If it's related to thinking, it's considered cognitive. Anxious parents might defend using flashcards with toddlers as "nurturing their cognitive development."
The adjective, cognitive, comes from the Latin cognoscere "to get to know" and refers to the ability of the brain to think and reason as opposed to feel. A child's cognitive development is the growth in his or her ability to think and solve problems. Many English words that involve knowing and knowledge have cogn- in them such as cognizant "aware of" and recognize "to know someone in the present because you knew them from the past."