🧠 Psychology · Developmental Psychology

Development tricks that make stages stick

Erikson, Piaget, attachment theory, and milestones — memorized.

🧒 Developmental

Memory tricks

Proven mnemonics — fast to learn, hard to forget.

Attachment Styles
Ainsworth: Secure, Anxious, Avoidant — SAA
Attachment Styles
Three primary attachment patterns based on caregiver responsiveness
Secure: explores freely, upset at separation, easily comforted. Anxious: clingy, very distressed, hard to soothe. Avoidant: indifferent to caregiver, suppresses attachment needs.
Secure
Explores freely, calmed by reunion
Anxious
Clingy, hard to soothe
Avoidant
Indifferent to caregiver
Object Permanence
Object permanence develops ~8 months: things exist when hidden
Object Permanence
Before 8 months, out of sight literally means out of mind
Infants under ~8 months won't search for a toy hidden under a blanket — they don't understand it still exists. After object permanence develops, they'll search for it.
Zone of Proximal Development
Vygotsky's ZPD: the gap between what you can do alone vs with help
Zone of Proximal Development
Learning happens best just beyond current ability with the right support
ZPD = what a learner can do with guidance but not yet alone. Scaffolding = teacher support that bridges this gap. Gradually remove support as competence grows.
Kohlberg's Moral Development
Kohlberg's 3 levels of moral development: Pre-conventional, Conventional, Post-conventional
Kohlberg's Moral Development
Three levels of moral reasoning — from self-interest to universal principles
Pre-conventional: morality based on consequences to self (punishment and reward). Conventional: morality based on social rules and laws. Post-conventional: morality based on universal ethical principles.
Prenatal Development Stages
Prenatal development: germinal (0-2 weeks) → embryonic (2-8 weeks, most vulnerable) → fetal (8 weeks-birth)
Prenatal Development Stages
Three stages from conception to birth
Germinal: fertilization through implantation (~2 weeks). Embryonic (2-8 weeks): major organs and structures form — most vulnerable to teratogens (alcohol, drugs, infections). Fetal (8 weeks to birth): growth and refinement of systems. Teratogens cause most damage during embryonic stage when organs are forming.
Infant Temperament
Temperament: easy, difficult, slow-to-warm-up — largely innate, influences parenting and development
Infant Temperament
Inborn differences in emotional reactivity and self-regulation
Thomas and Chess: Easy (40%): adaptable, positive mood, regular routines. Difficult (10%): intense reactions, slow to adapt, negative mood. Slow-to-warm-up (15%): initially withdraws, gradually adapts. Goodness of fit: match between child's temperament and parenting style predicts outcomes.
Parenting Styles
Authoritative parenting: high warmth + high control = best outcomes. Authoritarian: low warmth + high control.
Parenting Styles
Baumrind's four parenting styles and their outcomes
Authoritative: warm, responsive, consistent boundaries → children: confident, socially skilled, academically successful. Authoritarian: strict, low warmth, punitive → children: obedient but lower self-esteem. Permissive: warm but few rules → children: impulsive, lower achievement. Uninvolved: low warmth and low control → worst outcomes.
Authoritative
High warmth + high control — best outcomes
Authoritarian
Low warmth + high control — obedient but anxious
Permissive
High warmth + low control — impulsive
Uninvolved
Low warmth + low control — worst outcomes
Adolescent Development
Adolescence: identity formation (Erikson), formal operations (Piaget), puberty, peer influence peak
Adolescent Development
The key developmental tasks and changes of adolescence
Physical: puberty — hormonal changes, primary and secondary sex characteristics. Cognitive: formal operational thought — abstract reasoning, hypothetical thinking. Social: Erikson's identity vs role confusion — 'Who am I?' Peer influence peaks. Risk-taking increases — prefrontal cortex not fully developed until ~25.
Cognitive Aging
Aging: fluid intelligence (speed, working memory) declines. Crystallized intelligence (knowledge, vocabulary) maintained.
Cognitive Aging
How different types of intelligence change across the lifespan
Fluid intelligence: raw processing speed, working memory, novel problem-solving — peaks in 20s, declines gradually. Crystallized intelligence: accumulated knowledge, vocabulary, expertise — maintained or increases into old age. Successful aging: staying physically active, mentally engaged, and socially connected.
Infant Social Development
Stranger anxiety: ~8 months. Separation anxiety: peaks ~14 months. Both signal healthy attachment.
Infant Social Development
Two normal anxiety responses that signal healthy development
Stranger anxiety: distress at unfamiliar people — emerges ~6-8 months when infants can distinguish familiar from unfamiliar faces. Separation anxiety: distress when attachment figure leaves — peaks ~14 months, gradually decreases. Both signal that healthy attachment has formed. Absence may indicate attachment problems.
Theory of Mind
Theory of mind: understanding that others have different beliefs, desires, and knowledge than you do
Theory of Mind
The ability to understand other people's mental states
Develops around age 4. False belief task: child understands that another person can have a false belief. Before theory of mind: children assume everyone knows what they know (egocentrism). Autism spectrum disorder often involves theory of mind deficits. Foundation of empathy and social understanding.