The Formal Operational Stage of Cognitive Development

The formal operational stage is the fourth and final stage of Jean Piaget's theory of cognitive development. It begins at approximately age 12 and lasts into adulthood.

At this point in development, thinking becomes much more sophisticated and advanced. Kids can think about abstract and theoretical concepts and use logic to come up with creative solutions to problems. Skills such as logical thought, deductive reasoning, and systematic planning also emerge during this stage.

formal operational stage of cognitive development
Illustration by Brianna Gilmartin, Verywell

Piaget's Research

Piaget tested formal operational thought in a few different ways. Two of the better-known tests explored physical conceptualization and the abstraction of thought.

Conceptualizing Balance

One task involved having children of different ages balance a scale by hooking weights on each end. To balance the scale, the children needed to understand that both the heaviness of the weights and distance from the center played a role.

Younger children around the ages of 3 and 5 were unable to complete the task because they did not understand the concept of balance. Seven-year-olds knew that they could adjust the scale by placing weights on each end, but failed to understand that where they put the weights was also important. By age 10, the kids considered location as well as weight but had to arrive at the correct answer using trial-and-error.

It wasn't until around age 13 that children could use logic to form a hypothesis about where to place the weights to balance the scale and then complete the task.

Abstraction of Ideas

In another experiment on formal operational thought, Piaget asked children to imagine where they would want to place a third eye if they had one. Younger children said that they would put the imagined third eye in the middle of their forehead. Older children, however, were able to come up with a variety of creative ideas about where to place this hypothetical eye and various ways the eye could be used.

For example, an eye in the middle of one's hand would be useful for looking around corners. An eye at the back of one's head could be helpful for seeing what is happening in the background.

Creative ideas represent the use of abstract and hypothetical thinking, both important indicators of formal operational thought.

Deductive Logic

Piaget believed that deductive reasoning becomes necessary during the formal operational stage. Deductive logic requires the ability to use a general principle to determine a particular outcome. Science and mathematics often require this type of thinking about hypothetical situations and concepts.

Abstract Thought

While children tend to think very concretely and specifically in earlier stages, the ability to think about abstract concepts emerges during the formal operational stage. Instead of relying solely on previous experiences, children begin to consider possible outcomes and consequences of actions. This type of thinking is important in long-term planning.


In earlier stages, children used trial-and-error to solve problems. During the formal operational stage, the ability to systematically solve a problem in a logical and methodical way emerges. Children at the formal operational stage of cognitive development are often able to plan quickly an organized approach to solving a problem.

Hypothetical-Deductive Reasoning

Piaget believed that what he referred to as "hypothetical-deductive reasoning" was essential at this stage of intellectual development. At this point, teens become capable of thinking about abstract and hypothetical ideas. They often ponder "what-if" type situations and questions and can think about multiple solutions or possible outcomes.

While kids in the previous stage (concrete operations) are very particular in their thoughts, kids in the formal operational stage become increasingly abstract in their thinking.

As children gain greater awareness and understanding of their own thought processes, they develop what is known as metacognition, or the ability to think about their thoughts as well as the ideas of others.

Current Observations

The following observations were made about the formal operational stage of cognitive development:

  • From Neil J. Salkind, Ph.D., author of An Introduction to Theories of Human Development: "The formal operational thinker has the ability to consider many different solutions to a problem before acting. This greatly increases efficiency, because the individual can avoid potentially unsuccessful attempts at solving a problem. The formal operational person considers past experiences, present demands, and future consequences in attempting to maximize the success of his or her adaptation to the world."
  • From Christine Brain and Priscilla Mukherji, authors of Understanding Child Psychology: "In the formal operational stage, actual (concrete) objects are no longer required and mental operations can be undertaken 'in the head' using abstract terms. For example, children at this stage can answer questions such as: 'if you can imagine something made up of two quantities, and the whole thing remains the same when one quantity is increased, what happens to the second quantity?' This type of reasoning can be done without thinking about actual objects."
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Article Sources
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  1. Zeinstra GG, Koelen MA, Kok FJ, de Graaf C. Cognitive development and children's perceptions of fruit and vegetables; a qualitative study. Int J Behav Nutr Phys Act. 2007;4:30. Published 2007 Jul 9. doi:10.1186/1479-5868-4-30

  2. Berger KS. The Developing Person Through Childhood and Adolescence. Macmillan; 2008.

  3. Duchesne DS, McMaugh DA. Educational Psychology for Learning and Teaching. Cengage AU; 2018.

  4. Salkind NJ. An Introduction to Theories of Human Development. SAGE; 2004.

  5. Brain C, Mukherji P. Understanding Child Psychology. Nelson Thornes; 2005.

Additional Reading
  • Piaget, J. (1977). Gruber, H.E.; Voneche, J.J. eds. The essential Piaget. New York: Basic Books.

  • Piaget, J. (1983). Piaget's theory. In P. Mussen (ed). Handbook of Child Psychology. 4th edition. Vol. 1. New York: Wiley.

  • Santrock, John W. (2008). A topical approach to life-span development (4 ed.). New York City: McGraw-Hill.