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Developmental Psychology 101: Theories of Development


The Developmental Psychology 101 series addresses the theories, periods, and implications of development in a human life from conception all the way through to the stage of adolescence. Developmental psychology is a field which is studied by psychology students and academic researchers; its purpose is to understand individuals based on the biological and psychological changes they experience throughout their lifespan. Development is defined as modifications that momentarily or permanently change an organism in the journey from conception to death (Cole et al., 2005). This 101 series of articles will refer to development from a psychological perspective, discussing its social, emotional, cognitive, and physical areas. Moreover, the debate of nature versus nurture will be discussed in the development of the following four stages of life: prenatal period, infancy, childhood, and adolescence.

The Developmental Psychology 101 series is divided into six chapters:

1. Developmental Psychology 101: Theories of Development

2. Developmental Psychology 101: Methods of Studying Development

3. Developmental Psychology 101: Prenatal Development and Birth

4. Developmental Psychology 101: Development in Infancy

5. Developmental Psychology 101: Development in Childhood

6. Developmental Psychology 101: Development in Adolescence

Developmental Psychology 101: Theories of Development

Developmental science is “the field of study that focuses on the range of children’s physical, intellectual, social, and emotional development” (Cole et al., 2005, p. 2). This field of study is important for two reasons: it helps us understand the interaction of biological and cultural influences in the formation of human beings, and it allows us to devise methods that can ensure safe growth and proper social, emotional, cognitive, and physical progress for individuals.

Figure 1: The Developmental Stages of a Child (Online Psychology Degree Guide, 2021)

Various ideas that strive to explain the differences between the stages of development as well as the nature versus nurture interaction have surfaced in this field. Considerable research (Biddulph et al., 2022; del Valle et al., 2013; Fromm, 1958; Jung & Han, 2019; Olsson & Hwang, 2003) has been done analyzing the societal influences in the contrasts and variations of development. Both old and new developmental approaches seek the answers to questions such as the following: Why do children grow most between 8 and 15 years old? Why does technology influence their brain development? Why does the advice of mothers from generation to generation work or not work?

Science has always been preoccupied with the existential questions. From coming into existence to no longer existing, developmental psychology strives to explain different stages in life through theories. This first article of the 101 series proposes a comparative analysis between these theories by foregrounding their fundamental focuses to better understand the bigger picture of human development. Reading through the multitude of theories that have been published in the field of developmental psychology, one could spot similarities and differences between what they fundamentally stand for. The nature-versus-nurture conflict is apparent as soon as these theories are divided into a category inclined to the social aspects of living and another into the biological aspects that shape human beings.

Figure 2: Children's development in nature versus nurture (The Wall Street Journal, 2014).

Theories of Development

Before discussing how the theories differ and in what points they become similar, the definitions of a few key terms must be outlined:

  • nature is “the inherited biological predispositions of the individual” (Cole et al., 2005, p. 10);

  • nurture refers to “the influences exerted on development by the individual’s social and cultural environment and personal experiences” (Cole et al., 2005, p. 10);

  • plasticity is “the degree to which, and the conditions under which development is open to change and intervention” (Cole et al., 2005, p. 10);

  • the critical period, according to John Bruer (2001), a researcher in the field of Developmental Psychology, is “a period of growth during which a specific kind of experience must occur for a particular ability or behavior to develop”;

  • the sensitive period can be defined as “a time in an organism’s development when a particular experience (or lack of it) has an especially profound effect” (Bruer, 2001);

  • and the developmental stage is “a qualitatively distinctive, coherent pattern of behavior that emerges during the course of development” (Cole et al., 2005, p. 12).

The first theory to be discussed is the famous Psychosexual Stages Theory, based on the founder of psychoanalysis Sigmund Freud’s psychosexual stages of development. In his work, the psychoanalyst shows how universal developmental processes and stages can be understood by exploring the specific life experiences of individuals (Cole et al., 2005, p. 16). Freud (1953) divides development into five stages that are all connected to one of the main needs humans have: the reproduction need. The oral stage is the first of these stages, and it represents the period in which the mouth is the focus of pleasurable sensations. In their second year of life, a baby reaches the anal stage, in which the control of eliminations is gained. The phallic stage coincides with sexual curiosity and gratification. This is the stage in which Freud (1953) theorizes children start having sexual fantasies about the parent of the opposite sex. Latency happens from the seventh year of life all the way to adolescence when the genial stage is reached and sexual desires emerge.

Figure 3: The Psychosexual Stages of Development (Practical Psychology, 2021).

Next, the Psychosocial Theory, advanced by Erik Erikson, focuses on the behavioral part of the development that answers the question “who am I” based on an individual’s learning experiences and environment in each stage of development (Cole et al., 2005, p. 18). Erikson divides these stages in specific time periods when different identity aspects are gained (Eagle, 1997).

In the first year of their lives, children either gain trust or mistrust in others based on the fulfillment of their needs. Autonomy and initiative, which create self-determination, are two characteristics learned in between the second and the sixth year of life, as control of impulses and independence become focuses in development; although, if self-determination is not reached, shame, doubt and guilt start to form. From the seventh year of life, children learn skills and try to be effective in their actions, but they can develop a sense of inferiority instead of industry if they fail. In adolescence, perhaps the most impressive identity crisis occurs when role confusions interact and having a social life becomes one of the criteria for identity formation. In early adulthood, the intimacy-versus-isolation interaction becomes a very relevant aspect of development, as generativity versus stagnation stands out in the middle age stage. During old age, a person starts exploring the relationship between integrity and despair as they reflect on their past and remember their memories (Eagle, 1997).

Figure 4: Erickson's Stages of Development (Very Well Mind, 2022).

More theories have been postulated in order to accommodate the growing needs of explaining the developmental stages. The Behaviorist Theories promote the idea that personality and behavior are shaped through learning experiences, conditioning, and associating actions with consequences (Cole et al., 2005, p. 18). The Constructivist Theory was proposed by Jean Piaget, a psychologist known for his work with children, and postulates that cognitive development results from the construction of reality based on experiences (Cole et al., 2005, p. 19). The scientist affirms that development occurs as the child experiences new activities and tries to fit them into already existing cognitive schemas. If this fails, the child can suffer from an imbalance that can be resolved through assimilation or accommodation to the thing that failed to fit in the schema (Piaget & Inhelder, 2008). The Sociocultural Theory was put forward by Lev Vygotsky (1987), a psychologist known for his work in this field, and declares that nature and nurture shape development by interacting indirectly with one another through culture. In this framework, Vygotsky defines the "zone of proximal development" as “the gap between what children can accomplish independently and what they can accomplish when interacting with others who are more competent” (Cole et al., 2005, p. 22).

The Evolutionary Theories attempt to explain how human behavior influences the survival of this species as well as how past human experiences influence the present and future behavior of humankind (Cole et al., 2005, p. 23). These theories are grounded in ethology, a science that studies the biological and evolutionary foundations of behavior and how it is adapted to the environment in ways that increase the chances for an individual to reach reproductive maturity and have descendants. Due to this science, it is now known that adult individuals tend to take care of infants because of the baby face effect or “babyness” that evokes a positive response (Fullard & Reiling, 1976).

Figure 5: An example of how "babyface" works, measured through brain response activation (ResearchGate, 2009).

More theories that challenge the classical ones were approached from a social point of view as well as from a systemic perspective. The Social Learning Theories are rooted in behaviorism and explain development in terms of associations that children make between their actions and the follow-up consequences (Cole et al., 2005, p. 25). There are two main concepts that reflect the modifications of behavior by observing and interacting with others in social situations: "modeling" is the process in which children learn by observation and imitation, and "self-efficacy" is the concept that defines people’s beliefs in their own abilities to effectively meet standards and achieve goals (Bandura, 1997). The Information-Processing Theories view cognitive development from the way in which children process, store, organise, retrieve, and manipulate the information in increasingly efficient ways (Cole et al., 2005, p. 26).

The System Theories envision development in terms of complex whole mechanisms made up of parts. These theories explore how the parts interact and are organized in order to produce change over time (Cole et al., 2005, p. 26). This complex field of thought requires recognizing “the multiple, mutual, and continuous interactions of all levels of the developing system, from the molecular to the cultural” in order to understand children’s development (Thelen & Smith, 1998, p. 563). These theories study behavior as a system made up of processes, e.g. walking requires mental effort to organize the action and physical processing to organize the motion in itself as well as decisions to start and to arrive at a destination with a purpose. The System Theories are divided in two: Dynamic System Theories look at the less complex parts that interact in order to form a behavior, and Ecological System Theories focus on the interaction of the environmental elements in which children develop. Urie Bronfenbrenner (1992), a Russian-American psychologist, has formulated a model which explains how the "microsystems" of the daily basis influence the development by being integrated in "mesosystems" and "exosystems". Thus, from the interaction of parts, the child develops in different ways.

Figure 6: Ecological Systems Theory (Young, 2021).

Comparing Perspectives

As the theoretical field is compelled to expand with each new idea, having an overview of the past becomes of utmost importance. Psychosexual theories underline the importance of the reproductive system in development, while Psychosocial theories highlight the effects of the community in each stage of life. On one side there are the Constructivist, Evolutionist and Information-Processing theories, while on the other side there are the Socio-cultural, Social learning and Systems theories. What these two categories, the social based one and the biological based one, have in common is that they draw attention to the nature-versus-nurture conflict. Focusing on the physical and biological aspects gives those theories an essential foundation in genetics or human nature. Either the brain inclinations, alongside the cognitive aspects that were inherited together with the genotype, are influential in the development, or the environment, relationships, and the exo- and macrosystems determine the development.

It could be proposed that the development is shaped by both of these perspectives on development. If one were to have a preference for one of them, they would not be taking into consideration the other aspects; thus, possible variables could be neglected that would affect the end results. Only acknowledging the psychosexual and biological growth would imply a person is not developing cognitive or social skills. On the other hand, only recognizing the social aspects that affect development would fail to contribute in understanding how the genetical package can alter development as a whole and modify social adaptability. This is the reason why the 101 series chooses to take into consideration both sides of this coin, as they continuously influence each other and develop together. Every one of these theories has managed to add something important to the field of developmental psychology, and that is a new perspective. Truly understanding human development can only come after seeing the bigger picture that contains all of these elements, as a person does not only grow in one aspect but ages in them all.

Figure 7: Combining social interaction with cognitive development in different ages (Aussie Childcare Network, 2022).


There are a multitude of theories in the field of developmental psychology. These theories have been advanced and refined by researchers and scientists with the purpose of understanding the process of development. Coming up with new ways to improve parenting and ensure more life satisfaction, and increasing children’s wellbeing and comfort while growing up are the main consequences of purposeful study in this field.

From Psychodynamic Theories to Cognitive and Sociocultural ones, the frameworks manage to combine social, emotional, cognitive, and physical aspects of development that strive to explain changes in given times. The new theories take research one step forward and incorporate the already well-established knowledge in the field with new systems and ideas that can further flourish the field of developmental psychology.

Bibliographical References

Bandura, A. (1997). Behavior theory and the models of man (1974). In Notterman, J. M (Ed.) The evolution of psychology: Fifty years of the American Psychologist (pp. 154–172). American Psychological Association. Biddulph, M., Hopkins, P., & Tate, S. (2022). Why this matters to and for children, education, and society. In Hammond, L., Biddulph, M., Catling, S., McKendrick, J. H. (Eds.) Children, Education and Geography: Rethinking Intersections. Routledge, New York. Bronfenbrenner, U. (1992). Ecological systems theory. In R. Vasta (Ed.) Six theories of child development: Revised formulations and current issues (pp. 187–249). Jessica Kingsley Publishers. Bruer, J. T. (2001). A critical and sensitive period primer. In D. B. Bailey, Jr., J. T. Bruer, F. J. Symons, & J. W. Lichtman (Eds.) Critical thinking about critical periods (pp. 3–26). Paul H Brookes Publishing. Cole, M., Cole, S. R., & Lightfoot, C. (2005). The development of children (7th Ed.). Worth Publishers, New York. del Valle, J. F., Canali, C., Bravo, A., & Vecchiato, T. (2013). Child protection in Italy and Spain: Influence of the family supported society. Psychosocial Intervention, 22(3), 227-237. Eagle, M. (1997). Contributions of Erik Erikson. Psychoanalytic review, 84(3), 337-347. Freud, S. (1953). Three essays on the theory of sexuality (1905). In Strachey, J. (Ed.) The standard edition of the complete psychological works of Sigmund Freud, volume VII (1901-1905): A case of hysteria, three essays on sexuality and other works (pp. 123-246). Vintage Classics. Fromm, E. (1958). The influence of social factors in child development. Wissenschaft vom Menschen/Science of Man. Jahrbuch der Internationalen Erich Fromm-Gesellschaft, Münster (Lit-Verlag), Band 3 (1992), pp. 163-165. Fullard, W., & Reiling, A. M. (1976). An investigation of Lorenz's "babyness". Child Development, 1191-1193. Jung, E., & Han, S. (2019). Play in societies influenced by Confucian values. In P. K. Smith & J. L. Roopnarine (Eds.), The Cambridge handbook of play: Developmental and disciplinary perspectives (pp. 343–358). Cambridge University Press. Olsson, M. B., & Hwang, P. C. (2003). Influence of macrostructure of society on the life situation of families with a child with intellectual disability: Sweden as an example. Journal of Intellectual Disability Research, 47(4‐5), 328-341. Piaget, J., & Inhelder, B. (2008). The psychology of the child. Basic Books. Thelen, E., & Smith, L. B. (1998). Dynamic systems theories. In W. Damon & R. M. Lerner (Eds.) Handbook of child psychology: Theoretical models of human development (pp. 563–634). John Wiley & Sons Inc. Vygotsky, L. S. (1987). The collected works of LS Vygotsky: Problems of the theory and history of psychology (Vol. 3). Springer Science & Business Media.

Visual Sources

Cover: Nurturey. (2022). 5 reasons why some children grow slower. [Photo]. Retrieved from:

Figure 1: Online Psychology Degree Guide. (2021) .The Developmental Stages of a Child. [Illustration]. Retrieved from:

Figure 2: Gutierrez, L. (2014). Time to Retire The Simplicity of Nature vs. Nurture. [Illustration]. The Wall Street Journal. Retrieved from:

Figure 3: Practical Psychology (2021). Psychosexual Stages of Development (Definition and Examples). [Illustration]. Retrieved from:

Figure 4: Very Well Mind (2022). Erikson's Stages of Development. [Illustration]. Retrieved from:

Figure 5: ResearchGate (2009). Baby schema modulates the brain reward system in nulliparous women. [Photo]. Retrieved from:

Figure 6: Young, J. (2021). Ecological Systems Theory. [Illustration]. Twitter. Retrieved from:

Figure 7: Aussie Childcare Network (2022). How Educators Can Promote EYLF Learning Outcomes. [Photo]. Retrieved from: