Transcript Human Development Program 1 - Center for Research in Language

HDP 1 Midterm Review
Fall 2005
Topics covered
WEEK 0
Th 9/22
Introduction to course (Jeff Elman, Dept. of Cognitive Science)
WEEK 1
Tu, 9/27
Infancy and Evolution (Jim Moore, Dept. of Anthropology)
Th 9/29
The History of Childhood (Stefan Tanaka, Dept. of History)
WEEK 2
Tu 10/4
Genes, Brain Development and Behavior (Leslie Carver,
Dept. of Psychology)
Th 10/6
Brain Development: The Basics (Joan Stiles, Dept. of
Cognitive Science)
WEEK 3
Tu 10/11
CLASS CANCELLED
Th 10/13
Development of Visual Perception (Karen Dobkins, Dept.
of Psychology)
WEEK 4
Tu 10/18
Conceptual Development (Gedeon Deak, Dept. of Cognitive
Science)
Th 10/20
Social Development (Gail Heyman, Dept. of Psychology)
WEEK 5
Tu 10/25
Autism (Aubyn Stahmer, Children’s Hospital)
Introduction (Elman)
Important terms and concepts
• Maturation
• Learning
• Adaptation
• Evolution
• Emergentism
• Genetic conservatism
• The “Gene for X” fallacy
• Nature vs. (or and?) Nurture
The “Gene for X” fallacy
Less DNA
More DNA
Genetic conservatism
The power of the environment
from butterfly host
from alderfly host
Trichogramma (wasp)
from butterfly host
from alderfly host
Trichogramma (wasp)
Emergentism
• The whole is greater than the sum of its
parts
• Interactions create complexity
• Outcomes are not easily predictable
• Multiple sources of causation
• A prime example: Language
Infancy & evolution (Moore)
Important terms and concepts
• Life History Theory
• 5 stages of development
• The “obstetric dilemma”
• Bipedalism
• precocial species vs. altricial species
very rapid
growth,
but rate
falling fast
sudden
rapid
growth
again, then
rapid fall in
rate
slower,
even
growth
growth
rate drops
growth
stops
INFANT
(ends at weaning – 36 mos)
ADOLESCENT
(ends when socially & physically
adult-like – 19-25 yrs)
CHILD
(ends at end of brain
growth – 7 yrs)
JUVENILE
(ends at end of
dependence/puberty –
10-12 yrs)
ADULT
LIFE HISTORY THEORY
“…natural selection favors organismic life
cycles in which resources are allocated
among growth, maintenance and reproduction
in relation to age or size in a manner that
maximizes the reproductive potential across
individual life spans.”
Pereira 1993
A big question
• Why do humans extend the immature period?
Breaking it down…
• What is the reproductive disadvantage of
extended immaturity?
• What might compensate for this
disadvantage?
• What does the “obstetric dilemma” refer
to?
The obstetric dilemma
1. Bipedalism associated with change in
pelvic structure & smaller birth canal
2. Evolution of humans associated with
increased brain size
3. Energy cost for mother to continue
supporting fetal brain development
A possible solution
Be born “early”, and have an extended transition
from infancy to adulthood
Also: create “childhood”
a. Reduced nutritional needs
b. Help with caring for younger siblings
c. Gets young brains into enriched environment
The history of childhood (Tanaka)
Important terms and concepts
• Functional imperfection
• Ages of man
• John Locke (ideas about childhood)
• Emile Rousseau (ideas about childhood)
• Industrial Revolution (impact on childhood)
• Tutelary complex
• History of public education
History of childhood
• Culturally, childhood is modern and
somewhat peculiar to the U.S.
• Early views on childhood: “little adults”
• Later:
– J. Locke: “tabula rasa”
– E. Rousseau: to be protected and nurtured
• Industrial Revolution’s effects on child
labor
– Factories were dangerous environments
– Produced asymmetric growth & deformities
– Separated children from families
• Tutelary complex as response to
– Industrial Revolution
– Immigration and Migration
• Public education
– When? Mid-1800s
– Why? Socialize the poor & working class
Genes, brain development, & behavior (Carver)
Important terms and concepts
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Behavior Genetics (what is it? how does it work?)
Variation
Hereditability (as defined by Behavior Genetics)
Methods (twin studies; adoption studies)
Shortcomings and problems with B.G.
Reproductive cycle (meiosis, mitosis)
“Cross-over” events
(Do not need to know 6 phases of meiosis)
Embryogensis (what happens when, and where)
Early neural events: (see also Stiles lecture)
– proliferation
– Migration
– differentiation
Behavior Genetics
• Goal:
– Measure how different people are, as a
function of how closely they’re related
• Definition of heritability
– what is odd about this definition?
• Shortcomings
– Of twin studies
– Of adoption studies
Basics of genetics
• 22 pairs of chromosomes, plus 1 pair of
sex chromomes (X-X, X-Y)
• Meiosis (reproduction):
– 1 cell produces 1 cell
– Introduces variation
• Mitosis (basic cell division):
– 1 cell produces 2 cells
Brain development – the basics (Stiles)
Important terms and concepts
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Basic questions:
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How does such a complex organ as the brain get built?
How plastic/adaptable is the brain, in response either to damage or to abnormal
experience?
Important terms:
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ectoderm, endoderm, mesoderm
neural tube
proliferative zones
glial cells, neurons, radial glial cells
cell birthday
Radial Unit Hypothesis; protomap vs. protocortex hypotheses
active transport vs. passive transport; “inside-out” organization of the cortex
cortex (i.e., “cortical mantle”)
laminar organization of cortex
white matter; gray matter
“productive events”; “subtractive events”; synaptogenesis
The human brain
Parietal
Lobe
Occipital
Lobe
Frontal
Lobe
Temporal
Lobe
Corpus callosum
CORTEX
(neurons;
“gray matter”)
“white matter”
(axons)
Brain facts
1. Brain weight (adult and newborn)
3 lbs (adult); 0.8 lbs (newborn)
2. Number of neurons in cortex:
20 billion
3. Number of synapses:
60 trillion
4. Rate of early neuron growth & when greatest?
1st half of pregnancy
200,000/minute
7 important stages
1. Development of neural plate
E12
2. Formation of trilaminar disk begins
E15
3. Formation of neural tube begins
E18
4. Neural tube closes (top; then bottom)
E25; E27
5. Ventricular zone progenitor cells start dividing (symmetrically)
E28
6. VZ asymmetric cell growth (neurogenesis) starts
E42
7. Greatest production of neurons
E42-E125
Spina bifida
Anencephaly
What parts of the neural tube become what parts of the brain?
Ventricules: (fluid-filled) holes in the middle of the brain
Ventricular zone: inner surface of hollow tube where progenitor cells lie
Then…
• Migration
– Cell’s birthday
– Role of radial glial cells
– “inside/out” pattern of migration
– 6 cortical layers
• Cell differentiation
• Subtractive events
Importance of experience & cell
activity
(eyes)
(auditory
cortex)
(visual cortex)
(ears)
Importance of experience & cell activity
(“re-wiring the ferret” experiment)
(eyes)
(auditory
cortex)
Now acts like
visual cortex!
(visual cortex)
(ears)
Development of visual perception (Dobkins)
Important terms and concepts
• Basic questions:
– What are the perceptual consequences of neural changes?
– How is infant vision different from adult vision?
– What are the clinical implications?
• Important terms:
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sensitivity
threshold/contrast threshold
contrast
spatial frequency
grating stimulus
psychophysics
Snellen exam
acuity
Important terms and concepts
• Important terms (cont’d.):
– focus
– luminance
– chromatic
– depth perception
– stereopsis
– binocular vision
– monocular vision
– photoreceptors (differences between infant and adult, shape
and spacing)
Methods
Q: how do you test adults’ vision?
Q: how do you test infants’ vision?
Q: what level of performance is considered the threshold?
Q: what is the difference between threshold and
sensitivity?
Sensitivity
- measures sensitivity to contrast
Acuity
- measures to fine detail
- spatial frequency
3 cycles/deg
1 de gr e e
6 cycles/deg
1 de gr e e
The “rule of thumb”:
1 degree ~= what your thumb covers at arm’s length
Adult Data
100
90
Lower threshold is better
Higher sensitivity is better
80
70
60
Threshold =
0.7%
50
0.1
1
10
Luminance Contrast (%)
Sensitivity = 1/thr * 100
= 143
Changes in infant photoreceptors
Adult
What determines sensitivity?
morphology
What determines acuity?
spacing
22 weeks
gestation
Newborn
Changes in infant vision…
• Acuity and Sensitivity
– adult like by 3-5 years
• Color
– compared with adults?
Contrast sensitivity
1000 Low SF
Infants possess equally low sensitivity for
BOTH Luminance (Black/White) and
Chromatic (Red/Green) stimuli
INFANT COLOR VISION
IS RELATIVELY FINE!!
100
Luminance
Luminance
10
Chromatic
Chromatic
4
3
4
5
age(months)
Age
(in months)
Adults
2
Changes in infant vision…
• Acuity and Sensitivity
– adult like by 3-5 years
• Color
– compared with adults?
• Optimal visual stimuli for an infant?
Conceptual development (Deak)
Important terms and concepts
Important terms:
– “what” and “where” pathways
• Which is ventral stream? Which is dorsal stream?
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Object permanence
Means-end grasping
A-not-B error
False belief error
Attention-sharing (gaze- and point-following)
Timelines
• Object permanence
– At 4 mos: only motion matters
– By 6-7 mos: shape, color, texture, etc. matter
• Means-end grasping
– By 5 mos, can grasp
– By 6-7 mos, show means-end grasping
– By 8 mos, show “choosy [smart] reaching”
• A-not-B error
– 8-9 mos will perseverate
A
B
C
How do you interpret “surprise”(longer looking time)?
Which of the 2nd two displays would cause surprise at what ages? Why?
Timelines (cont’d.)
• Object awareness
– 6 mos: learn features that “go together”
– 10 mos: correlate object features w/location
• Use of gaze- and point-following
– 6 mos: follow if objects are in view (front of infant)
– 9 mos: follow if objects are in peripheral view
– 12 mos: follow if objects are out of sight (back of infant)
Social development (Heyman)
Methodological challenges
• Correlation vs. causation
• Multiple sources of causation
• Constraints on naturalistic (vs.
experimental) data
Milestones
• Newborns:
imitation; preferences for mother’s voice
• 12 mos:
stranger & separation anxiety
1st attempts at comforting & hurting
social referencing
• 18 mos:
aware that others’ desires may differ
• 2 yrs:
“terrible 2s”: independence
private speech
transition from parallel play to joint play
Milestones
• 3 yrs:
same-sex preference
ability to hide emotions
• 4 years:
able to pass “false belief” test
• 5 years:
gender constancy
understand difference between real
and apparent emotion
• 6yrs:
understand more complex emotions
(pride, shame, etc.)
Autism (Stahmer)
Important terms and concepts
• Definition of Autism Spectrum Disorder
• Echolalia
• Playlalia
• Incidence of autism
• Gender differences
• Etiology (=likely cause)
• Discrete Trial Training
• Pivotal Response Training (& profile of best responders)
Diagnosing Autism Spectrum
Disorder
• What 3 things are needed?
– Deficits in social behavior & attachments
– Deficits in verbal & nonverbal communication
– Perseverative, stereotyped, repetitive
behaviors
Behavioral treatments
• Discrete Trial Treatment
– Presenting instructions and questions:
• Child attending
• Easily discriminable instructions
• Short and consistent instructions
– Child responds or fails to respond
– Consequences
• Clear, consistent consequence (positive)
Limitations of DTT?
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Failure to generalize to novel situations
Lack of spontaneity
Robotic-like behavior
Require familiar prompts to engage
behavior
• Slow and time-consuming
• Not easy or pleasant for child or trainer
Pivotal Response Training
• Emphasizes
– Child choice (behaviors child wants to do)
– Direct reinforcement
– Intersperse maintenance (easy) tasks
– Frequent task variation
– Turn taking: let child initiate
– Tasks involve multiple simultaneous cues
Assessment
• Which child characteristics best predict
success on Pivotal Reponse Training?
– High toy use
– Low avoidance behaviors
Exam information
• Be on time: the exam will take 70-75 minutes
• Bring only pens/pencils
• Eyes and papers on desk!
• Know and write on each page:
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Your name
Your PID (e.g., A01234567)
Your Section ID (A02, A08, A11, etc.)
Your TA’s name and the day and time of your section
• Coverage:
– Lecture = 70%; readings = 30%
• Format:
– 73 questions
(most worth 3 pts)
• 42 multiple choice
– Beware of “Which of the following is NOT…” questions
– Only 1 answer will be correct for M.C. questions
• 9 True/False
• 22 fill-in-the-blank, matching, short answer
• Grading
1)
The evolutionary tension between infant brain size and
female pelvic shape in humans is typically referred to
as the: [3 pts]
a)
b)
c)
d)
2)
obstetric dilemma
gynecological situation
neural expansion hypothesis
big brain problem
Explain, in 3-4 sentences, what is meant by the “gene
for X” fallacy? [3 pts]
3)
True or False: White matter refers to the outer layer
of cells on the brain, also known as the cortex. [3 pts]
a)
b)
4)
T
F
Which of the following is NOT true of young children? [
3pts]
1)
2)
3)
4)
Most children pass the “false belief” test by 4 years of age.
Most children become aware of gender constancy by 3 years.
Few children below the age of 4 years understand the concept
of gender constancy.
Children become aware of more complex emotions around 6
years.
Good luck!