Theories of Adolescent Development

By Barbara M. Newman and Philip R. Newman

Adolescence is both universal and culturally constructed, resulting in diverse views about its defining characteristics. Theories of Adolescent Development brings together many theories surrounding this life stage in one comprehensive reference. It begins with an introduction to the nature of theory in the field of adolescence including an analysis of why there are so many theories in this field. The theory chapters are grouped into three sections: biological systems, psychological systems, and societal systems. Each chapter considers a family of theories including scope, assumptions, key concepts, contributions to the study of adolescence, approaches to measurement, applications, and a discussion of strengths and limitations of this family. A concluding chapter offers an integrative analysis, identifying five assumptions drawn from the theories that are essential guides for future research and application. Three questions provide a focus for comparison and contrast: How do the theories characterize the time and timing of adolescence? What do the theories emphasize as domains that are unfolding in movement toward maturity? Building on the perspective of Positive Youth Development, how do the theories differ in their views of developmental resources and conditions that may undermine development in adolescence?

• Includes biological, psychological and sociological theories
• Identifies historical roots, assumptions, key concepts, applications, measurement, strengths, and limitations of each theory
• Compares and contrasts theories
• Concludes with an integrated perspective across theories

• Language: English
• Publisher: Academic Press
• Release date: May 5, 2020
• ISBN: 9780128172544

Barbara M. Newman

Barbara M. Newman (Ph.D., University of Michigan) is a professor emeritus in the Department of Human Development and Family Studies at the University of Rhode Island. She has also been on the faculty at Russell Sage College and the Ohio State University, where she served as department chair in Human Development and Family Science and as associate provost for Faculty Recruitment and Development. She has taught courses in life-span development, adolescence, family theories, and the research process. An active researcher, Dr. Newman’s interests focus on parent-child relationships in early adolescence, factors that promote success in the transition to high school and the transition to college, and the sense of belonging in early and later adolescence. Her most recent research focuses on the development of the sense of purpose among college students with disabilities.

Book preview

Justice).

Preface

Theories have played a key role in highlighting the marvelous transformations that take place during adolescence. These theories have uncovered advances in reasoning, emotional expression and regulation, physical maturation, self-understanding, and the expansion of social roles and interpersonal relationships. Theories have led the way in focusing attention on the capacity of adolescents to direct the course of their development through their emerging sense of purpose and the formation of a personal identity. Yet, no theory of adolescent development addresses all these domains. There is no contemporary single volume that provides an overview of theories. Theories of Adolescent Development was written to fill this gap.

The book is written for advanced undergraduate students, graduate students, and researchers who are committed to the study of adolescent development, as well as for practitioners who hope to broaden their understanding of adolescence in order to support positive youth development. Our hope is that it will provide a valuable resource to design research, guide interventions, and inform policy. Because the study of adolescent development has become increasingly multidisciplinary, the selection of families of theories addressed in this book includes perspectives from a diversity of disciplines including psychology, human development, sociology, cultural anthropology, education, family science, and social ecology.

Theories change over time. We have tried to capture ways in which new evidence and observations have resulted in the expansion, revision, or rejection of aspects of earlier theories. Many contemporary theories take a probabilistic view of development, conceptualizing the dynamics of the changing person engaged in multiple environments that are also changing. The diversity of youth, including racial, ethnic, gender, social class, and cultural variations as well as international studies, cast a new light on normative expectations about pathways from childhood to adulthood. The diversity of settings has also received new attention through the study of families, peer groups, schools, and communities, resulting in an appreciation for the challenges adolescents face as they traverse multiple environments.

The book begins with an overview of the complex and somewhat ambiguous nature of adolescence and the resulting need for a variety of theories to account for the changes that take place during this period. Our intention is to inspire a more nuanced conceptualization of adolescent development wherein each cohort can be appreciated as simultaneously vulnerable, self-correcting, and novel; and where individuality can be examined along with normative patterns and trends. Twelve chapters focus on families of theories divided into three sections. Part I includes theories that focus on the biological system including evolution and evolutionary psychology, behavioral genetics and biosocial theories, and dynamic systems theories. Part II includes theories that emphasize the psychological system including psychoanalytic theories, psychosocial theories, cognitive developmental theories, and self-regulation theories. Part III includes theories that emphasize the societal systems including interpersonal theories, family theories, ecological theories, social role and life course theories, and cultural theories. Of course, this division of the theories is an overgeneralization. Each theory has something to say about biological, psychological, and societal factors.

A unique feature of this book is the inclusion of both applications and approaches to measurement associated with each theory. We have identified theories that have guided both application and research. We hope that through example, the chapters will inspire investigators to apply theoretical approaches to their areas of interest and to make use of a variety of research strategies. Exciting advances in the study of development can arise by pitting theories against each other and by using multiple research methods.

Each theory chapter includes the following sections:

A.The origins and intellectual traditions from which the theory emerges.

B.The scope or range of applicability of the theory including basic assumptions and key concepts.

C.Insights from the theory that address adolescent development and behavior.

D.Applications of the theory to various fields such as education, therapy/counseling, health, social policy, or juvenile justice.

E.Approaches to measurement.

F.Strengths and limitations of the theory.

A concluding chapter offers an integrated perspective highlighting contributions of the theories for Positive Youth Development, especially factors that contribute to well-being and thriving, and those that increase the probability of risky behavior or the disruption of optimal development.

Acknowledgments

This book is an outgrowth of a chapter on Theories of Adolescence that was published in the Encyclopedia of Adolescence (2011). We gratefully acknowledge B. Bradford Brown and Mitchell J. Prinstein, editors of the Encyclopedia of Adolescence, for inviting us to contribute that chapter, and for providing comments and suggestions for both the chapter and the proposal for the full-length book. We also thank those at Elsevier who encouraged the development of this book and its progress through the editorial and production phases, including Emily Elke, who suggested that we expand the encyclopedia chapter to a full length book, Barbara Makinster, our editorial project manager, Swapna Srinivasan, our production manager, and Narmatha Mohan, the permissions editor for this volume.

We have been involved in the study of adolescent development throughout our academic careers, beginning with our doctoral dissertations under the direction of James G. Kelly. Jim welcomed us into his multischool project and introduced us to the ecological perspective on coping and adaptation in adolescence. That work resulted in the publication of Adolescent boys in high school (edited by James G. Kelly), Lawrence Erlbaum Publishers, 1979 (republished by Routledge Library Editions, 2017). Our doctoral dissertations were the basis for two of the chapters in that book. We continued our focus on adolescent theory and development in subsequent work including: An introduction to the psychology of adolescence, Newman and Newman, The Dorsey Press, 1979; Adolescent development, Newman and Newman, Merrill Publishing, 1986; Theories of Human Development, 2nd ed., Psychology Press, 2016; and Development through life: A psychosocial approach, 13th ed., Cengage Learning, 2018. We want to recognize and thank the editors and supportive staff who have made these projects possible.

We dedicate this book to all those who come after us who will explore and advance our understanding of this fascinating and transformative time of life.

Chapter 1

Introduction

Abstract

This chapter introduces the concept of adolescence and the ambiguities surrounding its definition as a developmental stage. The chapter explains the complex, multidimensional nature of the transitions that take place during adolescence and why this period requires special attention within theories of human development. The features of a developmental theory and characteristics of a good theory are presented, followed by a discussion of why many theories are needed to explore this dynamic period of life. The chapter concludes with a description of the organization of the book into three families of theories: those that focus on the biological system; those that focus on the psychological system; and those that focus on the societal system. The organization for the content of each chapter is outlined.

Keywords

Adolescence; Developmental stage; Developmental theory; Biological system; Psychological system; Societal system

What is adolescence? When does it begin and end?

The term adolescence is generally defined as the period of transition between childhood and maturity. The word adolescence derives from the Latin adolescere, which means to grow up or mature. It has roots in terms that refer to ripening, unfolding, and growing up.

Adolescence is typically viewed as beginning with puberty. However, research regarding pubertal development finds that for some children the biological beginnings of puberty are in evidence as early as ages 8 or 9, earlier than we typically associate with the term adolescence (Dorn, Dahl, Woodward, & Biro, 2006). The period of adolescence is viewed as ending with maturity or adulthood. But that term is also ambiguous as it is linked with biological, social/cultural, legal, historical, and religious meanings. The idea of the age of majority suggests an end point of adolescence, implying that the person has legal control over actions and decisions. In the United States, age of majority varies by state from age 18 to 21 (U.S. Legal.com, 2018). Nonetheless, age of majority is not identical to the age associated with specific activities such as age of sexual consent, marriageable age, school leaving age, drinking age, driving age, voting age, smoking age, gambling age, or the age at which a person can consent to medical treatment without parental permission. Again, these all vary by state in the United States. Research on the maturation of the prefrontal cortex suggests that cognitive capacities for self-regulation and higher order decision-making continue into the mid-20s (Giedd et al., 2012). These ambiguities surrounding a beginning and ending point of adolescence support the need for theories of adolescent development that highlight particular aspects of this stage of life and the conditions that support or undermine development during these years (Sawyer, Azzopardi, Wickremarathne, & Patton, 2018).

Not only is the definition of adolescence ambiguous, but so is the language used to address this period of life. Terms including youth, teen or teenager, preteen, adolescent, and emerging adult are some of the words used to refer to people in this stage of life. What is more, studies that claim to focus on adolescent development may include young people in middle school, high school, or college. They may focus on young people who are not in school, employed or not employed, or in the military. Studies that address adolescents often do not include information about pubertal status, thereby ignoring important developmental differences that may exist among children of the same chronological age. What is more, the concept of adolescence has very different connotations in different societies (Brown, Larson, & Saraswathi, 2002). Cultural groups differ in their recognition of adolescence as a distinct period of life, the status or power allocated to adolescents, as well as the normative pathways to adulthood.

The concept of adolescence encompasses biological, psychological, and societal domains (Newman & Newman, 2018). Understanding adolescent development requires a multidisciplinary perspective. This period of comparatively rapid biological change is accompanied by numerous changes in family, school, peer group, community, government, and technology resulting in a cascade of transformations. The period of adolescence brings new physical and reproductive capacities, new cognitive abilities and insights, new understandings about oneself and the nature of one's society, one's role in the community, and new opportunities to express one's talents, formulate meaningful goals, and achieve clarity of purpose. At the same time, complex demands of society and one's social groups make entry into the full enactment of adult roles more difficult, prolonging adolescence and delaying the sense of oneself as fully adult (Furstenberg, 2010).

Why does adolescence deserve its own theories?

Given the multidisciplinary nature of the study of adolescence, there is a need to focus on each aspect of development as well as to understand the interactions among these domains. Adolescence is a period of biological change that is taking place over the years from approximately age 10 to 24. Physical changes in reproductive maturity, stature, strength, and endurance are accompanied by hormonal changes, as well as changes in the growth and sculpting of neural networks in the brain. Theories that focus on biological changes are needed to understand the factors that support or impede these changes, the impact of environmental conditions on biological changes, and the relationship of biological changes to interpersonal behaviors, academic abilities, athletic capacities, interests, and self-awareness.

Adolescence brings significant changes in the psychological system including an unfolding of new interests, a desire for new levels of autonomy and self-expression, new capacities for understanding complex problems, new approaches to the evaluation of risk and related decision-making, and new insights about oneself as a person with a past as well as with potential futures. Psychological theories focus on the conflicts that arise as a result of new drives and motivations, the creative process of self-definition and identities, and the pursuit of short- and long-term goals. These theories provide concepts that help illuminate processes that are typically difficult to observe directly. They provide a lens to private preoccupations that may, at times, contribute to an adolescent's feelings of social isolation, sullenness, rebelliousness, or unexplained exuberance. These theories lead to an appreciation of adolescence as a time to become more authentic, to engage in self-authorship, to experience heightened self-consciousness, or to be bound by rigid self-control.

Adolescence is experienced in the context of numerous societal circumstances including changing historical resources and pressures, family and peer group environments, social norms and cultural expectations, school environments, neighborhoods, and work settings. Societal theories provide a lens for examining the interpersonal relationships that shape adolescents’ values and their self-image; the social roles that impose norms and role expectations; and social identities including gender, race, ethnicity, social class, disability, and sexual orientation that impact a young person's ideas about self in society. These theories broaden the understanding of the current experiences of adolescents as specific to the particular culture and historical period during which the young person is maturing.

Adolescence can be understood as a time that links generations. Theories help account for how the history of a person's infancy and childhood contributes to the unfolding of a young person's self-understanding, values, morality, and desires for the future. Theories further understanding of the role adolescents play in the transformation of cultures as they encounter new technologies and social messages that guide them toward changing values. As young people make decisions that shape their goals and ambitions, the new capabilities of the period become salient. Emerging definitions of what it means to be successful, to be moral, or to be fulfilled become the essence of each new generation of adults. What is happening for youth serves as a precursor for the future of the society. Do young people come of age in a time of civility, productivity, and openness, or a time of fearfulness, cautiousness, and a survival orientation? Characteristics of the historical period as well as features of their immediate environments guide the adolescents’ adaptations.

Decisions and behaviors that occur in adolescence have significant physical, social, and mental health consequences. Attitudes formed regarding gender roles, educational goals, career aspirations, religious/moral values, and family formation can impact future opportunities and resources. Theories can be useful in guiding applications and interventions including human services, education, health, mental health, recreation, arts and music, sports, family life, social welfare, civic engagement, religious education, consumer science, the law, and juvenile justice.

What are characteristics of a scientific theory? What are features of a good theory?

A theory is a logical system of concepts that helps explain observations and contributes to the development of a body of knowledge as in a theory of evolution or guides an approach to practice as in a theory of education. We all have our informal, intuitive theories about why people behave as they do. For example, the adage The acorn doesn’t fall far from the tree, is an informal theory that predicts that children are going to grow up to behave a lot like their parents. However, a scientific theory is different from an informal set of beliefs. A formal scientific theory is a set of interconnected statements, including assumptions, definitions, and hypotheses, that explain and interpret observations. The function of this set of interconnected statements is to describe unobservable structures, mechanisms, or processes and to relate them to one another in order to explain observable events. For example, in learning, the information or strategies that have been learned are not observable nor is the process of learning. The information becomes observable by asking questions, giving a test, or presenting a situation where the information must be used to solve a problem. However, the process of learning the information is not directly observable and our understanding of this process relies on theories that attempt to explain how new information is acquired, remembered, and produced when needed. Components of a theory and characteristics of a good theory are listed in Table 1.1.

Table 1.1

In the field of human development, theory is differentiated from research and from facts. Research may be guided by theory; however, the research process is a separate approach to building a knowledge base. For example, in his cognitive developmental theory, Piaget (1972) introduced the idea of formal operational reasoning, an approach to logical thinking characteristic of adolescence that is qualitatively different from the problem-solving approach typical of middle childhood. He proposed that adolescents approach problem-solving with a new capacity for relativistic, hypothetical reasoning. A growing body of research stimulated by this theory, and coordinated with new evidence from neuroscience, has led to a more nuanced understanding of adolescents’ capacity for probabilistic reasoning, revealing significant individual differences in the ability to use principles of logic to analyze complex problems and introducing the importance of emotion and experience as well as advanced cognitive capacity in the young person's approach to reasoning (Kuhn, 2010).

Observations and facts are distinct from the theories that try to explain or account for them. For example, the birth rate for teens in the United States (births for every 1000 females ages 15–19) has declined substantially over the past 25 years (Office of Adolescent Health, 2016). This fact is indisputable. However, precisely why this has occurred is not fully understood. A variety of theories have been generated to address factors regarding teen sexual behavior, pregnancy, and childbearing. Each theory might help account for this decline. The theories do not change the facts, but the research generated from the theories may help further our understanding of the decline in teen pregnancy and the principles that should guide future interventions.

Components of a theory

There are four key features of each theory: the domain of the theory, its assumptions, key concepts, and hypotheses. Each theory identifies a domain such as cognition, language, family relationships, or identity development, which will be the focus of explanation. In order to understand a theory, one must be clear about which phenomena the theory is trying to explain. A theory of intellectual development may include hypotheses about the evolution of the brain, the growth of logical thinking, or the capacity to use symbolism. Such a theory is less likely to explain fears, motives, or friendship. Understanding the focus of the theory helps to identify its range of applicability. Although principles from one theory may have relevance to another area of knowledge, a theory is evaluated in terms of the domain it was originally intended to explain.

Assumptions are the guiding premises underlying the logic of a theory. These assumptions may not be testable; they provide a platform upon which the theory is built. In order to evaluate a theory, you must first understand its assumptions. Darwin assumed that lower life forms progress to higher forms in the process of evolution. Freud assumed that all behaviors are motivated and that the unconscious is a storehouse of motives and wishes. The assumptions of any theory may or may not be correct. Assumptions may be influenced by the cultural context that dominates the theorist's period of history, by the sample of observations from which the theorist has drawn inferences, by the current knowledge base of the field, and by the intellectual capacities of the theorist.

Each theory is composed of key constructs that refer to unobservable relationships or processes. You might think of these constructs as the principle characters in the story. We use constructs such as intelligence, motivation, and goals to explain human behavior. Developmental scholars work to measure explanatory constructs but there is controversy about approaches to measurement and criticism about the quality of instruments used to operationalize these constructs. Often these controversies lead to improvements in the techniques used for the measurement or revisions of the theory.

Finally, theories offer if-then links or testable hypotheses. What does the theory predict? For example, Skinner's theory of operant conditioning offered the following testable hypothesis: When a response is followed by a reward or reinforcement, the probability of its recurrence will increase. This means that successful actions (those that are rewarded) are more likely to be repeated than unsuccessful actions (those that are not rewarded). From this single hypothesis, one can interpret many observations about human behavior and predict others.

Requirements of a good theory

A formal theory should meet certain requirements (Newman & Newman, 2016; Swanson & Chermack, 2013) as follows:

1.Propositions of the theory should be logical and internally consistent, with no contradictory statements.

2.The hypotheses should be explored through systematic research in which the abstract concepts of the theory can be observed and measured. For example, the sociologist Charles Cooley coined the term the looking glass self, a hypothetical notion that people make judgments about what others think about them, and then they integrate those assessments into their self-concept. This hypothesis might be tested experimentally by manipulating interpersonal feedback under controlled conditions and then measuring changes in a person's self-concept.

3.The theory should be parsimonious, which means that the theory should be simple, relying on as few assumptions, constructs, and propositions as possible while still accurately accounting for the observations. Parsimony is relative. For example, Freud hypothesized that there were five stages of development. Erikson hypothesized that there were eight stages of development. Using the principle of parsimony, one might conclude that Freud's theory is a better one. However, Erikson's theory provides a more differentiated view of adulthood and aging, and, as a result, his theory offers more insight into the process of development over the life span. On the other hand, a theory that suggests 30 or 40 stages of life might be viewed as overly complex and less parsimonious than the one that provides a smaller number of integrated periods.

4.The theory should integrate previous research, and should deal with a relatively large area of science (Miller, 2016).

5.Theories add new levels of understanding by suggesting causal relationships, unifying diverse observations, and identifying the importance of events that may have gone unnoticed. The theory offers a set of logical steps to predict the nature and direction of constancy and change. Theories often stimulate research that leads to modifications of the theory, or the emergence of new theories that have their roots in earlier theoretical foundations.

An important aspect of any scientific theory is that it is viewed as tentative and open to revision based on new observations. Scientific theories are different from beliefs. They are created with an understanding that new technologies or measures, new observations, and new insights may result in new, integrative, and better explanations. Thus, scientific theories are works in progress, providing descriptions and explanations that are useful until more inclusive, accurate analyses become available (Bordens & Abbott, 2018).

Why so many theories?

It is probably not surprising that there is no one agreed-upon theory that accounts for all aspects of adolescent development. The families of theories discussed in the following chapters differ in their emphasis on domains of development, focusing to a greater or lesser extent on physical, cognitive, social, and emotional processes. The theories differ in their emphasis on particular periods of life, some more attuned to early, middle, or later adolescence. The theories differ in their emphasis on universal patterns as compared to unique cultural and historical contexts that influence development. The theories also differ in their level of analysis. Some theories focus on very specific moments in daily life; others focus on broad, system changes that may occur gradually over long periods of time.

How is this book organized?

The remainder of this book focuses on families of theories divided into three sections. Part I includes theories that focus on the biological system including evolution and evolutionary psychology, behavioral genetics and biosocial theories, and dynamic systems theories. Part II includes theories that emphasize the psychological system including psychoanalytic theories, psychosocial theories, cognitive developmental theories, and self-regulation theory. Part III includes theories that emphasize the societal systems including interpersonal theories, family theories, ecological theories, social role and life course theories, and cultural theories. The presentation of each family of theories begins with a brief interlude or overview in which the issues that tie the theories together are introduced. Of course, this division of the theories is an overgeneralization. Each theory has something to say about biological, psychological, and societal factors. However, we hope this organization will help to highlight some of the common threads among the theories, compare and contrast them, and identify their strengths and limitations.

Each theory chapter will include the following sections:

A.The classical origins and intellectual traditions from which the theory emerges.

B.The scope or range of applicability of the theory; basic assumption; and key concepts.

C.Insights from the theory that address adolescent development and behavior.

D.Applications of the theory to various fields such as education, therapy/counseling, health, social policy, and juvenile justice.

E.Approaches to measurement.

F.Strengths and limitations of the theory.

A concluding chapter offers an integrated perspective highlighting contributions of the theories for Positive Youth Development, especially factors that contribute to well-being and thriving, and those that increase the probability of risky behavior or the disruption of optimal development.

As you read each theory, we encourage a critical evaluation of its scientific merit and a consideration of its broad impact. These theories and their emerging extensions contribute in unique ways by guiding ongoing research, the design of interventions, and as frameworks for shaping opinions and attitudes about adolescence among those outside the limited circle of human development researchers and scholars. One of the most exciting aspects of the study of adolescent development and behavior is its openness to new and emerging conceptualizations that promise to improve interventions and enrich the life experiences of youth.

References

Bordens K.S., Abbott B.B. Research design and methods: A process approach. 10th ed. New York: McGraw Hill; 2018.

Brown B.B., Larson R.W., Saraswathi T.S. The world's youth: Adolescence in eight regions of the globe. Cambridge: Cambridge University Press; 2002.

Dorn L.D., Dahl R.E., Woodward H.R., Biro F. Defining the boundaries of early adolescence: A user's guide to assessing pubertal status and pubertal timing in research with adolescents. Applied Developmental Science. 2006;10:30–56.

Furstenberg F.F. Passage to adulthood. The Prevention Researcher. 2010;17:3–7.

Giedd J., Stockman M., Weddle C., Liverpool M., Alexander-Bloch A., Wallace G.L.,… Lenroot R.K. Anatomic magnetic resonance imaging of the developing child and adolescent brain. In: Reyna V.R., Chapman S.B., Dougherty M.R., Confrey J., eds. The adolescent brain: Learning, reasoning and decision-making. Washington, DC: American Psychological Association; 2012:15–35.

Kuhn D. What is scientific thinking and how does it develop?. In: Goswami U., ed. Handbook of childhood cognitive development. 2nd ed. Oxford: Blackwell; 2010.

Miller P.H. Theories of developmental psychology. 6th ed. New York: Worth; 2016.

Newman B.M., Newman P.R. Theories of human development. 2nd ed. New York: Psychological Press; 2016.

Newman B.M., Newman P.R. Development through life: A psychosocial approach. 13th ed. Boston, MA: Cengage Learning; 2018.

Office of Adolescent Health. Trends in teen pregnancy and childbearing. https://www.hhs.gov/ash/oah/adolescent-development/reproductive-health-and-teen-pregnancy/teen-pregnancy-and-childbearing/trends/indexhtml. 2016.

Piaget J. The psychology of intelligence. Totowa, NJ: Littlefield Adams; 1972.

Sawyer S.M., Azzopardi P.S., Wickremarathne D., Patton G.C. The age of adolescence. The Lancet: Child and Adolescent Health. 2018;2:223–228.

Swanson R.A., Chermack T.J. Theory building in applied disciplines. San Francisco, CA: Berrett-Koehler Publishing; 2013.

U.S. Legal.com. Age of majority law and legal definition. Retrieved from the internet on March 2, 2018 from https://definitions.uslegal.com/a/age-of-majority/. 2018.

Part I

The biological system

Part I

Introduction

The biological system includes all those processes necessary for the physical functioning of the organism and for mental activity. The brain and spinal cord (the central nervous system) and the peripheral nervous system are components of the biological system through which all sensory information is received, processed, and transmitted to guide behavior. Biological processes develop and change as a consequence of genetically guided maturation; environmental stimulation and resources, including social interactions, cognitive challenges, and nutrition; exposure to environmental toxins; encounters with accidents and diseases; and lifestyle patterns of behavior. The biological system is a multilevel, dynamic system in which maturation at one level can have profound, and sometimes unexpected, consequences for maturation at another level (Newman & Newman, 2018).

The three theories presented in this section have a strong biological emphasis. Of course, no theory of development claims that the story of growth is entirely about nature. No human, whatever his or her biological endowments, can live without environmental supports including air, food, water, and shelter. We are increasingly aware that humans also require social support and cognitive stimulation to thrive and grow. However, when we ask how development occurs, the theories in this part draw attention to biologically based processes that guide the direction and nature of growth.

Puberty refers to the period of biological transition from childhood to adolescence. Biological transformations take place across multiple domains including neurological maturation; relatively rapid increases in height and weight; changes in body shape, strength, and endurance; changes in the hormonal system; and maturation of the reproductive system. The three families of theories included in this part provide unique insights into the nature and significance of biological processes as they contribute to adolescent development and behavior.

Evolutionary theories

Evolutionary theories take the long-term look at the emergence of the human species. According to this perspective, humans of today carry with them genetically guided characteristics passed from generation to generation that have contributed to survival and reproductive success. This chapter introduces the place of adolescence within Darwin’s idea of fitness, the link between human adolescence and adolescence in other primates, and the concept of adaptation to an ecological niche. The chapter incorporates concepts from evolutionary psychology to consider the integration of genetic and social forces that result in phenotypes related to puberty, fidelity to a group, sex-specific sexual strategies, aggressiveness and bullying, and the adaptive nature of risky behaviors.

Biosocial theories

Biosocial theories provide insights into the interdependence of nature and nurture by considering different ways that genes and environments interact to influence development and behavior. Whereas evolutionary theories focus on the long history of human adaptation and the likely contributions of various physical and behavioral adaptations to fitness, biosocial theories build on the evolutionary base to focus on contemporary interactions of genetic and environmental processes. This chapter focuses on theories that consider the interaction of genetic factors with specific environmental conditions, for example, environmental toxins, harsh or nurturing parenting environments, and peer interactions, to account for outcomes such as cognitive abilities, personality characteristics, peer relationships, delinquency, and antisocial behavior.

Dynamic systems theories

Dynamic systems theories consider development as a probabilistic outcome of the interaction of processes at many levels and many systems. The dynamic systems perspective can be applied to any system that changes overtime, from the cellular level to the solar system. However, its relevance to adolescent development has become increasingly useful as it suggests a way to coordinate moment-to-moment change with longer-term developmental transformations. Dynamic systems theory approaches this time of life as a phase transition that results from forces within and outside the person, merging and influencing each other to produce new capacities and behaviors. The chapter examines characteristics of open systems, adaptive self-regulation and adaptive self-organization, and the idea of the norm of reaction as these ideas apply to adolescent development. Three topics of particular relevance for understanding adolescent development have been examined from a dynamic systems lens: dynamic skill development; parent-adolescent relationships; and antisocial development.

Similarities and differences

The three theories in this part share a focus on three aspects of development:

1.the importance of variability in understanding the nature and direction of development;

2.the need to identify essential components of the biological system that can foster or constrain development; and

3.the ongoing interaction of biological and environmental factors in shaping the direction of growth.

The theories differ in their focus on development over time. Evolutionary theory takes the long-term time frame, biosocial theory considers heritability across adjoining or nearby generations, and dynamic systems theory looks at the iterative impact of moment by moment or frequently repeated experiences that shape development.

The theories also have different views about causality. Evolutionary theory places the explanation for behavior in a history of adaptive fitness over many generations. Dynamic systems theory views the observed behavior as a probabilistic outcome that results from the self-organization of existing components or features of the system interacting over time. Biosocial theories fall somewhere in between, examining the sources of contemporary behavior by exploring the interpenetration of specific genetic and environmental conditions.

Reference

Newman B.M., Newman P.R. Development through life: A psychosocial approach. 13th ed. Boston, MA: Cengage Learning; 2018.

Chapter 2

Evolutionary theory

Abstract

The chapter reviews the intellectual tradition of evolutionary theory based on Darwin's concepts of natural selection, fitness, adaptation, and speciation, with early contributions to the study of adolescent development by G. Stanley Hall and Arnold Gesell. Five themes are of special interest for the study of adolescent development and behavior: the nature of puberty and the period of adolescence; fidelity to a group; sex-specific reproductive strategies; aggressiveness and bullying; and the nature of risky behaviors. Applications of evolutionary theory to adolescent development include health; risk-taking; sex differences in sexual selection; macrosystem interventions; and the impact of environmental mismatch for development. Approaches to measurement address forms of evidence that assess hypotheses derived from the theory. The chapter concludes with a summary of strengths and limitations of the theory.

Keywords

Evolution; Natural selection; Fitness; Adaptation; Puberty; Fidelity to a group; Reproductive strategies; Risk-taking; Aggression; Bullying

Evolutionary theories assume that the natural laws that apply to plant and animal life also apply to humans. These theories integrate humans into the vast array of all life-forms. They emphasize the importance of biological forces in directing growth, and describe gradual modifications of biological features as well as patterns of behavior as a product of functional adaptations to specific environmental resources, demands, and hazards.

What are the origins and intellectual traditions from which evolutionary theory emerged?

The general theory of evolution emerged in the late 18th century as scientists made observations suggesting that a species might change and evolve into a new species. Before this time, scientists had operated under the premise that all species had started out at the same time from the same source. The main resistance to theories of evolution was offered by religious leaders who believed in the theory of creation. The controversy between the creationist and the evolutionary view of the origin of human life continues to the present time.

Charles Darwin's theory of evolution explains how diverse and increasingly more complex life-forms come to exist. Darwin, born in 1809, was exposed to concepts associated with a theory of evolution through writings by his grandfather, Erasmus Darwin, who proposed the concept of sexual selection. According to this concept, the strongest and most active animal should propagate the species which should thus become improved (Darwin, 1794–1796). Erasmus Darwin's work was based primarily on logical propositions. In contrast, Charles Darwin was determined to base his work on a systematic analysis of observations in the natural world, fossil evidence, as well as plant and animal samples including those collected during his tenure as a naturalist aboard the H.M.S. Beagle (Darwin, 1859/1979). His thinking was influenced by the writings of Lyell (1830/1833) who introduced the concept of uniformitarianism, the principle that unchanging laws of nature apply uniformly throughout time. The challenge posed by this assumption was to discover the basic mechanism that could account for species change from the beginning of life to the present time. The basic mechanism that Darwin proposed was the law of natural selection.

What are the basic assumptions and key concepts of evolutionary theories?

Natural selection and fitness

The law of natural selection explains how, over generations, species gradually change to respond to changing environmental conditions. Every species produces more offspring than can survive to reproduce because of food supply limitations, competition for mates, and natural dangers. Darwin observed considerable variation among members of the same species within a specific location. The law of natural selection states that those individuals best suited to the characteristics of the immediate environment are more likely to survive, mate, have offspring, and rear their offspring to reach reproductive age. These offspring are likely to exhibit the characteristics best suited to their environment. Natural selection operates via organisms’ reproductive success, sometimes referred to as fitness. Over long periods of time, those members of the species that have the selective advantage are more likely to survive and reproduce, thus passing their characteristics on to future generations.

The concept of inclusive fitness was later added to the theory of natural selection (Hamilton, 1964). This idea suggests that fitness is not only determined by an individual's own reproductive success, but also by promoting the survival and reproductive success of others who exhibit similar characteristics. In human groups, behaviors that support one's family members or that make it possible for one's kin to be more attractive in the mating process would be considered examples of inclusive fitness. This concept highlights the adaptive advantage of supportive kin networks that selectively direct their resources toward members of their family, kinship network, tribe, or ethnic group.

The concept of sexual selection is only one aspect of Charles Darwin's broader concept of fitness, focusing on the ability of an organism to attract and successfully copulate with a mate. Males compete for access to females; females choose which males to mate with. Whereas Erasmus Darwin emphasized the male's strength in sexual selection, females also play a role in selecting reproductive partners.

Adaptation

Behavior is adapted to the environment in which it occurs. When used as a verb, adaptation is the process that underlies evolutionary change—a process by which living things develop structures and problem-solving mechanisms that enable them to thrive in a particular environment or environmental niche. When used as a noun, adaptations are specific characteristics that are the historical outcomes of evolution; they are functional in the face of specific problems the organism must solve (Schmitt & Pilcher, 2004). Evolutionary adaptations contribute in some specific way to fitness (Williams, 1966). For example, the need to distinguish edible from poisonous foods results in the adaptation of specific sensory capacities in taste, smell, and visual discrimination. The particular sensory abilities that evolve depend on the sources and variety of foods the organism encounters. Adaptation can operate at the biological level, as a change in some physical characteristic like protective coloration, or at the behavioral level, as in the shift toward bipedalism. If the environment changes (in climate, for example), only certain variations of organisms will survive. Forms of life that fail to adapt may become extinct, and others may emerge as modifications of the species or even new species. Thus, in the context of changing environmental conditions, evolutionary change takes place slowly and incrementally as individual organisms adapt and populations with similar adaptive characteristics dominate an environment.

A key feature of adaptation is phenotypic plasticity (West-Eberhard, 2003). This plasticity is a product of the inherent variability within species as well as the capacity of individuals of the same genetic makeup to respond to environmental conditions. Organisms of the same species can develop different physical and behavioral features in response to characteristics of their environments. These features, including physical characteristics, competitive strategies, and reproductive advantages, are triggered by conditions of the environment such as temperature, population density, or scarcity of food. What is more, there are individual differences in the extent of plasticity. Among humans, some individuals are more sensitive to environmental influences, both positive and negative environments, whereas others are more resistant or invulnerable to environmental conditions (Boyce, 2016).

Speciation

Darwin described two aspects of evolution (Mayr, 1991). The first is the breaking away from an earlier evolutionary lineage and the establishment of a new branch in the phylogenetic tree. This is the process of speciation that contributes to biological diversity. For example, among the human family tree, Homo erectus was a dominant hominin species whose fossil remains have been found in Africa as well as eastern and western Asia. Having lived between 2 million and 143,000 years ago, Homo erectus is thought to be the longest lived of the human species. At some point, additional human species and subspecies emerged including Homo heidelbergensis, Homo neanderthalensis, Denisovans, and Homo naledi. Modern humans, Homo sapiens, are estimated to have been present as long as 200,000–300,000 years ago, coexisting and likely intermingling with some of these other hominin species (Smithsonian Institution, 2018). The fact that only Homo sapiens exist today is an evolutionary anomaly in the context of thousands of years when multiple hominin species roamed the earth. Fossil remains of other hominins are helping to clarify the distinctions in brain structure that may account for the selective advantage of Homo sapiens over other hominins that were alive at the same time (Stringer, 2012).

The second aspect of evolution is the gradual change within a species over time from earlier to later forms. For example, among modern humans the onset of puberty including the age of the height spurt is occurring at a substantially earlier age than it did 120 years ago (Richter, 2006).

You will note that concepts such as genes, chromosomes, genotype, and phenotype are not used in Darwin's evolutionary theory. Despite his awareness of the importance of mechanisms of inheritance for the process of natural selection, Darwin was not familiar with the principles of biological inheritance as established through the work of Mendel (1866). The term genetics was not coined until 1905, more than 20 years after Darwin's death (Hayden, 2009). Without an adequate understanding of the biological basis of inherited characteristics, Darwin was unable to account for the ways that variability could be transmitted from one generation to another. Advances in the field of evolutionary genetics have begun to shed new light on the evolutionary process. Theories derived from these fields will be presented in subsequent chapters.

Evolution as a foundation for psychology

Darwin's Theory of Evolution provided the foundational theoretical framework for much of early American psychology through its influence on William James, G. Stanley Hall, Arnold Gesell, John Dewey, and their students. An underlying premise of natural selection is that new or emerging capacities are retained as a result of their adaptive value. William James elaborated on this perspective in his argument about the adaptive value of consciousness itself. Consciousness evolved and has been preserved among humans because it contributes positively to the chances of survival by supporting the ability to set goals, plan a course of action, assess progress toward the goal, and modify actions as needed. Consciousness is essential for the ability to flexibly adapt to changing environmental conditions or to the modification of environments to support reproductive success (Dewey, 1896; Green, 2009; James, 1890).

G. Stanley Hall, the founder of the American Psychological Association, was strongly influenced by Darwin's evolutionary theory. Hall's (1904) two volume work, Adolescence: Its psychology and its relations to physiology, anthropology, sociology, sex, crime, religion, and education, highlights the many domains in which development is taking place, the significance of this period for individual and societal development, and the important role of adults in guiding the maturation of adolescents into adulthood. Hall thought that adolescents as a group were capable of changing the course of their society. According to Hall, the capacity for personal and social change emerges as a result of the many maturational changes that occur simultaneously during adolescence including rapid physical growth, sexual maturation, increased emotional intensity and conflict, new forms of reasoning, and an awareness of complex moral, social, and political concerns.

Hall viewed adolescence as a turbulent period. He used the terms storm and stress to describe the recurring conflicts and confusion that accompany an adolescent's growing awareness of self and of the expectations and demands of society. Hall saw adolescence as a period of increased self-consciousness, impulsiveness, idealism, and intensity. According to this view, the challenge for adults as parents and teachers of adolescents is the ability to use their imagination and innovation to channel an adolescent's energy and new self-awareness into productive channels. He was critical of the existing educational institutions for failing to respond to adolescents’ emerging competences.

One of Hall's students, Arnold Gesell, used the observational method to formulate an empirically based description of normative patterns of growth and development. Similar to Darwin, Gesell relied on empirical evidence including observations, testing, and the analysis of films of children studied in his laboratory to describe patterns of behavior at different ages. Gesell saw development as a genetically guided maturational process that brings about an orderly sequence of physical and mental changes. He was a firm believer in the role of a biological plan for growth that sets the tempo and direction of development. Within this framework, Gesell characterized development as a rhythmic sequence or spiral in which children and adolescents experience periods of advance and forward movement followed by periods of retreat or consolidation. Growth may occur in spurts followed by times of relative equilibrium. In contrast to Hall's view of adolescence as a period of turbulence, Gesell viewed the years from 10 to 16 as a gradual period of ripening to maturity marked by a growing interest and search for a sense of self, a new concern about winning the approval of others, and a growing capacity for argumentation and analysis. By age 16, Gesell described adolescents as reasonably realistic and adequately adapted to the world's demands (Gesell, Ilg, & Ames,