This document summarizes Jean Piaget's theory of cognitive development. Piaget believed that children think very differently than adults and actively construct knowledge as they progress through four distinct stages of development - sensorimotor, preoperational, concrete operational, and formal operational. According to Piaget, teachers should understand the stage of development of each student to effectively utilize technology or other teaching methods appropriate for that age. Students are able to start using technology from age 2 onward when they can understand pictures, numbers, and symbols.