does any one know the name of the following study by Jean Piaget?

Question

He began his study by simply placing two lines of M ands M’s in front of different aged children. The M and M’s were placed far apart in the first line and closely together in the second line. Piaget found that children between the ages of 2years 6 months old and 3years 2 months could correctly tell the relative number of objects in the 2 rows apart whereas children between the ages of 3years 2 months and 4 years 6 months indicated that the longer line with M and M’s placed far apart had more. This is because it is believed that children loose the ability to conserve as they grow and then later regain it. After 4years 6months children seemed to once again distinguish correctly. Piaget’s results found that younger children have the ability to conserve; this shows that logical capacity for cognitive operations exists earlier than acknowledged. Young children can be equipped with certain qualities for cognitive operations depending on how long the structure of the task is. Children develop explicit understanding at ages five thus the child will count the M and M’s to decide which row has a higher number of M and M’s.

the study is about proving conservation in pre-operational children

Answer 1

I don't know if there is a name for the study in particular. He was studying "cognitive development in children and measuring levels and abilities at various age levels/.

Answer 2

Process of Cognitive Development