Piaget's Stage Theory and the Three Mountains Task

How thinking develops 🧠

A two-year-old and a fifteen-year-old do not just know different amounts; they **think in different ways**. Explaining how that changes is what developmental psychology is about. This module follows the most famous theory, by Jean **Piaget**, and the clever task that revealed how a young child sees the world.

The developing brain 🧬

Thinking depends on the brain, which develops from its main parts: - The **forebrain**: higher thinking, memory and decisions. - The **midbrain**: relays signals between areas. - The **hindbrain**, including the **cerebellum** (balance and coordination) and the **medulla** (vital functions like breathing and heart rate).

Match each brain part to its job

Schemas and how they grow 🧩

Piaget said we understand the world through **schemas**: mental frameworks or "files" for ideas. Schemas grow in two ways: - **Assimilation**: fitting new information INTO an existing schema. - **Accommodation**: CHANGING a schema (or making a new one) when new information does not fit. When our schemas make sense of the world, we reach **equilibrium**, a settled understanding.

Fit in or change?

A child calls every four-legged animal "dog". They meet a cat and simply add it to their "dog" schema. What is this?

• Assimilation: fitting new information into an existing schema
• Accommodation: changing the schema
• Equilibrium
• Object permanence

Four stages of thinking 📶

Piaget said all children pass through four stages in the same order: - **Sensorimotor** (0 to 2): learns through senses; develops object permanence. - **Pre-operational** (2 to 7): egocentric; lacks conservation. - **Concrete operational** (7 to 11): can conserve and think logically about real things. - **Formal operational** (11+): can reason abstractly and hypothetically.

The stages in order

An interactive activity.

Match each stage to its key feature

The Three Mountains Task ⛰️

To test young children, Piaget and Inhelder used the **Three Mountains Task**. A child sat at a model of three mountains, and a doll was placed at a different side. When asked to choose what the DOLL could see, young children chose the view they themselves saw, not the doll's. This revealed **egocentrism**.

Reading the task

In the Three Mountains Task, young children described the mountains only as they themselves saw them. What did this show?

• Egocentrism: pre-operational children struggle to see another point of view
• That they had object permanence
• That they could conserve number
• That they could reason abstractly

Working out a stage

An interactive activity.

Sorting Piaget

Select ALL THREE statements about Piaget's theory that are TRUE.

• A schema is a mental framework for understanding the world
• Object permanence develops in the sensorimotor stage
• Piaget's theory was very influential in education
• Assimilation means changing a schema
• Children can think in the formal operational way from birth
• The Three Mountains Task showed conservation

Strengths and weaknesses ⚖️

Piaget's theory was hugely influential: it showed that children think differently from adults and learn by actively doing, transforming education. But critics argue he **underestimated children** (later studies found some abilities earlier than he claimed), and that the stages are **not as fixed** as he suggested, with children varying more than the neat ages imply.

Piaget summary

Piaget said children pass through four stages. A _____ is a mental framework; fitting new information into one is _____, while changing it is accommodation. In the pre-operational stage children are _____, as the Three Mountains Task showed. Abstract reasoning appears in the _____ operational stage.