Samuel and Bryant

In one of his conservation tests Piaget demonstrated that if you show a child two beakers of water, one of which is tall and thin, the other short and fat, and ask the child which beaker contains the most water, most children under the age of 7 will say 'the tall one', even though they both contain the same amount of water. Piaget argued that this is because the child has not developed the ability to conserve volume.

Conservation of volume is the ability to realise that something may have the same volume, even though it is a different shape.

The aim of Samuel and Bryant’s study was to challenge Piaget's findings by altering the method used by Piaget. The participants were 252 boys and girls between the ages of 5 and 8.5. They children were divided into four age groups of 63 children, whose mean ages were;

5 years 3 months

6 years 3 months

7 years 3 months

8 years 3 months

Each group was divided into 3 subgroups which underwent a different condition.

The three conditions were:

1 Standard: This is the traditional two question conservation task as carried out by Piaget. The child is asked about the size of the object before and after the shape was changed.

2 One judgement: This is a conservation task like the original but this time with only one question asked, the post transformation question. That is, the child is only asked once about the size of the object and this is after the transformation has taken place.

3 Fixed array control: In this condition the child saw no transformation being made and only saw the post-transformation display. That is, the child just saw the objects after they had been changed and not before. The purpose of this third condition was to check that children who answered the post-transformation question correctly in the other two conditions did so by bringing over information from the pre-transformation display. Three different types of material were used for the conservation tasks - mass (Playdoh), number (counters) and volume (liquid).

(a) Mass: In this task children in condition 1 and 2 were first shown two equal and identical Playdoh cylinder shapes. The transformation was to squash one of these shapes into a sausage. After this, the children were asked to compare the cylinder and the sausage. The children in condition 3 also made this comparison without seeing the first display or the transformation.

(b) Number: In this task children in condition 1 and 2 were shown two rows of counters of equal length arranged side by side in one to one correspondence. The rows contained six counters. Then one row was spread out or bunched up. The condition 3 children saw only the post-transformation displays.

(c) Volume: In this task children in conditions 1 and 2 were first shown two identical glasses with the same amounts of liquid. Then the liquid from one glass was poured into a narrower one or a shallow wider one. The condition 3 children saw only the post-transformation displays.

The researchers recorded the number of errors children made in the tests. There were three main findings.

1. As predicted by Samuel and Bryant, children found the one judgement task significantly easier (they made less errors) than the standard conservation task and the fixed-array control. This was true of all three types of material.

Samuel and Bryant also found that;

2. There was a significant difference between the age groups, with older groups doing consistently better than the younger.

3. The children made fewer errors on the number task compared with the other two tasks

Samuel and Bryant gave an explanation for why children make fewer errors on the one judgement conservation task compared to the standard conservation task. They believe that in the standard conservation task, the pre-transformation question is unwittingly forcing the child to give the wrong answer by asking the same question twice (they call this the extraneous reason hypothesis).

For example if the child is asked a question about the volume of beakers and then sees the experimenter pour the liquid from one beaker into another, the child might believe that the experimenter must be doing it for a reason and therefore want the child to give a different answer.