Cognitive Development

With thanks to Jen Brace

Jean Piaget• “Father” of cognitive

development• Studied his children

Jacqueline, Lucienne & Laurent

• Where does knowledge come from?

Piaget’s Theory of Development

• Stage theory– Children think differently in different stages but

similarly within a stage– Prolonged period of time in a stage, relatively

abrupt transition to next stage• Four stages

– Sensorimotor, Preoperational, Concrete Operational and Formal Operational

Piaget’s Theory of Development

• 3 processes to move between stages– Assimilation: Transform incoming information to

fit existing way of thinking– Accommodation: Adapt thinking to new

experiences– Equilibration: Integrate pieces of knowledge into

unified whole

Sensorimotor Period• From birth to ~2 yrs old• Actions progress from simple

reflexes to deliberate movements

• Object permanence – realize object still exists even when it can’t be perceived

• Internal representation – ability to think about objects/events not immediately present

Preoperational Period• From ~2 yrs to ~7 yrs• Learn to use symbols, signs and language• Egocentrism – cannot understand another person’s point of

view (but nursery school pics/code switching)• Failure of conservation – do not yet understand that

quantity remains the same despite appearance

Concrete Operational Period

• From ~7 yrs to ~11 yrs• Thinking becomes systematic, quantitative and

logical• Success at all conservation tasks – number, solid

quantity, liquid quantity• Decentration of perception – ability to classify

objects in terms of more than one dimension

Formal Operational Period• From ~11 yrs to adult• Apply logical and systematic

thought to abstract problems• Deductive reasoning – specific

conclusions based on general hypotheses

• Inductive reasoning – make generalizations based on specific observations

• Handling multiple variables simultaneously

Strengths of Piaget’s theory• Good “feel” for what

children’s thinking is like • Asks the right questions• Covers broad age span• Covers broad spectrum of

developments in children’s thinking

• Surprising observations• Interplay of content &

mechanism

Weaknesses of Piaget’s theory

• Underestimates competence – children succeed earlier than predicted

• Can’t explain dissociations – success or failure depends on the way concept is tested

• No discrete stages - development occurs somewhat gradually or incrementally

Habituation

• Infants like to look at objects that are new and interesting to them

• Procedure– Familiarization: Object presented repeatedly until infants

no longer look at it much– New object introduced

• Method: Infants look longer at new object—allows testing of whether they perceive object as new or old

Occluded rod experiment• 4-month-old infants

familiarized with A, then presented with either B or C

• Results – Looked longer at C than B

• Conclusions– Broken rod more novel than

unbroken rod– Rod in display A was

originally perceived as unbroken

Drawbridge experiment• 4.5 month old infants• Two conditions

– B is ‘possible’– C is ‘impossible’

• Results – Looked longer at C

• Conclusions– Infants know box exists,

even when hidden – 4.5 month olds understand

object permanence

A-not-B experiment

• Experimenter hides toy under cover A• 9-month-old infant successfully retrieves toy• After several successful retrievals, experimenter then hides toy under

cover B• Results - Child still searches under cover A, even though he/she

watched the toy being hidden• Conclusions – 9 month olds do not understand object permanence

Information-Processing Theories

• Thinking = information processing– Representation of information– Processes - applied to representations– Constraints - memory limits constrain representation

and processing• Cognitive development = change in information

processing capability– Precise analysis of change mechanisms

• Change produced through continuous self-modification– Outcomes of child’s actions change information

processing in the future

Memory representations & capacity

• Leg-string Infants remembered that kicking made mobile move after 2 months

•Working memory span increases with age

- Iconic memory capacity also increases with age (1st grade = 2.5 digits, 4th grade = 3 digits, adults = 3.5 digits)

Rehearsal as information processing

• Increase in rehearsal speed leads to increase in working memory capacity

• Older children do better on recall tests because they use rehearsal as a memory strategy

Sociocultural Theories

• Vygotsky - father of sociocultural theories of development

• Cognitive development occurs in social interaction– Developmental change occurs through

internalization of socially shared processes– Zone of proximal development

• Psychological functioning is mediated by cultural tools & language