1.1 Piaget's Theory of Cognitive Development

“In order for a child to understand something, he must construct it himself.”

— Jean Piaget1

Drawing on his observations of children, Swiss psychologist Jean Piaget (1896-1980) developed a groundbreaking theory of cognitive development that included four distinct stages. Piaget theorized that people construct knowledge and meaning from their experiences of the world–a concept known as constructivism.

Key Concepts from Piaget's Congitive Development Theory

Excerpt from LIS 516: Youth Development and Behavior in a Digital Age by Dr. Katie Davis and the University of Washington


Dr. Katie Davis, University of Washington

People organize what they learn from their experiences into mental frameworks called schemas that help them make sense of the world. Fourteen-year-old Julia has developed schemas around what she and her peers consider on trend or out of style. She also has schemas for gender roles (girls can’t ask boys out) and what career paths are available to her (girls aren’t good at math, so she shouldn’t consider a STEM career).
We assimilate new information into our existing schemas.Julia grew up in a community mostly populated by people of a similar background. She has created schemas about people from another ethnic group based on TV, movies, and things she’s heard people say. When she reads something that fits with this stereotype, she absorbs or assimilates it into her existing schema.
We accommodate new information that doesn’t fit into our schemas by altering our beliefs. Julia’s family moves to a new town and she enters a high school with students from many different ethnic and cultural backgrounds. Her interactions with new friends may result in experiences that do not fit into her existing schemas, prompting her to change or alter her beliefs to accommodate the new information.

Stages of Cognitive Development

Instead of viewing children as miniature adults — a common attitude in his time — Piaget theorized that intellectual growth moves through a series of stages:

  • Sensorimotor (birth to around age 2): Reasoning is largely dependent on perception. Babies’ senses help them understand and experiment with their environment, and they use their eyes, mouths, and hands to learn more about objects.
  • Preoperational (around ages 2 to 7): Children can mentally represent objects and events without needing to use senses like touching, hearing, or seeing. For example, in this stage children might pretend a block is a phone, and interact with it the way they would with a real phone.
  • Concrete operational (around ages 7 to 11): Children can perform inductive reasoning around concrete objects — that is, they can logically generalize from a specific experience. For instance, if they sneeze a lot around their friend’s dog, they may conclude that they will be allergic to other dogs as well.
  • Formal operational (adolescence to adulthood): Teens and tweens start to be able to reason logically about abstract concepts like algebra, social justice, or freedom. They may begin to think more critically about moral or ethical issues, such as norms in an online community or principles regarding right or wrong. They are able to devise their own solutions and answers to problems without needing firsthand experience.


Researchers are finding that Piaget may have overestimated the reasoning skills of teens. Abstract and creative reasoning may exist in the teenage years, but recent research has found that the brain continues to develop up until the age of 25!2

Putting Cognitive Development Theory Into Practice

Most tweens and teens will be in the concrete operational stage or the early formal operational stage. They can reason logically and apply specific knowledge to general contexts. They are probably moving towards or have already started applying logic and morality to abstract concepts, and constructing their own solutions to individual and societal problems. Ask yourself the following questions about your teen programming and services:

  • What relevant cognitive schemas do the participants have? Do they reflect reality or are they skewed or distorted?
  • Will the teens assimilate what they learn, or will they have to accommodate new information?
  • Can you relate your program or activities to abstract societal issues, or should you focus on more concrete ideas?
  • Are your participants in the early formal operational stage? If so, can you help them develop further by integrating abstract concepts with the help of scaffolding (see Section 2: Vygotsky’s Sociocultural Learning Theory)?


Jane, a youth librarian, is creating a program for exploring STEM careers. She will be offering one version of the program for children ages 9 to 11, and another one for ages 12 to 18. What differences will there be between the two versions if Jane takes the participants’ stages of cognitive development into consideration while designing the program? 


Match the following situations with the type of thinking they represent: sensorimotor, pre-operational, concrete operational, or formal operational.

  1. Knowing that a graham cracker broken in half is still the same amount of graham cracker (not twice as much)
  2. Understanding how much different books weigh by picking them up
  3. Creating a list of potential impacts that a new library policy might have on teens
  4. Pretending a french fry is an airplane
  1. Concrete Operational: Understanding that a graham cracker broken in half is still the same amount of graham cracker (not twice as much)
  2. Sensorimotor: Understanding how much different books weigh by picking them up
  3. Formal Operational: Creating a list of potential impacts that a new library policy might have on teens
  4. Preoperational: Pretending a french fry is an airplane

test your knowledge

Jane had noticed that younger tweens were not usually able to discuss abstract concepts as well as older teens, and formed a schema regarding reasoning skills at different ages. Then she learned about Piaget and the stages of cognitive development. Will she assimilate or accommodate the new information?

Ideally, Jane will assimilate this new information. It does not appear to contradict her existing schema; rather, it adds to what she already believes.

1: Piers, M. W., Ed. (1972). Play and Development. New York, NY: Norton.

2: Johnson, S. B., Blum, R. W., & Giedd, J. N. (2009). Adolescent maturity and the brain: the promise and pitfalls of neuroscience research in adolescent health policy. Journal of Adolescent Health, 45(3), 216-221.