Thanks for your question. First, let me request that if any of the
following is unclear or if you require any further research ? please
don?t hesitate to ask me for a clarification.
You asked ?how useful is Jean Piaget's ?conservation task? for telling us about
young children's thinking??
This is a fascinating question, and I?ve enjoyed working on it greatly.
What is Piaget?s ?Conservation Task??
?The paradigm that has been most used to study the young
pre-operational child?s thinking processes is the *** conservation
task ***. This task, first described by Jean Piaget, has been used to
study young children?s understanding of many dimensions of quantity
including volume, weight, mass, number and length. The child is shown
two displays and asked to judge whether the object (or quantity) in
each is equivalent in the target dimension. The experimenter the[n]
alters the appearance of one of the displays. In conservation of
length task the experimenter moves one rod so that it now is higher on
the table than the other rod. The child is asked whether the two
displays are still equivalent or not. They are also asked to justify
Here is an image that demonstrates Piaget?s Conservation Task ?
According to the presentation at ?
The conservation task shows comprehension of three principles of
1) Reversibility: The pouring of water into the small container can be reversed.
2) Compensation: A decrease in the height of the new container is
compensated by an increase in its width
3) Identity: No amount of liquid has been added or taken away.
?Why do pre-operational children fail problems of conservation?
Because their thinking is not governed by principles of reversibility,
compensation and identity.?
Criticism of Piaget?s ?Conservation Task?
There is considerable controversy as to the degree to which the
?Conservation Task? reveals much about the young child?s understanding
of quantity ? or, indeed, the development and maturity of his thought
Turner (1998) writes:
?Despite the enormous influence of Piaget?s work others have not
always agreed that the conservation test reveals a fundamental
limitation in the child?s understanding of quantity. Instead others
have argued that the conservation task is an artificial situation
which makes little "human sense" to the child. They have argued that
the child may fail to conserve because they feel the experimenter
expects the to answer that the change has made a difference or because
they don?t understand relational term such as ?more than? and ?less
than? in the sophisticated way that we imagine.?
Turner also points to other, more recently developed tasks that have
been more effective in this respect:
?Many researchers have used variants on Piaget?s original procedure to
attempt to demonstrate some understanding of the conservation at ages
younger than children typically pass the standard Piagetian paradigm.
These efforts have met with some success with nearly double the number
of five and six year olds passing tests of conservation if the
question about the equivalence of the two displays is asked only once
after the critical transformation (Rose and Blank, 1974) or if the
transformation is bought about accidentally (McGarrigle and Donaldson,
1975; Light, Buckingham and Robbins, 1978).?
Samuel and Bryant (1984) point out that ?Children below 8 years have
problems with conservation tasks.?
For example, Samuel and Bryant (1984) cite Donaldson:
?Donaldson (1978, 1982) has pointed out that children take into
account the social aspects of the task before replying to the
experimenter's questions. Piaget's original tasks require the
experimenter to ask whether, for example, the balls are the same size,
not only after the transformation, but also before. Can you think why?
The problem with asking the same question twice is that the child may
think that the experimenter wants the child to change his answer. The
child takes into account the social aspects of the task!?
Rose and Blank (1974) demonstrated that Piaget?s original experiment
could be more successful if revised as follows:
?Rose and Blank (1974) demonstrated this by only asking the
post-transformational question to six year olds taking part in a
number conservation task. More children were able to conserve,
compared with those undertaking the traditional two-question task.?
As a result of conducting a revised experiment, Samuel and Bryant
(1984) conclude that:
?Piaget's view that children cannot conserve, for example, volume
until the age of 11 or 12, is challenged. It would be heresy to
suggest that Piaget was wrong to assert that children's thought is
'qualitatively' different from adults, but is seems that we can
disagree over the nature of this difference (i.e. 'social' rather than
Samuel and Bryant?s methodology can be found at ?
And an excellent discussion of Samuel and Bryant?s experiment and
methodology can be found here:
Porpodas (1987) also provided constructive criticism of Piaget?s methodology:
?Porpodas (1987) felt that 'inability to conserve' could be explained
in terms of the child 'forgetting'. Porpodas feels that the
experimenter talking to the child in the original experiment
interfered with the information stored in Short Term Memory (STM).
Porpodas used 3 conditions i) traditional, ii) one questions and iii)
one question with interference (i.e. performing the task whilst
chatting about something else). The interference task produced the
worst performance. It was concluded that the 'inability' to conserve
could sometimes really be interference with STM.?
Durr (2001) also questions Piaget?s methodology ? see ?
?In Piaget's studies, one thing was not accounted for, and that is
what I would like to clarify in this study. He failed to make any
distinction between more difficult and more simplified tasks within an
area of cognition development.?
Lenz (2003) writes ?
?If a conservation task is simple, it may be performed correctly, but
if it is more complex the child may still make the pre-operations
mistakes. Additionally, different children progress through these
stages at different speeds, the ages given being rough
In summary, having reviewed a large number of resources as cited
above, I would argue that while Piaget?s Conservation Task CAN be
useful in analyzing and understanding cognition among young children,
experiments must be performed in a non-biased manner while taking into
account the criticisms outlined above. If such bias and criticisms
are not taken into account, the ?Conservation Task? may not be very
useful at all?
I hope this response adequately addresses your request. Please let me
know if you are in need of additional information concerning this
Vasta, R., Haith, M. M. & Miller, S. A. (1995) Child Psychology: the
modern science. Chapter 8, pages 268-297.
Cole, M. & Cole, S. R. (1996) The Development of Children (3rd
edition). Freeman. Pages 485-498 & 502-507.
Smith, P. K., Cowie, H. & Blades, M. (1998) Understanding Children's
Development (3rd edition). Blackwell. Chapter 11, pages 343-365.
Butterworth, G. & Harris, M. (1994) Principles of Developmental
Psychology. Erlbaum. Chapter 9.
Wood, D. (1998) How Children Think and Learn (2nd edition). Blackwell. Chapter 3.
Goswami, U. (1998) Cognition in Children. Psychology Press. Chapters 7 & 8.
Rose, S.A., & Blank, M. (1974). The potency of context in children's
cognition: an illustration through conservation. Child Development,
McGarrigle, J. and Donaldson, M. (1975) Conservation accidents. Cognition 3: 341-50
Margaret Donaldson 1978, Children's Minds, William Collins, Glasgow.
Good presentation on Piaget?s theory with several graphic displays of
the conservation task.
More good discussion and graphical description of the conservation task
(see pages 17-18)
Good source, discussion of criticism of conservation task ? but
requires registration ?
"jean piaget" "conservation task"