Jean Piaget

Jean Piaget (1896-1980) is primarily considered a developmental psychologist, however he takes a cognitivist approach to this study. Piaget was particularly interested in the way in which we acquire knowledge throughout our development, and is renowned for the observation that knowledge acquisition is based on a biologically determined timetable. Furthermore, Piaget describes intellectual development as proceeding through a succession of identifiable stages, of which he described four:

1. Sensorimotor Stage - from birth to about age two, children begin by experiencing their, and eventually mastering their, senses. Basic motor control is also acquired during this stage.
2. Preoperational Stage - from about age two until about age seven, children acquire significant control of their sensory and motor functions.
3. Concrete Operational Stage - occurs from about age seven to about age eleven, children begin to use logical thought and cognate about concrete events and objects.
4. Formal Operational Stage - occurs from about age 11 onward, adolescents begin to use abstract reasoning, and display the ability to cognate events, objects, and concepts which have no concrete representation. This stage is not ever fully developed in some people, thus accounting for varying abilities of abstract reasoning.