Jean Piaget’s Cognitive Theory: Conservation, Classification, & Seriation

Photo Credit: Steemit  By Dr. Monique M. Chouraeshkenazi

Photo Credit: Steemit

By Dr. Monique M. Chouraeshkenazi

        Piaget’s cognitive development theory is a theoretical framework established in the 1930s by Swiss psychologist, Jean Piaget. Based on the natural development of human intelligence, Piaget’s theory focuses on specific actions of individuals and how they interact within their internal and external environments (Nance, 2017). The paradigm also compares the minds of children to adults because social and cognitive development is understood in different facets, as it relates to stages of cognitive progression. Social Worker, Angela Oswalt states “infants and young children understand the world much different than adults do, and as they play and explore, their mind learn how to think in way that better fits with reality” (n.d., para. 1). Additionally, Piaget’s theory is based on four stages of development: sensorimotor, pre-operational, concrete operational, and formal operational (McLeod, 2015). And such stages are predicated on the development of children’s thoughts and ideas through mental progression. This week’s topic will focus on the concrete operation stage, which centralizes on the primary concepts involving cognitive development.

Concrete Operational Stage

        The concrete operational stage is the third phase of Piaget’s theory and is a considerable transition process of a child’s intellectual development progression because it begins “logical or operational thought” (McLeod, 2015). In other words, children began to work out problems and find solutions without the use of physical objects or other things to assist their thought process and rely on rationale thinking to make decisions. Children are quite young during this stage (between seven and 11), so it is imperative to observe progression within internal and external environments. According to Saul McLeod (2010), during the concrete operational stage, children are maturing, forming opinions, understanding reasonable thinking methodologies, and conservation.

Three Phases

        The concrete operational phase focuses on the three elements: conservation, classification, and seriation. Conservation is the concept of things staying the same even though other elements change, which is based on rational thinking. Per Piaget’s theory, conservation, or logical thinking, should be apparent during the concrete operational stage and the maturing age is between the ages of seven and eleven (McLeod, 2010). An example of understanding conservation would be a child’s ability to identify two identical objects as the same no matter the order, placement, or location. I watched two videos of two children who were tested on the conservation stage. The boy was approximately four years old and the girl was about eight or nine. They both were tested on equal amounts of liquid in a glass (the same size and shape). Both agreed that the glass with the blue substance was an equal amount in both glasses. When the instructors poured one of the glasses of liquid in taller glasses, there were two different answers. The boy told the instructor the liquid poured in the taller glass had more liquid. He believed this because the glass was bigger (i.e. taller), so the amount of liquid increased. The girl stated the amount of liquid was still the same because it did not matter what object the liquid was poured into since it was established in the beginning both glasses contained equal amounts. This example shows the perception of two children of different ages and how they understand conservation. It is important when children are older to understand this concept because it is more than just logical reasoning; instead it is also based on learning experience and education, such as math and science (i.e. numbers, length, liquid, mass, area, weight, and volume) (Epstein, 2014).

        Classification is simply grouping properties as it relates to other types. This is an important concept for kids to comprehend, especially to solve problems. An example of classification would be a child’s ability to group specific objects based on color, shape, size, amount, and/or similarities. It is very important children understand classification because it is a concept of knowing what is different and what is the same. Authors Jeppson and Myers-Walls state children initially classify objects on what they see, hear, and feel and it takes time to understand other elements beyond this (n.d., para. 2.). As children’s cognitive development progresses, they will learn how some objects belong together as well as the purpose of each. Finally, there is seriation, which is the ability to group objects based on height, weight, and/or importance. An example of a seriation exercise would be: children putting objects in order from short to tall, thin to big, small to large, or of importance, and so forth. Because seriation deals with size, weight, or magnitude, this is a very important concept to master for children to learn in school, especially in math and science.


        Piaget’s theory includes three important phases that are indicative of the concrete operation stage in cognitive development. Conservation, classification, and seriation are essential phases that are responsible for a child’s cognitive progression. Based on logical thinking, distinction, and organization, the three phrases are considered mature elements that children should understand between the ages of seven and eleven, which are responsible for expanding their mental capabilities. It is important that each phase is taught to children so they can understand the world around them. Internal and external environments are critical to children’s cognitive progression and if not taught, could impair their intellectual capacity to rationalize, comprehend, and make decisions.



Epstein, V. (2014). Conservation tasks. What Piaget taught me about children. Parenting and Mentoring. Retrieved from (accessed on 1 March 2018).

Jeppson, J. & Myers-Walls, PhD, CFLE, J. A. (n.d.). Understanding same and different (classification). Purdue University. Retrieved from (accessed on 1 March 2018).

McLeod, S. (2015). Jean Piaget. Simply Psychology. Retrieved from (accessed on 1 March 2018).

McLeod, S. (2010). Concrete Operational Stage. Retrieved from (accessed on 1 March 2018).

Nance, S. (2017). Conservation psychology and its relationship with other fields of sciences. Conservation Psychology. Retrieved from (accessed on 1 March 2018).

Oswalt, A. (n.d.). Child & adolescent development: Overview Jean Piaget and child development. Gulf Bend Center. Retrieved from (accessed 1 March 2018).