Developmental Psychology

practical psychology logo
Published by:
Practical Psychology
Courtney Beatey
Reviewed by:
Courtney Beatey, B.Ed

If you're here, you're probably interested in researching developmental psychology. Have no fear because, on this page, you'll find a huge resource for everything there is to learn on the subject!

How did you become the person you are today? What roles did your parents play in this development? Could they have done anything to make you smarter, calmer, aggressive, or successful? Or does their input not matter in the grand scheme of things? Is your development all based on what is in your genetic code? 

These answers can significantly affect how you view personal development and self-esteem. If you believe you have control over your development, you may feel more confident enrolling in personal development courses or changing your life. Without control, how can we improve ourselves and the generations after us? 

I know these are big questions that often have complicated answers. Developmental psychology is a huge topic covering many theories, debates, and research areas. This video concerns developmental psychology and the people who have shaped this field since the 1800s. I’ll review how we develop, the theories surrounding these research areas, and the biggest questions developmental psychologists are still trying to answer. There is a lot to cover in one video, so buckle up!

What Is Developmental Psychology?

Developmental psychology is the study of the way that humans change, develop, and evolve over the course of their lives. The study of the change of the brain from birth to death has exploded with research in the past few decades.

Since there are so many different areas of developmental psychology out there, we will break it down for you.  

Types of Development Studied

Between the time we are born and adulthood, we have developed in many different ways. We have acquired many skills. We understand more about the world. We understand more about ourselves. 

Developmental psychology takes a look at all of the ways that we develop and age, including:

  • Cognitive development
  • Language development
  • Social development 
  • Development of sense of self and self-esteem
  • Emotional development 
  • Moral reasoning 
  • Personality development 

Developmental psychology helps us understand how we become the person we are. If there are shortcomings or developmental difficulties, these theories can help us pinpoint where things came up short and how a person can recover. 

What Are the Most Well-Known Theories in Developmental Psychology? 

Psychologists have been studying different forms of development since the late 1800s. In the late 19th century, German psychologist Wilhelm Preyer, often considered one of the pioneering developmental psychologists, authored "The Mind of the Child." In this work, he meticulously detailed his observations of his own child from birth until 2 ½.

While many psychologists began to observe children, it wasn’t long before the connection was made between child development and adult behavior. The theories that define developmental psychology today do more than just talk about children. These theories give us insight into adult decisions, behaviors, and relationships. 

Jean Piaget’s Theory of Cognitive Development 

Let’s start by talking about Piaget’s Theory of Cognitive Development. Jean Piaget was a child psychologist who observed subjects from birth until adolescence. At different ages, Piaget noted that the child developed different cognitive skills. Object permanence, for instance, is the realization that objects continue to exist even when invisible. Piaget observed that children develop object permanence between 4-7 months. 

Piaget laid out a series of stages, lasting until a child reaches the age of 12, in which cognitive development occurs.  

Lawrence Kohlberg’s Theory of Moral Development 

Piaget’s work was extremely influential in the world of developmental psychology. Lawrence Kohlberg was inspired by Piaget’s work and built upon it to formulate his own Theory of Moral Development. This theory encompasses three stages. Within each stage, individuals utilize distinct reasoning patterns to make moral judgments and determine what is “just.”

Sigmund Freud’s Theory of Psychosexual Development

Like Piaget, Sigmund Freud also formulated a development theory involving a series of stages. While most stages occur in childhood, Freud’s latent stage occurs from puberty until a person’s death. 

However, some significant differences exist between Freud’s and Piaget’s theories. Freud’s theory is concerned with a child’s psychosexual development. The child’s id is focused on a different erogenous zone at each stage. The child will experience different conflicts that end up shaping their personality. If the conflicts are overcome, and the stage is successfully completed, the child will develop a healthy personality. If there are lingering issues, the child will likely develop a fixation associated with that stage’s erogenous zone. 

​Erikson’s Theory of Psychosocial Development

Have you ever heard of the term “identity crisis?” It’s common for many people to experience an identity crisis around adolescence when they are figuring out just who they are and their role in the world. This idea was developed by Joan and Erik Erikson, two German-American psychologists who developed the Theory of Psychosocial Development. According to Erikson, eight stages of psychosocial development last from birth until old age. In each stage, a person goes through a crisis. Can they trust the world that they live in? Are they free to take action when they want to? Can they build a supportive network of friends or family? In Erikson's theory, each stage presents a psychosocial crisis that requires resolution. Successfully navigating these challenges results in acquiring a fundamental virtue (like love, hope, etc.). However, failure to adequately resolve these crises can lead to feelings of insecurity and other developmental challenges in subsequent stages of life.

Other Theories on Learning And Development 

Not all theories in developmental psychology outline stages of a person’s life. Some theories in developmental psychology merely categorize children and adults by the way in which they have developed. These theories look at the ways in which children learn about the world and relationships. 

Attachment Theory 

How do you learn how to be in a relationship: romantic, platonic, or otherwise? Many psychologists and therapists believe you learn these skills from your relationship with your parents. Psychologists John Bowlby and Mary Ainsworth observed children interacting with strangers and their parents. Some children felt secure interacting with both groups. Others showed signs of anxiety or detachment. This led to the creation of the four different Attachment Styles:

While this theory began by observing children, Attachment Theory can help adults assess their relationships and how they develop (or don’t) a secure attachment to their partners.

The Evolving Landscape of Attachment Theory and Its Impact on Adult Relationships

Attachment Theory, as introduced by psychologists John Bowlby and Mary Ainsworth, was initially rooted in understanding the bonds between infants and their caregivers. The early research observed how children responded to separation and reunion with their primary caregivers, identifying distinct attachment styles: Secure, Anxious, Avoidant, and Disorganized.

However, the realm of attachment has evolved significantly since those foundational studies. While the initial focus was on children, subsequent research has extrapolated these attachment styles to adulthood, exploring how early attachment patterns can influence romantic, platonic, and professional relationships later in life.

Attachment Styles in Adult Relationships

  1. Secure Attachment: Adults with a secure attachment style are more satisfied in their relationships. They feel comfortable with intimacy and independence, balancing the two.
  2. Anxious Attachment: Anxiously attached adults tend to be preoccupied with their relationships. They might be described as "clingy" or "needy," often fearing that their partner doesn't want to be as close as they would like.
  3. Avoidant Attachment: Those with an avoidant attachment style might seem hesitant about becoming too close to others, often trying to avoid commitment or emotional intimacy.
  4. Disorganized Attachment: This style can result in a mix of behaviors, and these individuals might fear being too close or distant from others.

Adult relationships influenced by these styles manifest in various ways. For instance, an individual with an anxious attachment might constantly seek validation from their partner or friends, fearing abandonment. In contrast, someone with an avoidant style might find it challenging to open up or commit to a relationship, often prioritizing their independence.

Furthermore, attachment styles can influence how individuals relate to others and how they view themselves. It can play into one's self-esteem, trust in others, and outlook.

Evolution of Attachment Theory

While Bowlby and Ainsworth laid the groundwork, subsequent researchers expanded and nuanced our understanding of attachment. For example, researchers like Hazan and Shaver highlighted the importance of these attachment patterns in adult romantic relationships, drawing parallels between child-caregiver bonds and romantic partnerships.

Furthermore, cultural considerations have come into play. Different cultures may prioritize different aspects of relationships, which can influence attachment patterns. For instance, cultures that highly value interdependence and community might foster different attachment behaviors than cultures emphasizing independence and autonomy.


Lev Vygotsky’s Zone of Proximal Development

Developmental psychology doesn’t just look at the way we relate to others. Many theories on learning in the classroom also stem from developmental psychology. Lev Vygotsky was a psychologist who observed how people learned new skills. He theorized that skills could be categorized into three stages: skills that a person could do without help, skills that were impossible for a person to do without assistance from another, and skills that required guidance from a more knowledgeable other (MKO.) This last zone included skills just a “step up” from skills they had already learned and acquired. This zone is known as the Zone of Proximal Development or ZPD. Every student’s ZPD is unique to their own skill set.  

Vygotsky is also associated with the Scaffolding theory, but he never coined the term himself. He created the theory of ZPD in the last three years of his life. His work, however, has become extremely influential to psychologists around the globe. Here's my article to learn more about the Zone of Proximal Development

Behavioral Development Theory 

Let’s say that as a child, you look up at the sun. It hurts your eyes. You aren’t likely to look at the sun again, right? 

Or, let’s say you use the toilet properly, and your parents give you candy. You’re going to want to use the toilet properly again, right? 

A lot of our learning comes from rewards and punishments. We like to be rewarded. We don’t like to be punished. When we associate an action with a reward, we are encouraged to do it again. 

This simple idea is where developmental psychology really began. John B. Watson was a behavioral and developmental psychologist who helped develop the behaviorism school. Utilizing the work of psychologists like B.F. Skinner and Ivan Pavlov, behaviorism became one of the leading theories in psychology. It came from well-known experiments like Pavlov’s experiments with dogs. 

These theories concluded that children learned behaviors and lessons through associations and reinforcements. 

Albert Bandura’s Social Learning Theory 

The last theory I will mention is Bandura’s Social Learning Theory. How do children learn? Sometimes, they go to school. Or, they learn through the conditioning that we just discussed. Bandura’s theory says there is more than just conditioning or textbooks. He says that children learn about the world merely through observation and modeling. His Bobo Doll experiment is one of the most famous experiments in developmental psychology. It showed that children who observed an adult being more aggressive were likelier to display aggressive behaviors. The things that a child sees, hears, and observes, Bandura concluded, will have a significant impact on the decisions the child makes and the behaviors they display. 

Debates in Developmental Psychology 

Developmental psychology theories address different development forms throughout a person’s life. However, these theories attempt to answer some general overarching questions about how we develop. 

These questions are often framed as debates. The three main debates within Developmental Psychology include: 

  • Nature vs. nurture
  • Continuity vs. discontinuity
  • Stability vs. change

Nature vs. Nurture 

What causes us to develop in one way or another? Is it the way our parents raise us? The media that we consume? The culture we grow up in? Or is it simpler than that? Can we look at genes and hereditary factors that determine our development? 

These are the questions within the nature vs. nurture debate. Nativists, on one side of the spectrum, believe that the answers to developmental psychology can be found in our biology. That gene can determine our personality and behavior. 

On the other side of the debate are empiricists. They believe that nurture determines everything. How a child is raised will determine how it behaves as an adult (Attachment Theory is an example of a theory that relies heavily on nurture.) 

This debate heavily influences parenting styles or how we assess people with particularly “bad” behavior. Do children have violent personalities because of genes, for example, or were they allowed to play violent games at a young age? 

Continuity vs. Discontinuity

You might have noticed that many theories mentioned above layout different stages of development. Freud maps out stages of psychosexual development. Erikson's theory has stages of psychosocial development. Is that how development really works? 

That’s another big question that developmental psychologists want to answer. These stages contribute to the idea of discontinuity. The discontinuity view maps out different stages and problems that children (or adults) go through when they reach a certain age. Not all children (or adults) go through these stages at the same rate, but everyone goes through these stages in the same order. 

On the other side of this debate is the continuity view. If discontinuity is a series of steps, continuity is a ramp. The continuity view sees development as something children go through based on their current skills and knowledge. They continue to build these skills as they grow taller. 

One idea associated with the Zone of Proximal Development is scaffolding. Scaffolding is the idea that children learn certain skills and then begin to build on top of those skills, like climbing a ladder. This is similar to the idea of continuity. Each child has their own ladder and develops at their own pace.   

Stability vs. Change

Have you ever heard a new parent say their baby has a calm personality? Or do they believe that their child has always been curious? This talk might just be from excited parents - or is it? 

The last debate that I’m going to talk about is stability vs. change. Do we have a stable personality established from the moment we are born? Or can the troublesome baby grow into a rule-abiding child? 

The environment a child grows up in, or care from parents, could influence a child’s personality - if personalities are subject to change. And while this sounds like the nature vs. nurture debate, it’s not exactly the same. Psychologists believe that personalities may change due to external factors, like parenting styles or trauma. They may also believe that personalities change due to maturation and internal factors. 

Ages Observed in Developmental Psychology

Many developmental psychologists observe infants and children developing into teenagers and adults. However, developmental psychology is about more than just kids. Even the “nature vs. nurture” stage impacts how adults approach personal development and change. Adults who become parents are certainly affected by developmental psychology: the approach they use to parent their children is often influenced by what psychologists say is “right” or “wrong” for a child’s development. 

And in some theories, like Erikson’s Stages of Psychosocial Development, we continue to develop and gain new virtues well into our 60s, 70s, and 80s. 

Delving Deeper into Developmental Psychology

Developmental psychology presents many theories, from Piaget's cognitive stages to Kohlberg's moral development, Erikson's psychosocial stages, and Vygotsky’s learning concepts. Each offers unique insights into human growth and behavior.

Reflecting on these theories can help us understand our actions and feelings. For example, Attachment Theory might shed light on relationship dynamics, while Erikson's stages could clarify life's broader challenges. Remember, these theories are guidelines, not absolute truths. They serve as tools for introspection and understanding, but individual experiences can vary.

For those keen on exploring further, numerous books, journals, and courses delve deeper into these subjects. Ultimately, developmental psychology offers a rich tapestry of insights, aiding in self-awareness and understanding human behavior.

Reference this article:

Practical Psychology. (2020, March). Developmental Psychology. Retrieved from

About The Author

Photo of author