Cognitive Development Psych 142

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Cognitive Development Psych 142

• Professor Leda Cosmides
• TA Andy Delton
• Office hours
• Cosmides Tuesdays, 1130-130pm, HSSB 1010
• Delton Mondays, 100-300 HSSB 1010
  (delton_at_psych.ucsb.edu)
• Course website http//mentor.lscf.ucsb.edu/course
  /fall/psyc142/
• E-res password clutch

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Questions to think about throughout 142...

• What does the child know about the world?
• How does the child come to know what she knows?
• Is the childs mind different from the adults
  mind, or does the child just know less?
• Does the child come factory equipped with any
  knowledge of the world?

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Questions to think about throughout 142...

• How does the environment affect development?
• How does maturation affect development?
• Why did scientists underestimate how much infants
  know?
• What is the competence/ performance distinction?
• Can one part of the brain know something that
  another part of the brain does not know?

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Questions to think about throughout 142...

• What is the difference between studying natural
  competences and side-effects?
• What does learning mean?
• How many learning processes are there?
• Is instinct the opposite of learning?
• What is the design of the instinct that causes
  learning in a given domain?

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Timeline of cognitive development

• Some developmental milestones...
• From birth to age 7...

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At Birth...
6 month fetus
2 days old

• Big head (obstetric dilemma)
• Bad vision (makes testing difficult)
• Preference for human faces

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Sharp image?
?As seen by 3 month old
As seen by 1 month old?
From 20 inches
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2 and ½ months old...

• Has an object concept
• Knows objects still exist, even when hidden
• Contrary to Piaget
• Babys mind defines object as a cohesive,
  bounded entity that moves as a unit

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7 months old...

• Understands physical causality
• Launching event one ball hits another, causing
  it to move
• Distinguishes from similar events lacking precise
  timing, spatial relations
• Babbling begins
• Onset of language production!

Can finally sit up crawling begins 7-10 months
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9 months old...

• Joint attention!
• (onset 9-14 months)
• Follows a point or eyegaze
• Awareness of a shared world of experience

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12 months old...

• Fear of strangers
• esp when mom out of room
• Start walking, 12-15 months
• Start to lose ability to make sounds not in
  native language
• Understand a few words

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18 months old...

• Words words words!
• Onset of pretend play
• Ability to represent what others think
• Activation of theory of mind mechanism?

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2 ½ years old...

• Language acquisition in full swing
• Simple sentences
• Understands uses many grammatical principles

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3 years old...

• Natural kind reasoning
• Inferences based on kind category (dolphin,
  shark) not based on perceptual properties
• Good social cognition

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4 years old...

• Mastered grammar of native language (mostly)
• Passes false belief task
• 4 year old has a mature theory of mind
  mechanism
• Can definitely represent the beliefs of others,
  even if these are false

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5-7 shift...

• Universal across cultures
• Child participates more in the world of adults
• Accompanied by major brain growth
• Tool concepts (age 6) conceptualize tools as
  designed for a particular function

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How can we know what babies think?

• What distinctions do they make?
• Preferential looking
• Habituation paradigm

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Preferential looking tasks (selective looking)
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If baby looks longer at one stimulus than the
other......what can we infer?

• Baby prefers looking at one stimulus over the
  other
• Baby can distinguish the stimuli views them as
  different
• If baby looks at both the same amount
• Does baby prefer them equally?
• Or can baby not distinguish them?
• What can we do to tell?

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To see if baby cannot distinguish...Take
advantage of short term learning/ boredom!

• Habituation paradigm
• Babies look at new stimuli, show interest
• After awhile, they stop looking (get bored) they
  habituate to the old stimulus
• Introduce another stimulus
• Is baby still bored? (thinks it is the same)
• Does baby recover interest? Does she
  dishabituate? (thinks new stim is different)

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using learning habituation
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habituation trial 2
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habituation trial N
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(No Transcript)
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Habituation processLooking time decreases with
trials
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Test trial, new stimulus... Is there
dishabituation?
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what happens when we change the stimulus?
new
old
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Data might look like this
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But
Is there really a recovery of attention with stim
B?
Or do babies just like stim B better than stim
Aeven without habituation?
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Important to control for preference!
Control
Control condition How intrinsically interesting
is each stimulus (that is, in the absence of
habituation trials)?
Note w/o habituation, babies like stim B (red
line) less than stim A (green line)
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Habituation
Control
Control for preference After habituation with
stim A Is there recovery of attention with stim
B? (w/o habituation, babies like stim B less
than stim A)
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Habituation
Control
In this case w/o habituation, babies like stim B
(purple line) more than stim A (green line) Is
there recovery of attention for B?
Not really! So babies must see B as very similar
to A
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Do babies see the world like we do?
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Philosophers Is the mind a blank slate? Hume,
LockeOr are there innate ideas? Kant, Plato

• Does the child come factory equipped with any
  knowledge of the world?
• Can one part of the brain know something that
  another part of the brain does not know?

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Are infants born with knowledge about human faces?

• Preferential looking study
• Compare schematic face to same with features
  scrambled
• One month olds do not show preference for face
  over scrambled, 2 months do...but...

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Born with knowledge of faces?9 minutes old...

• Preference study
• Head turning, eye tracking
• What are the appropriate control stimuli?

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Face gt Scrambled Face gt Blank Face

• Scrambled face has all the features of the
  regular face
• Same amount of contrast, color, contours, etc.
• Configuration matters
• Features in a face configuration? max tracking

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Can one part of the brain know something that
another part of the brain does not know?

• At birth Subcortical mechanism governing eye
  gaze and head turning for moving stimuli it
  knows about faces
• More precisely it is designed to respond
  preferentially to faces, keep them in view
• Cortical mechanisms governing looking time to
  stationary stimuli mature later...

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Response I dont believe it!

• Blank slate view There is nothing in the mind
  that was not first in the senses Thomas
  Aquinas)
• All ideas are built from experience with sense
  data
• I.e. The visual system might be designed to
  respond to low level features of the world
  (color, contrast), but anything more complex must
  be built up from experience with those things in
  the world. (Face complexly organized sense
  data)
• All organization comes from the world
• No high level categories no knowledge of face
  configuration w/o experience with faces

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Counter-hypothesis

• Brains of newborns are not equipped with
  knowledge of the configuration of facial features
• They can respond only to low level visual
  features
• They are just tuned to respond to the degree of
  contrast typical of the human face
• Note this would still imply natural selection
  designed brain mechanisms for attending to human
  faces
• Only contrast (amplitude spectrum) matters
• Below each pair has same config, but differs in
  amplitude

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Configural information, or just amplitude?

• Configuration info
• Phase (P) spectrum of
• face vs. lattice
• Contrast info
• Amplitude (A) spectrum of
• face vs. lattice
• Cross these two dimensions

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Configural information, or just amplitude?

• Amplitude only?
• Predict
• Af-Pf Af-Pl gt
• Al-Pf Al-Pl
• Does configuration matter too?
• Result
• Af-Pf gt Af-Pl gt
• Al-Pf Al-Pl
• Need face contrast, but given this, configuration
  matters!

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In development, the environment matters.

• But what does this mean?
• What counts as the environment?

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• Internal environment
• Where is the gene in the genome?
• What is the local biochemistry around the gene?
• External environment
• Species-typical environment (STE)
• Non-specific aspect of the STE
• Does not include information to be acquired
• Specific aspect of the STE
• Includes information to be acquired
• Individual-specific environment (ISE)

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What kind of experience matters?
Visual cliff

• When does baby fear the drop?
• Why do crawling babies fear, but not younger?
• Trial error learning? Or
• Triggering experience?

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What happens when baby is placed on center board
between deep and shallow?

• Crawling baby
• Moves only toward shallow
• Heart rate ? (fear) when looks over deep side
• Not-yet-crawling baby (of similar age)
• Heart rate ? (interest) when looks at either side
• Decrease greater when looks at deep side
• That is, baby can tell deep from shallow
• Same pattern for babies 2-6 months
• But what causes the difference?

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What causes the difference between crawling and
not-yet-crawling babies?

• Is it experience with falling?
• Trial error baby learns to fear falling by
  falling
• Individual-specific environment
• Or does onset of self-generated movement trigger
  fear of deep end?
• System designed to activate fear of vertical
  drops
• Comes online only when needed
• i.e., triggered when baby starts moving on own
• Species-typical environment non-specific aspect

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Critical experiment

• Not-yet-crawling babies 6-7 months old
• Let them use a walker for 40 hours
• surrounded by it cannot fall, but can move on
  their own (why is this important?)
• No experience of falling!
• Result ? heart rate (fear) when see deep side!
• Onset of self-generated movement triggers fear of
  deep end
• System designed to activate fear of vertical
  drops
• Is triggered when baby starts moving on own
• Species-typical environment non-specific aspect

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Maturation

• Chick pecking practice or maturation?
• Hopi children strapped to cradle board for 9
  months when walking?
• Twins, 9 months restrained (!)
• Smiling, cooing, sitting, grasping
• Twins practice stair climbing

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Role of experience in development is weirder than
you think!

• Folk theory I pay attention, figure things out,
  and learn about aspects of the environment that
  Im exposed to (like in class).
• Sometimes
• But
• Genes can be designed to respond differently,
  depending on what environmental stimuli you are
  exposed to

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Methylation patterns

• Mother rats lick babies
• High lickers versus low lickers
• Why? Difference in genes or experience?
• What happens if baby of low-licker is raised by
  high lick mom (and vice versa)?
• High licking triggers removal of methylation
  pattern from certain genes
• Mellow baby, low cortisol reactivity to stress
• Low licking methylation stays in place
• High cort reactivity to stress
• More ? sexually receptive

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Mallard duckling Preference for adult call?
Wood duck ?
Mallard duck ??
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Species-typical environment

• Specific aspect of STE?
• Hearing adult mallards call?
• What happens if hear only wood duck call?

Dont hear mallard
Hear wood duck
?
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Mallard duckling with no experience of either
call

• Prefers call of mallard adult over wood duck
  adult
• If give lots of experience hearing wood duck
  call, baby will run toward wood duck call
• But has equal preference for mallard call, even
  though has never heard it before!
• Preference for mallard adult call depends on
  experience
• but NOT of experience hearing adults call!

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Non-specific aspect of Species-Typical
Environment

• Duckling has contact content-contentment call
• Sounds nothing like adult call
• To prefer adult mallard call, baby needs to hear
  its own contact-contentment call the day before
  hatching
• This is sufficient experience
• It does not include the information to be
  acquired (non-specific aspect of STE)
• Triggers development of the neural circuits that
  cause the preference

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Rhesus monkey Fear of snakes

• See other rhesus show fear of snake
• Elicits fear of snakes
• See other rhesus show fear of flower
• Does not elicit fear of flowers
• BUT if monkey has eaten live insects
• Fears snakes without having seen another monkeys
  fear

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Why do we care?

• Practical
• Interacting with children
• Knowing their limitations
• not teaching before ready,
• not assuming they cannot understand,
• understanding versus performance limitations
• Developmental and other cognitive disorders
• Which mechanisms are malfunctioning?
• Which experiences can put development back on
  track?

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Why do we care?

• Theoretical What is the nature of human nature?
• Blank slate or evolved knowledge?
• Children are a natural experiment
• have little experience (ISE), the younger, the
  less
• Factory-equipped? Deepest questions about design
  of the mind
• Do we have innate ideas? Is the brain equipped
  with specialized knowledge of the world? (Core
  knowledge)
• Central to these debates Teasing apart
  competence versus performance