HDP 1 Midterm Review Fall 2005

Topics covered WEEK 0 Th 9/22Introduction to course (Jeff Elman, Dept. of Cognitive Science)Jeff Elman WEEK 1 Tu, 9/27Infancy and Evolution (Jim Moore, Dept. of Anthropology)Jim Moore Th 9/29The History of Childhood (Stefan Tanaka, Dept. of History)Stefan Tanaka WEEK 2 Tu 10/4Genes, Brain Development and Behavior (Leslie Carver, Dept. of Psychology)Leslie Carver Th 10/6Brain Development: The Basics (Joan Stiles, Dept. of Cognitive Science)Joan Stiles

WEEK 3 Tu 10/11CLASS CANCELLED Th 10/13Development of Visual Perception (Karen Dobkins, Dept. of Psychology)Karen Dobkins WEEK 4 Tu 10/18Conceptual Development (Gedeon Deak, Dept. of Cognitive Science)Gedeon Deak Th 10/20Social Development (Gail Heyman, Dept. of Psychology)Gail Heyman WEEK 5 Tu 10/25Autism (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

More DNALess DNA

Genetic conservatism

The power of the environment

from butterfly hostfrom alderfly host Trichogramma (wasp)

from butterfly hostfrom 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 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 – yrs) ADOLESCENT (ends when socially & physically adult-like – 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 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 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

The human brain Frontal Lobe Parietal Lobe Occipital 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? 1 st half of pregnancy 200,000/minute

7 important stages 1.Development of neural plateE12 2.Formation of trilaminar disk beginsE15 3.Formation of neural tube beginsE18 4.Neural tube closes (top; then bottom)E25; E27 5.Ventricular zone progenitor cells start dividing (symmetrically)E28 6.VZ asymmetric cell growth (neurogenesis) startsE42 7.Greatest production of neuronsE42-E125

Anencephaly Spina bifida

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) (ears) (auditory cortex) (visual cortex)

Importance of experience & cell activity (“re-wiring the ferret” experiment) (eyes) (ears) (auditory cortex) (visual cortex) Now acts like visual cortex!

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: –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

The “rule of thumb”: 1 degree ~= what your thumb covers at arm’s length

Lower threshold is better Higher sensitivity is better

Changes in infant photoreceptors Hendrickson & Yuodelis, 1984 Adult Newborn 22 weeks gestation 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) and Chromatic (Red/Green) stimuli INFANT COLOR VISION IS RELATIVELY FINE!! Low SF Contrast sensitivity Age (in months) Adults 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?

Conceptual development (Deak)

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 2 nd 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 1 st 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? 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 minutes Bring only pens/pencils Eyes and papers on desk! Know and write on each page: –Your name –Your PID (e.g., A ) –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.

Good luck!