Humans do not have the largest brain – but they have the largest EQ. Encephalization Quotient (EQ) –Average brain mass/body weights for a species. –Average for species/average mammalian value. SpeciesEQSpeciesEQ Human7.4Cat1.0 Dolphin5.3Horse0.9 Chimpanzee2.5Sheep0.8 Rhesus Monkey2.1Mouse0.5 Elephant1.9Rat0.4 Whale1.8Rabbit0.4 Dog1.2 Parrot2.5 difference between species EQ + IQ
brain development Most brain 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 yrs old 80% adult size –5 yrs old 90% adult size
developmental processes Neurogenesis – proliferation of neurons through cell division –250,000 cells “born” every minute Synaptognesis – formation of connections –Each neuron forms 1000’s of connections –Axons elongate towards specific targets –Dendritic “trees” increases in size and complexity –By 6 months 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 Examples? vision language
announcements Psychology Club Event –Volunteering in the Community –9/29 (next Weds) 5:15pm, ECTR 116 Feedback for in-class debate Group write-ups – pick up after class. Study session for Exam 01 –9/29 (next Weds) 7:00pm, ECTR 113 –35 MC/TF questions (2pts each) –2 essay q’s (20 pts + 10 pts) – I will give you potential q’s in advance
importance of experience Experience-dependent plasticity (experiences of individual) –Brain sculpted by idiosyncratic experiences –Responsive to richness of environmental stimuli –Important in development of expertise More brain resources dedicated to processing E.g. musicians’ cortical representation of hands
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, learning disabilities Babies most at risk of disruption –Premature infants in IC units
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.
attachment theory Attachment refers to the close, emotional bond between an infant and his/her primary caregiver. Psychoanalytic Theory (Freud) –Driven by oral needs during the first year –Emphasized early experiences on later outcomes Behaviorist Perspective (Skinner) –Driven by the need for food –Learns to associate contact with mother with food –Mother’s closeness continually reinforced
attachment theory Ethology (Lorenz) –Rooted in Darwin’s Evolutionary Theory –Focused on the adaptive value of behavior –Bond necessary for survival –Imprinting
primary criticisms 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
announcments Psyc Club – Volunteering in the Community Exam study session Weds, 7-9pm, ECTR113 Friday – Ch 4-6 Ask yourself Q’s due How do you want to spend Friday? –A) lecture –B) ask yourself q’s and study guide! Exam 01- Monday!
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 24 0 6 12 18 21-251-5 6-10 11-15 16-20 Age (in days).................... 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
attachment theory 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
attachment theory Mary 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 –You engage in an activity (reaching out one’s hand) –You 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 –communication of emotion 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 –Vibration
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
crying 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
early emotional expression Earliest emotion –global arousal states of attraction and withdrawal –set the stage for further development –develop into well-organized, sustained signals Basic emotions –emotions that can be directly inferred from facial expressions. happiness, interest surprise, fear, anger sadness, disgust
Basic emotions: A)Universal across all human cultures B)Present in other advanced species C)Include guilt, shame, embarrassment D)A&B E)All of the above
emotional self-regulation Strategies for adjusting emotional state to a comfortable (adaptive) level of intensity in order to accomplish goals Infants: withdrawal, distress, crying -- need soothing 4 mos: shift focus of attention 1 year: approach/retreat from stimulus Parent response to distress is important Sympathetic –child more easily soothed, more self-regulated Non-responsive (wait to intervene) –child enters into rapid, intense distress –harder to soothe –doesn’t develop self-regulation
emotional self-regulation When an infant’s needs are met, they can focus on 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.
emotions of others Emotional contagion: babies match the emotional expressions of caregiver 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) Still face experiment http://www.youtube.com/watch?v=apzXGEbZht0
Mirror neurons help infants experience others’ emotions: A)Yes, because they help them match emotional facial expressions B)Yes, because they stimulate a matching internal experience C)Yes, because they allow infants to empathize with others. D)A&B E)No, because mn’s are only involved in imitation of physical behavior
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 Visual cliff experiment http://www.youtube.com/watch?v=eyxMq11xWzM
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 sociability Differences in punishment/reward Which child will be harder to reward/punish? A)Easy child B)Difficult child
temperament styles What else affects the development of temperament? Gender Cultural differences Goodness of fit (with parents/environment)
theory differences Piaget stage theory Child as “blank slate” (everything learned) Focus on learning as a process within individuals Core-knowledge theory –Child possesses innate knowledge (domains of thought) 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.
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.