Cognitive Development

Learning Objectives

  • Give examples of behavior and key vocabulary in each of Piaget’s stages of cognitive development

Cognitive Theory of Development

Jean Piaget (1896–1980) is another stage theorist who studied childhood development (Figure 1). 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 1. 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 Blake learned the schema for dogs because his family has a Labrador retriever. When Blake sees other dogs in his picture books, he says, “Look mommy, dog!” Thus, he has assimilated them into his schema for dogs. One day, Blake sees a sheep for the first time and says, “Look mommy, dog!” Having a basic schema that a dog is an animal with four legs and fur, Blake thinks all furry, four-legged creatures are dogs. When Blake’s mom tells him that the animal he sees is a sheep, not a dog, Blake must accommodate his schema for dogs to include more information based on his new experiences. Blake’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.

Link to Learning

Watch this short video clip to review the concepts of schema, assimilation and accommodation.

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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 1. 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 behavior. 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.

Watch IT

Please take a few minutes to view this brief video demonstrating different children’s ability to understand object permanence:

You can view the transcript for “Piaget – Stage 1 – Sensorimotor Stage : Object Permanence” here (opens in new window).

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, she can’t predict what her experience with that stranger will be like, which results in a fear response.

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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 he zooms 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, dad gave a slice of pizza to 10-year-old Keiko and another slice to her 3-year-old brother, Kenny. Kenny’s pizza slice was cut into five pieces, so Kenny told his sister that he got more pizza than she 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.

Watch It

This video shows a 4.5-year-old boy in the preoperational stage as he responds to Piaget’s conservation tasks.

You can view the transcript for “A typical child on Piaget’s conservation tasks” here (opens in new window).

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 Kenny and Keiko again. Keiko’s birthday is coming up, so their mom takes Kenny to the toy store to choose a present for his sister. He selects an Iron Man action figure for her, thinking that if he likes the toy, his sister will too. An egocentric child is not able to infer the perspective of other people and instead attributes his own perspective. At some point during this stage and typically between 3 and 5 years old, children come to understand that people have thoughts, feelings, and beliefs that are different from their own. This is known as theory-of-mind (TOM).

Watch It

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. Watch the Three-Mountain Task in action in this short video from the University of Minnesota and the Science Museum of Minnesota.

You can view the transcript for “Piaget’s Mountains Task” here (opens in new window).

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Piaget’s third stage is the concrete operational stage, which occurs from about 7 to 11 years old. In this stage, children can think logically about real (concrete) events; they have a firm grasp on the use of numbers and start to employ memory strategies. They can perform mathematical operations and understand transformations, such as addition is the opposite of subtraction, and multiplication is the opposite of division. In this stage, children also master the concept of conservation: Even if something changes shape, its mass, volume, and number stay the same. For example, if you pour water from a tall, thin glass to a short, fat glass, you still have the same amount of water. Remember Keiko and Kenny and the pizza? How did Keiko know that Kenny was wrong when he said that he had more pizza?

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).

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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. Children in this stage can use abstract thinking to problem solve, look at alternative solutions, and test these solutions. In adolescence, a renewed egocentrism occurs. For example, a 15-year-old with a very small pimple on her face might think it is huge and incredibly visible, under the mistaken impression that others must share her perceptions.

Beyond Formal Operational Thought

As with other major contributors of theories of development, several of Piaget’s ideas have come under criticism based on the results of further research. For example, 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.

It seems that once we reach adulthood our problem solving abilities change: As we attempt to solve problems, 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.

Connect the concepts


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 behavior 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 (i.e., attenuating temperament), body (i.e., may be less prone to high blood pressure), and social environment (i.e., may seek people who are similar to them).

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Think It Over

Explain how you would use your understanding of one of the major developmental theories (psychosexual, psychosocial, or cognitive) to deal with each of the difficulties listed below:

  1. Your infant daughter puts everything in her mouth, including the dog’s food.
  2. Your eight-year-old son is failing math; all he cares about is baseball.
  3. Your two-year-old daughter refuses to wear the clothes you pick for her every morning, which makes getting dressed a twenty-minute battle.
  4. Your sixty-eight-year-old neighbor is chronically depressed and feels she has wasted her life.
  5. Your 18-year-old daughter has decided not to go to college. Instead she’s moving to Colorado to become a ski instructor.
  6. Your 11-year-old son is the class bully.


assimilation: adjustment of a schema by adding information similar to what is already known
accommodation: adjustment of a schema by changing a scheme to accommodate new information different from what was already known
concrete operational stage: third stage in Piaget’s theory of cognitive development; from about 7 to 11 years old, children can think logically about real (concrete) events
conservation: idea that even if you change the appearance of something, it is still equal in size, volume, or number as long as nothing is added or removed
egocentrism: preoperational child’s difficulty in taking the perspective of others
formal operational stage: final stage in Piaget’s theory of cognitive development; from age 11 and up, children are able to deal with abstract ideas and hypothetical situations
object permanence: idea that even if something is out of sight, it still exists
preoperational stage: second stage in Piaget’s theory of cognitive development; from ages 2 to 7, children learn to use symbols and language but do not understand mental operations and often think illogically
reversibility: understanding that objects can be changed and then returned back to their original form or condition
schema: (plural = schemata) concept (mental model) that is used to help us categorize and interpret information
sensorimotor stage: first stage in Piaget’s theory of cognitive development; from birth through age 2, a child learns about the world through senses and motor behavior
theory-of-mind: the understanding that people have thoughts, feelings, and beliefs that are different from our own


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