The age category ranges from one month to four months. Primary circular reactions follow the infant's reflexive actions such as crying and squirming. The infant develops repetitive patterns centered on his body. Examples of central body patterns are toe sucking, thumb sucking, or sucking on an object after observing it. The infant will intentionally repeat the pattern because he or she finds it satisfying. Piaget's four basic principles can be applied to the primary circular reaction substage. Since an infant has a sucking reflex, whenever an object touches their lips, they suck on the object. Piaget is said to have said that he had a “suction pattern”. The infant will develop new