Jean Piaget’s is a Swiss psychologist who studied and wrote about cognitive development. He began publishing seriously on one of his favourite subject, mollusks. His work became well known among European students of mollusks, who thought he was an adult when they heard his work. He published his first paper when he was 10 it was about a sighting of an albino sparrow. When he left university and he decided to research and study about cognitive development, According to Piaget there are four stages of cognitive development. The first stage is Sensorimotor, which is birth to two year old. The second is Preoperational, which is 2 to 7 years old. The third is Concrete Operational which is 7 to 12 years old. The last one is Formal Operational, which is 12 years old to adulthood. In this part of my essay I am going to be discussing and going into more detail about these stages. The first stage is sensorimotor; this is where infants use only their senses and motor abilities to adapt to the surrounding environment and to the world around them. In the beginning they only have involuntary reflexes to interact with objects or people. From birth they have simple reflexes for example grasping and sucking which they need to be able to feed from their mother. As this stage get closer to going into the next stage of cognitive development, infants senses and motor skills will become stronger and stronger. The second stage is Preoperational; at this time the infant develops concepts and language.