Age range: Birth - 2 years old (approximately)
Description of stage: At this stage, individuals learn through the senses. Cognitive development is built through the infant's interactions with the environment. The sensorimotor period is broken down into six substages.
Substage 1: The use of reflexes (children are victims of the environment)
Age Range: Birth - 1 month
Description of stage: Infants are born with inherited reflexes, and it is through the reflexes that the infant begins to make meaning and build understanding. Reflexes are highly stereotyped automatic behaviors that occur in response to specific stimuli. Reflexes include sucking and grasping, as well as eye movements, vocalization, and orientation to sound.
Example: grasping finger, sucking any object that comes in contact with the mouth.
Substage 2: primary circular reactions (children show first signs of intentionality)
Age range: 1 month - 4 months
Description of stage: Circular reactions are repetitive behaviors. Primary circular reactions are behaviors that occur unexpectedly from reflexes. A reflex will engage the child is some form of behavior. If the child finds that behavior pleasurable, the child will repeat the behavior.
Example: Sucking a thumb. The child does not intentionally coordinate putting his thumb in his mouth and sucking. By chance, when a child's hand comes in contact with the mouth sucking will occur. Getting a pleasurable sensation from this behavior, the child will attempt to recreate the behavior.
Substage 3: Secondary circular reactions (children interact with the environment)
Age range: 4 months - 8 months
Description of stage: Secondary reactions, unlike primary circular reactions, are not based on reflexes; therefore, secondary circular reactions are not contained within the body. However, similar to primary circular reactions, secondary circular reactions occur from an unintentional occurrence, but the occurrence involves the child interacting with the external environment.
Example: A child is moving about in a playpen and happens to hit the mobile overhead. The mobile spins and catches the baby's attention. Once the mobile stops spinning, if the child enjoyed the experience, the child will move his arms and legs again to try and hit to mobile. The child wants to repeat the behavior.
Substage 4: Coordination of secondary circular reactions (Child uses one to get another)
Age range: 8 months - 12 months
Description of stage: Before this stage, everything occurred by chance. Now, the child is starting to understand that one circular reaction can be used to get another circular reaction. Behaviors that the child displays are now for a reason. At this stage, the child begins to gain a sense of cause and effect. Also, a major event occurs during this stage: object permanence. Before now, children do not understand that an object out-of-sight continues to exist. Children acquiring a knowledge base of object permanence love to play peek-a-boo.
Example: A child wants the a rattle but a blanket is in the way. The child will move the blanket to get the rattle.
Substage 5: Tertiary circular reactions (The little scientist)
Age range: 12 months - 18 months
Description of stage: At this stage, an action occurs deliberately. The child displays a behavior purposely and continues the action because it is pleasurable. What separates this stage from the previous is that the action is repeated with some variation.
Example: A child beats on a pot with a wooden spoon. Then, the child beats on the floor with the wooden spoon. Next, the child beats on the refrigerator with a wooden spoon.
Substage 6: Coordination of tertiary circular reactions (Mental representation begins)
Age range: 18 months - 24 months
Description of stage: It is in this last stage that children internalize behaviors and began to build mental symbols! This stage is when children are able to participate in pretend play.
Example: A child is pretending to cook and needs to "mix the ingredients" in a bowl. However, the child does not have a spoon. The child will either pretend to use a spoon, or the child will use an object, similar to a spoon, in its place.