How did Jean Piaget describe the stages of children’s intellectual development?

Swiss psychologist Jean Piaget proposed that children progress through four distinct stages of intellectual development as they organize and adapt their experiences into increasingly sophisticated cognitive models. While he believed the sequence of these stages is universal, he noted that the specific ages at which children reach them may vary by culture.123

The four stages are:

• Sensorimotor stage (birth–2 years): Infants learn to modify reflexes and coordinate actions to interact with their environment. A key milestone is the development of object permanence, the understanding that objects continue to exist even when out of sight.14
• Preoperational stage (2–7 years): Children develop language and mental imagery. They learn to focus on single perceptual dimensions but often lack an understanding of cause-and-effect relationships or conservation.13
• Concrete-operational stage (7–12 years): Children acquire logical thinking skills and conservation, allowing them to recognize that fundamental properties remain the same despite changes in appearance. They operate best when manipulating concrete objects.13
• Formal-operational stage (12 years–adulthood): Individuals develop the ability to think abstractly, reason systematically, and solve hypothetical problems without needing immediate physical objects.12

It is important to note that while Piaget’s work was foundational, modern research suggests children are often capable of performing mental operations earlier than he originally estimated.1