chapter 11-human delvoepemnt

Human Development Overview

• Study of continuity and change across the lifespan

• Focus on young kids due to rapid change early in life

• Change can be:

  • Gradual (growth over time)

  • Stage-based (sudden new abilities)

• Continuity: what remains stable across life?

Sensation & Perception

• Sensation: detecting external stimuli

• Perception: processing and interpreting sensations

• Begins prenatally, becomes richer after birth

Cognition & Language

• How we think and develop language skills

• Strongly linked to sensory and motor development

Emotions

• Learning what emotions are

• Learning to control and express them

Periods of Development PCAA

• Prenatal & Infancy: conception to ~2-3 years

• Childhood: ~2-3 to 11 years

• Adolescence: 12 to brain maturity (~25 years)

• Adulthood: brain maturity to death

Early Memories

• First memories often emotionally charged

• Usually appear around age 2-3

• Early experiences shape lifelong development

• Exposure to people, language, food, music starts early

Prenatal Development GEF

• Begins at conception

• 3 stages:

  1. Germinal (Zygotic): fertilization to implantation (~2 weeks)

  2. Embryonic: implantation to 8 weeks, vital organs develop

  3. Fetal: 9 weeks to birth, organs develop, sensory learning begins

• At 20 weeks, fetus detects environmental stimuli

Brain development terms

• Neurogenesis: creation of neurons

• Myelination: myelin growth, speeds signals

• Synaptogenesis: new synapses form (connections)

• Synaptic pruning: unused synapses removed

Fetal Learning & Teratogens

• Fetal heart rate changes with sounds (e.g., mother's voice)

• Allergies can develop or resistances form prenatally

• Teratogens: substances causing fetal damage (e.g., alcohol)

• Earlier exposure → more severe effects

Neonatal Period (Right After Birth)

• Newborns sleep a lot for brain development

• Sleep breakdown (24h):

  • 8h active sleep (REM)

  • 8h quiet sleep (NREM)

  • 1h drowsing

  • 2.5h alert awake

  • 2.5h active awake

  • 2h crying

• REM sleep helps encode information

Perceptual Development

• Begins in utero; richer after birth (sounds clearer, direct stimuli)

• Measuring infant perception:

  • Adults: lens tests, reading, colorblind tests, EEG (expensive)

  • Infants: preferential looking—longer gaze at interesting stimuli

  • Grating test: prefer stripes over blank paddle; inability to discriminate indicates impairment

• Visual acuity improves rapidly:

  • Birth: 20/400

  • 1 month: 20/120

  • 6 months: adult-like acuity

• Color and depth perception develop in first 6 months

Infant Motor Development

• Closely linked to perception

• First movements: crying, head turn, kicking (even in utero)

• Mostly reflexive at birth:

  • Grasping

  • Rooting (turn toward cheek touch)

  • Sucking

  • Swallowing

  • Tonic neck reflex (turn head with arm)

• Some reflexes last lifetime (coughing, sneezing, blinking, withdrawal from pain)

Complex Motor Development Rules (2)

• After reflexes, skills develop via:

  • Cephalocaudal rule: head to toe progression

  • Proximodistal rule: center outward progression (shoulders before fingers)

Motor Development Timeline

• 0–1 month: lifts head prone

• 2–4 months: props chest up, rolls over

• 9–13 months: stands alone

• 11–14 months: walks alone

• 14–22 months: walks up steps

• Variation exists in timing among kids

Motor & Visual Development Link

• Walking infants have better visual perception than crawlers

• Walking provides faster and richer visual input

Piaget’s Cognitive Development Theory SPCF

• Divides cognition into 4 stages:

  1. Sensorimotor (0–2): learning through senses and actions, no object permanence, egocentric

  2. Preoperational (2–6): develops theory of mind, moves to sociocentrism

     (egocentrism to sociocentrism is the shift from focusing only on yourself to considering the views and needs of a group)

  3. Concrete operational (6–11): logical thinking about concrete things

  4. Formal operational (11+): abstract and hypothetical thinking

• Criticism: based on limited sample (own child)

Piaget’s Learning Processes

• Children organize knowledge into schemas (mental frameworks, alive” = pets)

• Assimilation: adding new info into existing schema (e.g., cat fits "alive" schema)

• Accommodation: modifying schema when new info doesn’t fit (e.g., trees are alive but not like animals)

Cognitive disequilibrium: when new info doesn't fit existing schema, triggering accommodation."

Children are constructivists—they learn by actively building knowledge.

Attachment & Social Development

Attachment: bond between infant and caregiver

• Essential for healthy development

• Strange Situation Task (measure attachment):

  1. Kid explores with mom → stranger enters

  2. Mom leaves → kid cries

  3. Mom returns

  4. Observe reactions

Secure Attachment:

• Uses mom as base

• Cries when she leaves, calms down when she returns

Insecure Attachment:

• Ignores mom, pushes her away, or can’t calm down

Disorganized Attachment (Infant)

• Contradictory behavior: wants closeness but also avoids parent

• Linked to abuse/trauma or erratic caregiver behavior

Attachment predicts:

• Academic success

• Emotional regulation

• Relationship quality

• Self-esteem

Self-Esteem Across Lifespan

• Young kids: high, based on others’ praise

• School age: drops due to comparisons, report cards

• Adolescents: low self-esteem, especially girls

• Adulthood: generally rises, dips after 65

• Rank-order stability: low self-esteem kids → low self-esteem adults

theory of Mind & False Belief Tasks

• Theory of Mind = understanding that people can have different thoughts, beliefs, and knowledge than you

• Develops around age 4

• False Belief Tasks test this ability

Sally-Anne Task:

1. Sally puts a ball in a basket and leaves

2. Anne moves the ball to a box

3. Child is asked: “Where will Sally look for her ball?”

Results:

• 3-year-olds: say "box" → fail (don’t understand Sally’s false belief)

• 4-year-olds: say "basket" → pass (understand Sally’s perspective)

💡 Shows shift from egocentrism → sociocentrism

• Children begin to understand that others can hold beliefs different from reality

Describe the principal components of identity formation according to Erik Erikson

• Stage: Identity vs. Role Confusion (teens)

  • Explore beliefs/goals → stable self

  • Success = Identity Achievement

  • Failure = Role Confusion

• Marcia’s 4 Identity Statuses:

  • Diffusion – no clue

  • Foreclosure – committed w/o exploring

  • Moratorium – exploring, not decided

  • Achievement – explored + committed

Unexpected Content Task

Children are tested on their ability to predict what others believe is inside a container based on appearance

Imprinting (Lorenz)

Newborn animals follow the first moving object they see, typically their caregiver (e.g., geese)

Harlow’s Monkeys Study

Monkeys preferred cloth mothers (comfort) over wire mothers (food), showing the importance of emotional connection.