inherent plasticity of human development, that is, the potential for systematic change throughout development. This potential exists as a consequence of mutually influential relationships between the developing person and his or her biological, psychological, ecological (family, community, culture), and historical niche.
These mutually influential relations involve the influence of a young person on his or her context (e.g., his or her influences on parents, peers, teachers, and community) and the influence of the components of his or her world on him or her. Termed developmental regulations, these bidirectional influences constitute the key focus of empirical study in contemporary research on adolescent development. When the exchanges between individual and context are mutually beneficial, developmental regulations are termed adaptive, and healthy, positive individual development should occur.
Plasticity, then, is instantiated from the regulation of the bidirectional exchanges between the individual and his or her multilevel context. Thus, the concepts of relative plasticity and developmental regulation combine to suggest that there is always at least some potential for systematic change in behavior and, as such, that there may be means found to promote positive development in adolescence.
Thus, plasticity legitimizes an optimistic view of the potential for promoting positive changes in youth. The presence of plasticity in development is a key strength of human development; when combined with the concept of adaptive developmental regulation, and when there is an alignment between the assets of an individual and the assets for positive development that exist in the ecology of youth, one may hypothesize that PYD will be promoted.
The key features of adolescent development underscore the importance of focusing on developmental regulations, in person-context relations, to understand the basic developmental process during this period. This focus allows as well an understanding of how plasticity may eventuate in PYD.
FEATURES OF ADOLESCENT DEVELOPMENT
Adolescent development involves adjustments to changes in the self (e.g., pertinent to puberty, cognitive and emotional characteristics, and social expectations), and also to alterations in family and peer group relations, and often to institutional changes as well (e.g., regarding the structure of the schools within which adolescents are enrolled or opportunities or rules for community service). Not all young people undergo these transitions in the same way, with the same speed, or with comparable outcomes. Individual differences are thus a key part of adolescent development, and are caused by differences in the timing of connections among biological, psychological, and societal factors—with no one of these influences (e.g., biology) acting either alone or as the prime mover of change (Lerner 2004).
In other words, a major source of diversity in developmental trajectories is the systematic relations that adolescents have with key people and institutions in their social context; that is, their family, peer group, school, workplace, neighborhood, community, society, culture, and niche in history. These person-context relations result in multiple pathways through adolescence.
In short, intra-individual changes in development and inter-individual differences in intra-individual change typify this period of life. Both dimensions of diversity must be considered in relation to the general changes of adolescence. The following examples of such general changes illustrate the nature and importance of diversity in adolescence and that the key process within this period (as is the case as well throughout the life span) is a relational one involving mutually influential relations between the developing individual and the multiple levels of the ecology of human development.
MULTIPLE LEVELS OF CONTEXT
Adolescence is a period of extremely rapid transitions in physical characteristics. Indeed, except for infancy, no other period of the life cycle involves such rapid changes. While hormonal changes are part of the development of early adolescence, they are not primarily responsible for the psychological or social developments during this period. Instead, the quality and timing of hormonal or other biological changes influence, and are influenced by, psychological, social, cultural, and historical factors.
Good examples of the integrated, multilevel changes in adolescence arise in the area of cognitive development during this period. Global and pervasive effects of puberty on cognitive development do not seem to exist. When biological effects are found they interact with contextual and experiential factors (e.g., the transition to junior high school) to influence academic achievement. Perspectives on adolescence that claim that behavioral disruptions or disturbances are a universal part of this period of life might lead to the assumption that there are general cognitive disruptions inherent in adolescence. However, evidence does not support this assumption. Rather, cognitive abilities are enhanced in early adolescence as individuals become faster and more efficient at processing informa-tion—at least in settings in which they feel comfortable in performing cognitive tasks.
Thus, relations among biology, problem behaviors associated with personality, and the social context of youth illustrate the multiple levels of human life that are integrated throughout adolescent development. For example, in 1993 researcher Avshalom Caspi and colleagues linked the biological changes of early pubertal maturation to delinquency in adolescent girls, but only among girls who attend mixed-sex schools; similarly, Hakan Stattin and David Magnusson linked pubertal maturation and delinquency with girls who socialize with older friends instead of same-age friends. Early maturation among girls in single-sex schools or in sex-age peer groups was not linked with higher delinquency.
ADOLESCENCE AS AN ONTOGENETIC LABORATORY
Given the structure and substance of the range of interrelated developments during adolescence, from the late 1970s to the mid-2000s researchers have come to regard adolescence as an ideal natural ontogenetic laboratory for studying key theoretical and methodological issues in developmental science. There are several reasons for the special salience of the study of adolescent development to understanding the broader course of life-span development.
First, although the prenatal and infant period exceeds adolescence as an ontogenetic stage of rapid physical and physiological growth, the years from approximately ten to twenty not only include the considerable physical and physiological changes associated with puberty but also mark a time when the interdependency of biology and context in human development is readily apparent. Second, as compared to infancy, the cognizing, goal setting, and relatively autonomous adolescent can, through reciprocal relations with his or her ecology, serve as an active influence on his or her own development, and the study of adolescence can inform these sorts of processes more generally. Third, the multiple individual and contextual transitions into, throughout, and out of this period, involving the major institutions of society (family, peers, schools, and the workplace), engage scholars interested in broader as well as individual levels of organization and provide a rich opportunity for understanding the nature of multilevel systemic change.
Finally, there was also a practical reason for the growing importance of adolescence in the broader field of developmental science: As noted by Laurence Steinberg and Amanda Sheffield Morris in 2001, the longitudinal samples of many developmental scientists who had been studying infancy or childhood had aged into adolescence. Applied developmental scientists were also drawn to the study of adolescents, not just because of the historically unprecedented sets of challenges to the healthy development of adolescents that arose during the latter decades of the twentieth century, but because interest in age groups other than adolescents nevertheless frequently involved this age group. For example, interest in infants often entailed the study of teenage mothers and interest in middle and old age frequently entailed the study of the middle generation squeeze, wherein the adult children of aged parents cared for their own parents while simultaneously raising their own adolescent children.
CONCLUSIONS
The theoretically interesting and socially important changes of adolescence constitute one reason why this age period has attracted increasing scientific attention. To advance basic knowledge and the quality of the applications aimed at enhancing youth development, scholarship should be directed increasingly to elucidating the developmental course of diverse adolescents.
In turn, policies and programs related to interventions must factor in adolescents’ specific developmental and environmental circumstances. Because adolescents are so different from one another, one cannot expect any single policy or intervention to reach all of a given target population or to influence everyone in the same way. Therefore, the stereotype that there is a single pathway through the adolescent years—for instance, one characterized by inevitable "storm and stress"—cannot be expected to stand up in the face of contemporary knowledge about diversity in adolescence. In future research and applications pertinent to adolescence, scholars and practitioners must extend their conception of this period to focus on changing relations between the individual characteristics of a youth and his or her complex and distinct ecology.
The future of civil society in the world rests on the young. Adolescents represent at any point in history the generational cohort that must next be prepared to assume the quality of leadership of self, family, community, and society that will maintain and improve human life. Scientists have a vital role to play in enhancing, through the generation of basic and applied knowledge, the probability that adolescents will become fully engaged citizens who are capable of, and committed to, making these contributions. As evidenced by the chapters in Richard M. Lerner and Laurence Steinberg’s Handbook of Adolescent Psychology (2004), high-quality scientific work on adolescence is being generated at levels of study ranging from the biological through the historical and sociocultural. As the work in this volume demonstrates, the study of adolescent development at its best both informs and is informed by the concerns of communities, of practitioners, and of policy makers.
