This stage includes children aged 11 years and older. “When adolescents enter this stage, they acquire the ability to think abstractly, the ability to combine and classify elements in a more sophisticated way, and the ability for higher order reasoning” (SimplyPsychology p.1). He had a different way of thinking. Even as his children grew, he studied their every movement and connected it to his theory he already had of a developing child. “According to Piaget, children are born with a very elementary mental structure (genetically inherited and evolved) on which all subsequent learning and knowledge are based” (SimplyPsychology