Why did Hughes do the policeman doll study?

Hughes believed that the original 3 mountains task used by Piaget was too difficult for children to understand - it involved them understanding what a doll saw and taking notes of different details and overall was a bit confusing for a young child to understand what they were being expected to do.Hughes' study was a much more child-friendly version of the 3 mountains task. Children were much more familiar with the concept of hiding from another person and this showed in results, as Hughes found that children were less egocentric than Piaget had originally concluded