Jean Piaget

A preschooler draws a picture of their family and places themselves in the center, saying, "Everyone is always with me because I’m the most important!"

A toddler shakes a rattle repeatedly, enjoying the sound it makes, and then tries shaking other objects to see if they produce similar noises.

A teacher pours water from a tall, thin glass into a short, wide one. A 9-year-old confidently states that the amount of water remains the same.

A 15-year-old develops a hypothesis about why plants grow faster in sunlight and designs an experiment to test their idea.

A 17-year-old solves a complex math problem by visualizing abstract concepts and testing multiple scenarios in their head before arriving at the solution.

A 4-year-old sees a toy car behind a glass of water and insists the car is "bigger" because it looks magnified through the glass.

A 5-year-old tells their friend that the moon follows them whenever they walk outside at night.

A 10-month-old searches for a toy hidden under a blanket, even though they can no longer see it.

A 10-year-old explains that breaking a rule, like lying, can have consequences not just for themselves but also for others who depend on their honesty.

A teenager considers the concept of justice and discusses how fairness might differ depending on cultural or societal norms.

A baby drops their spoon from the highchair repeatedly, giggling each time their caregiver picks it up. The baby seems to enjoy testing this cause-and-effect pattern.

An 8-year-old successfully organizes a set of blocks in order of size, from smallest to largest, without needing help.