Understanding Seriation in Piaget’s Theory of Cognitive Development

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What is Seriation in Piaget’s Theory?

Seriation in Piaget's theory refers to sorting things or ideas by size, color, shape, or type. It helps children organize thoughts and solve problems logically, which is important for their learning and understanding of how the world works.

Beyond conservation, Piaget also believed that children in middle childhood master hierarchical classification; the ability to simultaneously sort things into general and more specific groups, using different types of comparisons. Most children develop hierarchical classification abilities between the ages of 7 and 10. For example, kids who collect superhero trading cards might be able to sort their cards by good-guy/bad-guy status, gender, and particular category of superhero powers. The ability to perform hierarchical classification is very useful to children in school, as they begin to understand and appreciate science and social studies concepts that involve making just such comparisons, for instance, sorting living creatures into different groups based on whether they are animals or plants, etc.

What is Seriation?


Seriation involves the ability to put things in order based on quantity or magnitude. When we count numbers in order, we are demonstrating our ability to seriate, because numbers represent in abstract or generic form, specific quantities of things. When we count numbers in order, we are counting numbers in such a way as to arrange them so that the number we name immediately after another number will always represent a larger quantity of things than the previous number did. 

In the laboratory, Piaget tested children's seriation by showing that they could arrange sticks of different lengths into order from the smallest to the largest. However, children might also demonstrate their mastery of seriation by spontaneously arranging their stuffed animals or army toys from smallest to biggest on their bedroom shelf.

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In daily life, children often use their seriation skills in school contexts. Seriation is a fundamental ability, without which children cannot progress in math and science. You cannot appreciate what it means to measure the length or mass of something, for example (measurement being fundamental to all scientific endeavors) if you are incapable of reliably arranging things in order of their magnitude.

Piaget’s Theory: The Role of Seriation

Piaget's stages of development describe how children learn and grow. 

There are four stages: the sensorimotor stage (0-2 years), when babies explore using their senses, the preoperational stage (2-7 years), when kids start using language but struggle with logic, the concrete operational stage (7-11 years), when children think logically about real-life situations, and the formal operational stage (12 years and up) when teenagers develop abstract thinking skills and can solve complex problems. Each stage helps kids learn and understand the world around them in different ways.

Piaget's stages of cognitive development include the concrete operational stage, where children aged 7 to 11 begin to think logically and systematically about objects and events.

In this stage, seriation becomes evident as children can organize objects in a series based on a single attribute or multiple attributes, like arranging sticks by length or height. 

Seriation skills mark the transition from the preoperational stage, characterized by more intuitive and less logical thinking, to the concrete operational stage, where children develop the ability to use logic to solve problems and understand relationships between objects. 

Typically, children between the ages of 7 and 11 develop seriation skills as part of their cognitive growth.

Seriation Developmental Milestones

Different seriation skills may develop at different ages and may also vary amongst children. However, some age-specific milestones for seriation include:

  • Recognizing sequences: By age 5-6, children can begin to recognize simple sequences, such as arranging objects from smallest to largest.
  • Understanding order: Around age 7-8, children grasp the concept of order more fluently, sorting objects based on multiple attributes like size, color, or shape.
  • Mastering complex sorting: By ages 9-10, children can master more complex sorting tasks, arranging objects in intricate patterns or sequences.

Research by Piaget and his colleagues supports these developmental milestones. Piaget's observations of children's behavior and problem-solving abilities provided insights into the progression of seriation skills across different age groups.[1]

Seriation in Education

Seriation skills are fundamental in learning math and science. In math, seriation helps children understand numerical order, sequencing, and patterns, which are essential for arithmetic operations and problem-solving. 

For example, arranging numbers from smallest to largest aids in understanding addition and subtraction. 

In science, seriation assists in categorizing objects based on properties like size, shape, or weight, facilitating classification tasks and conceptual understanding. 

For instance, sorting objects by weight helps grasp concepts like density and mass in physics.

Assessment Methods for Seriation Skills in Academic Settings

Assessment methods for seriation skills in academic settings often involve practical tasks and observations. 

Teachers may use activities like sorting objects by size, shape, or color to assess students' seriation abilities. Performance on tasks such as arranging numbers in numerical order or sequencing events in a scientific process can also gauge seriation proficiency. 

Additionally, standardized tests and developmental assessments may include seriation tasks as part of cognitive assessments to evaluate children's cognitive development and problem-solving abilities in academic settings. 

These assessments provide valuable insights into students' mathematical and scientific reasoning skills and guide instructional strategies to support their learning needs.

Seriation in Daily Life

Children frequently use seriation in daily life. For example, they may:

  • Organize their toys by size, color, or type, helping them categorize and make sense of their belongings
  • Choose the largest cookie when selecting a cookie from a plate, demonstrating their understanding of size hierarchy
  • Arrange utensils from smallest to largest or in a particular order when setting the table
  • Organize books by height or genre, which helps to maintain order on bookshelves

For more context, consider these examples of children using seriation skills.

Sarah, a 6-year-old girl, enjoys playing with her building blocks. She spends time arranging them from smallest to largest, demonstrating her developing seriation skills as she creates intricate structures.

Jason, a 10-year-old student, excels in math class. His teacher observes him effortlessly arranging numbers in numerical order during a class activity, showcasing his advanced seriation abilities and mathematical aptitude.

These examples highlight how seriation is seamlessly integrated into daily activities, showcasing its practical relevance and importance in cognitive development.

Piaget and Spatial Reasoning

Finally, Piaget also suggested that kids develop spatial reasoning during middle childhood. Spatial reasoning is the ability to understand and reason (to draw conclusions) using cues in the environment that convey information about distance or direction. During middle childhood, children become able to discriminate objects that are nearby and far away based on their apparent size. They learn that objects that are further away will appear smaller than objects that are closer. Younger children who have not mastered spatial reasoning do not appreciate this seemingly obvious perceptual rule. Younger children will instead typically assume that far-away objects really are tiny. They appreciate that closer and farther away objects do differ in size, but do not understand that the size difference is only apparent, a perceptual illusion caused by distance and the nature of vision.

For the first time in their lives, middle-childhood-aged children become able to give directions using another person's vantage point rather than their own. For instance, a boy who wants to indicate to a woman seeking directions that she should turn to his left would know to tell the direction seeker (who is standing facing him) to turn to her right. Younger children cannot do this sort of thing, instead being limited to providing directions from their own perspective only.

Children's development of spatial reasoning skills, including their ability to represent places from multiple perspectives helps them to form more accurate cognitive maps (mental pictures of their environment) than they could previously. This refined knowledge enables them to produce realistically accurate maps of their neighborhood that other people can understand, complete with appropriate landmarks and relative distances between locations. Younger children's maps are less sophisticated and less accurate.

Even though middle childhood-aged children who have achieved the concrete operations stage have made many gains in their thinking abilities, they have not yet reached the level of adult thinking. Adults can reason not only about things that are concretely in front of them but also about more abstract concepts. By comparison, middle childhood-aged children are not skillful at thinking abstractly. They cannot easily (or at all) consider complicated hypothetical situations, generalize a wide range of outcomes to vague situations, or make sense of intangible ideas like "liberty".


  1. Piaget, J. (1971). The Construction of Reality in the Child. Routledge.

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