Piaget described four distinct periods of cognitive development. The first period begins at birth and ends at about 24 months. Piaget called it sensori-motor intelligence because infants learn through their senses and motor skills. This two year long period is subdivided into six stages.
The first two stages of sensorimotor intelligence are examples of primary circular reactions, which are reactions that involve the infant’s own body.
Stage one, called the stage of reflexes, last only for a month. It includes senses as well as reflexes, which are the foundation of infant thought. Reflexes become deliberate movements; sensation leads into perception and then cognition. Sensorimotor intelligence begins. As reflexes adjust, the baby enters stage two, first acquired adaptations. Adaptation is crucial to learning, as it includes both assimilation and accommodation, which the person uses to make sense of experience. This adaptation from reflexes to deliberate action occurs because repeated responses provide information about what the body does and how that action feels.
In stages three and four, development switches from primary circular reactions , involving the baby’s own body (stages one and two), to secondary circular reactions, involving the baby and a toy or another person.
During stage three (age 4 to 8 months), infants interact diligently with people and things to produce exciting experiences, making interesting events last.
Stage four (8 months to a year) is called new adaptation and anticipation, or “the means to the end,” because babies now think about a goal and begin to understand how to reach it. Thinking is more innovative in stage four than it was in stage three because adaptation is more complex. Piaget thought that the concept of object permanence emerges at about 8 months, this refers to the awareness that objects or people continue to exist when they are no longer in sight.
In their second year, infants start experimenting in deed and in...