1. Discontinuous (qualitative) change Invariant sequence
Stages involve
Discontinuous (qualitative) change
Invariant sequence
Stages are never skipped

2. Sensorimotor Stage (birth-2 years)
Newborns have reflexes (motor behavior) and basic perceptual abilities
Refine these innate responses (accommodation) during the first month of life

3. Gradually become capable of repeating satisfying behaviors that initially occurred by chance

4. First learn to repeat actions involving their own body
Ex: thumb sucking
Then learn to repeat actions involving objects
Ex: shaking rattle

5. Object Permanence: Understanding that objects continue to exist when they cannot be perceived directly
Infants have some understanding of object permanence at around 8 months

6. A-not-B error: Tendency to reach where objects have been found before, rather than where they were last hidden
Infants make this error until about 12 months of age

7. From 12 months on, infants increasingly engage in active exploration of objects and their functions

8. At end of sensorimotor stage, mental representations develop
Deferred Imitation: Imitation of a behavior after a period of delay
Implies mental representation (memory)

9. Egocentrism: Tendency to focus on one’s own viewpoint and ignore others’ perspectives
Ex: 3 Mountains Task

11. Centration: Tendency to focus on one feature of an object or event to the neglect of other important features

12. Conservation: Understanding that certain physical characteristics of objects remain the same even when their outward appearance changes