What is Development?

Human development or lifespan development is the scientific study of the ways in which people change, as well as remain the same, from conception to death. You will discover that the field, known more broadly as developmental science, examines changes and stability across multiple domains of psychological and social functioning. These include physical and neurophysiological processes, cognition, language, emotion, personality, moral, and psychosocial development, including our relationships with others.

Originally concerned with infants and children, the field has expanded to include adolescence and more recently, aging and the entire life span. Previously, the message was that once you are 25, your development is essentially completed. Our academic knowledge of the lifespan has changed, and although there is still less research on adulthood than on childhood, adulthood is gaining increasing attention. This is particularly true now that the large cohort known as the “baby boomers” are beginning to enter late adulthood.

The assumption that early childhood experiences dictate our future is also being called into question. Instead, we have come to appreciate that growth and change continues throughout life, and experience continues to have an impact on who we are and how we relate to others. We now recognize that adulthood is a dynamic period of life marked by continued cognitive, social, and psychological development.

You will also discover that developmental scientists investigate key questions, such as whether development occurs through a process of gradual accumulation or through qualitative shifts from one stage to another, and whether development is driven by genetics or by social contexts. From these questions, you may already be thinking that developmental science is related to other applied fields. You are right. Developmental theories and research inform applied work in areas like education, psychopathology, medicine, and intervention science. It also complements many other subspecialties within psychology, such as social, cognitive, and cross-cultural psychology. Lastly, it draws from other scientific disciplines like biology, sociology, anthropology, history, and political science.

Lifespan Perspective

This textbook is based on a lifespan perspective which, as described by Paul Baltes (Baltes, 1987; Baltes, Lindenberger, & Staudinger, 2006), is built on several underlying principles.

1. Development is lifelong. Lifespan theorists believe that development is life-long, and developmental changes are apparent across the lifespan. No single age period is more important than any other.
2. Development is multidirectional and multidimensional. Lifespan researchers hold that different people follow different developmental pathways, and proceed along pathways at different rates. Even within the same person, different dimensions or domains of development can change in different ways.
3. Development includes both gains and losses. Lifespan theorists do not agree with the traditional view of development that childhood is a period characterized by developmental gains, whereas old age is a time of loss. Instead, the lifespan approach holds that at every age, we may show gains in some areas of development, while showing losses in others. Every change, whether it is finishing high school, getting married, or becoming a parent, entails both growth and loss.
4. Development is characterized by plasticity. Plasticity is about malleability, or our potential to change and to follow a wide range of developmental pathways. For instance, neuroplasticity is illustrated in the brain’s ability to learn from experience and the many ways it can recover from injury.
5. Development is embedded in historical and cultural contexts. Lifespan researchers believe that development is influenced by the many social contexts in which it unfolds. How people develop will depend on their societal and cultural contexts, and on the historical period during which they develop.
6.  Development is multiply determined. Lifespan theorists argue that development is caused by multiple factors, and is always shaped by both biological and environmental factors. In addition, the individual plays an active role in their own development.
7. Development is multidisciplinary. As mentioned previously, human development is such a vast topic that it requires theories, research methods, and knowledge bases from many disciplines.

Contextualism as paradigm. Baltes (1987) identified three specific developmental systems of influence, all of which include biological and environmental forces.

1. • Normative age-graded influences: An age-grade is a specific age group, such as toddler, adolescent, or senior. Humans experience particular age-graded social experiences (e.g., starting school) and biological changes (e.g., puberty).
   • Normative history-graded influences: The time period in which you are born (see Table 1.1) shapes your experiences as you develop. A cohort is a group of people who are born at roughly the same period in a particular society. These people travel through life often experiencing similar historical changes at similar ages. History-graded influences include both environmental determinants (e.g., historical changes in the job market) and biological determinants (e.g., historical changes in life expectancy).
   • Non-normative influences: Development is also shaped by specific influences that are not organized by age or historical time, such as immigration, accidents, or the death of a parent. These can be environmental (e.g., parental mental health issues) or biological (e.g., life threatening illness).

Table 1.1. Which generation (cohort) are you?

adapted from Lally & Valentine-French, 2019

Domains of development. We change across three general domains/dimensions; physical, cognitive, and psychosocial. The physical domain includes changes in height and weight, sensory capabilities, the nervous system, as well as the propensity for disease and illness. The cognitive domain encompasses changes in intelligence, wisdom, perception, problem-solving, memory, and language. The psychosocial domain focuses on changes in emotion, self-perception, and interpersonal relationships with families, peers, and friends. All three domains influence each other. It is also important to note that a change in one domain may cascade and prompt changes in other domains. For instance, an infant who has started to crawl or walk will encounter more objects and people, thus fostering developmental change in the child’s understanding of the physical and social world.

Contextual perspectives, like the lifespan approach, highlight societal contexts that influence our development. An important societal factor is our social standing, socioeconomic status, or social class. Socioeconomic status (SES) is a way to identify families and households based on their shared levels of education, income, and occupation. While there is certainly individual variation, members of a social class tend to share similar privileges, opportunities, risks, lifestyles, patterns of consumption, parenting styles, stressors, religious preferences, and other aspects of daily life. Everyone born into a class system has a specific social position, and we may move up or down depending on a combination of both socially and individually created limits and opportunities.

Families with higher socioeconomic status usually are in occupations (e.g., attorneys, physicians, executives) that not only pay better, but also grant them a certain degree of freedom and control over their job. Having a sense of autonomy or control is a key factor in experiencing job satisfaction, personal happiness, and ultimately health and well-being (Weitz, 2007). Those families with lower socioeconomic status are typically in occupations (e.g., food service, retail industries, manual labor, ) that are more routine, more heavily supervised, and require less formal education. These occupations are also subject to lower wages and  more job disruptions, such as lay-offs.

Poverty level is an income amount established by the federal government that is based on a set of thresholds that vary by family size (United States Census Bureau, 2016). If a family’s income is less than the government threshold, that family is considered in poverty. As explained in the post, developmental researchers more realistically identify the poverty level at about twice the income set by the government. Those living at or near poverty level may find it extremely difficult to sustain a household with this amount of income. Poverty puts people at risk for poorer health and a lower life expectancy based on stressors associated with being poor in this country from birth to death, such as poorer prenatal care, higher infant mortality rates, poorer schools, more dangerous occupations and neighborhoods, and poorer quality healthcare,

Today, we are more aware of the variations in development and the impact that culture and the environment have on shaping our lives (Villadsen & Hviid, 2021). Culture is the totality of our shared language, knowledge, material objects, and behavior. It includes ideas about what is right and wrong, what to strive for, what to eat, how to speak, what is valued, as well as what kinds of emotions are called for in certain situations. Culture teaches us how to live in a society and allows us to advance because each new generation can benefit from the solutions found and passed down from previous generations. Culture is learned from parents, schools, houses of worship, media, friends and others throughout a lifetime.

The kinds of traditions and values that evolve in a particular culture serve to help members function and value their own society. We tend to believe that our own culture’s practices and expectations are the right ones. This belief that our own culture is superior is called ethnocentrism and is a normal by-product of growing up in a culture. It becomes a roadblock, however, when it inhibits understanding of cultural practices from other societies. Cultural relativity or humility is an appreciation for cultural differences and the understanding that cultural practices are best understood from the standpoint of that particular culture.

Culture is an extremely important context for human development. Within developmental science (and the social sciences more generally), this understanding is only slowly permeating the field (Garcia Coll et al., 1996; Iruka et al., 2022; Suarez Orozco et al., 2018). Much of what developmental theorists have described in the past has been culturally bound and difficult to apply across different cultural contexts. The reader should keep this in mind and realize that there is still much that is unknown when comparing development across subcultures within the USA and across cultures outside North American and western Europe.

Conceptions of Age

How old are you? Chances are you would answer that question based on the number of years since your birth, or what is called your chronological age. Ever felt older than your chronological age? We might notice that a peer seems more emotionally mature than we are, or that they are physically more capable. Some days we might feel like we are older, especially if we are not feeling well or are tired. So years since birth is not the only way we can conceptualize age.

Biological age. Another way developmental researchers think about the concept of age is to examine how quickly the body is aging compared to years lived, this is your biological age. Multiple factors determine the rate at which our body ages. Examples include our genetic history, physical activity, nutrition, sleeping habits, smoking, alcohol consumption, and stress.

Psychological age. Our psychologically adaptive capacity compared to others of our chronological age is our psychological age. This includes our cognitive capacity along with our mindset about how old we are. An individual who has cognitive impairments might be 20 years of age, yet has the mental capacity of an 8-year-old. A 70- year-old might be travelling to new countries, taking courses at college, or starting a new business. Compared to others of our age group, we may be more or less active and able to meet new challenges.

Social age. Our social age is based on the social norms of our culture and the expectations our culture has for people of our age group. Our culture often reminds us whether we are “on target” or “off target” for reaching certain social milestones, such as completing our education, moving away from home, having children, or retiring from work. However, there have been arguments that social age is becoming less relevant in the 21st century (Neugarten, 1979; 1996). If you look around at your fellow students at college you might notice more people who are older than traditional aged college students, those 18 to 25. Similarly, the age at which people are moving away from the home of their parents, starting their careers, getting married or having children, or even whether they get married or have children at all, is changing.

Those who study lifespan development recognize that chronological age does not completely capture a person’s age. Our age profile is much more complex than this. A person may be physically more competent than others in their age group, while being psychologically immature. So, how old are you?

Developmental Periods

Table 1.2 Age Periods of Development

adapted from Lally & Valentine-French, 2019

Table 1.2 shows the developmental periods that will be explored in this book, starting with prenatal development and continuing thought late adulthood to death. Both childhood and adulthood are divided into multiple developmental periods. So, while both an 8-month old and an 8-year-old are considered children, they have very different motor abilities, social relationships, and cognitive skills. The same is true of an 18-year-old and an 80-year-old, even though both are considered adults.

Prenatal Development. Conception occurs and development begins. All of the major structures of the body are forming, and the health of the mother is of primary concern. Understanding nutrition, teratogens, or environmental factors that can lead to birth defects, and labor and delivery are important to promoting healthy prenatal development.

Infancy and Toddlerhood. The first two years of life are ones of dramatic growth and change. A newborn, with a keen sense of hearing but very poor vision, is transformed into a walking, talking toddler within a relatively short period of time. Caregivers are also transformed from someone who manages feeding and sleep schedules to an active guide and safety inspector for a mobile, energetic child.

Early Childhood. Also referred to as preschool age, this period consists of the years that follow toddlerhood and precede formal schooling. As a three to five-year-old, the child is busy learning language, gaining greater independence and a sense of self, and  beginning to understand the workings of the physical world.

Middle and Late Childhood. The ages of six to the onset of puberty comprise middle and late childhood, and much of what children experience at this age is connected to their involvement in the early grades of school. Now the world becomes one of making friends and learning new academic skills, and assessing one’s abilities and accomplishments by making comparisons between self and others.

Adolescence. Adolescence is a period of dramatic physical change marked by an overall growth spurt and sexual maturation, known as puberty. It is also a time of social and cognitive change as the adolescent begins to think of new possibilities and to consider abstract concepts such as love, fear, and freedom. At the same time, adolescents have a sense of invincibility that puts them at greater risk for car accidents or contracting sexually transmitted infections that can have lifelong consequences.

Emerging Adulthood. The period of emerging adulthood is a transitional time between the end of adolescence and before individuals acquire all the benchmarks of adulthood. Continued identity exploration and preparation for full independence from parents are negotiated. Although at one’s physiological peak, emerging adults are most at risk for involvement in violent crimes and substance abuse.

Early Adulthood. The twenties and thirties are identified as early adulthood. Intimate relationships, establishing families (of all shapes and sizes), and work are primary concerns at this stage of life. For adults with children, developmental changes can become organized around the family life cycle.

Middle Adulthood. The forties through the mid-sixties are referred to as middle adulthood. This is a period in which aging becomes more noticeable and when many people are at their peak of productivity in love and work. At this age, some people are negotiating adolescent children and aging parents at the same time.

Late Adulthood. Late adulthood is sometimes subdivided into two categories: The young-old who are from 65-84 years and the oldest-old who are 85 years and older. One of the primary differences between these groups is that the young-old are still relatively healthy, productive, active, and the majority continue to live independently. With both age groups the risks of diseases such as arteriosclerosis, cancer, and cerebral vascular disease increase substantially.

Meta-theories of Human Development

The study of development is guided by the assumptions researchers hold about the nature of humans and their development. These assumptions are called meta-theories. “Meta” means “above” or “beyond,” like “meta-physics.” Other terms used to describe meta-theories are “world views,” “cosmologies,” “perspectives,” or “paradigms,” as in “paradigm shifts.” Explicit discussions of meta-theories are found most often in philosophy.

What are meta-theories of human development?

Meta-theories (or world views or paradigms) of human development are sets of assumptions people hold about the nature of humans and the meaning of development-- what it looks like, how it happens, what causes it. These assumptions are important because everyone has them, including researchers, but they are often implicit, meaning we are not always consciously aware of them. In the study of development, such assumptions influence everything about how research is conducted: the questions we ask, the measures and methods we use, and how we interpret data. For example, if researchers assume that development ends at 18, they do not look for developmental changes after that age. Or, if researchers assume that aging is a process of decline, then they never look for things that might improve as people get older.

All researchers have meta-theories, since assumptions are baked into the theories and methodologies they use. But researchers are often unaware of them, and so these assumptions are rarely acknowledged. It is important to note that meta-theories are not just cold cognitions. They are often deeply held convictions that researchers will fiercely defend. Many researchers think that their assumptions are self-evident truths. They are often convinced that their assumptions are right and everyone else’s are wrong.

Researchers holding different meta-theories can have difficulty communicating with each other. Since they are asking different questions and using different methods for research, they often argue past each other or misunderstand each other. One group of researchers will offer what they consider to be irrefutable proof of their ideas, which other researchers then dismiss as irrelevant. Discrepancies, inconsistencies, arguments, and furor often characterize areas of study in which researchers from multiple meta-theories are working.

For this reason, many scholars are in favor of collaboration and collective making, a process in which groups of researchers come together to share diverse perspectives on an area of study, and consider ways in which their differences in meta-theoretical and theoretical perspectives, as well as in their practical approaches to the study of psychology, can help the collective develop as a whole (Villadsen & Hviid, 2021).

What kinds of assumptions guide the study of human development?

We consider six key assumptions. You may have heard of many of them, since they are perennial issues in the study of development. They include:

1. Assumptions about human nature: whether people are born as blank slates (tabula rasa) or whether people are inherently good or bad.
2. Assumptions about the causes of development: whether development is determined by nature (genes, biology) or nurture (environment, learning).
3. Assumptions about the role of the individual in their own development: whether people are passive participants, reacting to external forces, or whether they are active in choosing and shaping their own development.
4. Assumptions about stability vs. change: whether traits, characteristics, and experiences early in life have permanent effects or whether people are malleable and open to change throughout life.
5. Assumptions about continuity vs. discontinuity: whether development involves quantitative incremental change or qualitative shifts.
6. Assumptions about universality vs. context specificity: whether development follows a universal pathway or depends more on specific experiences and environmental contexts.

Nature of Humans. What is the nature of humans? These assumptions refer to beliefs about the underlying qualities of our species-- whether humans are born as blank slates (tabula rasa) or whether we all bring intrinsic human characteristics with us into the world. For example, these different assumptions are readily apparent in alternative conceptualizations of motivation—some theories assume that motives and motivation are all acquired, whereas others assume that all humans come with intrinsic motivations like curiosity and the desire to play and explore.

Nature versus Nurture. Why are you the way you are? As you consider some of your features (height, weight, personality, having diabetes, etc.), ask yourself whether these features are a result of heredity or environmental factors, or both. Chances are, you can see the ways in which both heredity and environmental factors (such as lifestyle, diet, and so on) have contributed to these features. For decades, scholars have carried on the "nature vs. nurture" debate. Those on the side of nature argue that heredity plays the most influential role. Those on the side of nurture argue that the environment is most important. This debate can be found in research on almost every aspect of human development.

Active versus Passive. How much do you play a role in your own developmental path? Are you at the whim of your genetic inheritance or the environment that surrounds you? Some theorists see humans as agentic, that is, as playing a very active role in their own development. Piaget, for instance, believed that children actively explore their world and construct new ways of thinking to explain the things they experience. In contrast, many behaviorists view humans as more passive, that is, as largely reacting to outside forces.

Stability versus Change. How similar are you now to the way you were as a child? Were you always as out-going or reserved? Some theorists argue that the adult personality traits are rooted in the behavioral and emotional tendencies of the infant and young child. Others disagree, and believe that these initial tendencies are modified over time by later neurobiological developments and social and cultural forces.

Continuity versus Discontinuity. Is human development best characterized as a slow, gradual process, or as one of more abrupt change? The answer to that question depends on which developmental theory you consult. The theories of Freud, Erikson, Piaget, and Kohlberg are called stage theories. Stage theories or discontinuous development assume that developmental change occurs in distinct stages that are qualitatively different from each other, and that unfold in a set, universal sequence. At each stage of development, children and adults have different qualities and characteristics. Thus, stage theorists assume development is discontinuous. Others, such as behaviorists and information processing theorists, assume development is a more slow and gradual process known as continuous development. For instance, they would see the adult as not possessing new skills, but as using more advanced skills that were already present in some form in the child.

Universal vs. context specific. A final assumption focuses on whether pathways of development are presumed to be (1) normative and universal, meaning that all people pass through them in the same sequence, or (2) differential and specific, meaning that a variety of different patterns and pathways of developmental change are possible depending on the individual and the context. Some theorists, like Piaget or Erickson, assume that everyone progresses through the same stages of cognitive development in the same order, or that everyone negotiates the same set of developmental tasks at about the same ages. Other theorists, who endorse lifespan or ecological systems approaches, believe that development can take on a wide variety of patterns and pathways, depending on the specific cultural, historical, and societal contexts within which it unfolds.

What are the guiding meta-theories in human development?

These six basic assumptions are clustered into “packages” that go together. They are organized around metaphors, which are at the root of meta-theories of humans and their development. We consider four meta-theories, each with its own metaphor: (1) humans as seeds, as depicted by Maturational meta-theories; (2) humans as machines, as depicted in Mechanistic meta-theories (3) humans as butterflies, as depicted in Organismic meta-theories; and (4) humans as participants in a tennis game, conversation, or dance, as depicted by Contextualist meta-theories. For an overview of these guiding meta-theories, see this chart [pdf].

1. Maturational meta-theory. Maturational meta-theories can be understood using the plant as a metaphor. It is as if humans develop the same way as plants. The important thing to study is people’s “seeds,” that is, their genetic make-up. People are assumed to be passive, the product of their genes. The environment can provide support and nutrition (rain, sun, and soil), but can’t change a person’s nature (poppy seeds will always produce poppies). The role of the person is reactive—to their genes. The course of development will be continuous or discontinuous depending on the genetic program, although acorns always grow into oak trees.
2. Mechanistic meta-theory. Mechanistic meta-theories can be understood using the machine as a metaphor. It is as if humans change the same way as machines. People are assumed to be made up of pieces that can be studied in isolation. They are passive, with the energy coming from outside (like gasoline for a car). Development is continuous and people do not develop into something else (a car stays a car). The person can only react to the environment that is controlling them (like a car responding to the gas pedal or the brake). All causes for development come from the outside, from environmental forces.
3. Organismic meta-theory. Organismic meta-theories can be understood using the butterfly as a metaphor. It is as if humans develop the same way as butterflies. People are assumed to be made up of structured wholes. Their nature is to be curious, interested, and open to growth. They are active and develop through discontinuous qualitatively different stages (like the caterpillar, chrysalis, and butterfly). People construct their own next steps in development based on the affordances and opportunities provided by the environment. Development is caused by imbalances that lead to structural reorganizations. Development is progressive (gets better) and only goes in one direction (from caterpillar toward butterfly) and not the reverse.
4. Contextual meta-theory. Contextual meta-theories can be understood using the tennis game (or dance) as a metaphor. It is as if humans’ development is like a game of tennis or a dance. The important thing to study is the back and forth between the person and their context, both of which are assumed to be proactive and agentic (i.e., acting on their own agenda). Development can be continuous or discontinuous depending on how the game is played. Both person and environment are active partners in the system, which can lead to transformations in both.

What are examples of theories that fall within each meta-theory?

Each higher-order meta-theory contains a set of lower-level theories, sometimes called "families," because they share common properties, based on their similarity to the root metaphors and characteristics of the guiding meta-theories. This table contains several examples of “big” theories of development and provides an analysis of their defining features according to the meta-theoretical assumptions we have been discussing [pdf]. Based on this analysis, you can figure out the higher-order family to which each big theory or approach likely belongs.

Although Maturational meta-theories were prevalent in the beginning of the 20th century, their popularity has waxed and waned since then, and they have taken on many different forms. These include some formulations of behavioral genetics, sociobiology, evolutionary, ethological, neuroscience, temperament, and personality theories. Maturational assumptions are signaled by concepts such as “trait,” the search for “the aggression gene,” the discovery of the brain system, hormone, or neurotransmitter responsible for a specific condition or behavior, or any other descriptions suggesting that development is solely the product of innate and immutable characteristics of individuals.

Although not typically referred to as “maturational,” there are many kinds of theories that place all the active ingredients of behavior and development inside the brain or the head (e.g., social cognitions) of the person. Even if they are not direct descendants, these theories can be considered cousins of Maturational meta-theories because they are exclusively focused on the role of nature (i.e., the individual).

The prototypic Mechanistic theories are behaviorist, operant, and classical conditioning learning theories, like social learning theory. This family of theories dominated psychology from the early to the mid-20th century, but Mechanistic theories are still alive and well in many areas, such as learning and motivation, and especially in many theories that have been adapted for use in educational systems.

New kinds of machines serve as prototypes for mechanistic theories of memory, learning, and automatic functioning—focusing on the computer, the robot, and the automaton. Such assumptions have even pervaded our understanding of biological systems, as seen in metaphors like “the brain is a computer.” And although the “cognitive revolution” was supposed to have overthrown behaviorist assumptions, some cognitivistic theories treat humans as if they were information processing machines.

Perhaps surprisingly, there are also mechanistic assumptions embedded in certain progressive analyses of the effects of societal and social conditions, such as poverty, oppression, racism, and discrimination. Such approaches sometimes seem to imply that these external forces are the sole determinants of the development of stereotypes or implicit attitudes. In this case, because all people are presumed to passively internalize these societal prejudices, psychological phenomena are modeled after the metaphor of the “Xerox machine.” Just as in Maturational meta-theories, where humans could be seen as “hosts” to their genes, who were really running the show, in Mechanistic meta-theories, humans can be seen as “hosts” to their own behaviors, which are automatically reflexively produced based on previous social programming.

The prototypical Organismic theory is Piaget’s constructivist theory of cognitive and affective development, and the several neo-constructivist theories that were inspired by Piaget, such as Kohlberg’s theory of the development of moral reasoning. Other theories living under the Organismic umbrella include Werner’s comparative psychology, focusing on the orthogenetic principle of differentiation and integration, and Erikson, who posited universal age-graded developmental tasks.

Other theories that claim kinship with Organismic meta-theories (e.g., theories of intrinsic motivation) do not typically include notions of universal stages or tasks, but focus instead on Organismic assumptions about the nature of humans, specifically, that humans are innately active, curious, and interested, and inherently desire to explore, understand, and fit in with their social and physical environments. With the rise of radical contextualism and cultural relativism in psychology, theories of “universal” anything (e.g., psychological needs, stages, developmental tasks) have come increasingly under attack.

Some of the better-known members of the Contextualist family include Bronfenbrenner’s bio-ecological model and the lifespan approach, both of which arose in reaction to dominant meta-theories of their day, with their almost exclusive focus on the child as a developing individual (experimental child psychology and Piagetian psychology, respectively). The “contextualist” moniker reflects these perspectives’ insistence that development unfolds within and is shaped by multi-level ecological or contextual forces outside the individual, such as microsystem settings, and societal, cultural, and historical contexts.

Does the field of psychology have meta-theories?

During different historical periods, specific meta-theories dominated the field of psychology. For example, during the 1940s and 1950s, behaviorism held sway. In the 1960s, Piaget’s theories were introduced to the United States and captured the field’s attention. Some fierce theoretical and empirical battles were fought between behaviorists and Piagetians.

When a specific meta-theory governs the field, it becomes very difficult for those from opposing meta-theories to do research. They have trouble obtaining funding and getting their study findings published, and they are marginalized by other researchers. For example, when the area of motivation was dominated by behaviorists (who believed that all behavior was motivated by rewards and punishments), it was very difficult for researchers to study and publish research on intrinsic motivation.

What is the dominant meta-theory in the field today?

“Cognitivism” is a guiding meta-theory in the field of psychology today. “Cognitivism” is the assumption that all the causal factors that shape human behavior and development are inside the mind or belief system of the person. You can hear the assumptions in the theories of the field: self-efficacy, self-esteem, attributions, perceived social support, values, sense of purpose, goal orientations, internal working model, identity, and so on.

The paradigm that is currently taking over the field of psychology is neuroscience. That is, the brain is in charge of behavior, and neurobiology is destiny. Some branches of neuroscience are predominantly Maturational, as seen in discussions of the brain systems that are solely responsible for certain actions, predilections, and characteristics. Other branches are more Contextual, for example, research on neuroplasticity, which examines the way that social contexts and interactions shape the developing brain.

News flash: In the field of psychology outside developmental, most researchers assume that people don’t develop. In personality, social, cognitive, and industrial-organizational psychology, researchers largely examine individual differences as indicators of people’s permanent characteristics. We could say that most of them hold adevelopmental meta-theoretical assumptions.

Who else has meta-theories?

Everyone has meta-theories about human nature and development: parents, teachers, nurses, social workers, doctors, therapists, business people, artists, politicians, students, and so on.

For example,

• doctors assume that weight loss is all about diet and exercise (nurture), so no one can do research on physiological differences in metabolism (nature).
• teachers have assumptions about whether students come with motivation (nature) or have to be motivated from the outside (nurture), and organize their classrooms accordingly.
• parents often argue about the nature of children’s development, whether it’s just the child’s personality (maturational), or the child is going through a normal stage (organismic), or if they are rewarding the wrong behavior (mechanistic).
• some clinicians focus on their patients' neurophysiology (maturational) and some work with patients to co-create narratives and meaning of their experiences (contextual, Borden, 2021).

What is the meta-theory that guides our class and this book?

Our class endorses a lifespan approach to human development. Lifespan perspectives, as part of the contextualist family, fought their way through the dominant perspectives in child psychology (e.g., development ends at age 18), starting in the 1980s to become one of the major meta-theories governing the field of developmental science today. Note that your instructors chose your book, so their meta-theory is influencing the meta-theoretical filter through which you are learning about development.

What is the correct meta-theory?

There is no single correct meta-theory or definition of development. Really. Even the lifespan approach has its drawbacks.

However, as research accumulates, many theories derived from certain meta-theories have been found to be incomplete. For example, so far researchers have not found any significant aspect of development that is caused only by nature or only by nurture. Therefore, most researchers currently say they favor interactionist meta-theories, like contextualist or systems meta-theories. However, it is important to look carefully at researchers’ actual work, because sometimes they say that they endorse one meta-theory, but their research seems to be guided by assumptions from a different meta-theory.

Do I have a meta-theory about development?

Yes, you do. And you can figure out what it is. Although it may take some reflection, you can discern your own assumptions about development—by thinking about which assumptions make the most sense to you. You can also see which kinds of theories you prefer and what kinds of recommendations you would make about how to structure development, like how people should parent, teach, or make public policies. The hardest part about discovering your own meta-theory is realizing that it is made up of assumptions (based on your experiences and messages from society) that aren’t necessarily true. Our meta-theories sure seem true to each of us!

How do I get rid of my meta-theory?

It’s not really possible to get rid of all of our assumptions. It is our goal to become aware of our own assumptions or meta-theories, to realize that they are not the truth but are our current working models of how the world operates and people develop. The most important thing is to be explicit about our assumptions and to be cognizant of how they are guiding our actions. It is a goal of this class to help students figure out their own assumptions and to help them become (or remain) open to alternative viewpoints.

Adapted from: Ellen Skinner, Glen Richardson, Jennifer Pitzer, and Cynthia Taylor. Portland State University.

Historical Theories of Development

Preformationist View. Well into the 18th century, children were merely thought of as little adults. Preformationism, or the belief that a tiny, fully formed human is implanted in the sperm or egg at conception and then grows in size until birth, was the predominant early theory. Children were believed to possess all their sensory capabilities, emotions, and mental aptitudes at birth, and as they developed these abilities unfolded on a predetermined schedule (Thomas, 1979). The environment was thought to play no role in determining development.

John Locke (1632-1704). Locke, a British philosopher, refuted the idea of innate knowledge and instead proposed that children are largely shaped by their social environments, especially their education-- as adults teach them important knowledge. He believed that a child is socialized through education, where they learn what is needed to be an appropriate member of society.

Locke advocated thinking of a child’s mind as a tabula rasa or blank slate, and posited that whatever comes into the child’s mind comes from the environment. Locke emphasized that the environment is especially powerful in the child’s early life because he considered the mind the most pliable at that time. Locke indicated that the environment exerts its effects through associations between thoughts and feelings, behavioral repetition, imitation, and rewards and punishments (Crain, 2005). Locke’s ideas laid the groundwork for the behavioral perspective and subsequent learning theories of Pavlov, Skinner, and Bandura.

Jean-Jacques Rousseau (1712-1778). Like Locke, Rousseau also believed that children were not just little adults. However, he did not believe they were blank slates, but instead held that they developed according to a natural plan which unfolded in different stages (Crain, 2005). He did not believe in teaching them the correct way to think, but believed children should be allowed to think by themselves according to their own ways and an inner, biological timetable. Rousseau's focus on biological maturation was a primary reason why he was considered the father of developmental psychology. Followers of Rousseau’s developmental perspective include Gesell, Montessori, and Piaget.

Arnold Gesell (1880-1961). Gesell spent 50 years at the Yale Clinic of Child Development, and with his colleague studied the neuromotor development of children. Gesell believed that the child’s development was activated by genes and he called this process maturation (Crain, 2005). Further, he believed that development unfolded in fixed sequences, and he opposed efforts to teach children ahead of schedule as he believed they would naturally engage and learn when their nervous systems had matured sufficiently.

Sigmund Freud (1856-1939). Freud was an influential figure in developmental psychology. He emphasized the importance of early childhood experiences in shaping later personality and behavior. He argued that, in our natural state, we are biological beings and are driven primarily by instincts. During childhood, however, we begin to become social beings as we learn how to manage our instincts and transform them into socially acceptable behaviors.

He assumed that personality was formed during the first few years of life. The ways in which parents or other caregivers interacted with children were assumed to have a long-lasting impact on children’s emotional states. His psychodynamic theories of psychosexual development and psychopathology dominated the field of psychiatry until behaviorism gained prominence in the 1950s.

However, Freud’s theory has been heavily criticized for multiple reasons. First, it has proven very difficult to test scientifically (Crews, 1998). Freud suggested that much of what determines our actions is unknown to us, and as scientists we cannot measure these unconscious concepts. A second criticism is that Freud’s theories were based on his interpretations of individual case studies, which were not replicated or validated by other scientists. Many later theories, particularly behaviorism and humanism, emerged  as challenges to Freud’s views.

Contemporary Theories on Development

Erikson (1902-1994) and Psychosocial Theory. Now, let's turn to a less controversial psychodynamic theorist, Erik Erikson. Erikson presents eight developmental tasks that encompass the entire lifespan. For that reason, Erikson’s psychosocial theory forms the foundation for much of our discussion of psychosocial development.

Erikson (1950) proposed a model of lifespan development that provides a useful guideline for thinking about the changes we experience throughout life. Erikson broke with Freud’s emphasis on sexuality as the cornerstone of social-emotional development and instead suggested that social relationships fostered development. Erikson proposed that each period of life has a unique challenge or crisis that the person who reaches it must face, referred to as a psychosocial crisis or developmental task.

According to Erikson, successful development involves dealing with and resolving the goals and demands of each of these psychosocial crises in a positive way. If a person does not resolve a task successfully, it may hinder their ability to deal with later tasks. For example, a person who does not develop a sense of trust (Erikson’s first task) may find it challenging as an adult to form a positive intimate relationship (Erikson’s sixth task). Or an individual who does not develop a clear sense of purpose and identity (Erikson’s fifth stage) may become self-absorbed and stagnate rather than work toward the betterment of others (Erikson’s seventh stage). However, most individuals are able to successfully complete the eight developmental tasks he proposed (See Table 1.3).

Table 1.3 Erikson's Psychosocial Stages

adapted from Lally & Valentine-French, 2019

Erikson’s theory has been criticized for focusing so heavily on crises and assuming that the completion of one developmental task is a prerequisite for the next. His theory also focused on certain kinds of social expectations that are found only in some cultures. For instance, the idea that adolescence is a time of searching for identity might translate well in the middle-class culture of the United States, but not as well in other cultures where, for example, the transition to adulthood coincides with puberty and is negotiated through rites of passage or where identities and  adult role offer fewer choices.

Learning Theory. Also known as Behaviorism, is based on the premise that it is not possible to objectively study the mind, and therefore psychologists should limit their attention to the study of behavior itself. The most famous behaviorist was Burrhus Frederick (B. F.) Skinner (1904–1990), who expanded the principles of behaviorism and also brought them to the attention of the public at large. Skinner used the ideas of stimulus and response, along with the application of rewards or reinforcements, to train pigeons and other animals. In addition, he used the general principles of behaviorism to develop theories about how best to teach children and how to create societies that are peaceful and productive (Skinner, 1957, 1968, 1972).

The behaviorists made substantial contributions to psychology by identifying the principles of learning. Although the behaviorists were incorrect in their beliefs that it was not possible to measure thoughts and feelings, their ideas provided new insights that helped further our understanding regarding the nature-nurture debate as well as the question of free will. The ideas of behaviorism are fundamental to psychology and have been developed to help us better understand the role of prior experiences in a variety of areas of psychology, especially in education (e.g., Hayes, 2021; Yusra et al., 2022).

Jean Piaget (1896-1980) was one of the most influential developmental theorists. He explored the ways that children’s ability to think and reason develop by carefully observing his own children. He was one of the first to recognize and map out the ways in which children's intelligence differs from that of adults (Piaget, 1929). He became interested in this topic while testing children's IQ by asking them standardized questions. He began to notice that there were patterns in the wrong answers they gave. Children didn't simply know less than adults; they interpreted the world differently. Children of different ages had qualitatively different ways of thinking and reasoning. He believed that children's intellectual skills change over time based on their interactions with the social and physical worlds, and that their development could not be speeded up through training. Piaget theorized that children progressed through four stages of cognitive development (see Table 1.4).

Table 1.4 Piaget's Stages of Cognitive Development

adapted from Lally & Valentine-French, 2019

Piaget has been criticized for overemphasizing the role that maturation plays in cognitive development and in underestimating the role that culture and experience plays. Looking across cultures reveals consistency in the sequence of children's cognitive development, but considerable variation in timing, that is, what children are able to do at various ages. Research has also shown that movement to a new stage does not happen all at once in an "all-or-nothing" fashion. Instead some aspects come first and others emerge later. So development seems to be both continuous and discontinuous.

Lev Vygotsky (1896-1934) was a Russian psychologist who worked in the early 1900s, but whose writings were not discovered by researchers in the United States until the 1960s and then became more widely known in the 1980s (Crain, 2005). His sociocultural theory emphasizes the importance of culture and participation in the development of cognitive abilities. Vygotsky differed from Piaget in that he highlighted the role of other people and learning activities in creating a zone of proximal development, in which an individual's potential abilities can be realized if given the proper guidance and scaffolding. Vygotsky's theories on teaching and learning have been adopted and are in use by educators today.

Urie Bronfenbrenner (1917-2005) developed the ecological systems model, which provides a framework for understanding and studying the many contextual influences on human development (Bronfenbrenner, 1979; Bronfenbrenner & Morris, 2006). As the engines of development, Bronfenbrenner focused on proximal processes, defined as ongoing reciprocal interactions between the developing individual and the features of their local contexts, such as other people (e.g., family members, peers, teachers), objects, tasks, rules, and so on. These processes take place within complex social ecologies that include larger societal and historical forces. From this perspective, an understanding of how these contextual forces shape individual-context interactions is essential for understanding development.

The individual is impacted by systems at several levels, including:

• Microsystems involve local face-to-face settings (like home, school, and the neighborhood) and the interaction partners (like parents, teachers, and friends) who interact with the developing person. These interactions are shaped by the attributes and actions of the individual as well. Microsystems are important because that is where proximal processes take place.
• Mesosystems involve the connections and interactions between two or more microsystems. So, for example, communication between home and school would comprise a mesosystem (i.e., the home-school mesosystem). The idea of mesosystems is important because microsystems work together in influencing development.
• Exosystems involve settings (like the parent's workplace or teachers' homes) that have an impact on children's development even though children do not spend any time there. Exosystems also include places like policy makers' offices or union meetings where important decisions are made that can have a downstream impact on children's micro- and meso-systems. Because children are not present, researchers often overlook the effects of exosystems, but they can contain important levers for change.
• Macrosystems includes larger organizational structures and cultural institutions, such as the economic, legal, political, educational, criminal justice, and healthcare systems. They also include global economic conditions, war, technological trends, values, philosophies, and a society’s responses to the global community.

Figure 1.9 is a schematic of Bronfenbrenner’s Ecological Systems model. Over the decades since the Ecological Model first appeared, it has been critiqued by researchers interested in the development of minoritized children and youth. These researchers have offered more inclusive and culturally-attuned ecological models (Garcia Coll et al., 1996; Iruka et al., 2022; Spencer, 2006; Suarez Orozco et al., 2018).

Supplemental Materials

• This article discusses the importance of critical reflection on the underlying assumptions of developmental psychology as a science.

Teo, T. (1997). Developmental Psychology and the Relevance of a Critical Metatheoretical Reflection. Human Development, 40(4), 195–210. https://doi.org/10.1159/000278723

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OER Attribution: "Lifespan Development: A Psychological Perspective, Second Edition" by Martha Lally and Suzanne Valentine-French is licensed under a CC-BY-NC-SA-3.0

Additional written material (Meta-theories of Human Development) by Ellen Skinner, Glen Richardson, Jennifer Pitzer, and Cynthia Taylor, Portland State University is licensed under a CC BY-NC-SA 4.0.