Piaget’s stages of intellectual development

• Piaget’s theory explains how knowledge is acquired through schema and disequilibrium /equilibration. He also explained cognitive development as a set of stages, each characterised by a different level of reasoning ability. Exact ages vary but all children go through the same sequence of stages.
• Sensorimotor 0-2 years

  A baby's focus is on physical sensations and basic co-ordination between what they see and body movement. Babies also develop object permanence: the understanding that objects still exist when they are out of sight:

  • Before 8 months, babies immediately switch their attention away from an object once it is out of sight.
  • After 8 months babies continue to look for it. This suggests that babies then understand that objects continue to exist when removed from view.
• Pre-operational 2-7 years (1/3)

  Conservation was tested e.g. by pouring water from wider glass into tall, thin one and asking children if the two glasses held the same amount of liquid. Pre-operational said no (because they looked different). They were not able to understand that quantity remains constant even when the appearance of objects changes.
• Pre-operational 2-7 years (2/3)

  Egocentrism was tested in the three mountains task (Piaget and Inhelder), each mountain had a different feature: a cross, a house or snow. Pre-operational children tended to find it difficult to select a picture that showed a view other than their own.
• Pre-operational 2-7 years (3/3)

  Class inclusion was tested, e.g. using a picture of five dogs and two cats, 'Are there more dogs or animals?' Pre-operational children tend to respond that there are more dogs (Piaget and Inhelder). They cannot simultaneousy see a dog as a member of the dog class and the animal class.
• Concrete Operations 7-11 years

  Children have mastered conservation and are improving on egocentrism and class inclusion. However they are only able to reason or operate on physical objects in their presence (concrete operations).
• Formal Operations 11+ years

  Abstract reasoning develops - being able to think beyond the here and now. Children can now focus on the form of an argument and not be distracted by its content. For example, they can process syllogisms: All yellow cats have two heads. I have a yellow cat called Charlie. How many heads does Charlie have?' The answer is two but younger children are distracted by the fact that cats do not have two heads.