Samuel and Bryant (1984)


Piaget was a Swiss psychologist who spent is known for his research into the cognitive development of children. Piaget  noticed that many of the illogical things children do and say in fact have a logic all of their own. He described children as “cognitive aliens” because their thought processes are completely different from adults’.


Piaget put forward a maturational theory of cognitive development. This means that Piaget thought that intellectual development happened instages, and that a child would only go on to the next stage once he/she had completely mastered the first one. Each stage is seen as a kind of ‘building block’ for the next stage to rest on. In each stage, Piaget said, the child would develop new ways of thinking which had developed out of what went before, but which were different from previous ways.

Therefore development is seen to be caused by nature not nurture.

Piaget outlined four stages of cognitive development, and gave approximate ages at which children reached those stages. Individual children might go through the stages at a different speed but they would always go through the stages in the same order.


Piaget said that it is possible to observe these different thought patterns through the errors of reasoning that children make. He devised some clever tests to demonstrate this different style of thinking. The most famous of these tests relate to the pre-operational stage. In this stage Piaget said that children were:

  • Unable to conserve. For example, they cannot appreciate that if you change the shape of an object it keeps the same mass.
  • Unable to reverse mental operations – if they’ve seen some action take place they can not mentally ‘rewind the tape’.

According to Piaget, in all these cases the child can only take into consideration ONE aspect of the physical world at a time – THUS if it LOOKS different it MUST BE different!

Although Piaget’s findings had major implications on teaching and learning in the 1960s & 70s, his theory has come under question because it was developed using methodologies that were seen as inappropriate for young children. . Rose and Blank (1974) suggested that the reason for the children’s mistakes in Piaget’s tasks was due not poor understanding but to the manner in which Piaget posed the questions.


To find out if children give the wrong answer when asked a question twice during conservation tasks (replicating Piaget).


  1. Being asked only one question will result in more children conserving than when asked two.
  2. Older children will conserve more often than younger ones.
  3. Children will conserve better at mass, then number, then volume.

Method & Design

A laboratory experiment with a mixed factorial design (independent and repeated measures).

Independent Variables:

  1. žAge: 5.3 years, 6.3 years, 7.3 years, 8.3 years
  2. žQuestion type (3 conditions): Standard: traditional conservation task, asked two questions, One Question: Only one question asked after the display was changed, Fixed array control: Only saw one display, the post transformation one, and asked the question.
  3. žConservation material (3 conditions): Mass, Number, Volume

Dependent Variable: ability to conserve


žThe sample consisted of 252 boys and girls aged from 5 to 8 years grom schools and playgroups in and around Devon.

There were ž4 age groups

  • 5 yrs 3 months
  • 6 yrs 3 months
  • 7 yrs 3 months
  • 8 yrs 3 months

žThese age groups were divided into 3 sub groups for the experimental conditions (Standard, One-Question, Fixed Array). 21 in each sub group.


žEach child was given four trials with each kind of material, two with unequal and two with equal quantities.

žThe order of these trials and the order in which the three types of materials were introduced were systematically varied between children.




  • Errors decreased with age: 5 year olds made the most mistakes whilst those aged 7-8 made the least mistakes. These results support Piaget’s theory – the older the child the more able they are to conserve.

Question type:

  • žFewest errors were made in the one-question condition, whilst the most errors were made in fixed-array condition. This supports Rose and Blank’s (1974) experiment and challenges Piaget’s methods.


  • žAll age groups made fewer errors in when conserving using number, most errors were made in the volume condition.


Samuel and Bryant concluded that children could conserve better than Piaget originally thought and the reason some children gave a wrong answer the after the second question was because they were asked the same question twice, leading them to believe they answered the first question wrong. Therefore Piaget’s methodology was flawed which caused him to underestimate the age of conservation.

BUT, the results also provide support for Piaget’s theory, because as the age of the children increased the children made fewer errors of conservation, regardless of which condition they were tested in. Childrens reasoning does seem to develop as they get older.

Controls in the study: each child participated in each three tasks, the order of the tasks were systematically varied to reduce order effects



+ High in reliability – the study was carried out in a laboratory setting which had high levels of control as all variables  except the crucial one of questioning were kept constant.

+ A large sample size with children from a large age range. This enabled researchers to draw conclusions about the age at which children started to conserve.

+ Quantitative data obtained on numbers of errors made by children which can be subjected to statistical analysis, subsequently allowing easy comparisons between groups.

+ The study has important implications for teaching children and for psychologists who question children. The findings clearly show that repeating the same question twice causes children to give the wrong answer.


– Experimental designs lack ecological validity. For example, the tasks themselves were artificial. It is not an everyday occurrence to ask the children this type of question in this type of setting. Therefore the findings cannot generalise to real life situations where these everyday skills come to play.

– Ethnocentric sample as they all came from one area in Devon, therefore they may not be representative of children from other areas of the country that may use different teaching strategies which might affect the children’s cognitive abilities.

– Quantitative data is reductionist as it reduces behaviour to numbers. As no qualitative, rich data was obtained the research gave a lack of insight into how the children responded towards the tasks.

– As different children participated in each condition, there may have been individual differences between groups of children and thus findings may lack validity.

Click here for model answers and exam practice

Useful resources:

Section A Questions

Section B Questions

Multiple Choice Quiz

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