Topic 3.4 Notes – Cognitive Development Across the Lifespan

How Cognitive Development Changes Thinking Across the Lifespan

A lot of this topic makes more sense once you hold onto one idea. Development is both continuous and discontinuous.

• Continuous change means thinking is always being adjusted through experience.
  • A schema is a mental framework, or a category your mind uses to organize information.
  • Assimilation happens when you fit new information into a schema you already have.
    • Example: a child sees a butterfly and calls it a bird.
  • Accommodation happens when the old schema no longer works, so it gets changed or a new one is made.
    • Example: the child learns butterflies are insects, not birds.

Piaget said the child is an active constructor of knowledge. Kids are building and revising ideas, not just soaking up facts. Vygotsky agreed development matters, but he emphasized something else. He saw the child as a social learner whose thinking is shaped by other people and culture.

Piaget’s Four Stages of Cognitive Development

Piaget divided cognitive development into four broad stages, each with its own way of thinking.

Piaget’s four stages of cognitive development

Sensorimotor stage

Birth to about age 2. Knowledge comes through senses and actions.

• The key idea is object permanence.
• This means understanding that objects still exist even when you can’t see them.
• In the classic hidden-object task, a baby with object permanence will search for the toy after it is covered.

Preoperational stage

About ages 2 to 7. Symbolic thinking grows fast.

• Kids use words, images, and pretend play.
• They also show several classic limits:
• Conservation means knowing quantity stays the same even if appearance changes.
• Reversibility means mentally undoing a change.

Conservation of liquid task

• Egocentrism means difficulty seeing from another person’s point of view. In Piaget’s three-mountains task, children often pick their own view instead of the doll’s.
• Animism means giving lifelike qualities to nonliving things.
• Theory of mind begins developing here. This is understanding that other people have different beliefs, desires, and knowledge.

Sally-Anne false-belief task

A child who passes a false-belief task knows someone else can believe something that is wrong.

Concrete operational stage

About ages 7 to 11. Thinking becomes logical for real, familiar situations.

• Children now succeed at conservation and use reversibility.
• They can classify, put things in order, and handle simple cause and effect.
• Abstract and hypothetical thinking is still weak.

Formal operational stage

About age 12 and up. Abstract and hypothetical reasoning becomes possible.

• People can test hypotheses and isolate variables.
• Piaget’s pendulum problem checks this. A formal thinker changes one variable at a time.
• Piaget also said not all adults use formal operational thinking all the time.

What Piaget Got Right and Where His Theory Is Limited

Piaget was right that children think differently from adults. That idea was huge. He also made thinking visible by turning it into tasks.

Limits matter too:

• Stage ages are approximate
• Development can be uneven
• Children may do better when tasks use simpler language or less memory
• Culture and schooling affect performance

One test favorite:

• Object permanence = hidden object still exists
• Conservation = quantity stays the same after appearance changes

Vygotsky’s Sociocultural Theory

Vygotsky said cognitive development happens through interaction with more knowledgeable others. Culture matters because language, tools, values, and teaching methods shape thinking.

He did not propose universal stages.

Zone of proximal development

The zone of proximal development is the gap between what you can do alone and what you can do with help. Best learning happens in that gap.

Scaffolding

Scaffolding is temporary support matched to the learner’s need.

1. A helper models or gives hints
2. The task is broken into manageable parts
3. Feedback guides the learner
4. Support is gradually removed

That matters for Piaget too. Piaget stressed independent discovery. Vygotsky stressed guided learning. On the AP exam, treat them as different emphases, not enemies.

Cognitive Development in Adulthood

Crystallized and fluid intelligence

Typical aging vs. dementia

Normal aging can include slower processing and occasional retrieval problems.

Dementia is major cognitive decline that interferes with daily functioning. It can affect memory, reasoning, judgment, attention, and language. It is not a normal part of aging.

Alzheimer’s disease is a common cause of dementia, but the terms are not the same.