Piaget, a Swiss psychologist, studied the basis for learning and development of the mind. He is considered to be the founder of cognitive psychology. Cognitive psychology is the study of thinking, logical reasoning, and the ability of the human mind to understand abstract and symbolic ideas. Piaget studied the development of children and their progressive stages of motor development. He believed that motor activity stimulated mental development. For example, an infant beginning to experience her environment may shake a rattle, which produces a noise. Over time and with repetition, the infant learns that this motor activity produces a sound. Piaget theorized that cognitive development is based on the child’s interaction with her environment. The following table summarizes Piaget’s developmental learning stages.
| Developmental Period | Age Group | Description |
| Sensorimotor | Birth to 2 years | Children learn about the world through their senses and motor skills |
| Preoperational | 2–6 years | Children begin to think symbolically and form language skills; they pretend and fantasize during play; thinking is self-centered |
| Concrete operations | 7–11 years | Children perceive differences and begin to reason; they can classify and attend to multiple situations |
| Formal operations | 12–adulthood | Children and adults can grasp abstract concepts, more formal notion of time, and long-term goal setting develops; learning takes place by relating new material to past material |