HDP 1 Midterm Review Fall 2005. Topics covered WEEK 0 Th 9/22Introduction to course (Jeff Elman,...
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Transcript of HDP 1 Midterm Review Fall 2005. Topics covered WEEK 0 Th 9/22Introduction to course (Jeff Elman,...
Topics coveredWEEK 0
Th 9/22 Introduction to course (Jeff Elman, Dept. of Cognitive Science)
WEEK 1Tu, 9/27 Infancy and Evolution (Jim Moore, Dept. of Anthropology)
Th 9/29 The History of Childhood (Stefan Tanaka, Dept. of History)
WEEK 2Tu 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 3Tu 10/11 CLASS CANCELLED
Th 10/13 Development of Visual Perception (Karen Dobkins, Dept. of Psychology)
WEEK 4Tu 10/18 Conceptual Development (Gedeon Deak, Dept. of Cognitive Science)
Th 10/20 Social Development (Gail Heyman, Dept. of Psychology)
WEEK 5Tu 10/25 Autism (Aubyn Stahmer, Children’s Hospital)
Important terms and concepts
• Maturation
• Learning
• Adaptation
• Evolution
• Emergentism
• Genetic conservatism
• The “Gene for X” fallacy
• Nature vs. (or and?) Nurture
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
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
slower, even
growth
sudden rapid
growth again, then rapid fall in
rate
growth stops
growth rate drops
INFANT(ends at weaning – 36 mos)
CHILD(ends at end of brain
growth – 7 yrs)
JUVENILE(ends at end of
dependence/puberty – 10-12 yrs)
ADOLESCENT(ends when socially & physically
adult-like – 19-25 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
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
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
Important terms and concepts
• 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
Important terms and concepts
• Basic questions:– 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:– 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
Brain facts1. 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 pregnancy200,000/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
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(“re-wiring the ferret” experiment)
(eyes)
(ears)
(auditory cortex)
(visual cortex)Now acts likevisual cortex!
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:– 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?
1 degree
3 cycles/deg
1 degree
6 cycles/deg
The “rule of thumb”:
1 degree ~= what your thumb covers at arm’s length
0.150
60
70
80
90
100
1 10Luminance Contrast (%)
Adult Data
Threshold = 0.7%
Sensitivity = 1/thr * 100 = 143
Lower threshold is betterHigher sensitivity is better
Changes in infant photoreceptors
Hendrickson & Yuodelis, 1984
Adult
Newborn22 weeksgestation
What determines sensitivity?morphology
What determines acuity?spacing
Changes in infant vision…
• Acuity and Sensitivity– adult like by 3-5 years
• Color – compared with adults?
Infants possess equally low sensitivity for BOTH Luminance (Black/White) andChromatic (Red/Green) stimuli
INFANT COLOR VISIONIS RELATIVELY FINE!!
Luminance
Chromatic
age(months)2 3 4 5
10
1000
100
4
Low SFC
on
tras
t se
nsi
tivi
ty
Age (in months)
Ad
ults
Luminance
Chromatic
Changes in infant vision…
• Acuity and Sensitivity– adult like by 3-5 years
• Color – compared with adults?
• Optimal visual stimuli for an infant?
Important terms and concepts
Important terms:– “what” and “where” pathways
• Which is ventral stream? Which is dorsal stream?
– 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)
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.)
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?
• 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:– 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) obstetric dilemma
b) gynecological situation
c) neural expansion hypothesis
d) big brain problem
2) 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) T
b) F
4) Which of the following is NOT true of young children? [ 3pts]
1) Most children pass the “false belief” test by 4 years of age.
2) Most children become aware of gender constancy by 3 years.
3) Few children below the age of 4 years understand the concept of gender constancy.
4) Children become aware of more complex emotions around 6 years.