According to Piaget, children develop their ability to think through a series of stages that occur as we age.
- Sensory Motor Stage
- Pre-Operational Stage - Child is learning to use symbolism, language and general rules about mental operations. Piaget said that they are unable to conserve, unable to reverse mental operations, are egocentric and rely on their intution.
- Concrete Operational Stage - Child is able to use some sophisticated mental operations but is still limited in a number of ways.
- Formal Operational Stage.
In Piagets conservations experiments, children were asked whether the two displays were the same, before and after the transformation. In Rose and Blank's experiment they were only asked after the transformation. Children who had failed the task with two questions often succeeded when only asked one question which suggested that children only failed because they were confused by the question. R & B only looked at the number task and only tested 6 year olds, S & B aimed to find out if the same results would occur with other tasks and a wider range of participants.
- Investigate the question of whether children under the age of seven or eight are able to understand the principle of invarience of quantity (conservation)
Procedure, Method and Sample
- 252 boys and girls aged between 5 and 8 1/2 from Devon. The children were divided into four groups, whose mean ages were
- 5 years and 3 months
- 6 years and 3 months
- 7 years and 3 months
- 8 years and 3 months.
- Each groups was subdivided into three task groups, which were closely age matched.
- Condition 1 - Standard Condition - Children were asked questions before and after the transformation
- Condition 2 - One Judgement Condition - Children were asked questions after the transformation
- Condition 3 - Fixed Array Control - This group only saw the post transformation display and were then asked the question.
The third condition checked if the children could see a difference in the post-transformation display without seeing the transformation
If children fail the third condition then it shows that they need to see the pre-transformation display to answer correctly
- Each child had four trials with each of the three materials (Mass, number, volume) The trials consisted of two equal and two unequal quantities.
Lab Experiment/Quasi Experiment
- Experiment was carried out in Lab Conditions, not in the participants own homes so there is a low ecological validity
- Quasi Experiment because researchers cannot influence the age of a participant.
- Number of errors in each condition of each age group
- Number of errors in each condition of each material
- No differences found in the equal and unequal conditions.
- In each conditions, the mean number of errors decreased as age increased.
- The material that had the most mean errors in each condition was volume, wheras the least was number.
- Older children made fewer errors
- Children made the fewest errors when shown the transformation and asked only one question
- Children did worse on the control condition, which means that those who were successful on the other conditions were so, because they were using the information from the transformation.
- Failure on the two-question task may be to do with being asked two questions rather than the ability to conserve.
- Children may posses certain cognitive abilities but may not display these when questioned in a certain way.
- Lab Experiment
- Tasks were similar to real life activities.
- Using children
- Psychological harm - children more impressionable