Thursday, July 24, 2008

Jean Piaget's Four-Stage Theory

Jean Piaget is one of the giant's of 20th century psychology, and second only to Freud in academic citations. While some elements of his theories have been disproved over the years, his stage model of how children acquire knowledge remains the legacy for which he is most known.

Over at PsyBlog, as the tenth installment in a series on child psychology studies, they posted a nice overview of Piaget and his work.

While you should go read the whole post, I want to present the four-stage model, which is the centerpiece of the integral model for the intellectual development line.

Piaget's four-stage theory of development

While many parents play games with their children like this, what set Piaget apart was that he used these observations along with many experiments to develop a theory of how children acquire knowledge, a theory for which he is rightly best-remembered.

This theory is a four-stage ladder up which Piaget thought children climbed as they gathered knowledge about the world:
  • Sensorimotor (birth to 18-24 months): infants are aware only of their sensations, fascinated by all the strange new experiences their bodies are having. They are like little scientists exploring the world by shouting at, listening to, banging and tasting everything.
  • Pre-operational (18-24 months to 7 years): during this stage children can process images, words and concepts but they can't do anything with them, they can't yet operate on them. It's like they've acquired the tools of thought, but don't yet know how to use them. E.g. in maths they can't understand that 2 x 3 is the same as 3 x 2.
  • Concrete operations (7 to 12 years): at this stage children gain the ability to manipulate symbols and objects, but only if they are concrete - abstract operations are still a challenge.
  • Formal operations (12 and up): from here on children are able to think in abstract terms about the world. Now they can understand concepts such as the future, values and justice. From around this age children start thinking like adults.
It's for this grand theory of development that Piaget is much admired. Unfortunately, like many an ambitious theory, over time evidence was uncovered that contradicted aspects of this neat time-line.

For example Piaget's conclusions about his daughter Jacqueline's failure to reach for the duck were probably wrong. Subsequent studies have revealed infants as young as 3.5 months appear to understand object permanence. Psychologists nowadays might explain Jacqueline's behaviour as a failure of memory or an inability to grasp something that is out of view.
In the integral model, formation operations is not the final stage, but for the majority of people it does remain the last developmental stage. For a comprehensive explanation of the integral model, check out this pdf.

As an example of how influential Piaget was, his work influenced Erik Erikson's
theory on social development, Kieran Egan's stages of understanding, Lawrence Kohlberg's stages of moral development, and James W. Fowler's stages of faith development.

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