Piaget's Theory

Assimilation - Absorbing new information into existing mental constructs.
Accommodation - Modifying mental contracts to fit new information

Sensory-motor (-2yr)

• Differentiates self from physical objects
• Recognizes ability to interact with psychical world
• Achieves object permanence
• eg: understands object exists when not in view

Pre-operational  (2-7)

• Learns language
• Can represent things with images and words
• Very self-centered world view
• Classifies objects by single feature

Concrete operational  (7-11)

• Capable of logical thinking
• Achieves conservation of number
• Can classify objects based on several features
• Can order objects based on single attribute

Formal operational  (11

• Ability of think logically
• Think abstracticly
• Systematic testing of hypothesi
• More concern with hypothetical
• future and ideological problems

Current views

• Non-discreet but continual and overlapping
• Pre-schoolers are not as egocentric
• Children/infants display cognitive development 
• Culuture and education