Bronfenbrenner 2005 2001

From U. Bronfenbrenner (Ed),Making human being« human: Bioecologicolperspectives on human development (pp. 3-15). Thousand Oaks, CA: Sage.

Article 1!.~;( : ..,"~':;",1, .: The Bioecological

Theory of HumanDevelopment

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The bioecological theory of human development reached maturity 10years after the publication of "Ecological SystemsTheory" (Article 10 ofthis volume), which had called the future of the "ecology of humandevelopment" into question as a discipline. The following successor tothat article accepts the bioecological theory asa paradigm for the futureand specifies its defining properties.

The bioecologícal model, together with its corresponding researchdesigns, is an evolving theoretical system for the scientific study of

human development over time. Within the bioecologicaltheory, development is defined as the phenomenon of continuity and change in ihe biopsychological characteristics of human beings both as indioiduals and as groups. Thephenomenon extends over the lije course across successive generaiions andthrough historical time, both past and presento

Source: Bronfenbrenner, U. (2001). The bioecological theory of humandevelopment. In N. J. Smelser & P.B. Baltes (Eds.), lniernational encyclopedia 01 thesocial and behavioral sciences (Vol.10,pp. 696~970). New York:Elsevier. Reprintedwith permission from Elsevier Science Ltd.

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4 On the Nature of Bioecological Theory and Research

Defining Properties of the Bioecological Model

The term evolving highlights the fact that the model, along with its corresponding research designs, has itself undergone a process of developmentover its own "lífe course." Another defining property of the bioecologicalmodel specifies that it deals with two closely related but neverthelessfundamentally different developmental processes, each taking place overtime. The first defines the phenomenon under investigation: namely, thatof continuity and change in the biopsychological characteristics of humanbeings. The second focuses on the development of the scientific tools-thetheoretical models and corresponding research designs required forassessing the continuity and change.

These two tasks cannot be carried out independently, for they are thejoint product of emerging and converging ideas, based on both theoretical and empirical grounds-a process called "developmental science inthe discovery mode" (Bronfenbrenner & Evans, 2000, pp. 999-1000). Inthe more familiar "verification mode," the aim is to replicate previousfindings in other settings to make sure that the findings still apply. Bycontrast, in the discovery mode, the airn is to fulfill two broader but ínterrelated objectives:

1. Devising new altemative hypotheses and corresponding research designsthat not only call existing results into question but also stand a chance ofyielding new, more differentiated, more precise, replicable research findings and thereby producing more valid scientific knowledge.

2. Providing scientific bases for the design of effective social policies and programs that can counteract newly emerging developmentally disruptiveinfluences. This has been an explicit objective of the bioecological modelfrom its earliest beginnings.

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A majar challenge to today' s bioecological model is to discover how suchnew working hypotheses and corresponding research designs can be developed for the future. One answer lies in the possibility that, despite historícal change, sorne elements of the model, and their interrelationships, mayremain constant across both time and space. From this perspective, today'smodel has several distinctive defining properties that become the foundation for the rest. Sorne are of relatively recent origin; others date back tothe model's earliest formal beginnings. Each is expressed here in the formof a proposition.

The Bioecological Theory of Human Development 5

Proposition 1An early critical element in the definition of the ecological model is

experience. The term is used to indicate that the scientifically relevantfeatures of any environment for human development indude not onlyits objective properties but also the way in which these properties aresubjectively experienced by the persons living in that environment. Thisequal emphasis on an experiential as well as an objective view springsneither from any antipathy to behavioristic concepts nor from a predilection for existential philosophical foundations. It is dictated simply bya hard fact. Very few of the extemal influences significantly affectinghuman behavior and development can be described solely in terms ofobjective physical conditions and events,

A critical term in the foregoing formulation ís the word solely. In thebioecological model, both objective and subjective elements are posited asdriving the course of human development; neither alone is presumed sufficient. Moreover, these elements do not always operate in the same direction, It is therefore important to understand the nature of each of thesetwo dynamic forces, beginning on the phenomenological or experiential side.Both of the underlined terms are relevant because, while related to eachother, they are typically applied to somewhat different spheres. The former is more often used in relation to how the environment is perceivedand changed by human beings at successive stages of the life course,beginning in early infancy and proceeding through childhood, adolescence, adulthood, and, ultimately, old age.

By contrast, experience pertains to the realm of subjective feelings:for example, anticipations, forebodings, hopes, doubts, or personal beliefs.These, too, emerge in early childhood, continue through life,and are characterized by both stability and change. They can relate to self or to others, andespecially to family, friends, and other close associates. They can also applyto the activities in which one engages: for example, those that one most orleast likes to do. But the most distinctive feature of such experiential qualitiesis that they are uemotionally and motivationally Ioaded," encompassing bothlove and hate, joy and sorrow, curiosity and boredom, desire and revulsion,often with both polarities existing at the same time but usually in differingdegrees. A significant body of research evidence indicates that such positiveand negative subjective forces, evolving in the past, can also contribute inpowerful ways to shaping the course of development in the future.

But these are not the only powerful forces at work. There are othersthat are more objective in nature. This does not mean, however, that they


are necessarily either more or less influential, mainly because the two setsof forces are interdependent and affect each other. Like their subjectivecounterparts, thesemore objectivefactors also rely for their assessment oncorresponding theoretical models and associated research desígns thathave evolved over time. These more objective relationships are documented below in the form of two propositions (Bronfenbrenner& Evans,2000;Bronfenbrenner & Morris, 1998).The fírst specifies the theoretícaImodel and provides concrete examples: the second foreshadows thecorresponding research designs for their assessment.

Proposition IIOver the lifecourse, human development takes place through processes

of progressively more complex reciprocal interaction between an active,evolving biopsychologicalhuman organism and the persons, objects,andsymbols in its immediate external environment. Tobe effective,the interaction must occur on a fairly regular basis over extended periods of time.Such enduring forms of interaction in the immediate environment arereferred to as proximal processes. Examplesof such processes inc1udefeeding or comfortíng a baby;playing with a young child;chíld-child activities;group or solitary play; reading, learning new skills; athletic activities;problem solving; caring for others; making plans; performing complextasks; and acquiring new knowledge and know-how.

For the younger generation, participation in such interactive processesover time generates the ability, motivation, knowledge, and skill toengage in such activities both with others and on one's own. For example,through progressively more complex interaction with their parents,children increasinglybecome agents of their own development, to be sureonly in partoIn sum, proximal processes are posited as the primary engines of devel

opment. The next defining property speaks to the corresponding researchdesigns.

Proposition IIIThe form, power, content, and direction of the proximal processes

producing development vary systematically as a joint function of thecharacteristicsof the developing person (includinggenetic inheritance); of theenvironment-both immediate and more remote--in which the processesare taking place; of the nature of the developmental outcomes under consideration; and of fue continuities and changes occurring in the environment

The Bioecological Theory of Human Deve!opment 7

over time, through the !ifecourse, and during the historical period in whichthe person has líved.

Propositions II and III are theoretically interdependent and subject toempirica! test. An operational research design that permits their simultaneous investigation is referred to as a procese-person-coniexi-time model(PPCT for short).In the corresponding research designs for the bioecological model, the

e!ement of time has special importance. To show that development hasactually occurred, the research design must demonstrate, or at least makeplausible, that the elements in the design, and their dynamic relationshipsto each other, have influenced the biopsychological characteristics of thedeveloping person over an extended period of time. For example, a richdata archive generously made available by Small and Luster (1990) fromtheir statewide studies of youth at risk in Wisconsin has made possiblesome reanalyses of working hypotheses derived from the newly emergingformulations.

Parental monitoring was defined as "the effort by parents to keepinformed about and set limits on their children's activities outside the'home." Higher levels of academic performance require mastery of progressively more complex tasks and hence are more difficult to achieve.The relation between parental monitoring and school grades shows adeclining curvilinear trend. This effect, however, is far stronger for girlsthan for boys, particularly in families with two biological parents.

Both of these results are consistent with two working hypothesesderived from the bioecological modelo The first stipulates that proximalprocesses (in this instance, parental monitoring) are likely to have greaterimpact in two-parent families than in those in which the mother is a singleparent or the father is a step-parent, The second hypothesis posits astronger and longer-lasting influence of the family on the development offemales than of males.

In addition, a distinctive feature of the pattem for girls is that the curvemarkedly flattens at higher levels of monitoring and, in the case of daughters of single-parent mothers, even becomes a tumaround. This findingsuggests that under such circumstances the demands on the girls maybecome so great that the existing proximal processes are not equal to thetask and, as a result, bring fewer educational returns. Finally, an analysisof data on students whose mothers had no more than a high schooleducation revealed a similar pattern, but the constructive influence ofmonitoring was appreciably weaker, and its greater benefit to girls wasreduced. Nevertheless, daughters of mothers with less than a high schooleducation both in single-parent and in stepfather families still had higher


grade point average (GPA)scores than did sonsoMoreover,within eachlevel of mother's educatian statistically significant differencesby familystructure were found in schoolachievement, with students growing up intwo-parent families receiving the highest grades and those frorn singleparent families the lowest.Also, a second analysis was carried out assessing the influence of the

mother's educational level on the effects of her parental monitoring.Because, for a nurnber of reasons, the addition of this parameter makesthe interpretation of the findings in graphic form rather complex, thernain results are summarized below.

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1. The effect oí parental monitoring on students' ePA was clearly greatest forthose who were living with both biologícal parents and whose mothers hadhad sorne education beyond high school. Also, the extent and positiveeffect of mothers' monitoring was greatest at the beginning of high schooland decreased gradualIy thereafter.

2. The constructive influence oí mothers with educatíon beyond hígh school bothin "mother-only" farnilies and in those with "own mother and stepfather"was considerably less and declined more rapidly.

3. The results of parental monitoring by mothers with less than a high schooleducation were also positive but not as strong. Mothers from families withtwo biological parents were again the most effective monitors, but less sothan those with sorne education beyond high school. The means for thethree types of family structures were in the same order but also closertogether.

The interpretation of these findings is eonfounded by the absenee ofseparate statistics for males and females, a condition arising from the lowfrequencies of subjects of both genders among ehildren in families otherthan those consisting of two biologicalparents.In conclusion, two qualifieations are required regarding the scientific

validity of the reported findings. First and foremost,most of the reportedresearch was condueted a decade ago and may not, in a11instances, applyto the outeorne of parent-ehild rnonitoring in the present year, 2001.Second, it is not always the case that separated or single-parent familiesput the future developrnent of their children at risk. In sorne instances,such farnily forrnslead to new relationships and structures that rnakepossible a constructive change in the course of their children's developrnent.Totum to a related issue: although proximal proeesses function as the

engines of developrnent, the energy that drives them comes from deeper


sources that take us back to the experiential world of Proposition l. Boththe subjective and the objective forces exert an especially strong influenceon development during the formative years (from early infancy to youngadulthood). A substantial body of research over the past century indicatesthat, two or three decades ago, these forces lay mainly within the family,with parents acting as the principal caregivers and sources of emotionalsupport for their children, and with other adult family members livingin the home being next in lineoTo a lesser extent, other relatives, familyfriends, and neighbors also functioned in this role.

There has been a marked change in this pattern, however, over the pastthree decades. Parents, and other adult family members as well, havebeen spending increasing amounts of time cornmuting to and workingat full-time jobs (in which overtime is increasingly often required orexpected).

The nature of this trend and its relevance for human development areconveyed in the propositions that follow. (Por brevity's sake, the termchild is used below to encompass the entire period from infancy throughyoung adulthood.)

Proposition IVIn order to develop-intellectually, emotionally, socially, and morally

a child requires, for a11of these, the same thing: participation in progressívely more complex actioities, on a regular basis over an extended period oftime in the child's lífe, with one or more persons with whom the childdevelops a strong, mutual emotional atiachmeni, and who are commítted to thechild's tuell-being and deoelopment, preferably for lije (Bronfenbrenner &Evans, 2000;Bronfenbrenner & Morris, 1998).The prerequisites stipulatedin Proposition IV then lead to the developmental consequences describedin the next proposition.

Proposition VThe establishment of a strong mutual emotional attachment leads to

internalization of the parent's activities and expressed feelings of affection.Such mutual ties, in turn, motívate the child's interest and engagement inrelated activities in the immediate physícal, social, and-in due coursesymbolic environment that invite exploration, manipulation, elaboration,and imagination. The next proposition broadens the family circle.


Proposition VI

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The establishment and maintenance of patterns of progressively morecomplex interaction and emotional attachment between parent and childdepend in substantial degree on the availability and involvement ofanother adult, a third party, who assists, encourages, spells off, gives status to, and expresses admiration and affection for the person caring forand engaging in joint activity with the child. It also helps, but is notabsolutely essential, that the third party be of the opposite sex from thatof the other person caring for the child because this is likely to expose andinvolve the child in a greater variety of developmentaHy instigative activities and experiences (Bronfenbrenner,McClelland,Wethington,Moen,&Ceci, 1996).Where this is an attachment to two or more parent figures,each can serve as a third party to the other.The research evidence for this proposition carne mainly by default. It

was produced by demographic data documenting a rapid rise in the proportion of single-parent households. The trend began in the 19805andthen continued at an even faster rate through most of the 1990s.The overwhelming majority of such homes were those in which the father wasabsent and the mother bore primary responsibility for the upbringing ofthe children.A large number of investigations of developmental processes and out

comes in families of this kind have since been conducted across a rangeof cultural and social c1assgroups. In general, the findings lead to twocomplementary conclusions.First, even in families living in favorable socioeconomiccircumstances,

children of single-parent mothers or fathers for whom no other person isacting reliably in a "third-party" role are at greater risk for experiencingone or more of the following developmental problems: hyperactivity orwithdrawal; lack of attentiveness; difficultyin deferring gratification;pooracademic achievement; schoolmisbehavior; and frequent absenteeism.Second, at a more serious level, such children are at greater risk for

a so-called "teenage syndrome" of behaviors that tend to be associatedtogether: dropping out of school; involvement in socially alienated ordestructive peer groups; smoking; drinking; frequent sexual experience;adolescent pregnancy; a cynical attitude toward work; and-in the moreextreme cases-drugs, suicide, vandalism, violence, and criminal acts.Most of these effects are more pronounced for boys than for girls(Bronfenbrenner et al., 1996).Not all single-parent farnilies,however, exhibited these disturbed rela

tionships and their dísruptive effectson children's development.Systematic

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srudies of the exceptions have identified what may be described as ageneral "immunízíng" factor.For example, children of single parents wereless likely to experience developmental problems especially in families inwhich the mother (or father) received strong support from other adultsliving in the home. Also helpful were nearby relatives, friends, neighbors,members of religious groups, and, when available, staff members offamily support and child care programs. What mattered most was notonly the attention given to the child-important as this was-but also theassistance provided to the single parent or by others serving in the supportive roles cited in Proposition VI. It would seern that, in the familydance, "it takes three to tango."But dancing is not the whole story. By the 19805,theory and research

in the ecology of human development had documented an acceleratingtrend toward greater permissiveness in styles of child rearing inAmericanfamilies.At the same time, successivescientificinvestigationshad revealedprogressively greater developmental advantage for strategies that placedincreased emphasis on parental discipline and demando The interpretation that emerged from analyses of the available data suggested thatwidespread application of these research findings could serve as an effective response to the developmentally disruptive changes taking place incontemporary society.At this point, it is important tomention two other bodies of research that

contributed significantIyto the development of bioecologicaltheory andits corresponding research designs. The first is now of long standing. Aquarter-century ago, the sociologistGlen H. Elder Jr.,in his classicvolumeChiidren of the Great Depression (1974,1999),extended the concept of development beyond the formativeyears to encompass the entire life course.The secondaddition has yet tobe fully exploited.In1994,Bronfenbrenner

and Ceci, taking the bioecologicalmodel as their point of departure, suggested an empirically testable alternative to the established scientificparadigm used in behavior genetics. The proposed altemative model(a)allows for nonadditive synergistic effects;(b) employs direct measuresof the environment; and (e)proposes proximal processes as mechanisms ofperson-environment interaction through which genotypes for developmental competence are transformed into phenotypes. Themodel predictsthat (a) estimates of heritability (hZ) for developmental competenceincrease markedly with the magnitude of proximal processes; (b) herítability measures the proportion of variation in individual differencesthat are attributable onIy to actualized genetic potential, with the degreeof unactualized potential remaining unknown; and (e) actualized geneticpotential (h') will vary with the quality of the envirorunent and will


increase as that quality is improved (for example, through providing [obopportunities, health services, and intervention programs in low-incomeneighborhoods).

The authors also suggested that high levels of such pattems of parentalbehavior as "neglect, abuse, or domination" can serve as powerful mechanisms for aetualizing genetic potentials for developmentally maladaptivebehaviors that both disrupt proximal proeesses and produce developmental disarray.

The Bioecological Modelin the Discovery Mode: Future Perspectives

This section is based on propositions and working hypotheses derivedfrom the bioecologiealmodel for which, as yet, there are few empiricaldata. Jt begins with future prospects for addressing the second stated goalof the bioeeologicalmodel, that of "providing needed seientifiebases forthe design of effective social policies and programs that can counteractnewly emerging developmentally disruptive influenees."

In accordwith the latter objective,the sectionbeginswith an unorthodoxproposal. By and large, thus far, theory and research on human development have been concemed with the influenceof the older generationon thedevelopment of the younger. In the proposition that follows, the directionis reversed. It should be noted that the basic idea under1yingthis proposition is not new and is foreshadowed both in the theory of Vygotsky(1978)and in the contemporary "action" theory of Brandtstadter (1998,1999).

Proposition VIIIThe psychological development of parents is powerfully influenced by

thebehavior and development of their children. Thisphenomenon occursthrough the life eourse; is more evident during the formative years, whenmost children are living at home in the care of their parents: and oftenbecomes especially pronounced during adolescence, when the youngbegin to strive for independence both as individuals and as membersof peer groups. Such behavior is particularly likely to occur amongthose adolescents or youth who have comparatively little contact withtheir parents or other caring adults earlier in life.Although many studieshave focused on the development of such alienated young people, theimpact of the latter's behavior on the subsequent development of theirparents has yet to receivethe systematic investigation that itdeserves. The

The Bíoecological Theory of Human Development 13

converse of the foregoing proposítion-the ínfluence of the successfultransition of children through adolescence and young adulthood on theconstructíve development oí their parents-has regrettably receíved evenless scientificattention.

Proposition IXOver the life course, the process of attachment exhibits a turnaround.

In the begínning, it is the children who are the beneficiarlesof the parents'irrational commitment, whereas toward the end the roles are reversed.Then it is the elderly parents who receive the love and care of their nowmiddle-aged children. If, however, there was no attachment at the beginning, there may be no attachment at the end.

In this regard, developmental scíencehas yet to address a curious omission with respect to both theory and research designoResort to searchengines in psychology and related fields has thus far failed to identífy anyinvestigations of the influence of parent-child attachment in the futuredevelopment of the parent in contrast to that of the child.This is not quite the case, however, for the next propositíon in

the discovery mode. The theoretical model, the corresponding researchdesign,and half of the necessary empirical data are already available. Theonly problem is to find or conduct a study that meets the followingrequirements.

Proposition XIf an investigatíon conducted in the past meets the requirements of the

bioecologicalmodel, including assessment of developmental outcomes"over an extended period of time," then replication of the study at a laterpoint in time would reveal whether the processes under investígationwere still valid or had been nullified or superseded by subsequent historical changes. When the latter occurs, the investigator is confronted withthe challenge of proposíng alternative working formulations for explaining the observed phenomena.At the conclusion of this artícle, we move from the domain of theory

and research design to the world of reality and action. In the bioecologicalmodel, these twoworlds have never been far apartoEspeciallyover thelast three decades, they have become ever doser to each other.At a moregeneral level, the findíngs from both domains reveal what has beenreferred to as "growing chaos" in the lives of children, youth, farnilíes,schools, the world of work, and the ever-greater comrnuting in between.


Themost recent report of this phenomenon contains the following surrunaryabout the nature of "chaos" and its developmental consequences(Bronfenbrenner & Evans, 2000):

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IChaos integrates the various elements involved, and foreshadows the role [ofchaos] in the bioecological model in terms oí what is called a "chaotic system." Such systems are characterízed by frenetíc activity, lack of structure,unpredictability in everyday activities, and high levels of ambient stimulation. Background stimulation is high, and there is a general lack of routinization and structure in daily life. The environment is also a major source ofinterruption oí proximal processes in the forro of residential noise, crowding,and classroom designo (p. 121)¡

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':1At the tum of the century, we are Ieft with a troubling question: From

the perspective of the bíoecological model, what ís the prospect for thefuture development of our species? Today the answer to that question Hesin the willingness of the United States and other economically developedcountries to heed the emerging lessons of developmental science, At themoment, it is difficult to know what the answer will be. The future couldgo either way.Given this altemative, surely it becornes the responsibility of develop

mental science to communicate such knowledge as we possess and to doso in words that can still find an echo. Here is a first draft.

In the United States it is now possible for a youth, female as well asmale, to graduate from high school, or a university, without ever caringfor a baby; without ever looking after someone who was ill,old, or loneIy;and without comforting or assisting another human being who reallyneeded help. The developmental consequences of such a deprivation ofhuman experience have not as yet been scientifically researched. But thepossible social implications are obvious, for-sooner or later, and usuallysooner-all of us suffer illness, loneliness, and the need for help, comfort,and companionship. No society can long sustain itself unless its membershave Ieamed the sensitivities, motivations, and skills involved in assistingand caring for other human beings.

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References

i, .Brandtstadter, J. (1998). Actíon perspectives on human development. In

W. Damon (Series Ed.) & R. M. Lemer (Vol.Ed.), Handbook 01chiid psychology:Vol. 1. Theoretical models 01 human development (5th ed., pp. 807-863).New York:[ohn Wiley.


Brandtstadter, J. (1999). The self in action and development: Cultural, biosocial,and ontogenetic bases of intentional self-development. In J. Brandtstadter &R. M. Lemer (Eds.), Action and self-development: Theory and research through thelife span (pp. 37-65). Thousand Oaks, CA: Sage.

Bronfenbrenner, V., & Ceci, S. J. (1994). Nature-nurture reconceptualized:A bio-ecological modelo Psych%gica/ Review, 10/(4), 568-586.

Bronfenbrenner, V., & Evans, G. W. (2000). Developmental scíence in the 21stcentury: Emerging theoretical rnodels, research designa, and empírica! findings. Social Deoelopmeni, 9(1), 115-125.

Bronfenbrenner, U., McClelland, P., Wethington, E., Moen, P.,& Ceci, S. J. (1996).The state of Americans: This generaiion and the next. New York: Free Press.

Bronfenbrenner, U., & Morris, P. A. (1998). The ecology of developmentalprocesses. In W. Damon (Series Ed.) & R. M. Lemer (Vol. Ed.), Handbook ofchild psychology: Vol. 1. Theoretical models of human development (5th ed.,pp. 993-1028). New York: [ohn Wiley.

Elder, G. H., Jr. (1974). Children of the Creat Depreseion. Chícago: University ofChicago Press.

Elder, G. H. (1999). Children of the Creat Depression (25th Anniversary Edition).Chicago: University of Chícago Press.

Small, S., & Luster, T. (1990, November, 27). Youth at risk for parenthood. Paperpresented at the Creating Caring Community Conference, Michigan StateUniversity, East Lansing.

Vygotsky, L. S. (1978). Mind and society: The deve/opment of higher psychologicalprocesses. Cambridge, MA: Harvard University Press.

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Bioecological Perspectives onHuman Development

Urie Bronfenbrenner, EditorComell University

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Bronfenbrenner 2005 2001