AP Psychology · Concepts hub

AP Psychology Definitions: Key Terms by Unit

The AP Psych exam rewards precise vocabulary. These AP Psychology definitions are grouped under College Board’s five current units, and every term carries a one-line definition plus an example you could use in an answer. Where a term has a deeper guide, the entry links to it.

Updated September 2026By Mahmudul Hasan

Unit 1: Biological Bases of Behavior

Neurotransmitter

A chemical messenger that carries a signal across the synapse from one neuron to the next. Losing dopamine in the brain’s motor pathways is what produces the tremor of Parkinson’s disease.

Neuroplasticity

The brain’s capacity to reorganize itself by forming new connections. After a stroke damages one region, neighbouring areas can take over part of its work.

Unit 2: Cognition

Encoding

The conversion of sensory input into a form the brain can store, in three ways: visual, acoustic and semantic. Tying a new term to something you already know is semantic encoding, and it is the version that lasts. Full guide: encoding ap psychology definition

Schema

A mental framework that organizes and interprets information. Your restaurant schema expects a menu, then food, then a bill, which is why a waiter handing you the bill first feels wrong. Full guide: schema ap psychology definition

Concept

A mental grouping of similar objects, events or people. A prototype is the best example of a category, which is why a robin comes to mind faster than a penguin.

Availability heuristic

A judgment shortcut that rates how likely something is by how easily examples come to mind. People overrate the danger of flying because crashes are reported and safe landings are not. Full guide: availability heuristic ap psychology definition

Unit 3: Development and Learning

Operant conditioning

Learning in which behavior is shaped by its consequences, through reinforcement and punishment. A rat that gets food for pressing a lever presses it more often; the food is the reinforcer. Full guide: operant conditioning ap psychology

Cognitive map

A mental representation of a physical space — how you find your kitchen in the dark. It is usually taught alongside learning rather than memory, from Tolman’s rats that had learned a maze without being rewarded for it. Full guide: cognitive map ap psychology definition

Generativity vs. stagnation

Erikson’s seventh stage, in midlife: contributing to the next generation against feeling stuck. Mentoring someone junior is generativity; coasting through the same job with no sense of contribution is stagnation. Full guide: generativity vs stagnation ap psychology definition

Identity vs. role confusion

Erikson’s fifth stage, in adolescence: forming a coherent sense of self against drifting between roles. Trying on different friend groups, styles and beliefs at sixteen is the work of this stage, not a failure of it.

Unit 4: Social Psychology and Personality

Evaluating yourself by measuring against other people, upward (better off) or downward (worse off). Scrolling past a classmate’s result and feeling worse is upward comparison doing its damage. Full guide: social comparison ap psychology definition

Fundamental attribution error

The habit of explaining other people’s behavior by their character while explaining your own by the situation. The driver who cuts you off is reckless; when you do it, you are late for something. Full guide: fundamental attribution error ap psychology

Cognitive dissonance

The discomfort of holding two conflicting beliefs, or of acting against a belief you hold. A smoker who knows the risks often resolves the tension by doubting the evidence rather than by stopping. Full guide: cognitive dissonance ap psychology definition

Unit 5: Mental and Physical Health

Conversion disorder

Psychological distress appearing as physical symptoms with no organic cause, also called functional neurological symptom disorder. Sudden loss of vision or movement with no injury or lesion that explains it. Full guide: conversion disorder ap psychology definition

Generalized anxiety disorder

Persistent, free-floating worry that is not tied to a specific trigger. Months of low-level dread about everything and nothing, rather than fear of one identifiable thing.

Cognitive-behavioral therapy

A talk therapy that changes thought patterns in order to change behavior. A therapist helps a client catch the thought “everyone noticed” and test it against what actually happened.

How the exam tests AP Psych vocabulary

The exam runs 2 hours 40 minutes and is taken entirely in Bluebook. The format College Board publishes is 75 multiple-choice questions in 1 hour 30 minutes, worth 66.7% of the score, then two free-response questions in 1 hour 10 minutes, worth 33.3% between them.

Each of the five units carries 15% to 25% of the multiple-choice section, so no unit is safe to skip. Within that section the marks are split by skill rather than by topic, and College Board publishes that split as approximate rather than fixed.

Roughly two thirds of the multiple-choice section hands you a scenario and asks which concept it shows. That is why every term above carries an example rather than a definition on its own.

That split is the argument against bare flashcards. The exam almost never asks you to state a definition; it hands you a short scenario and asks which concept it demonstrates, so a term you can recognize but not apply earns nothing. Learn each one with the situation attached.

The two free-response questions are the Article Analysis Question, which gives you one peer-reviewed study to interpret, and the Evidence-Based Question, which gives you three sources and asks you to make a claim and defend it. College Board weights the two equally, at 16.65% each, so neither is worth more than the other. Older study guides still describe a free-response question that asks you to apply five to seven named concepts to a single scenario. That question type no longer exists, and neither does the nine-unit course it belonged to: College Board’s AP Psychology course page lists five.

Frequently asked questions

Quick answers, checked against College Board.

Does College Board publish an official AP Psychology vocabulary list?

No. College Board publishes the course framework and the exam’s skill weightings, not a list of terms. Every “official” vocabulary list circulating online is a teacher’s or a publisher’s, which is why no two of them agree. Check your coverage against the five units instead of against somebody else’s list.

How many AP Psychology terms do I actually need to know?

There is no defensible number, and anyone quoting one is guessing. Published lists run from about 35 terms to more than 500. Even coverage across all five units is a better target than a total, because the exam samples every unit.

Are the redesigned AP Psych units very different from the old nine?

The content is largely the same, regrouped. What changed for revision is that older notes and flashcard sets are filed under headings your exam no longer uses, so a term can look as though it was dropped when it has only moved. If a set is sorted into nine or eleven units, it predates the current framework.

What is the fastest way to memorize this many definitions?

Spaced repetition, with a short scenario on the back of each card rather than a definition on its own. Write the definition in your own words before you test yourself: recognizing a term when you see it is not the same skill as producing it under time pressure.

Which research methods does the AP Psych exam expect me to recognize?

Experiments, correlational studies, case studies, naturalistic observation and surveys, along with the vocabulary that describes them: operational definitions, independent and dependent variables, random assignment and sampling bias. Research design carries its own share of the multiple-choice section, separate from the concept questions.

Where to go next

Work through the highest-yield terms in one pass with the ap psychology concept map review packet.
Once the vocabulary holds up, move on to the exam itself with the AP Psychology review.
For every other subject on the site, start from the AP study guide index.