BCS 111 Lecture 12

Piaget’s Cognitive development stages

• Sensorimotor stage (birth - ~ 1.5 yo)

• Preoperational stage (1.5 – 7 yo)

• Concrete operations stage (7 – 12 yo)

• Formal operations stage ( > 12 yo)

Operation

• Why is it called “operation”?→ Mental operation of “representations”

What is exactly a mental representation?

Simply put: a long-term memory trace of an object/concept/word/event, etc.

• Each box = mental representation

Sensorimotor stage (birth - ~ 1.5 yo)

Building up the “database” of memory representations through sensory input and perception

(cont)

Lack of object permanence: Why peek-a-boo is funny to babies (esp. before 8 mo).

• Due to very weak memory representation of objects → weak concept of “existence”

Preoperational stage (1.5 – 7 yo)

• Burst of vocabulary size

• Arbitrary connection between sound and object

  • Language-specific labels (i.e. words)

(cont)

Egocentric: thinking from one’s own perspective

Development of “Theory of Mind”

Seeing from others’ perspectives: Three-mountain task

Development of Theory of mind in the preoperational stage:

Interpretation of others’ behaviors and feelings

• Seeing from others’ perspectives

• Sympathy

• Lying/cheating

• Socialization

Testing Theory of Mind

Sally-Anne false belief task

Sally (left) has a basket and Anne has a box. Sally put her marble in the basket and then left. Anne moved the marble to the box. Where will Sally look for her marble when she returns?

(cont)

If answer: The box: from “your” (observer’s) perspective (failed the test!)

The basket: Sally’s perspective (evidence of ToM)

Theory of mind

• Children with autism spectrum disorder (ASD): tend to look for the marble in the box

• Delayed development of ToM

Another characteristic of preoperational stage: fail to mentally reverse an action

• Conservation tasks: judge if the two sets of dots are of equal quantity or length

• Preoperational children judge only by perceived difference → incorrect judgment on transformed stimulus

Concrete operations stage (7 – 12 yo)

• Theory of mind developed

• Ability to “reverse” transformation in the conservation task → better judgment

• Developed sense of quantity

Formal operations stage ( > 12 yo)

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Logical thinking

solving abstract logic problems

Reflective abstraction

learning by self-reflection from past experiences

• Capable of abstract mental operations using mental representations

Potential problems with Piaget’s theory

• Does everyone follow those discrete stages of development?

• Age range reliable in each range?

• Theorized based on small sample size (Piaget’s 3 children)

(cont)

Experimenter’s bias in asking questions

One evidence against Piaget’s theory of development: Perceptual development in infancy

• Predictions based on Piaget’s theory: babies in sensorimotor stage should show no differences in their responses when seeing both events.

• HOWEVER, 3-mo babies already show surprisal effect when seeing the impossible event!!

Other views on cognitive development…a review

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Nativism

biologically determined (nature)

Empiricism

learning through experiences (nurture)

Behaviorism

conditioning and reinforcement

Nature vs. Nurture debate

which one plays a bigger role in development

• Some insights from studies of twins who grow apart

• Twins studies show that genes seem to play a bigger role in development, but learning and experiences are still crucial

Other perspectives on cognitive development

Empiricism: Mind as a blank slate at birth

• Knowledge built upon experiences and education

(cont)

Behaviorism

• Learning through conditioning and
  reinforcement

• Stimulus-response

Chomsky’s view of development - Nativism

• Pre-wired biological functions - innateness

• Innate ability to acquire any language regardless of how complex it is

• The input from the environment is not good enough for children to acquire their native language

Brain development

• Growing frontal lobe: developing language, emotion, inhibitory control, etc.

• Growing gyri and sulci

• Development of neural network: expanding connections among regions

Development of Attention

Shift from holistic to analytic approaches as a child gets older

• “Find the two pictures that match exactly.” Older children can do this better than younger children

  • Pay more attention to details/features (analytic approach)

Development of object recognition

• 2-3 yo categorize objects by shape with the same label: “shape bias”

• 12-18 mo don’t show strong shape bias → less attentive to shapes

What if we manipulate the details of the object to examine how children categorize them?

• 16.5 - 29 mo young children divided into 3 groups based on vocabulary size (see next slide)

• English as their first language

• Task: Object identification by pointing at or picking up the picture

Development of object recognition

• 3 subgroups of young children with varying vocabulary size

• Productive vocabulary: words they can produce

(cont)

• Group III showed no sig. diff. among the 3 types of objects

• Among the 3 types of objects, categorization of shape caricature is highly correlated with vocab. size → Larger vocab. size leads to better categorization just by rough sketches of objects

Development of working memory

• Working memory capacity increases with age

• Alternative explanations:

  • Processing speed (instead of memory capacity) increases with age

  • Less familiar with the experimental contexts and procedures at younger ages

Summary: Cognitive development

• Some potential problems with Piaget’s stages of development: age range, sample size, “operations” in each stage

• Nature vs. Nurture: twins studies show that genes seem to play a bigger role in development, but learning and experiences are still crucial.

• Young children (before 3 yo) pay less attention to details of an object in categorization → shape bias shown in 2-3 yo

• Abstraction in categorization develops with vocabulary size.

• Working memory development can also correlate with processing speed and familiarity with the tasks.