Piaget proposed four stages of cognitive development: sensorimotor, preoperational, concrete operational, and formal operational. In the sensorimotor stage from birth to age 2, infants learn through senses and actions. In the preoperational stage from ages 2 to 7, children use symbols but think egocentrically. During the concrete operational stage from ages 7 to 11, children think logically about concrete events. In the final formal operational stage from age 11 onward, adolescents reason abstractly and hypothetically. Piaget's theory emphasized how children construct knowledge through interactions with their environment.

1. Piaget’s Theory of Cognitive
Development
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2. Prefrontal
cortex
Figure 8.1
The Prefrontal Cortex
This portion of the brain (bright blue) shows extensive
development from 3 to 6 years of age and is believed to
play important roles in attention and working memory
2

3. 7.2 Piaget’s Four Stages of
Cognitive Development
The Sensorimotor Stage
The Preoperational Stage
The Concrete Operational Stage
The Formal Operational Stage
3

4. Piaget’s Stages of Cognitive
Development
Inborn Reflexes
Sensorimotor Period
Preoperational Period
Concrete Operations
Formal Operations
(~Birth to 2 yrs)
(~2 to 6 yrs)
(~ 7-12 yrs)
(adolescence to adult)
Piaget’s Stages of Cognitive
Development
4

5. SENSORIMOTOR
STAGE
PREOPERATIONAL
STAGE
CONCRETE
OPERATIONAL
STAGE
FORMAL
OPERATIONAL
STAGE
The infant constructs an
understanding of the
world by coordinating
sensory experiences
with physical actions.
And infant progresses
from reflexive, instinctual
action at birth to the
beginning of symbolic
thought toward the end
of the stage
The child begins to
represent the world with
words and images.
These words and images
reflect increased
symbolic thinking and go
beyond the connection of
sensory information and
physical action.
He child can now reason
logically about concrete
events and classify
objects into different sets
The adolescent reasons
in more abstract,
idealistic, and logical
ways.
Birth to 2 Years of Age 2 to 7 Years of Age 7 to 11 Years of Age
11 Years of Ages
Through Adulthood
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6. 7.2 The Sensorimotor Stage
• From birth to approximately 2 years
• Begins with reflexive responding and ends
with using symbols
• Object permanence: understanding that
objects exist independently
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7. 7.2 The Preoperational Stage
• From approximately 2 to 7 years
• Children use symbols but are many errors in
thinking
> Egocentrism: The inability to distinguish
between one’s own perspective and someone
else’s perspective.
> Confuse appearance and reality
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8. Three Mountains Problem
7.2: The Preoperational Stage
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9. The Three Mountain Tasks
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10. Conservation Tasks
7.2: The Preoperational Stage
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11. Piaget’s Conservation Task
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12. B C
A
B C
A
Figure 8.8
Piaget’s Conservation Task
Child is asked if (A)
and (C) have the same
amount of liquid. The
preoperational child
says “no” and will
point to (C) as having
more liquid than (A).
Two identical beakers
shown to child, and
then experimenter
pours liquid from (B)
into (C)
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13. Type of
conservation Number Matter Length
Initial
presentation Two identical
rows of objects
shown to child
Two identical
balls of clay
shown to child
Two sticks are
aligned in
front of child
Manipulation
One row is
spaced
Experimenter
changes shape
of one ball
Experimenter
moves one
stick to right
Preoperational
child’s answer to
“Are they still
the same?”
“No, the longer
row has more”
“No, the longer
one has more”
“No, the one
on top is
longer”
Figure 8.9
Some Dimensions of Conservation:
Number, Matter, and Length
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14. 7.2 The Concrete Operational
Stage
• From approximately 7 to 11 years
• Thinking based on mental operations
(strategies and rules that make thinking more
systematic and powerful)
• Operations can be reversed
• Focus on the real and concrete, not the
abstract
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15. 7.2 The Formal Operational
Stage
• From approximately 11 years to adulthood
• Adolescents can think hypothetically
• Use deductive reasoning
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16. Object Permanence and the
“Impossible Event”
7.3: Criticisms of the Theory
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17. Theory of Mind
7.4 The Child as Theorist
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18. The Sociocultural Perspective:
Vygotsky’s Theory
• Cognitive development is inseparable from social
and cultural contexts
• Zone of proximal development: difference
between what can do alone or with assistance
• Scaffolding: teaching style that matches
assistance to learner’s needs
The Zone of Proximal Development (ZPD)
student can work with the student can work
assistance of an instructor ________________________ independently
ZPD
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19. 19

20. Vygotsky
• Strong emphasis
• Social constructivist
• No general stages
• Zone of proximal
development, language,
dialogue, tools of the
culture
•It has a major role in
shaping thought
•It has a central role
•Teacher is facilitator
and guide, not director
Piaget
• Little emphasis
• Cognitive constructivist
• Strong emphasis on stages
• Schemata, assimilation,
accommodation, operations,
conservation, classification,
hypothetical-deductive
reasoning
•It has a minimal role
•It just defines existing skills
•Teacher is facilitator and
guide, not director
Figure 8.11
Comparison of
Vygotsky’s and
Piaget’s Theories
Sociocultural Context
Constructivism
Stages
Key processes
Role of language
View on education
Implications for
teacher
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21. Figure 8.13
Developmental Changes in Memory Span
In one study:
memory span
increased
from 3 digits
at age 2, to 5
digits at age
7, to 7 digits
at age 12.
8
0
1
2
3
4
5
6
7
6
2 8 10 Adult
4 12
Age (years)
Digit
Span
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22. Piaget’s Stages of Cognitive Development
22
Sensorimotor Birth to
2 years
Infants know the world through their
senses and through their actions. For
example, they learn what dogs look
like and what petting them feels like.
Preoperational 2 - 7
years
Toddlers and young children acquire
the ability to internally represent the
world through language and mental
imagery. They also begin to be able to
see the world from other people’s
perspectives, not just from their own.

23. Piaget’s Stages of Cognitive Development
23
Concrete
Operational
7 - 12
years
Children become able to think
logically, not just intuitively. They now
can classify objects into coherent
categories and understand that
events are often influenced by
multiple factors, not just one.
Formal
Operational
12+ years Adolescents can think systematically
and reason about what might be as
well as what is. This allows them to
understand politics, ethics, and
science fiction, as well as to engage
in scientific reasoning.

24. Sensorimotor Substages
24
Sub Age Description
1
Birth – 1
month
Infants begin to modify the
reflexes with which they are born
to make them more adaptive.
2
1 – 4
months
Infants begin to organize
separate reflexes into larger
behaviors, most of which are
centered on their own bodies.

25. Sensorimotor Substages
25
Sub Age Description
3
4 – 8
months
Infants becoming increasingly
interested in the world around them.
By the end of this substage, object
permanence, the knowledge that
objects continue to exist even when
they are out of view, typically emerges.
4
8 – 12
months
During this substage, children make
the
A-Not-B error, the tendency to reach
to where objects have been found
before, rather than to where they were
last hidden.

26. Object permanence
 Objects are tied to infant’s awareness of
them
– “out of sight, out of mind”
 Hidden toy experiment
– 4 months: no attempt to search for hidden
object
– 4-9 months: visual search for object
– 9 months: search for and retrieve hidden object
 A-not-B task (Diamond, 1985)
– 9 months: A/B error after 1/2 second delay
– 12 months: 10 second delay needed to produce
error
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27. Piaget’s A-Not-B Task
27

28. Sensorimotor Substages
28
Sub Age Description
5
12 – 18
months
Toddlers begin to actively and
avidly explore the potential uses
to which objects can be put.
6
18 – 24
months
Infants become able to form
enduring mental representations.
The first sign of this capacity is
deferred imitation, the repetition
of other people’s behavior a
substantial time after it occurred.

29. Preoperational Stage
 A mix of impressive cognitive
acquisitions and equally
impressive limitations
– A notable acquisition is symbolic representation, the use
of one object to stand for another, which makes a variety of
new behaviors possible
– A major limitation is egocentrism, the tendency to perceive
the world solely from one’s own point of view
– A related limitation is centration, the tendency to focus on
a single, perceptually striking feature of an object or event
– Preoperational children also lack of understanding of the
conservation concept, the idea that merely changing the
appearance of objects does not change their key properties
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30. Piaget’s Three-Mountain Task
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31. Egocentric Conversations
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32. The Balance Scale: An Example of Centration
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33. 33
Procedures Used to Test Conservation

34. Concrete Operational Stage
 Children begin to
reason logically
about the world
 They can solve
conservation
problems, but their
successful reasoning
is largely limited to
concrete situations
 Thinking
systematically
remains difficult
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35. Inhelder and Piaget’s Pendulum Problem
 The task is to compare the
motions of longer and
shorter strings, with lighter
and heavier weights
attached, in order to
determine the influence of
weight, string length, and
dropping point on the time it
takes for the pendulum to
swing back and forth
 Children below age 12
usually perform
unsystematic experiments
and draw incorrect
conclusions
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36. Formal Operational Stage
 Cognitive development culminates in the
ability to think abstractly and to reason
hypothetically
 Individuals can imagine alternative worlds
and reason systematically about all
possible outcomes of a situation
 Piaget believed that the
attainment of the formal
operations stage, in
contrast to the other
stages, is not universal
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37. Implications for Education
 Piaget’s view of children’s cognitive development
suggests that children’s distinctive ways of
thinking at different ages need to be considered in
deciding how best to teach them
 In addition, because children learn by mentally
and physically interacting with the environment,
relevant physical activities,
accompanied by
questions that call
attention to the lessons
of the activities, are
important in
educational practice
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38. Critique of Piaget’s Theory
 Although Piaget’s theory remains highly
influential, some weaknesses are now
apparent
– The stage model depicts children’s thinking as
being more consistent than it is
– Infants and young children are more cognitively
competent than Piaget recognized
 Object permanence in 3-month-olds (Bower,
1974)
 Number conservation in 4 year olds
(McGarrigle & Donaldson, 1974)
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39. Critique of Piaget’s Theory
– Piaget’s theory understates the contribution of
the social world to cognitive development
 Piaget’s tasks are culturally biased
 Schooling and literacy affect rates of development
– e.g. Greenfield’s study of the Wolof
 Formal operational thinking is not universal
– e.g. Gladwin’s study of the Polynesian islanders
– Piaget’s theory is vague about the cognitive
processes that give rise to children’s thinking
and about the mechanisms that produce
cognitive growth
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