This chapter was written almost precisely fifty-two years after I completed my PhD (in April 1971 at the City University of New York). With no false modesty, I never imagined that I might still be doing research, teaching, mentoring students, and publishing a half century after I came out of my dissertation defense. Yet, I am still doing all these things and I have been asked by the editor of this book to reduce to a few thousand words the scholarship I have done across seven decades.

Fortunately, it is easy to explain how it happens that I have had the career I have had: it is because of the people whom I have been blessed to have as mentors, colleagues, students, and collaborators (and who are named and thanked in prior publications about my career, e.g., Lerner, Reference Lerner, Lerner, Petersen, Silbereisen and Brooks-Gunn2014, Reference Lerner2018, Reference Lerner2021), and because of one good idea that has framed all of my scholarship.

The One Good Idea in My Career

In the early 1970s, I attended a meeting of the Society for Multivariate Experimental Psychology (SMEP) held on the campus of the Educational Testing Service in Princeton, New Jersey. The keynote speaker at the meeting was the famed life span developmental psychologist, K. Warner Schaie. Warner discussed methodological features of his Seattle Longitudinal Study, but what I most remember from his talk was his advice – when a scientist encounters a great idea, it should be pursued with dedication and vigor. He credited his concept of cohort effects as the great idea that shaped his career and its success. Warner’s comments reinforced my interest in the one great idea I had encountered. However, this idea was not mine. It belonged to the renown comparative psychologist, T. C. Schneirla.

In 1957, Schneirla published a chapter in The Concept of Development, a book edited by Dale B. Harris. In a section of this chapter, “Circular Functions and Self-stimulation in Ontogeny,” Schneirla explained that individuals are, in effect, in relationships with themselves over the course of their development. He said:

Circular functions were predicated on the idea that the specific characteristics of individuality of an organism evoke differential reactions from its context, including other organisms; these reactions constitute feedback to the individual and become a significant portion of the experience that promotes the development of further individual distinctiveness. In essence, by influencing the physical and social world that influence it, a circular function, a dynamic feedback loop, is created, and the organism becomes a source of its own development. As such, the integration of actions becomes the focal process of development.

Schneirla’s “good idea” is the concept I have used to frame my career. It is the foundation of the conceptual frame I have used to contribute to the enhancement of the lives of diverse youth in the United States and globally.

Graduate School Roots

In my penultimate year of graduate education, I shared my interest with Sam Korn about studying circular functions, and that it appeared to me to be an innovative approach to addressing processes that seemed (albeit vaguely to me, at the time) to go beyond the nature–nurture controversy. Sam had been a PhD student of Herbert Birch, who had been a PhD student of Schneirla, and so Sam was glad that one of his students wanted to follow in the Schneirla tradition. However, unlike Schneirla, whose organisms of interest were army ants and kittens, I was interested in studying human children and adolescents. However, I was not clear about how to study these circular functions in children and adolescents.

One of my last courses in graduate school was a seminar in personality development in childhood and adolescence, and the text for the course was Children and Adolescents: Behavior and Development written by Boyd R. McCandless. McCandless discussed the work of Harvard physician, William Sheldon, who had identified three body types in men: endomorphs (whose bodies were dominated by adipose tissue), mesomorphs (whose bodies were marked by strong musculature), and ectomorphs (whose bodies were thin and linear). Sheldon claimed that the genes that gave men their body types also gave them their temperaments. However, McCandless cited a 1954 publication by Brodsky that found that there were different social stereotypes associated with drawings of adult male endomorphs, mesomorphs, and ectomorphs. He suggested that these stereotypes might serve to differentially socialize men with different body builds and that social learning could account for links between body type and temperament, or personality more broadly.

McCandless did not suggest precisely how the presence of social stereotypes translated into different personality development, but I thought that circular functions could be involved. If children, adolescents, and adults with different body builds elicited differential (and stereotyped) reactions from the people in their social world, these reactions could be associated with differential reactions (feedback) from people to them. If this feedback was associated with differential opportunities for some behaviors and constraints on other behaviors, a social-relational process could occur that might channel people with different body builds into at least some stereotype-consistent behaviors. As such, a self-fulfilling prophecy would be created. Of course, all these ideas were also speculations. I had no data.

I reasoned that social channeling might be especially true if the people possessing different body builds had the same body build–behavior stereotypes as found generally in society. If so, then people with different body builds might themselves be a source of differential opportunities for and constraints on their own behavior. If the stereotype for their body type was essentially negative, they might be loath to engage in some behaviors because of anticipated approbations from people in their social milieu; in turn, if the stereotype was relatively positive, they might engage in some behaviors because they would anticipate support or approval from others in their social milieu.

Conducting the longitudinal research necessary to verify this intricate circular function process was not feasible for a dissertation. However, I could present the model and assess part of it. I could see if children, adolescents, and (young) adults of different body builds had the same stereotypes about body build–behavior relations that were generally held in their social world. I found that they did. Therefore, I used the circular functions idea to frame a study of the relation between the body builds of male children, adolescents, and young adults and their social stereotypes about body build–behavior relations.

Empirical Beginnings

Both research I published prior to my dissertation and the results of my dissertation were consistent with the Schneirla-influenced theoretical model I had developed. This work was my initial foray into testing the “one good idea” I had, that individuals, through their effects on and actions in the context and the resulting actions of the context on them, could create circular functions and thereby provide a source of their own development. I believed I had some quite limited information (e.g., it was not derived from longitudinal data) that the circular functions could be applied to human development.

Accordingly, I began to think beyond body build–behavior relations because, if this circular function was in fact a fundamental process in human development, evidence for it should exist for other individual attributes (e.g., level of physical attractiveness or differences in behavioral style, or temperament). I began to study the importance of these physical and behavioral attributes with a person who shared my interest in these theory-predicated ideas, Jacqueline Rose Verdirame. Our collaboration became so multidimensionally productive that we have kept it going across six decades, although Jackie changed her name in 1977 to Jacqueline V. Lerner. The basic idea framing our scholarly work together was that the specific feedback to the individual, initiated by the individual’s specific characteristics, shaped the further development of the specific features of the individual. In short, we reasoned that circular functions are a basis of person-specific, that is, idiographic, development.

Intrigued by the idea of idiographic development I devoted a chapter to it in the first, 1976, edition of my first book, Concepts and Theories of Human Development. However, I did not have the methodological skills to empirically study idiographic development until I came to Penn State (Pennsylvania State University) and began to learn about such methods through the mentorship of John R. Nesselroade. This mentorship has been the foundation for, at this writing, current research I am conducting on the specific, idiographic pathways of development of diverse children and adolescents.

However, at the time of my dissertation defense, both my methodological skills and my vocabulary about the individual⇔context process, and about the idiographic (person-specific) pathways of development that would be produced by this process, were limited. Nevertheless, I did think I was on to something important by my partial test of Schneirla’s idea.

Some Beginning Theoretical Ideas

My reading and thinking about the ideas of Schneirla continued – in particular, reading a 1970 festschrift volume in memory of Schneirla, Development and Evolution of Behavior: Essays in Memory of T. C. Schneirla, edited by Lester R. Aronson, Ethel Tobach, Daniel S. Lehrman, and Jay S. Rosenblatt, and what I discovered was a very related 1933 book by Ludwig von Bertalanffy, Modern Theories of Development. I realized that the circular functions process was only one instance of the dynamic relations across integrated levels of organization, ranging from the inner physiological, through the psychological and behavioral, to the social relational, physical ecological, cultural, and historical that comprised the ecology of human development. Within and across these integrated levels, variables coacted dynamically with each other. These coactions meant that changes in any one variable were products and producers of changes at all other levels in what, I began to understand, was a dynamic developmental system. Just as there were individual⇔context circular functions between, say, the physical and/or behavioral attributes of an individual and others in the ecology of the individual, there were also dynamic coactions between a family and the community, between the community and cultural institutions, between culture and the physical ecology, or between the physical ecology and social or ecological variables changing across time (or history).

In addition to the first edition of Concepts and Theories of Human Development, another important product derived from this thinking was my first attempt to publish a refereed article about the evolving theory I was developing about human development. In this 1978 article, “Nature, nurture, and dynamic interactionism,” I contributed my first peer-reviewed statement in “the” theory journal within developmental science, Human Development. The article discussed how Schneirla’s concept of circular functions was an instance of the dynamic relations within what the eminent developmental scientist Willis (Bill) Overton was discussing as a dynamic, relational developmental system. Gaining enormous insights from Overton’s work and mentoring, this model evolved across the ensuing four-plus decades and was used as a frame for the research I was conducting.

The Emergence of an Applied Developmental Scientist

About a decade after I began publishing “theory papers,” I “discovered” – through the prodding of my Penn State colleague, Richard (Rick) Birkel – that my ideas could be the basis of applications to enhance the development of all individuals. Irving Sigel, a researcher at Educational Testing Service and, at that time, the editor of the Journal of Applied Developmental Psychology, thought that the readers of his journal would be interested in learning more about current trends in developmental theory, and he invited me to write an article on this topic. I happily accepted this invitation, although I was not certain my ideas were relevant to the application of developmental science. But, with Rick and another Penn State colleague, Michael A. (Mick) Smyer, we argued they were. In a 1989 article we said that the dynamic coactions being described in my specific model derived from the ideas in what Overton termed the relational developmental system (RDS) metamodel could do more than explain the specific pathways of development enacted across the life span of the individual. The relative plasticity of human development that I had discussed as deriving from the dynamics of the relational developmental system meant that, if there were changes in system coactions, then different pathways – for better or worse – could occur. Simply, the plasticity of the dynamic, relational developmental system meant that the course of life was malleable.

The presence of at least relative plasticity meant that human development could be changed in the direction of optimizing its course across time and place, an idea emphasized by life-course sociologist Glen H. Elder, Jr., and developmental scientist Urie Bronfenbrenner. Researchers could test their explanations of human development by modifying specific individual⇔context relations in the ecology in which people lived, and then assess whether theory-predicated changes occurred. Such explanatory research is also, at the same time, optimization research, and could be instantiated through the design, implementation, or evaluation of intervention programs or social policies.

The model of dynamic RDS I was developing provided a rationale for optimism that systematic changes in each person’s individual⇔context relations could create bases for positive developmental change, even regarding children and adolescents whose lives had been marginalized by racism, sexism, poverty, and other disparities associated with who one was, where one came from, who one loved, or what one believed. If so, developmental science could do more than just describe and explain human development; it could also contribute to optimizing human life and, as such, contribute also to social justice. Simply, program and policy research and evaluations derived from a dynamic, RDS-based approach to human development could help explain how models of specific facets of the coactions of individuals and contexts provided a basis of specific trajectories and outcomes of development. Such specificity reflects the fundamental relational process of human development, a process that Marc Bornstein has described as the Specificity Principle. In short, then, there is no conceptual split between basic and applied research within a dynamic, RDS-based approach to human development.

I began to write about the then burgeoning field of applied developmental science and, with Celia B. Fisher and Richard A. Weinberg, I founded in 1997 a new journal, Applied Developmental Science, which I continued to edit through 2019.Footnote ² In addition, at about this time, I saw opportunities to instantiate my theory-predicated, individual⇔context approach to application within the portion of the life span within which I was devoting most of my empirical attention: adolescence.

Longitudinal Studies of Positive Youth Development (PYD)

Through the 1990s, much of the study of adolescent development was framed by the nature-based, deficit perspective of this life period discussed by G. Stanley Hall’s 1904 storm-and-stress conception of adolescence. In the 1990s a new lens for viewing adolescent behavior and development emerged, spurred by the convergence of the work of youth program professionals, particularly Rick Little, founder of the International Youth Foundation, and Donald Floyd, President of the National 4-H Council. Practitioner beliefs in the strengths of youth and their potential for positive development converged with theory and research in developmental biology, comparative psychology, and developmental science regarding the relative plasticity of human development across the life span. These ideas suggested that there was a potential for systematic change in the features and trajectories of youth development. The behaviors of an adolescent seen at a specific time in his or her life and/or in a specific context were not genetically fixed or neuronally hardwired, and thus immutable. Indeed, if young people could be placed into positive development-promoting circumstances, then, through their coactions within the relational developmental system, they could have the capacity to change these attributes.

With Jacqueline Lerner, I developed a formulation that focused on what was subsequently labeled the Five Cs of PYD (competence, confidence, character, connection, and caring), a conception owing its origin to Rick Little. In collaboration with the National 4-H Council, Lerner and Lerner launched a longitudinal, ten-year project, the 4-H Study of PYD (involving more than 7,000 youth from Grades 5 to 12 across forty-two states). We proposed that youth would thrive when, in psychologically and socially safe spaces, their strengths were aligned with key contextual resources. When high degrees of these Cs emerged, a “sixth C,” contribution, would follow.

Our findings across eight waves of data confirmed our expectations. We found that PYD was developed when, in safe spaces (1) the contextual assets in the lives of youth, for example, (a) an adult, such as a parent, teacher, mentor, coach, or faith leader, provided a positive, developmentally nurturant relationship with a youth; (b) life skills were modeled and developed in this relationship; and (c) youth were able to use these skills to participate in or take a leadership role in valued activities; were integrated with (2) the presence of youth developmental assets, for example, intentional self-regulation abilities, hope for the future, school engagement, and spirituality. We also found that youth who showed high scores of the Five Cs were likely to contribute more to their families, schools, and communities and, at about the tenth grade for most youth, such contributions were transformed into instances of positive civic engagement. We also found that scores for the “sixth C” of contribution were inversely related to scores for problem behaviors and depression.

The Lerner and Lerner “Five Cs” model of PYD represented, as did all PYD models associated with dynamic developmental systems-based ideas, an optimistic view about the potential efficacy of programs or policies to promote PYD. If such efforts were able to capitalize on developmental plasticity and focused on the specific strengths of young people, the course of their lives could be enhanced.

As my work on PYD continued, I became increasingly involved with efforts to promote one C in particular, positive character. Supported by the John Templeton Foundation, the Templeton Religion Trust, and the Templeton World Charity Foundation, I became very interested in the vision and philosophy of Sir John Templeton. As such, much of my research on PYD came to focus specifically on character and on the implications of character virtue development for active and engaged citizenship. Following the ideas of Larry Nucci, Marvin Berkowitz, Bill Damon, and Anne Colby, I sought to understand the connections between character development and “doing the right thing” (morally and behaviorally) across time and place. Using ideas of individual⇔context relations derived from RDS-based concepts, my colleagues, students, and I began a series of studies that focused on character attributes associated with mutually positive benefits to both self and others. Across about two decades, and with the support of all three Templeton foundations, we conducted longitudinal research on character, and its implications for positive civic engagement and democratic leadership through collaborations with Boy Scouts of America, Girl Scouts of the USA, the Williamson College of the Trades, WGBH Public Television, the Positive Coaching Alliance, and the United States Military Academy at West Point.

In addition, Alistair Sim, the leader of the research arm of Compassion International (CI), an international child sponsorship organization serving more than two million youth in twenty-five nations within low- and middle-income countries, created a partnership with my lab and corresponding labs in Boston College (led by Jackie Lerner) and Fuller Theological Seminary (led by Pamela Ebstyne King) to enact the CI Study of PYD. In this work we conduct both variable focused and person-specific longitudinal studies in El Salvador, Uganda, and Rwanda. We have also extended this work to South Africa, in a partnership with the leaders of an out-of-school-time program, Thanda.

Both in this research and in US-based research done in collaboration with child psychiatrist Pamela Cantor, the founder of Turnaround for Children, and sociologist David Osher of American Institutes for Research, I have continued to use the idea of circular functions and the resulting specificity of individual⇔context relations in my research. We have been developing youth specific measures of PYD and, as well, of learning-to-learn skills (sometimes labeled “21st Century Skills”) and used them in person-specific (idiographic) longitudinal studies of youth development, particularly among individuals marginalized because of racism, poverty, and other instances of inequity.

However, as I discussed the implications of this research for youth programs, policies, and social justice, the intellectual “nemesis” of genetic reductionism continued to elicit the attention of researchers, practitioners, and policymakers. Proponents of this perspective spoke of genetic constraints on positive development, asserting that there was a genetic blueprint that was the most influential source of a person’s development. Accordingly, I worked to counter the narrative of genetic life-span reductionism.

Confronting the Counterfactual Nature of Genetic Reductionism

In the 1970s, Overton (in 1973) and then I (in 1978) published articles in Human Development explaining the conceptual and methodological errors (including egregiously flawed statistical analyses and misinterpretations of the findings from these analyses) of then-current instantiations of genetic reductionist ideas: behavior genetics and heritability analysis. Overton and I warned of the substantive and applied “dangers” of this flawed work. Our articles built on earlier ones by, for instance, Schneirla and Anne Anastasi. As different instantiations of genetic reductionism appeared (e.g., sociobiology, evolutionary psychology, and evolutionary developmental psychology), Overton and I, and many others (discussed in Lerner, Reference Lerner2021) critiqued the conceptual, logical, and methodological problems of all these genetic reductionist formulations.

The critiques contended that pernicious societal implications of genetic reductionism could be attenuated, if not completely eliminated, if developmental scientists and scholars from other fields made the refutation of genetic reductionist ideas ubiquitous parts of their writing, public speaking, and teaching. This “new normal” could create a new generation of scientists informing the general public, media, and policymakers that genes are plastic components within and, in fact, followers of dynamic coactions in the relational developmental system. Genes are not blueprints that, at conception, design the course of human behavior and development across ontogeny, generations, and contexts. By eliminating genetic reductionism from scientific prominence, this new normal might also elevate the contribution of developmental science to social justice (e.g., see Lerner et al., Reference Lerner, Lerner, Murry, Smith, Bowers, Geldhof and Buckingham2021).

Conclusions: Developmental Theory and the Promotion of Social Justice

The dynamic, RDS-based approach to human development can integrate explanatory and optimization efforts to contribute to equity and social justice. Developmental scientists taking this approach have theory-based methods to act in the service of promoting a better life for all people and therefore a more socially just world.

The scientific and societal value on which the developmental science of the future will be judged is whether the theoretical and methodological tools of the field describe and explain the diversity and dynamism of human development and, as well, whether the scholarship of developmental scientists effectively capitalizes on the malleability of individuals’ developmental pathways to promote sustained individual thriving and social justice. The developmental science of the future can act as a producer and a product of a more just world, one wherein every individual is born within a social context wherein science and society collaborate to enable each human and humanity to flourish.

Schneirla’s good idea has taken me a long way. Across the seven decades, from the late 1960s to, at this writing, the early years of the 2020s, I have elaborated the idea of dynamic, individual⇔context relations in a scholarly journey that has taken me from body build stereotypes to appeals for the promotion of social justice. My personal journey is not over, but it is certainly nearer to its end than it was in when I began it in the 1960s. My hope is that I will make useful contributions to this fused conception of developmental science for the remainder of my career. Even more, I hope that new generations of developmental scientists will bring this focus to better and better resolution in the years after me. If so, then the full story of the use of Schneirla’s good idea remains to be written.