Infancy Chapter 4-6 Psyc311 Dr. Jen Wright. There are a lot of physical changes that happen during...
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Transcript of Infancy Chapter 4-6 Psyc311 Dr. Jen Wright. There are a lot of physical changes that happen during...
Infancy
Chapter 4-6Psyc311
Dr. Jen Wright
There are a lot of physical changes that happen during the first years of life,
The most important (and dramatic) of which is brain development.
One of the last organs to fully develop…
brain development 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
Most growth occurs in first 3 yrs•3 yr old 80% adult size
brain development Neurogenesis – proliferation of neurons
through cell division•At peak, 250,000 cells “born” every minute
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
Synaptic pruning – elimination of excess synapses•Streamlines neural processing
•Without synaptic pruning, children wouldn't be able to walk, talk, or even see properly.
Myelination – insulating sheath•Happens at different rates into adolescence
•Certain areas are myelinated first
importance of experience 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 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 InteractionTwo levels of environmental influence:
Environment
Genes: Genotype
Genes: Phenotype
Effect of deprivation
Sleep and brain development
Infants sleep about 17 hours or more a day
Regular and ample sleep correlates with normal brain maturation, learning, emotional regulation, and psychological adjustment in school and within the family.
states of arousal Arousal exists
along a continuum from deep sleep to intense activity.
REM sleep – critical for neural development in brain, esp. for activity-dependent development•E.g. visual system
•Facilitates learning/memory Sleep deprivation linked with later
problems•E.g. ADHD
Babies most at risk of disruption•Premature infants in IC units
•Snoring
What is attachment? Attachment refers to the close,
emotional bond between an infant and his/her primary caregiver.
Early views of attachment Psychoanalytic Theory (Freud)
•Driven by oral needs during the first year
•Emphasized early experiences on later outcomes
Behaviorist Perspective •Driven by the need for food
•Learns to associate contact with mother with food
•Mother’s closeness continually reinforced
Ethology 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 Love (i.e., attachment) seen as
secondary to instinctive or survival needs
Harlow believed that the need for love and affection was necessary for survival
Harlow’s Monkeys (1958) Early work with monkeys Cloth & wire mother
•Only one equipped with feeding apparatus
•Monkeys randomly assigned
•Observed for 5 months Both groups preferred cloth mother
Contact Time with Wire and Cloth
Surrogate Mothers
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Age (in days)
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Infant monkey fed on wire mother
Infant monkey fed on cloth mother
Hours per day spent with wire mother
Hours per day spent with cloth mother
Mean hours per day
http://www.youtube.com/watch?v=hsA5Sec6dAI
http://www.youtube.com/watch?v=caM4-f6ZZBE&feature=related
John Bowlby 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? Ainsworth (1979)
•Developed Strange Situation
•Work revealed 4 types of attachment behavior•Securely Attached
•Insecure Avoidant
•Insecure Resistant
•Insecure Disorganized
http://www.youtube.com/watch?v=QTsewNrHUHU
mirror neurons 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.
MN’s play a clear role in learning/imitation. May also play a role in “mind-reading”
•grasping intentions, goals, desires.
crying 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
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. 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
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
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 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 attention1 year: approach/retreat from stimulus
Parent response to distress importantSympathetic:
child more easily soothed,more interestedmore self-regulated
Non-responsive (wait to intervene): child enters into rapid, intense
distressharder to soothedoesn’t develop self-regulation
emotions of others
“emotional contagion”: babies match the emotional expressions of caregiver
Still face experiment7-10 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 emotionsEmotions that can be directly inferred from
facial expressions happiness, interest
surprise, fear, angersadness, 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 reactionsDynamic 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 systemo amygdala/hippocampus link
o Improve memory of evento Highlight issues of importanceo Make things personally relevant
temperament Constitutionally based individual
differences in •Emotion
•Motor function
•Attentional reactivity
•Self-regulation Influences the way that children
develop, display, and control emotions Foundation for later personality
Temperament styles Types
•Easy
•Difficult
•“Slow to warm up” Differences in punishment/reward Differences in sociability Bi-directional issues
•Gender
•Cultural differences
•Goodness of fit (with parents/environment)
Gene/environment interactions
Passive genotype-environment correlation. Evocative genotype-environment correlation. Each child’s genes elicit other people’s
responses, and these responses shape development. • 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), • thus genetic influences in adulthood increase.
Slides below this point were not covered in class!
Groups – language exercise•swibbing
•a grop
•some drupes
•prebbed
•the norves pudu
Image #1
Image #2
Image #3
Image #4
Image #5
Word learning
Fast mapping•Whole object assumption
•Mutual exclusivity assumption Pragmatic cues
•Social context•Attention
•Intentionality
Linguistic context Syntactic bootstrapping
Language development What is language? Involves the use of symbols to
• Represent our thoughts, feelings, and knowledge
• Communicate with others Generativity: infinite combinations of finite lexicon
Language comprehension• Comprehension comes before production
• Due to vocal complexity (sign language example) Language production
• 1st grader’s utterances as correct grammatically as the avg. college freshman
Language development
Phonological development•Learning the system of sounds (phonemes)•200 possible sounds (English has 45)
Semantic development•Learning the system for expressing meaning
(morphemes) Syntactic development
•Learning the grammar (syntax – rules for combining words)
Pragmatic development•Learning cultural rules of how language is used
Meta-linguistic knowledge•Learning about language itself
What is required for language?
A human brain•Language is species-specific and
species-universal
•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
native language
2nd language
What is required for language?
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)
Language style – strategies children develop to learn language•Referential (analytic) - monosyllabic
•Expressive (holistic) - conversational
•Wait-and-see – late speakers (4-5yrs)
Current theoretical issues
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
Interactionist views (environment)•Language as a social skill – communicative
function
•Sensitivity to environmental cues
•Statistical sensitivity to underlying regularities
Connectionist views (language itself)•Neural network account
•Gradual strengthening/weakening of connections
•Self-modification of network
•Trial and error learning
Theory differences Piaget stage theory
•Child as “blank slate”
•Focus on learning as a process within individuals
•Development is discontinuous (qualitative) Information processing
•Development is continuous (quantitative) Core-knowledge theory
•Child possesses innate knowledge Socio-cultural theory
•Focus on learning as a social process between individuals
Piaget’s theory Constructivist approach – children actively
construct knowledge for themselves in response to their experiences.
Child as scientist:•Generate hypotheses•Perform experiments•Draw conclusions
Children learn many things on their own•without the help of instruction from adults.
Children are intrinsically motivated to learn. Discontinuous (qualitative) change
•different ages think differently.
conservation of quantity (1)
conservation of quantity (2)
Information processing 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, better learning “algorithms”
• More content knowledge (learned facts) to draw upon
Core-knowledge theories 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 Some advanced capacities already present
(innate) Move from “general” to “domain specific”
specialized learning mechanisms
Naïve physics Infants have a surprisingly sophisticated
understanding of how the physical world works.
understanding intentions 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
?