Infancy Chapter 4-6 Psyc311 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 Interaction Two 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 Babies most at risk of disruption • E.g. ADHD • 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) 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 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 Both groups preferred cloth mother • Only one equipped with feeding apparatus • Monkeys randomly assigned • Observed for 5 months 24 Mean hours per day 18 . . . . . . . 12 . . 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) http://www.youtube.com/watch?v=hsA 5Sec6dAI http://www.youtube.com/watch?v=caM 4-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=QTsewNrH UHU 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 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 o o o o amygdala/hippocampus link Improve memory of event Highlight issues of importance 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 Differences in punishment/reward Differences in sociability Bi-directional issues • Easy • Difficult • “Slow to warm up” • 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 Pragmatic cues • Whole object assumption • Mutual exclusivity assumption • Social context •Attention •Intentionality Linguistic context Syntactic bootstrapping Language development What is language? Involves the use of symbols to Generativity: infinite combinations of finite lexicon Language comprehension Language production • 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 Phonological development Semantic development 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) Pragmatic development Meta-linguistic knowledge • Learning cultural rules of how language is used • Learning about language itself What is required for language? 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? 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 Information processing Core-knowledge theory 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 Constructivist approach – children actively construct knowledge for themselves in response to their experiences. Child as scientist: Children learn many things on their own Children are intrinsically motivated to learn. Discontinuous (qualitative) change • 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 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 ?