AP Psychology Review Guide: All 5 Units Explained

AP Psychology was redesigned for the 2024-25 school year. The old 9 units are now 5 broader units, and the exam emphasizes real-world application more than memorizing researchers. The content is still rich, but the new structure makes it easier to study if you know how to use it.

This guide walks through all 5 units, the researchers you must know, the define-then-apply FRQ template, and the concepts that trip people up (negative reinforcement vs punishment, sensation vs perception, correlation vs causation).

What the exam looks like

Exam structure and scoring

• 2 hours total.
• Section I: 75 multiple choice in 90 minutes. Worth 67 percent.
• Section II: 2 free response in 70 minutes. Worth 33 percent.
• FRQ #1: Article Analysis Question (AAQ). You read a research article summary, describe design, apply concepts, evaluate claims.
• FRQ #2: Evidence-Based Question (EBQ). You apply psychology concepts to a scenario.
• No calculator. No formulas to speak of. This is a concepts exam.

Unit 1: Biological Bases of Behavior

What you need to know (15-25 percent)

Nervous system, brain structures, sensation and perception, consciousness. The biological foundation for all other units.

Neurons and neurotransmitters

• Neuron parts: dendrites (receive), cell body (soma), axon (send), myelin sheath (insulation, speeds signal), terminal buttons (release neurotransmitters).
• Action potential: all-or-nothing electrical signal. Resting potential (negative inside) -> depolarization (sodium rushes in) -> repolarization (potassium out).
• Synapse: gap between neurons. Neurotransmitters cross and bind to receptors.
• Key neurotransmitters: dopamine (reward, movement; too little = Parkinson's, too much = schizophrenia), serotonin (mood, sleep; low = depression), GABA (main inhibitor), glutamate (main excitor), acetylcholine (memory, muscle), norepinephrine (alertness, arousal), endorphins (pain suppression).
• Agonists mimic a neurotransmitter. Antagonists block it. Drugs work this way.

Brain structures and lobes

• Brainstem: medulla (breathing, heart rate), pons (arousal, sleep). Most primitive.
• Cerebellum: balance, coordination, procedural memory.
• Limbic system: thalamus (sensory relay), hypothalamus (body regulation, hunger, thirst, sex), hippocampus (memory formation), amygdala (emotion, especially fear).
• Cerebral cortex: four lobes. Frontal (decision-making, planning, personality, Broca's area for speech production). Parietal (sensory, spatial). Temporal (auditory, Wernicke's area for language comprehension). Occipital (vision).
• Split brain: corpus callosum connects hemispheres. When severed, hemispheres process independently (Sperry, Gazzaniga studies).
• Plasticity: brain can rewire after injury (especially in young).

Sensation and perception

• Sensation: detecting stimuli. Perception: interpreting them.
• Vision: light enters pupil, lens focuses on retina. Rods (dim light, peripheral) and cones (color, center). Optic nerve to visual cortex.
• Hearing: sound waves move eardrum, bones amplify to cochlea. Hair cells send signal to auditory cortex.
• Gestalt principles: proximity, similarity, closure, continuity. The brain organizes sensory input.
• Signal detection theory: ability to detect a stimulus depends on both signal strength and decision criteria (noise, motivation).
• Top-down (based on expectations) vs bottom-up (based on raw data) processing.

Unit 2: Cognition

What you need to know (15-25 percent)

Memory, thinking, intelligence, language. How the mind processes information.

Memory

• Three stages: encoding (getting info in), storage (holding), retrieval (getting it out).
• Three storage systems (Atkinson-Shiffrin model): sensory memory (< 1 second), short-term / working memory (~20 seconds, 7 +/- 2 items), long-term memory (potentially unlimited, permanent).
• Long-term memory types: explicit / declarative (semantic = facts, episodic = events), implicit / non-declarative (procedural = how to do things, conditioned responses).
• Serial position effect: remember first (primacy, encoded to LTM) and last (recency, still in STM) items best.
• Forgetting: encoding failure, storage decay, retrieval failure.
• Interference: proactive (old info disrupts new), retroactive (new info disrupts old).
• Mnemonics: chunking, method of loci, acronyms.

Thinking and problem solving

• Concepts: mental groupings. Prototypes are the best examples.
• Algorithms (step-by-step, guaranteed solution) vs heuristics (shortcuts, faster but sometimes wrong).
• Availability heuristic: judging by what comes to mind easily. Leads to overestimating vivid events (plane crashes).
• Representativeness heuristic: judging by how much something resembles a stereotype.
• Confirmation bias: seeking info that confirms existing beliefs.
• Framing: how info is presented affects decisions (same surgery with 90 percent survival vs 10 percent mortality).
• Fixation: inability to see a problem from a new angle. Functional fixedness (stuck on typical function of an object).

Intelligence and language

• Intelligence theories: Spearman's g (general intelligence), Gardner's multiple intelligences (linguistic, logical, musical, spatial, bodily, interpersonal, intrapersonal, naturalistic), Sternberg's triarchic (analytical, creative, practical).
• IQ: mean 100, SD 15. Bell curve. Normal distribution.
• Stereotype threat: worry about confirming a negative stereotype impairs performance.
• Language: phonemes (sounds), morphemes (meanings), grammar (rules).
• Language acquisition: universal stages. Babbling, one-word, two-word, telegraphic speech.
• Whorf's linguistic relativity: language shapes thought (debated).

Unit 3: Development and Learning

What you need to know (15-25 percent)

Lifespan development and how organisms learn (conditioning, observation). Combines biological and environmental factors.

Development theories

• Piaget's cognitive stages: sensorimotor (0-2, object permanence), preoperational (2-7, pretend play, egocentric, lacks conservation), concrete operational (7-11, can reason logically about concrete objects), formal operational (12+, abstract reasoning).
• Erikson's psychosocial stages (8 across lifespan): trust vs mistrust (infancy), autonomy vs shame, initiative vs guilt, industry vs inferiority, identity vs role confusion (adolescence), intimacy vs isolation, generativity vs stagnation, integrity vs despair.
• Kohlberg's moral development: preconventional (avoid punishment, rewards), conventional (social approval, law and order), postconventional (social contract, universal ethics).
• Attachment: Harlow's monkeys showed comfort more important than food. Ainsworth's Strange Situation: secure, avoidant, anxious/resistant attachment.
• Nature vs nurture: both matter. Twin studies reveal genetic influence on intelligence, personality.

Classical conditioning

• Pavlov's dogs: learning through association. Neutral stimulus (bell) paired with unconditioned stimulus (food) becomes conditioned stimulus that elicits conditioned response (salivation).
• Acquisition: learning the association.
• Extinction: CS alone (no US) stops eliciting CR.
• Spontaneous recovery: after extinction, CR returns briefly.
• Generalization: similar stimuli elicit the response. Discrimination: responding only to specific CS.
• Watson's Little Albert: human classical conditioning of fear.

Operant conditioning

• Skinner: learning through consequences. Reinforcement increases behavior; punishment decreases it.
• Positive reinforcement: add a pleasant stimulus (praise, money).
• Negative reinforcement: remove an unpleasant stimulus (taking Tylenol for headache).
• Positive punishment: add an unpleasant stimulus (spanking).
• Negative punishment: remove a pleasant stimulus (grounding, time-out).
• Reinforcement schedules: continuous (every response) vs partial (intermittent). Partial schedules more resistant to extinction.
• Ratio schedules (based on behaviors): fixed (every nth) or variable (slot machines).
• Interval schedules (based on time): fixed (paycheck) or variable (checking social media).
• Variable schedules produce highest, most persistent responding.
• Shaping: reinforcing successive approximations toward target behavior.

Observational learning

• Bandura's Bobo doll experiment: children imitate aggressive behavior they observe.
• Mirror neurons may provide neurological basis.
• Media and TV have observational learning effects on behavior.

Unit 4: Social Psychology and Personality

What you need to know (15-25 percent)

Social influences, attitudes, personality theories. People in context.

Social thinking and influence

• Attribution theory: explaining behavior via disposition (personality) vs situation (environment).
• Fundamental attribution error: overemphasizing disposition, underemphasizing situation when judging others. (We do the opposite for ourselves: self-serving bias.)
• Cognitive dissonance: discomfort when attitudes and behavior conflict. People change attitudes to match behavior.
• Conformity: Asch line study. People often agree with the group even when group is wrong. Driven by informational influence (want to be right) or normative influence (want to be liked).
• Obedience: Milgram's shock study. 65 percent administered lethal shocks when authority figure said to.
• Zimbardo's Stanford Prison Experiment: ordinary people adopt brutal or submissive roles.
• Bystander effect: people less likely to help when others present (Kitty Genovese case). Diffusion of responsibility.
• Group polarization: groups make more extreme decisions than individuals.
• Groupthink: desire for harmony overrides realistic appraisal (Bay of Pigs).
• Social facilitation: presence of others improves performance on easy tasks, hurts on hard tasks.

Personality

• Psychodynamic (Freud): id (pleasure), ego (reality), superego (morality). Defense mechanisms (denial, projection, rationalization, sublimation, repression).
• Humanistic (Maslow, Rogers): hierarchy of needs (physiological to self-actualization). Unconditional positive regard.
• Trait theories: Big Five (OCEAN - Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism).
• Social-cognitive (Bandura): reciprocal determinism. Behavior, environment, and person interact.

Unit 5: Mental and Physical Health

What you need to know (15-25 percent)

Motivation, emotion, stress, disorders, therapies. Practical applications.

Motivation and emotion

• Drive reduction: motivated to reduce physiological need (hunger, thirst).
• Arousal theory: seek optimal arousal (Yerkes-Dodson: moderate is best).
• Maslow's hierarchy: physiological -> safety -> belongingness -> esteem -> self-actualization.
• Intrinsic (internal reward) vs extrinsic (external reward) motivation. Overjustification effect: external rewards can reduce intrinsic motivation.
• Theories of emotion: James-Lange (body first, then emotion), Cannon-Bard (simultaneous), Schachter-Singer two-factor (arousal + cognitive label).

Stress and health

• Selye's general adaptation syndrome: alarm, resistance, exhaustion.
• Problem-focused coping (tackle the problem) vs emotion-focused (manage the feelings).
• Stress weakens immune system, contributes to heart disease, depression.
• Social support, exercise, mindfulness reduce stress.

Psychological disorders

• DSM-5 categorizes disorders.
• Anxiety disorders: generalized anxiety, panic disorder, phobias, OCD.
• Depressive and bipolar disorders: major depressive disorder, persistent depressive, bipolar I and II.
• Schizophrenia spectrum: positive symptoms (hallucinations, delusions), negative (flat affect, social withdrawal).
• Personality disorders: antisocial, borderline, narcissistic.
• Neurocognitive: Alzheimer's, dementia.
• Eating disorders: anorexia, bulimia.
• Dissociative: amnesia, identity disorder.

Therapy

• Psychoanalysis (Freud): free association, dream analysis, uncovering unconscious conflicts.
• Humanistic / client-centered (Rogers): unconditional positive regard, active listening, help client reach self-actualization.
• Behavior therapy: classical conditioning techniques (systematic desensitization for phobias), operant (token economies).
• Cognitive therapy (Beck, Ellis): identify and change distorted thinking patterns.
• Cognitive-behavioral therapy (CBT): combines cognitive and behavior approaches. Evidence-based for many disorders.
• Biological: medications (SSRIs for depression, antipsychotics for schizophrenia, lithium for bipolar), ECT (electroconvulsive therapy).

Researchers you must know

• Freud: psychoanalysis, unconscious, defense mechanisms.
• Pavlov: classical conditioning (dogs).
• Skinner: operant conditioning (rats, pigeons).
• Watson: behaviorism. Little Albert (fear conditioning in humans).
• Bandura: observational learning (Bobo doll), self-efficacy.
• Piaget: cognitive development stages.
• Erikson: psychosocial stages across lifespan.
• Kohlberg: moral development.
• Maslow: hierarchy of needs, humanistic psychology.
• Rogers: client-centered therapy, unconditional positive regard.
• Asch: conformity (line study).
• Milgram: obedience (shock study).
• Zimbardo: Stanford Prison Experiment.
• Harlow: attachment (monkeys).
• Ainsworth: Strange Situation, attachment styles.
• Sperry and Gazzaniga: split-brain studies.
• Beck and Ellis: cognitive therapy.
• Selye: general adaptation syndrome (stress).
• Loftus: memory and eyewitness testimony.

How to attack the two FRQs

The define-then-apply template

Both FRQs reward specific definitions followed by specific application. This template works for every single AP Psych FRQ:

1. First sentence: DEFINE the concept. 'Negative reinforcement is the removal of an aversive stimulus to increase a behavior.'
2. Second sentence: APPLY it to the scenario. 'In the scenario, Sarah puts on her seatbelt to stop the annoying beep, which makes her more likely to put on the seatbelt in the future.'
3. Connect your application to the specific facts in the scenario. Quote details. Do not stay abstract.

If you just name-drop the term without defining it, you lose the point. If you define without applying, you lose the point. DO BOTH.

How to score a 5 on AP Psychology

1. Master the researchers. They are tested constantly. Make flashcards: name on one side, contribution on the other.
2. Master the neurotransmitters. Match each to function and associated disorders.
3. Know the difference between classical and operant conditioning. This is tested every year and students confuse them.
4. Use the define-then-apply template on every FRQ. Every term needs both a definition and an application.
5. Practice reading research abstracts. The AAQ requires you to evaluate studies.

Common mistakes

• Confusing negative reinforcement with punishment. Negative reinforcement INCREASES behavior (by removing something bad). Punishment DECREASES behavior.
• Using 'prove' or 'cause' when a study only shows correlation. Correlational studies cannot establish causation.
• Mixing up retroactive (new info disrupts OLD) and proactive (OLD disrupts new) interference.
• Forgetting perception vs sensation. Sensation = detecting a stimulus. Perception = interpreting it.
• Confusing classical and operant conditioning. Classical: associating two stimuli. Operant: consequences shaping behavior.
• Attributing Pavlov's name to operant conditioning (it's classical). Skinner's to classical (it's operant).
• Forgetting to define terms on FRQs. Just listing 'this is negative reinforcement' does not earn full credit.
• Incorrect stage assignments. Piaget's preoperational is 2-7 (not 0-2). Erikson's intimacy vs isolation is young adulthood (not adolescence).

AP Psych rewards clear definitions and specific applications. Know the researchers, know the terms, apply them to examples. Master the define-then-apply template, and the FRQs become mechanical.