Answer:
conservation
Step-by-step explanation:
Conservation: In psychology, the term conservation was proposed by Jean Piaget and is considered as one of the developmental accomplishments that occur during the age of seven to eleven years. It refers to the child's logical or rational thinking capability that allows him or her to describe that a particular quantity will be considered as same in the presence of any change in the container, adjustment in shape, size, etc.
In reference to the question, Nathan has not developed the concept of conservation.