Jean Piaget's theory of cognitive development outlines four stages: sensorimotor, preoperational, concrete operational, and formal operational. The sensorimotor stage from birth to age 2 involves developing object permanence through interacting with the environment. During the preoperational stage from ages 2 to 7, children can use symbols and language but still cannot perform logical operations. Piaget found that preoperational children fail conservation tasks because they cannot apply the logical principles of reversibility, compensation, and identity.

1. Jean Piaget’s Theory of
Cognitive Development

2. Outline
• (1) General introduction.
• (2) Sensory-Motor period.
• (3) Pre-operational period.
• (4) Concrete operations.
• (5) Formal operations.
• (6) Evaluation.

3. I: Terms and concepts.

4. Genetic Epistemology: A
constructivist theory
• No innate ideas...not a nativist theory.
• Nor is the child a “tabula rasa” with the
“real” world out there waiting to be
discovered.
• Instead, mind is constructed through
interaction with the environment; what is
real depends on how developed one’s
knowledge is

5. How does Piaget describe
developmental change?
• Development occurs in stages, with a
qualitative shift in the organization and
complexity of cognition at each stage.
• Thus, children not simply slower, or less
knowledgeable than adults  instead, they
understand the world in a qualitatively
different way.
• Stages form an invariant sequence.

6. Stages of Cognitive Development
• (1) Sensorimotor (0-2 years)
• (2) Pre-operational (2-7 years)
• (3) Concrete Operational (7-11 years)
• (4) Formal Operational (11-16 years)

7. What develops? Cognitive
structures
• Cognitive structures are the means by which
experience is interpreted and organized:
reality very much in the eye of the beholder
• Early on, cognitive structures are quite
basic, and consist of reflexes like sucking
and grasping.
• Piaget referred to these structures as
schemes.

8. How do cognitive structures
develop?
• Through assimilation and accomodation.
• Assimilation: The incorporation of new
experiences into existing structures.
• Accommodation: The changing of an old
structures so that new experiences can be
processed.
• Assimilation is conservative, while
accommodation is progressive.

9. Why accommodate?
• Normally, the mind is in a state of
equilibrium: existing structures are stable,
and assimilation is mostly occurring.
• However, a discrepant experience can lead
to disequilibrium or cognitive “instability”
• Child forced to accommodate existing
structures.

10. Active view of development
• Child as scientist
• Mental structures intrinsically active 
constantly being applied to experience
• Leads to curiosity and the desire to know
• Development proceeds as the child actively
refines his/her knowledge of the world
through many “small experiments”

11. Instructional learning viewed as
relatively unimportant
• Teachers should not try to transmit
knowledge, but should provide
opportunities for discovery
• Child needs to construct or reinvent
knowledge  adult knowledge cannot be
formally communicated to the child
• Limited importance of socio-cultural
context; importance of peer interaction.

12. II: The Sensorimotor Period
(0-2 years)
• Only some basic motor reflexes grasping,
sucking, eye movements, orientation to
sound, etc
• By exercising and coordinating these basic
reflexes, infant develops intentionality and
an understanding of object permanence.

13. II: The Sensorimotor Period
(0-2 years)
• Intentionality refers to the ability to act in a
goal-directed manner  in other words, to
do one thing in order that something else
occurs.
• Requires an understanding of cause and
effect

14. II: The Sensorimotor Period
(0-2 years)
• Object permanence refers to the
understanding that objects continue to exist
even when no longer in view.
• Need to distinguish between an action and
the thing acted on.

15. Stage 1 (0-1 month)
• Stage of reflex activity.
• Many reflexes like reaching, grasping
sucking all operating independently.
• Objects like "sensory pictures".
• Subjectivity and objectivity fused.
• Schemes activated by chance: No
intentionality.

16. Stage 2 (1-4 months)
• Stage of Primary Circular Reactions.
• Infant’s behaviour, by chance, leads to an
interesting result & is repeated.
• Circular: repetition.
• Primary: centre on infant's own body.
• Example: thumb-sucking.

17. Object concept at stage 2
• Passive expectation: if object disappears,
infant will continue looking to the location
where it disappeared, but will not search.
• In the infant mind, the existence of the
object still very closely tied to schemes
applied to experience

18. Intentions at stage 2
• Intentionality beginning to emerge: infant
can now self-initiate certain schemes (e.g.,
thumb-sucking)

19. Stage 3 (4-8 months)
• Stage of Secondary Circular Reactions
• Repetition of simple actions on external
objects.
• Example: bang a toy to make a noise.

20. Intentionality at stage 3
• Poor understanding of the connection
between causes and effect limits their
ability to act intentionality.
• “Magical causality”  accidentally banging
toy makes many interesting things happen

21. Object concept at stage 3
• Visual anticipation.
• If infant drops an object, and it disappears,
the infant will visually search for it.
• Will also search for partially hidden objects
• But will not search for completely hidden
objects.

22. Stage 4 (8-12 months)
• Co-ordination of secondary circular
reactions.
• Secondary schemes combined to create new
action sequences.

23. Intentionality at Stage 4
• First appearance of intentional or in Piaget’s
terms, means-end behavior.
• Infant learns to use one secondary scheme
(e.g., pulling a towel) in order that another
secondary scheme can be activated (e.g.,
reaching and grasping a toy)

24. Object concept at stage 4
• Infant will search for hidden objects.
• Does infant understand the object as
something that exists separate from the
scheme applied to find the object?
• No. Evidence?
• A not B error.

25. The A not B task
The A not B task
1 A trials

26. The A not B task
The A not B task
1 A trials

27. The A not B task
The A not B task
1 A trials

28. The A not B task
The A not B task
2 A trials

29. The A not B task
The A not B task
2 A trials

30. The A not B task
The A not B task
2 A trials

31. The A not B task
The A not B task
B trials

32. The A not B task
The A not B task
B trials

33. The A not B task
??
B trials

34. A not B error
• Infant continues to search at the first hiding
location after object is hidden in the new
location.
• Object still subjectively understood.
• Object remains associated with a previously
successful scheme.

35. Stage 5 (12-18 months)
• Stage of Tertiary Circular Reactions.
• Actions varied in an experimental fashion.
• Pursuit of novelty
• New means are discovered.
• Limited to physical actions taken on objects

36. Object concept at stage 5.
• Can solve A not B.
• Cannot solve A not B with invisible
displacement (Example from Piaget).

37. Stage 5 and invisible
displacement
• Can only imagine the object as existing
where it was last hidden.
• Invisible displacement requires the infant to
mentally calculate the new location of the
object.

38. Stage 6 (18-24 months)
• Can solve object search with invisible
displacement.
• Infants now mentally represent physically
absent objects.
• Understands object as something that exists
independently of sensory-motor action.

39. Stage 6 (18-24 months)
• Sensori-motor period culminates with the
emergence of the Symbolic function
• An idea or mental image is used to stand-in
for a perceptually absent object
• Trial-and-error problem solving does not
need to enacted but can undertaken through
mental combination.

40. Summary
• Sensori-motor period culminates in the
emergence of symbolic representation.
• Object permanence understood.
• Basic means-ends skills have emerged.

41. Piaget – Part 2
Beyond the sensorimotor period

42. III: The pre-operational period
• Symbolic thought without operations.
• Operations: logical principles that are
applied to symbols rather than objects.
• 3 examples: reversibility, compensation,
and identity
• In the absence of operations, thinking is
governed more by appearance than logical
necessity.

43. Pre-operational thinking and
problems of conservation

44. Pre-operational thinking and
problems of conservation
Conservation of liquid

45. Pre-operational thinking and
problems of conservation

46. Pre-operational thinking and
problems of conservation

47. Pre-operational thinking and
problems of conservation

48. Pre-operational thinking and
problems of conservation

49. Pre-operational thinking and
problems of conservation

50. Pre-operational thinking and
problems of conservation

51. Pre-operational thinking and
problems of conservation
• Why do pre-operational children fail
problems of conservation?
• Because their thinking is not governed by
principles of reversibility, compensation
and identity

52. Pre-operational thinking and
problems of conservation
Reversibility: The pouring
of water into the small
container can be reversed.

53. Pre-operational thinking and
problems of conservation
Compensation: A decrease
in the height of the new
container is compensated by
an increase in its width

54. Pre-operational thinking and
problems of conservation
Identity: No amount of
liquid has been added or
taken away.

55. Pre-operational thinking and
problems of conservation
• Why do pre-operational children fail
problems of conservation?
• Because their thinking is not governed by
principles of reversibility, compensation
and identity
• If children applied these principles, they
would conclude liquid is conserved

56. Characteristics of Pre-Operational
Thinking
• Not governed by logical operations
• Consequently, it appears egocentric (e.g., 3
mountains task) and intuitive (e.g.,
conservation tasks)

57. 3 Mountains Task
Doll 1 Doll 2
Child

58. 3 Mountains Task
Doll 1 Doll 2
Child

59. Characteristics of Pre-Operational
Thinking
• (1) Egocentric
• (2) Intuitive  problem solving is not
reasoned or logical

60. Nature of intuitive reasoning
• No reversibility  Cannot mentally undo a
given action.
• Perceptual centration Focus on only one
dimension of a problem.
• States versus transformations 
Transformations relating different states
ignored.

61. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.

62. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.
• Examples:
(3) Other conservation problems.

63. Conservation of mass

64. Conservation of mass

65. Conservation of mass

66. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.
• Examples:
(3) Other conservation problems.

67. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.
• Examples:
(3) Other conservation problems.
(4) Emotion reasoning.

68. Emotion reasoning

69. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.
• Examples:
(3) Other conservation problems.
(4) Emotion reasoning.
(5) Moral reasoning.

70. What makes Pre-operational
thinking stage-like?
• Because it appears to be a general
characteristic of children’s thinking at this
age.
• Examples:
• Other conservation problems.
• Emotion reasoning.
• Moral reasoning.  focus on consequences

71. IV: Concrete operational thinking
(7-12 years)
• Qualitatively different reasoning in
conservation problems.
• Flexible and decentered.
• Co-ordination of multiple dimensions.
• Logical vs. empirical problem solving.
• Reversibility.
• Awareness of transformations.

72. IV: Concrete operational thinking
(7-12 years)
• Physical operations now internalized and
have become cognitive
• Still, logic directed at physical or concrete
problems

73. Horizontal decalage
• Different conservation problems solved at
different ages.
• Some claim it is a threat to Piaget’s domain
general view of cognitive development
• Example: volume vs mass
• But, invariant sequence observed.

74. V: Formal operations
• Thought no longer applied strictly to
concrete problems.
• Directed inward: thought becomes the
object of thought.
• Advances in use of deductive and inductive
logic

75. V: Formal operations
• Deductive thought in period of concrete
operations confined to familiar everyday
experience: “If Sam steals Tim’s toy, then
how will Tim feel?”
• Formal operations: “If we could eliminate
injustice, would the world live in peace?”
• Thinking goes beyond experience, more
abstract

76. Inductive reasoning
• Example: Pendulum problem
• Scientific thinking: from specific
observations to general conclusions through
hypothesis-testing

77. Inductive reasoning
• Example: Pendulum problem
How fast?

78. Inductive reasoning
• Formal operational children will
systematically test all possibilities before
arriving at a conclusion

79. VI: Evaluating Piaget
• Difficult.
• An enormous theory.
• Covers many ages and issues in
development.

80. Strengths
• Active rather than passive view of the child.
• Revealed important invariants in cognitive
development.
• Errors informative.
• Perceptual-motor learning rather than
language important for development.
• Tasks.

81. Weaknesses
• The competence-performance distinction

82. Competence
• Knowledge, rules, and concepts that form
the basis of cognition.
• Inferred from behaviour.

83. Performance
• Energy level, interest, attention, language
skills, motivation etc.
• Factors that effect the expression of a
competence.

84. Competence-performance
distinction.
• Piaget attributed infants success (or lack of
success) to competence.
• However, he gave no consideration to
performance factors that may have
constrained the expression of knowledge.
• Example: A not B

85. Performance-competence
distinction and A not B
• A not B errors thought to indicate poor
understanding of objects.
• However, motor components of the task
may constrain the expression of infants
knowledge.
• Example: Baillergeon.
• Object permanence observed in 5 month-
olds using a looking time task.

86. Other examples
• Borke (1975) & the 3 mountains task.
• Bruner (1966) & the liquid conservation
task.
• More detailed task analysis required.

87. Stages?
• Stage like progression only observed if one
assumes a bird-eye view.
• Closer inspection reveals more continuous
changes (Siegler, 1988).

88. Summary
• Piaget’s theory is wide-ranging and
influential.
• Source of continued controversy.
• People continue to address many of the
questions he raised, but using different
methods and concepts.