• Sensorimotor stage (birth to 2 years): Children learn through sensory experiences and exploring their environment.
• Preoperational stage (2 to 7 years): Children begin to use language to think and communicate, but their thinking is still egocentric (centered on their own perspective).
• Concrete operational stage (7 to 11 years): Children can reason logically and begin to understand the concept of conservation (e.g., that the amount of liquid in a glass remains the same even if poured into a different container).
• Formal operational stage (11+ years): Adolescents can engage in abstract and hypothetical thinking, and can solve problems using logical and systematic reasoning.

This theory has been widely influential in education, but has also been criticized for not fully capturing the complexity of human thought and development.