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Piaget's Tests in Practice


Piaget's Tests

Through numerous tests Piaget has shown that mistakes children make are not random and unintelligible, but are based on a consistent logic which is simply different to that of adults.

Numerous tests were devised by Piaget and his co-workers. The tests covered a variety of subject areas, such as number, space and logical operations. By researching children's responses to these tests, and by questioning the children about how they reached their answer, Piaget has increased our understanding of children's thinking.


The tests devised by Piaget and his co-workers are quite simple because they only require a straight forward answer from the child, to questions such as 'Which one weighs more?' or 'What belongs here?'. This is only the beginning of the test, however, and can easily lead to an open-ended series of questions related to or a variation of the original question and how the answer was reached. From this, we can begin to see where the child is coming from and how their logic works. There are both strengths and weaknesses in Piaget's methods, though. They do reveal a lot about the child's thought processes, but the questioning is is quite unstructured. This leads to the fact that even a slight variation in questioning would probably offer a variation in the information obtained, and therefore the conclusions drawn may be incorrect.

The tests Piaget devised cover a variety of areas of development:

Logical Operations


Transitivity and Seriation

Number Concepts

Spatial Concepts


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Logical Operations



Group objects according to common attributes.

The majority can classify a group of objects in three different ways from the age of 9.


Group objects according to common attributes, but by touch alone.

Young children find it harder to classify by tactile-kinaesthetic than by visual, but no great difficulties by age of 8.


Classify objects, but say what they will do instead of physically doing it.

All children found it easier to classify than to anticipate.

Composition of classes

Understanding of the relation between a set of objects.

Ability present in most children by the age of 9.

Class inclusion or logical inclusion

Understanding of relationships between a group of objects and its subgroupings.

Hard to state results - answers likely to be related to the verbal sophistication of the child due to wording of questions.

Multiplicative classification

Classify using two attributes at a time, such as size and colour.

Most able to cope with multiplicative classification by the age of 8.

Multiplication of classes (matrices)

Consider two attributes of an object and replace a missing object in a matrix.

The majority have this ability by age 8.

Multiplication of relations

Two relative attributes have to be combined to give the next in a series (i.e. each object is smaller and darker than the previous one).

The majority have this ability by the age of 8.


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Tests of Conservation


Conservation of continuous quantity - liquids

Appreciate that variations in the shape of a container,do not affect the quantity of liquid.

Summary of results unclear.

Conservation of continuous quantity - solids

Appreciate that changes in the shape of a solid (e.g. plasticine) does not change the quantity of that shape.

A child who is uncertain of his/her judgements (common in young children) is more likely to be affected by variables in the experiment, therefore there are inconsistencies in the results.

Conservation of weight

Appreciate that changes in the shape of an object do not cause changes in its weight.

Results similar to conservation of solids.

Conservation of volume

Appreciate that changes in the shape of an object do not change its volume.

Results similar to conservation of solids and weight, but greater inconsistencies.

Conservation of number

Appreciate that the number of objects in a collection remains the same regardless of whether the collection is spread out or bunched together.

Young children have difficulties in conservation of number, but this can depend on whether they have begun school or not.

Conservation of length

Appreciate that the comparative length of two objects (e.g. rods) is unaffected by their relative positions or straightness.

Children find it easier to conserve length than to conserve continuous quantity, weight, volume or number.


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Tests of Transitivity and Seriation


Transitivity of discontinuous quantity

Ability to appreciate the transitive relationship between three collections of different numbers of objects.

Overall summary below

Transitivity of weight

Ability to relate the weights of two objects, given the relationship between their weights and a third object.

Overall summary below

Transitivity of length

Understanding of the relationships between the lengths of three rods.

Overall summary below


Ability to put a number of objects in order according to their size, weight or numerousness.

Overall summary: remarkable consistency between tests. At the age of about 8, most children have mastered the concepts of transitivity and seriation.


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Tests of Number Concepts


Correspondence and composition

Ability to relate each object in one collection to an object in another collection (one-to-one correspondence).

Overall summary below

Addition and subtraction of one unit

Recognise that adding an object to a collection and than taking one away leaves it the same.

Overall summary: a large number of children don't understand what we consider very simple operations. About 1/5 of seven year olds don't understand addition and subtraction of one unit.

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Tests of Spatial Concepts


Spatial concepts

Understanding of simple geometrical ideas, such as the concepts of vertical and horizontal.

Even the 11 year olds who were tested did not fully understand and realize the invariance of the vertical and the horizontal.

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