Piaget built his theories about children's development by observing his own children

How Piaget Learned About How Children Think

If you’ve ever watched a child stack blocks, chase a ball, or pretend a banana is a telephone, you’ve caught a glimpse of Piaget’s world. He cared less about labels and more about what goes on inside a child’s mind as it grows. The big question he asked wasn't “What can a child do?” so much as “How does a child come to know what they know?” The most straightforward answer, and the one we still lean on today, is this: Piaget developed most of his theories by observing his own children. It’s a story of patient watching, curious questions, and a belief that thinking unfolds in real time, right before our eyes.

The humble start: a parent’s curiosity turned into a theory factory

Let me explain how it happened. Piaget wasn’t content with tidy lab results or abstract ideas alone. He believed cognitive development was best understood by watching kids in action—how they play, solve problems, and explain their thoughts. He began with the simplest tasks, the kind you and I might hand to a toddler: a toy, a puzzle, a visible problem to solve. Then he watched what the child did, how they approached the problem, where they hesitated, where they improvised.

He didn’t rely on large-scale experiments in a classroom or a school on day one. He observed his own children and a few other young minds up close, noting patterns in their thinking as it emerged across time. This wasn’t about collecting data to fit a preconceived theory; it was about letting the mind reveal its current stage through natural actions. The result was a family-sized but still universal map of how children learn—one that felt less like a set of rules and more like a narrative of growing minds.

From there to the four stages: a tripod for understanding children's thinking

Piaget didn’t just notice little changes and call them breakthroughs. He proposed concrete milestones—stages—that describe the typical way thinking changes as children grow. The stages aren’t rigid borders you step across in a day; they’re evolving ways of knowing that feel like a natural progression.

1. Sensorimotor stage (birth to about 2 years)

In these early years, thinking is all about action. Babies learn through touching, moving, mouthing, and exploring the world directly. They begin to understand object permanence—the idea that something exists even when they can’t see it. Think of a game where you hide a toy under a blanket: some babies will search, others seem to forget the toy exists. For Piaget, these moments were clues about how babies start to connect actions with outcomes.

2. Preoperational stage (roughly 2 to 7 years)

Language blossoms, symbols appear, and imaginary play takes off. But this is also a time when thinking can be egocentric; a child may have a hard time taking another person’s point of view. They’re great at making scenes out of blocks or doll play but often struggle with rules that require logical thinking about other people’s perspectives. It’s a vivid window into how imagination and social understanding grow side by side.

3. Concrete operational stage (about 7 to 11 years)

Here, kids begin to think more logically about concrete objects and events. They grasp concepts like conservation (the idea that quantity doesn’t change just because the arrangement changes) and understand more than one aspect of a problem at once. Tasks that stump a younger child can start to click when the child uses real props and concrete examples.

4. Formal operational stage (12 years and up)

Abstract reasoning becomes possible. Teens can formulate hypotheses, test them, and think about possibilities that aren’t anchored in the present moment. They can reason about hypothetical situations, elaborate plans, and systems of thought. It’s not that every adolescent hits every stage perfectly, but the trend is clear: thinking broadens from concrete things to ideas that live in the realm of “what might be.”

What Piaget’s method added to the mix

You might wonder how watching his own kids translates into a theory that’s used by teachers and researchers. The strength of Piaget’s observational approach is that it foregrounds the child as an active explorer. Children aren’t blank slates to be filled with facts; they’re builders who test ideas, revise strategies, and learn by doing. This is where his ideas started to shape classrooms and educational philosophy.

• Active learning matters: If children learn by doing, then giving them chances to manipulate, experiment, and discover is a good thing.

• Readiness has a point: The brain needs to reach a certain level of maturity to handle particular kinds of thinking. It’s not about rushing kids to the next stage; it’s about aligning activities with where their thinking naturally sits.

• Mistakes aren’t failures; they’re signals: When a child slips into a preoperational mindset, a teacher can gently guide them toward more logical ways of testing ideas.

In other words, Piaget’s work offered a gentle nudge toward classrooms that honor exploration, questions, and hands-on problem-solving. You can hear it in the way many early education settings now emphasize play-based learning, discovery stations, and tasks that invite students to think through problems rather than memorize fixed answers.

A few classroom-ready takeaways (without turning the clock back)

If you’re studying for topics around Piaget, here are practical takeaways you can tuck into your notes, ready to be discussed in class or woven into lesson planning:

• Match activities to the child’s current way of thinking

• In the sensorimotor phase, emphasize sensory play and simple cause-and-effect games.

• In the preoperational stage, provide plenty of symbolic play and story-based tasks, but add perspective-taking prompts.

• In concrete operational tasks, use concrete objects and hands-on experiments that require logical thinking with real materials.

• In the formal operational stage, offer abstract problems, hypothetical scenarios, and opportunities to argue from different viewpoints.

• Encourage active problem-solving

• Pose questions that invite children to test ideas: “What would happen if we…” or “Why do you think this happened?”

• Let them fail safely and try again. A little trial-and-error is a powerful teacher when guided with questions.

• Use concrete supports

• Visuals, manipulatives, and real-life examples help bridge the gap between thinking and doing, especially in the earlier stages.

• Observe, don’t over-structure

• Just as Piaget did with his own children, observe what ideas emerge naturally. If you’re a teacher, notice how children approach a task and adjust prompts to foster deeper thinking.

A quick caveat: where Piaget’s view meets modern science

Piaget’s observations were groundbreaking, but they’re not the final word on child development. Critics point out that:

• The samples were relatively small and culturally specific. Some argue that children in different cultures may reach milestones at different times or show different patterns of thinking.

• The stages describe general trends, not strict milestones everyone must hit at the same ages.

• Some contemporary researchers emphasize the role of social interaction and guided learning more than Piaget did.

That doesn’t erase his influence. Instead, it sits as a reminder that ideas evolve as new methods and broader samples emerge. The core value remains: development is a process, not a single moment of change, and children learn best when they are active, curious, and supported in exploring their world.

Let’s connect the dots beyond the room

It’s easy to miss just how personal Piaget’s approach was—how a parent’s curiosity stitched together with careful observation can reframe a field. But the impact lands in real classrooms. When teachers design experiences that let kids explore, test, and reflect, they’re following a thread Piaget started more than a century ago.

Consider a simple morning in a busy preschool. A table set with water, cups, and various containers invites children to pour, measure, and compare. Ask a few open questions: “What do you notice about these amounts?” “Why did this cup fill faster than that one?” You’ll likely see children revising their ideas, drawing on prior play, and adjusting their strategies. That’s Piagetian thinking in motion: learning through doing, adapting as thinking grows more precise.

A personable closing thought: the mind is a working garden

Piaget didn’t pretend that mind growth is a fixed destination. Think of it as a garden that keeps changing with each season. In the early days, a child might splash water and discover that a full cup isn’t heavier; later, they’ll reason about balancing equations in their head, even if the math feels far away from pouring water. The continuity between these moments—between the concrete actions of a toddler and the abstract reasoning of a teen—illustrates a journey that’s both wonderfully human and scientifically informative.

If you’re studying Piaget for your curriculum or your own professional growth, remember this: his most enduring contribution wasn’t a single theory but a lens. It’s a lens that invites us to pause, watch, and listen to children as they think through problems in real time. It’s a reminder that learning is an active process—a collaboration between curious minds and the world they’re trying to understand.

In the end, Piaget’s method—watching his own children, then watching countless others—gave us a blueprint that still feels fresh. It invites teachers to create spaces where thinking can happen, not just where information is handed out. And it invites students to bring their questions, their missteps, and their most creative ideas to the center of the learning moment. That, more than anything, is the heartbeat of Piaget’s legacy.