Samuel and Bryant's
experiment is one of many studies which have attempted to challenge
Piaget's theory of cognitive development through criticising his
methods. It is
important that we firstly understand Piaget's theory of cognitive
learning approach to child development maintains that development is
simply a process of learning more as one gets older.
So, for example, cognitive or moral progress for Bandura was
merely a process of learning more - quantitative change.
However Piagetís structuralist
approach to child development provides a very different account
of child development. For
example, Piaget believes that development is a systematic,
structured process. Piaget
believes that it is not just the amount of knowledge which
distinguishes a young child from an older child.
There is actually a qualitative difference in their thoughts.
To Piaget, changes in the way a child thought about the world
signified a change in cognitive, or intellectual development.
As the child's intellect develops, it becomes increasingly
capable of carrying out actions upon its environment which will
ensure its survival.
psychologist, Jean Piaget, put forward one of the most influential
structuralist theories about how a childís mind develops.
Piaget thought that intellectual development happened in
stages, and that a child would only go on to the next stage once it
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.
four stages of cognitive development, and gave approximate ages at
which children reached those stages.
He stressed, though, that these ages are only averages;
individual children might go through the stages at a different speed
but they would always go through the stages in the same order.
These maturational stages, in brief, are:
1. Sensory motor
stage (birth to around 18 months).
During this stage the child gains understanding of its
environment by using its senses in combination with movement.
stage (18 months to about 7 years). During this stage the child becomes able to represent
objects or events by symbols or signs.
The child is now able to use language and express ideas.
The child is also developing some general rules about mental
operational stage (7 to around 12 years).
During this stage the child is able to use more sophisticated
mental operations. For
example, the child is said to have decentred.
Decentring simply means being able to take account of more
than one aspect of a situation.
However the child is still limited in a number of ways, for
example, they tend to think about the world in terms of how it is,
and find it hard to speculate on how it might be.
Formal operational stage (12 years and above). This stage is
mainly governed by formal logic and is the most sophisticated stage
numerous tests which highlighted the errors children make with
certain problems. These
errors demonstrated the different quality of thought children have
in different stages.
One of the most
well known tests Piaget used to show the limitations of child
thinking in the pre-operational stage was the conservation
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, the
pre-operational child (i.e. child under 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, which does not develop
until the child is in the concrete operational stage.
Conservation of volume is the ability to realise that
something may have the same volume, even though it is a different
demonstrated that if you roll a piece of clay into a sausage shape,
show it to a pre-operational child and then roll it into a ball, the
child will say that there is more clay in the sausage shape.
demonstrated that, if you present a pre-operational child with a row
of five buttons spread out and a row of five buttons close together,
the child will say that the spread-out row contains more buttons.
Piaget argued that
the inability to conserve is due to the child's failure to
understand that things remain the same (constant) despite changes in
their appearance (how they look).
Piaget believes this is an example of centration.
The pre-operational child has not decentred and is therefore
centring on just one dimension.
For example, the child is centring on just one dimension of
the beaker, usually its height, and so fails to take width into
Piagetís work has
given psychologists many insights into the qualities and limitations
of child thought. However,
from the late 1970s onwards, there have been many replications of
Piaget's methods, which have demonstrated that Piaget often
underestimated the cognitive abilities of children.
In particular, it is argued that Piagetís findings were a
result of the structure of his original tests rather than the
limitation of child thought.
The aim of Samuel
and Bryantís study was to
challenge Piaget's findings by altering the method used by Piaget.
were 252 boys and girls between the ages of 5 and 8.5.
They were all in schools and playgroups in and around
Crediton, Devon. They
were divided into four age groups of 63 children, whose mean ages
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.
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.
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.
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
types of material were used for the conservation tasks.
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.
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
rows contained six counters. Then
one row was spread out or bunched up. The condition 3 children saw only the post-transformation
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.
Each child was
given four trials with each kind of material and the order of the
tests was systematically varied between the children.
Therefore there are
three independent variables.
conditions, the four age groups and the three kinds of materials
variable was the number of errors made by the children.
recorded the number of errors children made in the tests.
Examples of errors would include when a child said one lump
was bigger than the other, or one row had more counters than the
other, or one glass had more liquid than the other. The researchers
made the following conclusions.
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.
Bryant also found that;
There was a significant difference between the age groups,
with older groups doing consistently better than the younger.
The children made fewer errors on the number task compared
with the other two tasks
Samuel and Bryant
give 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.
The ability to
conserve (or understand the principle of variance as Samuel and
Bryant put it) marks the end of pre-operational thought and the
beginning of operational thought (at about seven) and is a
significant landmark within Piaget's theory of cognitive
However Samuel and
Bryant's experiment and many other studies have challenged Piaget's
explanations of conservation by criticising his methods.
Samuel and Bryant demonstrate that the tasks used by Piaget
actually made it difficult for children to give the correct answers
and demonstrate that children below the age of seven can conserve.
of cognitive development explained how a childís ability to think
progresses through a series of distinct stages as they mature. Piaget believed that these stages were maturational.
That is, development is genetic and largely unaffected by
However, Samuel and
Bryant advocate a cognitive approach to child development.
According to this perspective, as children learn more about
their world they will adopt new strategies with which to process
children who do not demonstrate the ability to conserve have simply
not acquired the strategies for this skill or are not applying the
Despite this the
Samuel and Bryant experiment did demonstrate two findings which
Firstly, they found
that older children did do significantly better than younger
children on the conservation tasks.
8 year olds did significantly better than 7 year olds, who
did significantly better than 6 year olds, and so on - perhaps
supporting Piaget's stage approach.
discovered, like Piaget, that children could conserve number before
they could conserve mass and volume tasks.
The main strength of Samuel and Bryantís
experiment was the amount of control they had over possible
confounding variables. The
children had to do four attempts at each conservation task which
eliminates the possibility that the children answered incorrectly or
correctly by chance, and order effects were controlled for by
varying the order of the tasks.
A weakness of the number task was that the
children could have counted the number of counters used and this
could account for the level of accuracy on the number task.
A further weakness could have been that the
children may have felt nervous doing the tasks (perhaps the younger
children more so) and therefore resulted in the answers being
spontaneous rather than thought out.
Samuel and Bryant
argue that Piaget's theory of cognitive development places too much
emphasis on maturational factors.
Using a cognitive approach they believe that children learn
new strategies and skills. Samuel
and Bryant also criticise Piaget for emphasising how children learn
as individuals. Samuel
and Bryant argue that children do not learn in isolation, and that
they learn far more readily and efficiently when they are working
together than when they are alone.
However two of
Samuel and Bryant's findings do support Piaget's theory and Piaget's
theory is still one the most influential theories of child
thought. Of particular
value are Piagetís insights into how children do think about the
world qualitatively different to adults.
Samuel, J. & Bryant, P. (1984) Asking only one question in the
conservation experiment. Journal of Child Psychology and Psychiatry,
GROSS, R. (1999) Key Studies in
Psychology, 3rd Edition. London: Hodder and Stoughton
AND GRAYSON, A. (2000) Introducing Psychological Research; Seventy
Studies that Shape Psychology, 2nd Edition. London: Macmillan