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Chapter 15 – Physical and Cognitive Development: Key Vocabulary

Learning Outcomes

  • 15.1 Describe basic issues in developmental psychology

  • 15.2 Distinguish the three main research designs used by developmental psychologists

  • 15.3 Describe physical development across the life span and its psychological impact

  • 15.4 Describe perceptual and cognitive development in infancy, childhood, adolescence

  • 15.5 Describe cognitive changes associated with ageing

Concept Map – Overview

  • Dual Foci - Physical development -> bodily growth, maturation, neurological change

    • Cognitive development -> perception, thinking, memory, language

  • Three perennial questions - Nature vs nurture

    • Critical / sensitive periods

    • Stage-like vs continuous change

  • Research strategies - Cross-sectional

    • Longitudinal

    • Sequential

Issues in Developmental Psychology

  • Nature & Nurture - Maturation = biologically programmed, orderly changes (e.g., infants crawl -> walk)

    • Environment turns genes on/off; sensory input vital (e.g., occipital-lobe neurons need light)

    • Gene–environment interaction: combined vulnerabilities multiply risk (e.g., anxiety)

    • Gene–environment correlation: genotype influences chosen context (e.g., antisocial peers)

  • Critical vs Sensitive Periods - Critical: must occur for typical outcome (e.g., gosling imprinting)

    • Human evidence mixed; language likely critical (Genie, wild boy)

    • Sensitive: optimal but not exclusive windows (e.g., synaptic pruning in adolescence)

  • Stage vs Continuity - Stage models (Piaget) -> qualitative shifts

    • Continuous models -> gradual quantitative accumulation

    • Current view: both operate; stages clearer in childhood, variability later

Studying Development

  • Cross-Sectional - Compare age-groups once; snapshot of age differences

    • Vulnerable to cohort effects (culture, history)

  • Longitudinal - Follow same individuals; reveals age change, individual trajectories

    • Time-consuming; still cohort-specific

  • Sequential - Multiple cohorts tracked longitudinally; separates age vs cohort influences

    • Gold standard but costly, decades long

  • Applied example: Internet-attitude survey of Year 3, Year 9, 21- & 60-year-olds = cross-sectional; cannot infer intra-individual change

Physical Development & Psychological Consequences

Prenatal Period

  • Stages - Germinal 0-2 wk: zygote implantation

    • Embryonic 3-8 wk: organogenesis, CNS vulnerable

    • Fetal 9 wk-birth: rapid musculature, viability approx 28 wk

  • Teratogens - Alcohol -> FAS / FASD (physical anomalies, learning deficits); Kimberley Lililwan study 13/108 affected

    • Nicotine, cocaine, radiation, rubella

    • Maternal stress (Congo war, PTSD epigenetics) alters birth-weight, ADHD risk

    • Timing principle (Fig. 15.3): highest risk during embryonic organ formation; before 2 wk usually miscarriage

Infancy

  • Reflexes: rooting, sucking; disappear by approx 6-7 mo

  • Motor sequence head->trunk->legs; universal but pace modifiable - Aboriginal infants sit approx 2.5 mo vs 4-5 mo in Anglo peers

    • Back-sleeping (SIDS prevention) delays crawling; plagiocephaly risk mitigated by ‘tummy-time’

  • Brain: exuberant synaptogenesis followed by pruning; experience-expectant wiring

Childhood & Adolescence

  • Growth - Similar until approx 10 yr; girls’ spurt peaks approx 12, boys approx 14-15

    • Puberty = reproductive capability; menarche approx 11-13; sperm-arche approx 14.5

  • Psychosocial effects - Early-maturing boys: athletic status, confidence

    • Early-maturing girls: distress, delinquency; family stress may hasten onset

Adulthood & Ageing

  • Gradual decline from 30s: muscle, vision (presbyopia), hearing (presbycusis), reaction time

  • Menopause - Mean age approx 51.3 yr; HRT helps but increased risk of breast cancer, CVD

  • Male midlife: testosterone decreases, fertility retained, ‘beer belly’

  • Later life - Sensory losses: contrast, dark adaptation, HF sounds; can fuel ageism

    • Use-it-or-lose-it applies to body and mind

Cognitive Development: Infancy -> Adolescence

Infant Perception & Memory

  • Orienting reflex / habituation methods reveal discrimination - Newborns recognise mother’s voice, prefer faces

  • Intermodal processing present within days (lip–voice sync)

  • Object permanence emerges earlier than Piaget claimed (approx 4-5 mo)

  • Memory - Implicit present at birth (kicking-mobile, word-stem facilitation)

    • Explicit/hippocampal functions mature 8-18 mo; infantile amnesia persists

    • Representational flexibility grows; 9-mo form relational memories (eye-tracking studies)

Piaget’s Stage Theory

  1. Sensorimotor (0-2 yr) - Thought = action; object permanence; egocentrism

  2. Preoperational (2-7 yr) - Symbolic thought & language

    • Limitations: centration, egocentrism (three-mountains task), literalism

  3. Concrete Operational (7-12 yr) - Mental operations on concrete objects; conservation of liquid/number/mass; decentration; transitivity

  4. Formal Operational (12 yr+) - Abstract, hypothetical, systematic reasoning

  • Mechanisms: assimilation + accommodation -> equilibration

  • Critiques - Underestimates infants, overestimates stage unity, ignores culture, small flawed samples

    • Neo-Piagetians (Case): working-memory expansion drives stage-like advances

Vygotsky’s Sociocultural Theory

  • Zone of Proximal Development (ZPD): span from solo to assisted mastery

  • Learning via guided participation, scaffolding, imitation; culture shapes cognition

Information-Processing Approach

  • Continuous quantitative gains - Processing speed rises to approx 15 yr (exponential curve)

    • Automatization frees WM

    • Knowledge base widens (10-yr chess experts > adult novices)

    • Strategy use evolves (rehearsal -> categorisation)

    • Metacognition & metamemory improve; critical for transfer and learning to learn

Integrative / Neo-Piagetian Views

  • Combine stage sequence with domain-specific, WM-focused mechanisms

  • Working-memory central executive matures to approx 10 yr; enables coordination of multiple representations (art perspective study)

Technology & Adolescents

  • Multitasking is common; may challenge deep focus but trains task-switching

  • Action games enhance visual–spatial skills, dyslexia remediation; violent games link to aggression

Cognitive Development & Ageing

  • Psychomotor speed decreases from mid-20s; affects complex reasoning via limited-time & WM-decay hypotheses

  • Working memory & executive control decline; bilateral activation vs left-lateralised in youth (fMRI)

  • Long-term memory - Encoding largely intact with time/support

    • Retrieval deficits in recall > recognition

    • Implicit memory spared

    • Autobiographical ‘reminiscence bump’ 10-30 yr

  • Intelligence - Fluid decreases after mid-20s

    • Crystallised increases through 50s–60s, plateau late

    • Everyday problem solving: gist > detail; workplace productivity stable (meta-analysis N > 38,000)

  • Individual variability - Seattle Longitudinal Study: < 25% show decline before 60; education >= 9 yr protective

    • Cognitive training (iPad, digital photography) boosts episodic memory & processing speed

  • Dementia - Overall prevalence approx 1%; Alzheimer’s > 50% of cases

    • Australian projections: 400,833 cases in 2016 -> > 1.13 million by 2050

    • Indigenous rates approx 12-13%; earlier onset

    • Neuropathology: neurofibrillary tangles, beta-amyloid, decreased acetylcholine; hippocampal atrophy correlates with deficits

    • Experimental ultrasound therapy (UQ) shows promise in mice

Ethical, Philosophical & Practical Implications

  • Cash incentives in prenatal memory studies; ensure informed consent, no coercion, maternity/infant safety reviews

  • Ageism in workplace & healthcare; implicit bias shown via priming (old->negative traits faster)

  • Policy: SIDS guidelines vs motor delays; FASD education in Kimberley; digital literacy for seniors

Numerical & Statistical References

  • 9.6 million Australians >= 65 yr predicted by 2064

  • FASD in Lililwan: 13/108 = 12.0% prevalence

  • Processing-speed ratio curve S = 3 * exp(-0.1 * (age - 6)) (approx)

  • Menopause mean age = 51.3 yr (SD approx 4); premature (< 40 yr) 2%

  • Dementia prevalence >= 80 yr: males 12%, females 21%

Connections & Examples

  • Allegra Clarke (age 9) university physics enrolment -> nature–nurture debate on giftedness

  • Wild Boy of Aveyron & Genie -> critical period for language

  • Visually deprived monkeys (Carlson et al., 1987) -> sensitive periods for perception

  • Three-mountain task, beaker conservation, peek-a-boo illustrate Piagetian constructs

  • SIDS back-sleeping policy & crawling delay; interplay of health intervention & development

Quick Reference – Research Designs

  • Cross-Sectional -> age differences snapshot; N_age = 4 groups in tech-attitude study

  • Longitudinal -> ATP (Victorian cohort 1982-present); Mater–UQ mothers 1981-21 yr

  • Sequential -> 3-cohort staggered study controlling for 9/11 event

Key Terms Cheat-Sheet

  • Assimilation, Accommodation, Object Permanence, Centration, ZPD, Automatization, Metacognition, Psychomotor Slowing, Fluid vs Crystallised Intelligence, Teratogen, Sensitive Period, Sequential Design

Study Tips

  • Link Piagetian stages to real-life tasks (e.g., when children grasp conservation -> introduce fractions)

  • For exams, practise identifying research design from vignette

  • Memorise teratogen timing with mnemonic ‘G-E-F’ (Germinal-Embryonic-Fetal)

  • Use dual-coding: sketch Piaget’s beakers, Vygotsky’s ZPD ladder, lifespan physical changes timeline