Transcript Chapter 04-06

Infancy
Chapter 4-6
Psyc311
Dr. Jen Wright
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There are a lot of physical changes that
happen during the first years of life,
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The most important (and dramatic) of
which is brain development.
One of the last organs to fully develop…
brain development
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Largest brain/body mass of any animal.
Encephalization Quotient (EQ) = 7.4
• Dolphin = 5.3
• Chimp = 2.5
• Elephant = 1.9
• Whale = 1.8
Most development happens outside (instead of
inside) the womb
• Monkey newborn 70% adult size
• Human newborn 25% adult size
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Most growth occurs in first 3 yrs
• 3 yr old 80% adult size
brain development
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Neurogenesis – proliferation of neurons
through cell division
• At peak, 250,000 cells “born” every minute
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Synaptognesis – formation of connections
• Each neuron forms thousands of connections
• Axons elongate towards specific targets
• Dendritic “tree” increases in size and complexity
• 6 mos have 2 x more synaptic connections
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Synaptic pruning – elimination of
excess synapses
• Streamlines neural processing
• Without synaptic pruning, children wouldn't
be able to walk, talk, or even see properly.
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Myelination – insulating sheath
• Happens at different rates into adolescence
• Certain areas are myelinated first
importance of experience
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Plasticity – brain’s ability to change w/
experience
Experience-expectant plasticity
(experiences present throughout
evolution)
• Economizes on material encoded in genes
• Development will occur within a normal
range of environments
• Level of vulnerability in timing
•Sensitive periods
importance of experience
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Experience-dependent plasticity
(experiences of individual)
• Brain sculpted by idiosyncratic experiences
• Brain responsive to richness of stimuli
• Important in development of expertise
•More brain resources dedicated to processing
•E.g. musicians’ cortical representation of hands
Gene/Environment Interaction
Two levels of environmental influence:
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Environment
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Genes: Genotype
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Genes: Phenotype
Effect of deprivation
Sleep and brain development
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Infants sleep about 17 hours or more a day
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Regular and ample sleep correlates with normal brain
maturation, learning, emotional regulation, and
psychological adjustment in school and within the family.
states of arousal
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Arousal exists
along a
continuum from
deep sleep to
intense activity.
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REM sleep – critical for neural development
in brain, esp. for activity-dependent
development
• E.g. visual system
• Facilitates learning/memory
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Sleep deprivation linked with later problems
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Babies most at risk of disruption
• E.g. ADHD
• Premature infants in IC units
• Snoring
What is attachment?
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Attachment refers to the close,
emotional bond between an infant and
his/her primary caregiver.
Early views of attachment
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Psychoanalytic Theory (Freud)
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Behaviorist Perspective
• Driven by oral needs during the first year
• Emphasized early experiences on later outcomes
• Driven by the need for food
• Learns to associate contact with mother with food
• Mother’s closeness continually reinforced
Ethology
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Rooted in Darwin’s
Evolutionary Theory
Focused on the
adaptive value of
behavior
Bond necessary for
survival
Lorenz (1952) Imprinting
Primary criticism of these early
perspectives
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Love (i.e., attachment) seen as
secondary to instinctive or survival
needs
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Harlow believed that the need for love
and affection was necessary for survival
Harlow’s Monkeys (1958)
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Early work with monkeys
Cloth & wire mother
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Both groups preferred cloth mother
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• Only one equipped with feeding apparatus
• Monkeys randomly assigned
• Observed for 5 months
24
Mean
hours
per
day
18
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12
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6
0
Infant monkey fed on
cloth mother
Infant monkey fed on
wire mother
Hours per day spent
with cloth mother
Contact Time with
Wire and Cloth
Surrogate Mothers
.
.. . .. .. . Hours
per day spent with
wire mother
.
.
1-5
11-15
21-25
6-10
16-20
Age (in days)
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http://www.youtube.com/watch?v=hsA
5Sec6dAI
http://www.youtube.com/watch?v=caM
4-f6ZZBE&feature=related
John Bowlby
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Observations of children in
institutionalized care
Infant has built-in behaviors to keep
parent close
Gives way to true affectionate bond
Serves 2 purposes
• Secure base
• Internal working model
Does attachment vary by individual?
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Ainsworth (1979)
• Developed Strange Situation
• Work revealed 4 types of attachment behavior
• Securely Attached
• Insecure Avoidant
• Insecure Resistant
• Insecure Disorganized
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http://www.youtube.com/watch?v=QTsewNrH
UHU
mirror neurons
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Found in the frontal and parietal lobes
Fire when you
• engage in an activity (reaching out one’s hand)
• observe someone else engaging in the same activity.
Fire more strongly when action has some
purpose or content
• reaching out one’s hand for a cup.
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MN’s play a clear role in learning/imitation.
May also play a role in “mind-reading”
• grasping intentions, goals, desires.
crying
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Crying – infant form of communication
• Response to distress
•Development of emotional self-regulation
•Mastery of environment – agency
•Biofeedback loop
• Soothing
•Swaddling – tight wrapping of baby in cloth
•Touch
•Sweet taste
•Soft, rhythmic sounds
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When an infant’s needs are met, they
are able to turn their focus to the world
around them and explore.
• Their brains take in and adapt to stimulation
from the external world.
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When they aren’t met, they become
fixated on trying to get their needs met
• They stop exploring and shut out other
stimulation from the external world.
crying disorders
• Colic (1 in 10 infants; birth – 12 weeks)
•Extended periods of intense crying
•Cause unknown
• Immature nervous system
• Hyper-sensitivity
• Digestive problems
• Prolonged crying (beyond 12 weeks)
•Exhibit developmental and behavioral disorders
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Prolonged crying expose the brain to high levels
of cortisol, adrenaline, and other damaging
chemicals.
• Damage to hippocampus
• Reduced levels of vasopressin and serotonin
• Reduced levels of emotional regulation
• Impaired memory
• Increased levels of aggression/violence/bullying
• Increased levels of anxiety disorders
stress and brain development
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Exposure to excessive stress hormones is bad for
brain development.
Early symptoms of PTSD
The brain can become incapable of producing
normal stress responses.
• Hyper-vigilance (Ghosts in the Nursery)
• Emotional flatness
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Physical/emotional abuse and neglect can be
equally damaging.
emotional self-regulation
Strategies learned for adjusting emotional
state to a comfortable (adaptive) level
of intensity in order to accomplish goals
Infants: withdrawal, distress, need
soothing
4 mos: can shift focus of attention
1 year: approach/retreat from stimulus
Parent response to distress important
Sympathetic:
child more easily soothed,
more interested
more self-regulated
Non-responsive (wait to intervene):
child enters into rapid, intense distress
harder to soothe
doesn’t develop self-regulation
emotions of others
“emotional contagion”: babies match the
emotional expressions of caregiver
Still face experiment
7-10 mos: infants perceive facial expressions as
organized patterns, can match facial
expression to emotion
8-10 mos: social referencing- relying on another
person’s emotional reaction to appraise
situation (e.g.- visual cliff)
social referencing
Example of how adults help child regulate
emotion
Permits toddlers to compare their
assessments of situations with others
Helps young children move beyond simply
reacting to emotional messages
basic emotions
Emotions that can be directly inferred from
facial expressions
happiness, interest
surprise, fear, anger
sadness, disgust
Universal in humans and our primate ancestors
• Long evolutionary history of adaptation
• Important communicative function
• Present in infancy
emotional expression
Earliest emotions: global arousal states of
attraction and withdrawal
These basic states set the stage for
further development
Over time (6+ mos), these develop into
well-organized, sustained signals
(dynamic systems perspective)
emotions and cognition: bi-directional
Emotional reactions
Dynamic bidirectional interplay
between emotion and cognition.
 Lead to learning that is essential for
survival
 Influence how a situation is
perceived, interpreted, and
remembered.
o Limbic system
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amygdala/hippocampus link
Improve memory of event
Highlight issues of importance
Make things personally relevant
temperament
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Constitutionally based individual
differences in
• Emotion
• Motor function
• Attentional reactivity
• Self-regulation
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Influences the way that children develop,
display, and control emotions
Foundation for later personality
Temperament styles
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Types
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Differences in punishment/reward
Differences in sociability
Bi-directional issues
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• Easy
• Difficult
• “Slow to warm up”
• Gender
• Cultural differences
• Goodness of fit (with parents/environment)
Gene/environment interactions
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Passive genotype-environment correlation.
Evocative genotype-environment correlation.
Each child’s genes elicit other people’s responses,
and these responses shape development.
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In other words, a child’s environment is partly the result
of his or her genes.
Active genotype-environment correlation.
Children, adolescents, and especially adults
choose environments that are compatible with
their genes (called niche-picking),
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thus genetic influences in adulthood increase.
Slides below this point were not covered
in class!
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Groups – language exercise
• swibbing
• a grop
• some drupes
• prebbed
• the norves pudu
Image #1
Image #2
Image #3
Image #4
Image #5
Word learning
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Fast mapping
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Pragmatic cues
• Whole object assumption
• Mutual exclusivity assumption
• Social context
•Attention
•Intentionality
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Linguistic context
Syntactic bootstrapping
Language development
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What is language?
Involves the use of symbols to
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Generativity: infinite combinations of finite lexicon
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Language comprehension
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Language production
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• Represent our thoughts, feelings, and knowledge
• Communicate with others
• Comprehension comes before production
• Due to vocal complexity (sign language example)
• 1st grader’s utterances as correct grammatically as the avg.
college freshman
Language development
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Phonological development
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Semantic development
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Syntactic development
• Learning the system of sounds (phonemes)
• 200 possible sounds (English has 45)
• Learning the system for expressing meaning (morphemes)
• Learning the grammar (syntax – rules for combining
words)
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Pragmatic development
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Meta-linguistic knowledge
• Learning cultural rules of how language is used
• Learning about language itself
What is required for language?
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A human brain
• Language is species-specific and speciesuniversal
• Dominantly left-hemisphere activity
•Wernike’s area – speech comprehension
•Broca’s area – speech production
• Critical period – between age 5 – puberty
•Victor and Genie
•Bi-lingual evidence
production
comprehension
both languages
2nd language
native language
What is required for language?
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A human environment
• Exposure to language speaking environment
• Infant-directed speech (IDS) -“Motherese”
•Used universally (across cultures/gender/age)
•Emotional (affectionate) tone
•Exaggerated tone and facial expressions
•Slow, clear, simple speech
•Present also in non-verbal communication
• (e.g. sign language)
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Language style – strategies children
develop to learn language
• Referential (analytic) - monosyllabic
• Expressive (holistic) - conversational
• Wait-and-see – late speakers (4-5yrs)
Current theoretical issues
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Nativist views (hardwired)
• Modularity hypothesis
•innate, self-contained language-specific structure
in brain
• Universal grammar
•common to all languages (Chomsky’s LAD)
• Spontaneous developments of language
•E.g. congenitally deaf children
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Interactionist views (environment)
• Language as a social skill – communicative
function
• Sensitivity to environmental cues
• Statistical sensitivity to underlying regularities
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Connectionist views (language itself)
• Neural network account
•Gradual strengthening/weakening of connections
•Self-modification of network
• Trial and error learning
Theory differences
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Piaget stage theory
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Information processing
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Core-knowledge theory
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Socio-cultural theory
•Child as “blank slate”
•Focus on learning as a process within individuals
•Development is discontinuous (qualitative)
• Development is continuous (quantitative)
• Child possesses innate knowledge
• Focus on learning as a social process between
individuals
Piaget’s theory
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Constructivist approach – children actively
construct knowledge for themselves in response
to their experiences.
Child as scientist:
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Children learn many things on their own
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Children are intrinsically motivated to learn.
Discontinuous (qualitative) change
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• Generate hypotheses
• Perform experiments
• Draw conclusions
• without the help of instruction from adults.
• different ages think differently.
conservation of quantity (1)
conservation of quantity (2)
Information processing
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Computational approach – cognitive development as
a passive maturation process that occurs over time.
Child as a computational system
Children undergo continuous (quantitative) cognitive
change
Development through increasingly sophisticated
hardware and software
• Faster and more efficient processing, larger memory bank,
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better learning “algorithms”
More content knowledge (learned facts) to draw upon
Core-knowledge theories
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Child as well-adapted product of evolution
Emphasis on sophistication of children’s thinking in
areas that have had evolutionary importance.
• Eg. environment navigation, face recognition, language
• Naïve physics, psychology, biology
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Some advanced capacities already present (innate)
Move from “general” to “domain specific” specialized
learning mechanisms
Naïve physics
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Infants have a surprisingly sophisticated
understanding of how the physical world works.
understanding intentions
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They also have a pretty sophisticated understanding of how
the psychological world works
• e.g., they understand that there are goals and intentions and that
only certain creatures can have them.
primitive morality
?