Samuel and Bryant

Context
piaget developed a theory of how children's thinking changes as they get older. one of his key research methods was the conservation task. the task was used to assess whether the child had reached the concrete operational stage of thinking i.e was able to think in a systematically logical way.
piaget found that children under the age of 7 or eight years old could not think in this way. however his methods were criticised because of the way he asked questions. it was argued that the use of 2 questions might confuse children as they might think they had to give a different answer the second time. 

Aim
rose and blank (1974)  tried asking just one question and found that children coped better i.e were more likely to show conservation. the aim of samuel and bryants study was to extend rose and blanks research.

Participants
children cam from Devon, England. 
four age groups were tested; 5, 6, 7 and 8 years old. total = 252 children.

Procedure
lab experiment using both repeated measures and independent measures design.
each child was tested 4 times on each of the three materials = 12 tests.
mass: children were shown a Plasticine cylinder which was then transformed by being made flatter (and so looked like there was more).
number: a row of counters which was then transformed by being spread out so the row was longer.
volume: a glass filled with water which was then transformed by being poured into a taller, thinner beaker so what the water level was higher. 

Each age group was subdivided into three age groups:

. standard condition, as used by Piaget where the key question 'are they the same?' is asked twice.

. one question condition, as used by Rose and Blank where the key question was only asked after the transformation of the display.

. fixed array was a control condition where the key question was asked once and there was no transformation.

Results
Samuel and Bryant found 
. older children performed better than younger children
. all children made fewer errors on the number task (an error is when a child fails to conserve)
. all children made fewer errors when asked one question post transformation.

Conclusion
Results show that Piaget's methods were flawed. Asking two questions on the conservation task may have confused the younger children and therefore they did not truly demonstrate their abilities. it might be possible that children in the one question condition simply ignored the information in the post-transformation display and that's why they did better however this cannot be the case because otherwise the children in the fixed array control would also have done well and they didn't, the results do also support Piaget because there was still an association between age and ability to conserve.