Psychology theories, explained

How people develop

Six accounts of what changes as a person grows up, what shapes it, and what the evidence says about each.

• Kohlberg's stages of moral development

  Kohlberg's six stages of moral reasoning, the dilemma he built them from, what the long study found, and the two criticisms that stuck.

• Vygotsky's sociocultural theory

  Vygotsky's sociocultural theory in plain words: the zone of proximal development, the more knowledgeable other, language as a tool, and what later research supports.

• Erikson's stages of development

  Erikson's eight stages of psychosocial development, the tension in each one, what it is said to build, and how much of the scheme has been tested.

• Piaget's stages of cognitive development

  Piaget's four stages of cognitive development, the tasks behind them, and what later experiments showed about the ages he gave.

• Nature versus nurture

  Nature versus nurture: where the phrase came from, what fifty years of twin studies found, and what heritability means and does not mean.

• Bronfenbrenner's ecological systems theory

  Bronfenbrenner's ecological systems theory: the five nested systems around a child, where the model came from, what later research supports, and how he revised it.

How behavior is learned

What a signal, a consequence, a model to copy and a loss of control do to what somebody does next.

• Classical conditioning

  Classical conditioning explained: the four terms, what Pavlov actually did, acquisition and extinction, and why pairing two events is not enough on its own.

• Operant conditioning

  Operant conditioning explained: reinforcement and punishment in four boxes, the schedules that make a behavior stubborn, and where rewards backfire.

• Learned helplessness

  Learned helplessness: the 1967 experiment, the attribution version, and the 2016 reformulation that turned the original claim around.

• The Little Albert experiment

  The Little Albert experiment: what Watson and Rayner did in 1920, what the study really showed, the ethics, and what happened to the child.

• The Bobo doll experiment

  The Bobo doll experiment: what Bandura, Ross and Ross did in 1961, what the children copied, and what it cannot show.

• Social learning theory

  Social learning theory in plain words: the four processes Bandura named, vicarious reinforcement, self-efficacy, and the evidence.

People in groups

What other people, a first impression, an assigned role and belonging to a side do to a judgment.

• The Milgram experiment

  The Milgram obedience experiment: what the 1963 study did, the 65 percent figure, how the variations changed it, and what later work says it shows.

• Social identity theory

  Social identity theory explained: the three steps, the minimal group experiments behind it, and what it does and does not say about prejudice.

• The Stanford prison experiment

  The Stanford prison experiment: what happened in the basement in 1971, the demand characteristics, and what it does not prove.

• The Robbers Cave experiment

  The Robbers Cave experiment: two groups of boys at a 1954 summer camp, what set them against each other, and what ended it.

• The halo effect

  The halo effect: how one impression of a person spreads into ratings of everything else about them, where Thorndike found it, and what blunts it.

Inside the person

What a person wants, and what they do with a fact that does not fit what they believe.

• Defense mechanisms

  Defense mechanisms explained: eight of the common ones with everyday examples, where the list came from, and how much of it modern research supports.

• Cognitive dissonance

  Cognitive dissonance explained: Festinger's theory, the one dollar and twenty dollar experiment, effort justification, and the rival account.

• Maslow's hierarchy of needs

  Maslow's hierarchy of needs: the five levels, where the pyramid came from, and why the evidence does not support a fixed order.

Why these pages exist

Learn teaches psychology in short lessons, one idea at a time. These pages are the longer read behind some of those ideas: no account, no sign-in, and nothing to finish. If one of them interests you, the lessons are where you practice it.