The correct answer to this open question is the following.
Unfortunately, you did not mention who were the theorists you discussed during the course. You forgot to include their names.
However, trying to help you, we can share the name of the author that best reflects my beliefs on how children develop.
We choose Jean Piaget.
Jean Piaget(1896-1980) was born in Switzerland and during his career, he could understand the behavior of children. He proposed a four-stage in which he put emphasis on the way children grew and mature while receiving external stimuli.
The four stages proposed in the development of children were: sensori-motor stage, pre-operating stage, concrete operations stage, and formal operational stage.
I consider that his approach is methodical and delivers positive results when parents are trying to understand the way children behave and grow during these different stages.
