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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12

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21-251-56-10

11-1516-20

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

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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

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