How Logical Reasoning Changes With Age

The Key Improvements in Logical Reasoning from Childhood to the Tween Years

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Tweens demonstrate a variety of cognitive changes, including an increase in logical thinking. Compared to young children, tweens' logic improves in four main ways.

Logical Reasoning: Outward Appearance Becomes Less Important

Young tweens begin to understand that objects and beings can change their outward appearance and yet stay the same. One of the foremost child development psychologists, Jean Piaget demonstrated that young children lack this understanding.
Piaget poured liquid from a tall, thin glass into a thick, short glass right in front of their eyes, young children thought the liquid became a different amount simply because the liquid's outward appearance changed. By the time they are tweens, however, kids are able to understand that the amount of liquid doesn't change.

This logical reasoning development is clear in tweens' understanding of the world around them. For instance, while young children may get confused and upset when they see someone dressed as a six-foot Mickey Mouse, tweens understand that it's a person in costume.

Young children tend to focus on only one feature of a problem at a time. Thus, they think that the amount of liquid changed because they were only paying attention to the height or the width of the glass, not both. On the other hand, tweens can understand that the shorter height is made up for by the thicker glass, providing the same amount of space overall.

The ability to consider multiple features at once extends well beyond the physical world. For instance, it allows tweens to grasp complex social dilemmas that have multiple pros and cons. They also begin to see how an action by one person or group could offset an action made by another.

Categorization Improves

As the tween years begin, children become skilled at categorizing people and objects, another development in logical reasoning.
Unlike during their younger years, they now thoroughly understand how things can be grouped together by like properties. They also realize that hierarchies of groupings exist. For example, they know that "animals" can be divided into groups including "mammals" and "reptiles," and that those groups can be further broken down into types of mammals like "dogs" and "leopards." They also grasp that there are always a greater quantity of objects within a broad category (such as "animal") than there are in a specific category (such as "dog"). While this may seem obvious to us adults, this is a major step forward in logical thinking, allowing for advancements in math and science understanding.

Tweens Understand That Things Can Change Back to Original Form

A final key logical reasoning development is the understanding of reversibility. Reversibility refers to the fact that sometimes things can be altered and then be changed back again. A simple example that kids understand early on is that you can roll a ball of clay into a long snake and then roll it back into a ball without changing its internal properties.
A full understanding of the consequences of reversibility - such as how reversibility can be used to understand division and multiplication - continues to develop over the course of the tween years.


Berger, Kathleen. The Developing Person Through the Lifespan. 2008. 7th Edition. New York: Worth.

Santrock, John. Children. 2009. 11th Edition. New York: McGraw-Hill.

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