81 Theories of Development

Learning Objectives

By the end of this section, you will be able to:

  • Discuss Freud’s theory of psychosexual development
  • Describe the major tasks of child and adult psychosocial development according to Erikson
  • Discuss Piaget’s view of cognitive development and apply the stages to understanding childhood cognition
  • Describe Kohlberg’s theory of moral development
  • Compare and contrast the strengths and weaknesses of major developmental theories

There are many theories regarding how babies and children grow and develop into happy, healthy adults. We explore several of these theories in this section.

Psychosexual Theory of Development

Sigmund Freud (1856–1939) believed that personality develops during early childhood. For Freud, childhood experiences shape our personalities and behaviour as adults. Freud viewed development as discontinuous; he believed that each of us must pass through a series of stages during childhood, and that if we lack proper nurturance and parenting during a stage, we may become stuck, or fixated, in that stage. Freud’s stages are called the stages of psychosexual development. According to Freud, children’s pleasure-seeking urges are focused on a different area of the body, called an erogenous zone, at each of the five stages of development: oral, anal, phallic, latency, and genital.

While most of Freud’s ideas have not found support in modern research, we cannot discount the contributions that Freud has made to the field of psychology. Psychologists today dispute Freud’s psychosexual stages as a legitimate explanation for how one’s personality develops, but what we can take away from Freud’s theory is that personality is shaped, in some part, by experiences we have in childhood. These stages are discussed in detail in the chapter on personality.

Psychosocial Theory of Development

Erik Erikson (1902–1994) (Figure LD.4), another stage theorist, took Freud’s theory and modified it as psychosocial theory. Erikson’s psychosocial development theory emphasizes the social nature of our development rather than its sexual nature. While Freud believed that personality is shaped only in childhood, Erikson proposed that personality development takes place all through the lifespan. Erikson suggested that how we interact with others is what affects our sense of self, or what he called the ego identity.


A photograph depicts Erik Erikson in his later years.
Figure LD.4 Erik Erikson proposed the psychosocial theory of development. In each stage of Erikson’s theory, there is a psychosocial task that we must master in order to feel a sense of competence.

Erikson proposed that we are motivated by a need to achieve competence in certain areas of our lives. According to psychosocial theory, we experience eight stages of development over our lifespan, from infancy through late adulthood. At each stage there is a conflict, or task, that we need to resolve. Successful completion of each developmental task results in a sense of competence and a healthy personality. Failure to master these tasks leads to feelings of inadequacy.

According to Erikson (1963), trust is the basis of our development during infancy (birth to 12 months). Therefore, the primary task of this stage is trust versus mistrust. Infants are dependent upon their caregivers, so caregivers who are responsive and sensitive to their infant’s needs help their baby to develop a sense of trust; their baby will see the world as a safe, predictable place. Unresponsive caregivers who do not meet their baby’s needs can engender feelings of anxiety, fear, and mistrust; their baby may see the world as unpredictable.

As toddlers (ages 1–3 years) begin to explore their world, they learn that they can control their actions and act on the environment to get results. They begin to show clear preferences for certain elements of the environment, such as food, toys, and clothing. A toddler’s main task is to resolve the issue of autonomy versus shame and doubt, by working to establish independence. This is the “me do it” stage. For example, we might observe a budding sense of autonomy in a 2-year-old child who wants to choose their clothes and dress themselves. Although their outfits might not be appropriate for the situation, their input in such basic decisions has an effect on their sense of independence. If denied the opportunity to act on their environment, they may begin to doubt their abilities.

Once children reach the preschool stage (ages 3–6 years), they are capable of initiating activities and asserting control over their world through social interactions and play. According to Erikson, preschool children must resolve the task of initiative versus guilt. By learning to plan and achieve goals while interacting with others, preschool children can master this task. Those who do will develop self-confidence and feel a sense of purpose.

During the elementary school stage (ages 7–11), children face the task of industry versus inferiority. Children begin to compare themselves to their peers to see how they measure up. They either develop a sense of pride and accomplishment in their schoolwork, sports, social activities, and family life, or they feel inferior and inadequate when they don’t measure up.

In adolescence (ages 12–18), children face the task of identity versus role confusion. According to Erikson, an adolescent’s main task is developing a sense of self. Adolescents struggle with questions such as “Who am I?” and “What do I want to do with my life?” Along the way, most adolescents try on many different selves to see which ones fit. Adolescents who are successful at this stage have a strong sense of identity and are able to remain true to their beliefs and values in the face of problems and other people’s perspectives. Others might feel unsure of their identity and confused about the future.

People in early adulthood (i.e., 20s through early 40s) are concerned with intimacy versus isolation. After we have developed a sense of self in adolescence, we are ready to share our life with others. Erikson said that we must have a strong sense of self before developing intimate relationships with others.

When people reach their 40s, they enter the time known as middle adulthood, which extends to the mid-60s. The social task of middle adulthood is generativity versus stagnation. Generativity involves finding your life’s work and contributing to the development of others, through activities such as volunteering, mentoring, and raising children.

Erikson’s final stage is from mid-60s to the end of life, which is concerned with integrity versus despair. He said that people in late adulthood reflect on their lives and feel either a sense of satisfaction or a sense of failure. People who feel proud of their accomplishments feel a sense of integrity, and they can look back on their lives with few regrets. However, people who are not successful at this stage may feel as if their life has been wasted. Table LD.1 summarizes the stages of Erikson’s theory.

Table LD.1 Erikson’s Psychosocial Stages of Development
Stage Age (years) Developmental Task Description
1 0–1 Trust vs. mistrust Trust (or mistrust) that basic needs, such as nourishment and affection, will be met
2 1–3 Autonomy vs. shame/doubt Develop a sense of independence in many tasks
3 3–6 Initiative vs. guilt Take initiative on some activities—may develop guilt when unsuccessful or boundaries overstepped
4 7–11 Industry vs. inferiority Develop self-confidence in abilities when competent or sense of inferiority when not
5 12–18 Identity vs. confusion Experiment with and develop identity and roles
6 19–29 Intimacy vs. isolation Establish intimacy and relationships with others
7 30–64 Generativity vs. stagnation Contribute to society and be part of a family
8 65– Integrity vs. despair Assess and make sense of life and meaning of contributions

Cognitive Theory of Development

Jean Piaget (1896–1980) is another stage theorist who studied childhood development (Figure LD.5). Instead of approaching development from a psychoanalytical or psychosocial perspective, Piaget focused on children’s cognitive growth. He believed that thinking is a central aspect of development and that children are naturally inquisitive. However, he said that children do not think and reason like adults (Piaget, 1930, 1932). His theory of cognitive development holds that our cognitive abilities develop through specific stages, which exemplifies the discontinuity approach to development. As we progress to a new stage, there is a distinct shift in how we think and reason.


A photograph depicts Jean Piaget in his later years.
Figure LD.5 Jean Piaget spent over 50 years studying children and how their minds develop.

Piaget said that children develop schemata to help them understand the world. Schemata are concepts (mental models) that are used to help us categorize and interpret information. By the time children have reached adulthood, they have created schemata for almost everything. When children learn new information, they adjust their schemata through two processes: assimilation and accommodation. First, they assimilate new information or experiences in terms of their current schemata: assimilation is when they take in information that is comparable to what they already know. Accommodation describes when they change their schemata based on new information. This process continues as children interact with their environment.

For example, 2-year-old Majd learned the schema for dogs because his family has a Labrador retriever. When Majd sees other dogs in his picture books, he says to his parents, “Dog!” So Majd has assimilated them into his schema for dogs. One day, Majd sees a sheep for the first time and says to his parent, “Dog!” Having a basic schema that a dog is an animal with four legs and fur, Majd thinks all furry, four-legged creatures are dogs. When Majd’s parent tells him that the animal he sees is a sheep, not a dog, Majd must accommodate his schema for dogs to include more information based on his new experiences. Majd’s schema for dog was too broad, since not all furry, four-legged creatures are dogs. He now modifies his schema for dogs and forms a new one for sheep.

Like Freud and Erikson, Piaget thought development unfolds in a series of stages approximately associated with age ranges. He proposed a theory of cognitive development that unfolds in four stages: sensorimotor, preoperational, concrete operational, and formal operational (Table LD.2).

Table LD.2 Piaget’s Stages of Cognitive Development
Age (years) Stage Description Developmental issues
0–2 Sensorimotor World experienced through senses and actions Object permanence
Stranger anxiety
2–6 Preoperational Use words and images to represent things, but lack logical reasoning Pretend play
Language development
7–11 Concrete operational Understand concrete events and analogies logically; perform arithmetical operations Conservation
Mathematical transformations
12– Formal operational Formal operations
Utilize abstract reasoning
Abstract logic
Moral reasoning
The first stage is the sensorimotor stage, which lasts from birth to about 2 years old. During this stage, children learn about the world through their senses and motor behaviour. Young children put objects in their mouths to see if the items are edible, and once they can grasp objects, they may shake or bang them to see if they make sounds. Between 5 and 8 months old, the child develops object permanence, which is the understanding that even if something is out of sight, it still exists (Bogartz, Shinskey, & Schilling, 2000). According to Piaget, young infants do not remember an object after it has been removed from sight. Piaget studied infants’ reactions when a toy was first shown to an infant and then hidden under a blanket. Infants who had already developed object permanence would reach for the hidden toy, indicating that they knew it still existed, whereas infants who had not developed object permanence would appear confused.

Link to Learning

Watch this brief video demonstrating different children’s abilities to understand object permanence to learn more.

In Piaget’s view, around the same time children develop object permanence, they also begin to exhibit stranger anxiety, which is a fear of unfamiliar people. Babies may demonstrate this by crying and turning away from a stranger, by clinging to a caregiver, or by attempting to reach their arms toward familiar faces such as parents. Stranger anxiety results when a child is unable to assimilate the stranger into an existing schema; therefore, the child can’t predict what their experience with that stranger will be like, which results in a fear response.

Piaget’s second stage is the preoperational stage, which is from approximately 2 to 7 years old. In this stage, children can use symbols to represent words, images, and ideas, which is why children in this stage engage in pretend play. A child’s arms might become airplane wings as they zoom around the room, or a child with a stick might become a brave knight with a sword. Children also begin to use language in the preoperational stage, but they cannot understand adult logic or mentally manipulate information (the term operational refers to logical manipulation of information, so children at this stage are considered to be pre-operational). Children’s logic is based on their own personal knowledge of the world so far, rather than on conventional knowledge. For example, a parent gave a slice of pizza to 10-year-old Hatsu and another slice to their 3-year-old sibling, Rei. Rei’s pizza slice was cut into five pieces, so Rei told their sibling that they got more pizza than Hatsu did. Children in this stage cannot perform mental operations because they have not developed an understanding of conservation, which is the idea that even if you change the appearance of something, it is still equal in size as long as nothing has been removed or added.

Link to Learning

Watch this video of a boy in the pre-operational stage, responding to Piaget’s conservation tasks, to learn more.

During this stage, we also expect children to display egocentrism, which means that the child is not able to take the perspective of others. A child at this stage thinks that everyone sees, thinks, and feels just as they do. Let’s look at Rei and Hatsu again. Hatsu’s birthday is coming up, so their parents take Rei to the toy store to choose a present for their sibling. They select an Iron Man action figure for Hatsu, thinking that if they like the toy, their sibling will too. An egocentric child is not able to infer the perspective of other people and instead attributes their own perspective.

Link to Learning

Watch this short video, from the University of Minnesota, of the three-mountain task in action. Piaget developed the Three-Mountain Task to determine the level of egocentrism displayed by children. Children view a 3-dimensional mountain scene from one viewpoint, and are asked what another person at a different viewpoint would see in the same scene.

Children in the concrete operational stage also understand the principle of reversibility, which means that objects can be changed and then returned back to their original form or condition. Take, for example, water that you poured into the short, fat glass: You can pour water from the fat glass back to the thin glass and still have the same amount (minus a couple of drops).

The fourth, and last, stage in Piaget’s theory is the formal operational stage, which is from about age 11 to adulthood. Whereas children in the concrete operational stage are able to think logically only about concrete events, children in the formal operational stage can also deal with abstract ideas and hypothetical situations. This is because they tend to think more flexibly and creatively. Children in this stage can use abstract thinking to problem solve, look at alternative solutions, and test these solutions.

Beyond Formal Operational Thought

As with other major contributors of theories of development, several of Piaget’s ideas have come under criticism, several contemporary studies support a model of development that is more continuous than Piaget’s discrete stages (Courage & Howe, 2002; Siegler, 2005, 2006). Many others suggest that children reach cognitive milestones earlier than Piaget describes (Baillargeon, 2004; de Hevia & Spelke, 2010).

According to Piaget, the highest level of cognitive development is formal operational thought, which develops between 11 and 20 years old. However, many developmental psychologists disagree with Piaget, suggesting a fifth stage of cognitive development, known as the postformal stage (Basseches, 1984; Commons & Bresette, 2006; Sinnott, 1998). In postformal thinking, decisions are made based on situations and circumstances, and logic is integrated with emotion as adults develop principles that depend on contexts. One way that we can see the difference between an adult in postformal thought and an adolescent in formal operations is in terms of how they handle emotionally charged issues.

In adulthood problem-solving abilities typically change, we tend to think more deeply about many areas of our lives, such as relationships, work, and politics (Labouvie-Vief & Diehl, 1999). Because of this, postformal thinkers are able to draw on past experiences to help them solve new problems. Problem-solving strategies using postformal thought vary, depending on the situation. What does this mean? Adults can recognize, for example, that what seems to be an ideal solution to a problem at work involving a disagreement with a colleague may not be the best solution to a disagreement with a significant other.


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Everyday Connection


The genetic environmental correlation you’ve learned about concerning the bidirectional influence of genes and the environment has been explored in more recent theories (Newcombe, 2011). One such theory, neuroconstructivism, suggests that neural brain development influences cognitive development. Experiences that a child encounters can impact or change the way that neural pathways develop in response to the environment. An individual’s behaviour is based on how one understands the world. There is interaction between neural and cognitive networks at and between each level, consisting of these:

  • genes
  • neurons
  • brain
  • body
  • social environment

These interactions shape mental representations in the brain and are dependent on context that individuals actively explore throughout their lifetimes (Westermann, Mareschal, Johnson, Sirois, Spratling, & Thomas, 2007).

An example of this would be a child who may be genetically predisposed to a difficult temperament. They may have parents who provide a social environment in which they are encouraged to express themselves in an optimal manner. The child’s brain would form neural connections enhanced by that environment, thus influencing the brain. The brain gives information to the body about how it will experience the environment. Thus, neural and cognitive networks work together to influence genes (e.g., attenuating temperament), body (e.g., may be less prone to high blood pressure), and social environment (e.g., may seek people who are similar to them).

Sociocultural Theory of Development

Lev Vygotsky was a Russian psychologist who proposed a sociocultural theory of development. He suggested that human development is rooted in one’s culture. A child’s social world, for example, forms the basis for the formation of language and thought. The language one speaks and the ways a person thinks about things is dependent on one’s cultural background. Vygotsky also considered historical influences as key to one’s development. He was interested in the process of development and the individual’s interactions with their environment (John-Steiner & Mahn, 1996)

Moral Theory Of Development

A major task beginning in childhood and continuing into adolescence is distinguishing right from wrong. Lawrence Kohlberg (1927–1987) attempted to extend Piaget’s ideas about stages of cognitive development to moral development, suggesting that morality too was developed over a series of stages throughout life. To develop this theory, Kohlberg posed moral dilemmas to people of all ages and placed them in particular stages based upon analysis of their answers.  Using this framework, Kohlberg claimed that more males than females reach higher stages and that females seem to be deficient in their moral reasoning abilities (1969). Carol Gilligan, who worked with Kohlberg, challenged his framework interpretations in her book In a Different Voice: Psychological Theory and Women’s Development (1982).Kohlberg studied predominantly upper-middle class, white, male-identified people and Gilligan pointed out the obvious bias inherent in basing a theory on such a narrowly defined group of people. Using female-identified participants, she redefined Kohlberg’s stages to allow moral problems to be considered from different perspectives.

Although an improvement over Kohlberg’s theories, the dilemma-based tasks used by Gilligan assessed moral reasoning, which is different from moral behaviour. Sometimes what we say we’d do in a situation is not what we actually do. We might “talk the talk,” but not “walk the walk.” So, how exactly does one define moral behaviour? The definition of what makes a “good person” has long been the subject of philosophical debate and is unlikely to reach consensus anytime soon. As a tool for measuring moral development, neither Kohlberg’s nor Gilligan’s dilemmas are feasible in young children, who do not have the language comprehension required for these tests. In fact, Kohlberg lumped all children under the age of 10 in the same level of moral development.

An alternative approach is to measure specific components of morality which are easier to define, like prosocial behaviour, defined as any behaviour done with the intention of benefiting someone else. This includes acts such as helping, consoling, and sharing, and can be assessed using simple behavioural tests. For example, participants can be asked to allocate resources to themselves and others under different conditions. Research using these simpler tasks has revealed that helping behaviour and sharing are evident in children as young as 2 years old, and that the nature of these prosocial behaviours changes over the course of development (Warneken & Tomasello, 2006; Williams et al., 2014).

One 2019 study compared rates at which infants demonstrated prosocial behaviours across three different age ranges; 16-, 19-, and 24-months-old. To do this, infants were placed in a situation where a researcher, using verbal communication and body language, indicated they needed help with a basic task, such as finding a hidden toy. They then recorded infants’ prosocial behaviour according to three different categories; instrumental helping (such as offering the researcher a different object), comforting (such as hugging the upset researcher), and indirect helping (such as asking another adult in the room for help). The study found that 24-month old children were significantly more likely to demonstrate prosocial behaviours than the 16- and 19-month olds, particularly when it came to comforting. This suggests that the second year of life is an extremely important period in the development of this important component of morality (Walle et al., 2019).

This approach remedies some of the problems with Kohlberg’s studies in that he didn’t specifically define specific “good” or “bad” behaviours. Rather he assumed his own ideas about good versus bad behaviour were true and incorporated these assumptions into the design of his studies. Therefore, the outcomes of Kohlberg’s studies were strongly influenced by his culturally informed ideas about morality. By instead focusing on one aspect of morality, like prosocial behaviour described above, it allows researchers to assess developmental changes without judging this aspect as morally good or bad. This approach also ensures that judgements about what constitutes “good” behaviour doesn’t colour the scientific data being collected or the design of the studies being done.


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Introduction to Psychology & Neuroscience (2nd Edition) Copyright © 2020 by Edited by Leanne Stevens, Jennifer Stamp, & Kevin LeBlanc is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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