Review AP Psychology Unit 2 to build a complete picture of how people perceive, think, remember, and measure intelligence. This unit carries 15-25% of the exam weight and covers everything from Gestalt principles and heuristics to the forgetting curve and IQ testing.
Use the topic guides, key terms, and practice questions available for this unit to work through all eight topics before your exam.
Cognition is the study of mental processes: how you take in information, make sense of it, store it, and use it to make decisions. Unit 2 moves from perception through memory to intelligence, showing how each process can work well or break down.
Topics 2.1 and 2.2 explain how bottom-up and top-down processing shape what you perceive, how Gestalt principles organize visual scenes, and how heuristics like the availability and representativeness shortcuts lead to systematic judgment errors.
Topics 2.3 through 2.6 trace information through the multi-store and working memory models, explain how encoding strategies like chunking and the spacing effect improve retention, and show how context-dependent and state-dependent cues aid retrieval.
Topics 2.7 and 2.8 cover why memories fail through interference, the forgetting curve, and constructive memory errors, then shift to how intelligence is theorized (Spearman's g, Gardner, Sternberg), measured with standardized IQ tests, and complicated by stereotype threat and the Flynn Effect.
Every process in Unit 2 shows that the mind constructs rather than records. Perception is filtered by schemas and culture. Memory is reconstructed at retrieval, not played back like a video. Intelligence scores reflect test design, access, and societal factors as much as raw ability. Keeping this constructive view in mind helps you apply concepts to novel scenarios on the exam.
Covers bottom-up and top-down processing, schemas and perceptual sets, Gestalt principles (closure, figure-ground, proximity, similarity), selective attention, inattentional blindness, binocular and monocular depth cues, perceptual constancies, and apparent movement.
Covers concepts and prototypes, schema assimilation and accommodation, algorithms versus heuristics, representativeness and availability heuristics, mental set, functional fixedness, framing, anchoring, executive functions, and creativity.
Covers explicit memory (episodic, semantic), implicit memory (procedural), prospective memory, long-term potentiation, the multi-store model, the working memory model (central executive, phonological loop, visuospatial sketchpad), and the levels of processing model.
Covers mnemonic devices (method of loci, acronyms), chunking, the spacing effect (distributed vs. massed practice), the serial position effect (primacy and recency), and how encoding depth affects later retrieval.
Covers sensory memory (iconic, echoic), short-term memory capacity and duration, working memory, long-term memory, maintenance versus elaborative rehearsal, highly superior autobiographical memory, retrograde and anterograde amnesia, Alzheimer's disease, and infantile amnesia.
Covers recall versus recognition, retrieval cues, context-dependent memory, mood-congruent memory, state-dependent memory, retrieval practice, the testing effect, and metacognition.
Covers the Ebbinghaus forgetting curve, encoding failure, proactive and retroactive interference, the tip-of-the-tongue phenomenon, repression, the misinformation effect, source amnesia, constructive memory, and imagination inflation.
Covers theories of intelligence (Spearman's g, Gardner's multiple intelligences, Sternberg's triarchic theory), IQ measurement history, psychometric principles (standardization, construct and predictive validity, test-retest and split-half reliability), the Flynn Effect, stereotype threat, misuse of IQ scores, and achievement versus aptitude tests and mindset.
This snapshot uses Fiveable practice activity to show where students tend to miss questions and which review moves are worth prioritizing first.
Across 78k multiple-choice practice attempts for this unit.
Practice activity included in this snapshot.
Across 155 scored free-response attempts for this unit.
Review Intelligence and Achievement with attention to how the concept appears in AP-style source and evidence questions.
Review Perception with attention to how the concept appears in AP-style source and evidence questions.
Review Introduction to Memory with attention to how the concept appears in AP-style source and evidence questions.
Review Thinking, Problem-Solving, Judgments, and Decision-Making with attention to how the concept appears in AP-style source and evidence questions.
Perception is the brain's interpretation of sensory input. It is shaped by both the raw data coming in and by internal expectations. Gestalt psychologists identified organizing principles that explain how humans group visual elements automatically. Depth perception relies on binocular cues (retinal disparity, convergence) and monocular cues (relative size, texture gradient, linear perspective, interposition, relative clarity). Perceptual constancies keep objects stable even when retinal images shift.
| Cue type | Requires both eyes? | Examples |
|---|---|---|
| Binocular | Yes | Retinal disparity, convergence |
| Monocular | No | Texture gradient, linear perspective, interposition, relative size, relative clarity |
Thought is organized around concepts and prototypes. Schemas are updated through assimilation (fitting new info into existing frameworks) or accommodation (revising the framework). Problem-solving uses algorithms (exhaustive, guaranteed) or heuristics (fast, fallible). Common heuristics include the representativeness heuristic and the availability heuristic. Biases like mental set, functional fixedness, anchoring, and framing affect decisions. Executive functions including working memory, inhibitory control, and cognitive flexibility support higher-order thinking.
| Strategy | How it works | Risk |
|---|---|---|
| Algorithm | Tests all possible solutions systematically | Slow and resource-intensive |
| Heuristic | Uses a mental shortcut to reach a quick judgment | Can produce systematic errors and biases |
Memory is not a single system. Explicit memory (episodic and semantic) can be consciously described; implicit memory (procedural) cannot. Prospective memory involves remembering to do something in the future. Long-term potentiation (LTP) is the biological basis of memory: repeated activation strengthens synaptic connections. Three major models describe memory structure: the multi-store model (sensory, short-term, long-term), the working memory model (central executive, phonological loop, visuospatial sketchpad), and the levels of processing model (structural, phonemic, semantic encoding).
| Memory type | Conscious access? | Examples |
|---|---|---|
| Episodic | Yes | Memory of your last birthday |
| Semantic | Yes | Knowing that Paris is in France |
| Procedural | No | Riding a bike, typing |
| Prospective | Yes | Remembering to take medication at noon |
Encoding is the process of getting information into memory. The strategy used determines how well information is later retrieved. Mnemonic devices (method of loci, acronyms, acrostics) create retrieval-friendly associations. Chunking groups information into meaningful units to reduce cognitive load. The spacing effect shows that distributed practice produces stronger encoding than massed practice. The serial position effect predicts better recall for items at the beginning (primacy) and end (recency) of a list.
Memory storage systems differ in duration, capacity, and content. Sensory memory holds raw input briefly (iconic for visual, echoic for auditory). Short-term memory holds about 7 items for roughly 20 seconds without rehearsal. Working memory actively processes current information. Long-term memory has essentially unlimited capacity and duration. Maintenance rehearsal repeats information to keep it active; elaborative rehearsal connects new information to existing knowledge and produces stronger storage. Amnesia (retrograde and anterograde), Alzheimer's disease, and infantile amnesia illustrate how storage can be disrupted.
| Storage system | Duration | Capacity |
|---|---|---|
| Sensory memory | Milliseconds to ~4 seconds | Large but fleeting |
| Short-term memory | ~20 seconds without rehearsal | ~7 items (plus or minus 2) |
| Working memory | Active processing duration | Limited, task-dependent |
| Long-term memory | Potentially lifetime | Essentially unlimited |
Retrieval is getting stored information back out of memory. Recall involves producing information without cues (free recall) or with partial cues (cued recall). Recognition involves identifying correct information when it is presented. Retrieval is enhanced when the context, mood, or physical state at retrieval matches encoding conditions. Retrieval practice (the testing effect) strengthens memory more than passive rereading. Metacognition, or monitoring your own understanding, helps you judge whether you actually know material.
Forgetting is not random. Ebbinghaus's forgetting curve shows rapid memory loss shortly after learning that levels off over time. Encoding failure means information was never properly stored. Proactive interference occurs when old learning disrupts new memory; retroactive interference occurs when new learning disrupts old memory. The tip-of-the-tongue phenomenon reflects retrieval failure despite storage. Psychodynamic theory attributes some forgetting to repression. Memory accuracy is also compromised by the misinformation effect (Loftus), source amnesia, and constructive memory processes including imagination inflation.
| Cause of forgetting | Mechanism |
|---|---|
| Encoding failure | Information was never properly stored in the first place |
| Proactive interference | Old memories block recall of new information |
| Retroactive interference | New memories block recall of old information |
| Repression | Psychodynamic: unconscious blocking of distressing memories |
| Misinformation effect | Post-event information overwrites or distorts the original memory |
Intelligence has been defined as a single general factor (Spearman's g), a set of primary mental abilities (Thurstone), multiple independent intelligences (Gardner), or three interacting abilities (Sternberg's triarchic theory). Early IQ tests divided mental age by chronological age; modern tests use standardized scoring. All useful psychological tests must be standardized, valid (construct and predictive validity), and reliable (test-retest and split-half). The Flynn Effect describes rising IQ scores over generations due to societal factors. IQ scores have historically been misused to restrict immigration, military rank, and educational access. Achievement tests measure current knowledge; aptitude tests predict future performance. Fixed versus growth mindset beliefs affect academic outcomes.
| Theory | Theorist | Core claim |
|---|---|---|
| General intelligence (g) | Spearman | One factor underlies all cognitive performance |
| Multiple intelligences | Gardner | Eight or more independent intelligences (linguistic, logical-mathematical, musical, etc.) |
| Triarchic theory | Sternberg | Analytical, creative, and practical intelligence are three distinct but related abilities |
Try AP-style multiple-choice questions and written prompts after you review the notes.
| Term | Definition |
|---|---|
| monocular depth cues | Depth perception cues that work with one eye, including relative clarity, relative size, texture gradient, linear perspective, and interposition. |
| visual perceptual constancies | The tendency to perceive objects as maintaining their properties (size, shape, color) even when the retinal image changes due to distance or viewing angle. |
| apparent movement | The visual perception of movement in objects that are not actually moving, such as in the phi phenomenon. |
| overconfidence effect | A cognitive bias in which people overestimate the accuracy of their own beliefs and judgments, often leading to poor decision-making. |
| multi-store model | Atkinson and Shiffrin's model proposing three sequential memory systems: sensory memory, short-term memory, and long-term memory. |
| phonological loop | The component of working memory that temporarily stores and processes verbal and acoustic information. |
| visuospatial sketchpad | The component of working memory that temporarily stores and processes visual and spatial information. |
| levels of processing model | Craik and Lockhart's model proposing that deeper semantic encoding produces stronger, more durable memories than shallow structural or phonemic encoding. |
| Chunking | Grouping individual pieces of information into larger meaningful units to reduce cognitive load and improve encoding. |
| Spaced learning | Distributing study or practice sessions over time rather than in a single massed session, which improves long-term retention through the spacing effect. |
| Recency Effect | Better recall for items presented at the end of a list, one component of the serial position effect. |
| State-Dependent Memory | The phenomenon in which retrieval is better when the physiological or psychological state at recall matches the state during encoding. |
| constructive memory | The process by which memories are rebuilt at retrieval using existing knowledge and expectations, making them vulnerable to distortion through imagination inflation and source amnesia. |
| Repression | A psychodynamic defense mechanism in which distressing memories or thoughts are unconsciously pushed out of conscious awareness. |
| construct validity | A test has construct validity if it accurately measures the theoretical construct it claims to measure, such as intelligence or anxiety. |
Proactive interference runs forward: old information blocks new learning. Retroactive interference runs backward: new information disrupts old memories. A helpful anchor is that 'retro' means backward, so retroactive interference works backward on older memories.
The availability heuristic is about ease of recall (how quickly an example comes to mind). The representativeness heuristic is about similarity to a prototype (how much something matches a mental category). Both cause errors, but through different mechanisms.
The multi-store model (Atkinson-Shiffrin) describes three sequential stores. The working memory model (Baddeley-Hitch) replaces the single short-term store with an active system that has three components: the central executive, phonological loop, and visuospatial sketchpad.
IQ scores are influenced by test design, cultural context, access to education, and socioeconomic factors. The Flynn Effect shows scores change across generations. Stereotype threat demonstrates that situational factors depress scores independently of ability.
Reliability means a test gives consistent results across administrations. Validity means the test actually measures what it claims to measure. A test can be reliable without being valid: it consistently measures the wrong thing.
AP Psychology questions frequently describe a person's behavior or experience and ask you to identify the correct psychological concept. For Unit 2, practice reading a scenario and deciding whether it illustrates a specific heuristic, a type of interference, a memory model component, or a validity issue with a test. The key skill is matching the mechanism to the described outcome, not just recalling a definition.
Questions may describe a memory or perception experiment and ask you to explain the result using a specific concept such as the spacing effect, the misinformation effect, or the forgetting curve. Be ready to name the concept, explain the mechanism, and connect it to the described outcome in precise psychological language.
Unit 2 includes psychometric principles that appear in questions asking you to evaluate whether a test is valid or reliable. Know the difference between construct validity and predictive validity, and between test-retest and split-half reliability. Questions may also ask you to identify how stereotype threat or cultural bias could affect score interpretation.
Open the individual guides for Unit 2 when you want a closer review of one topic.
browse guidesUse AP-style practice after you review the notes so you can check what you understand.
start practicePractice free-response reasoning and compare your answer with scoring guidance.
practice FRQsUse unit cheatsheets for a quick visual review after you work through the notes.
open cheatsheetsEstimate your broader AP score goal after you review the course and exam format.
open calculatorAP Psych Unit 2 covers 8 topics built around perception and cognition: Perception (2.1), Thinking and Problem-Solving (2.2), Introduction to Memory (2.3), Encoding Memories (2.4), Storing Memories (2.5), Retrieving Memories (2.6), Forgetting and Other Memory Challenges (2.7), and Intelligence and Achievement (2.8). Together they trace how the brain takes in, processes, stores, and retrieves information. See the full breakdown at AP Psych Unit 2.
AP Psych Unit 2 makes up 15-25% of the AP exam, making it one of the heavier-weighted units. That means roughly 12-20 multiple-choice questions could come from this unit alone. The unit covers perception, memory processes like encoding and storing memories, thinking and problem-solving, forgetting, and intelligence, so strong preparation here pays off significantly on exam day.
The AP Psych Unit 2 progress check includes both MCQ and FRQ sections drawn from all 8 topics in the unit. MCQ questions test your recall and application of perception, encoding memories, storing memories, retrieving memories, forgetting, thinking, and intelligence. The FRQ section typically asks you to apply memory or cognition concepts to a scenario, so knowing the stages of memory and key terms like chunking or the forgetting curve is essential. Practice with matched questions at AP Psych Unit 2 before attempting the progress check.
AP Psych Unit 2 FRQs most often draw from memory topics like encoding memories, storing memories, retrieval, and forgetting, as well as perception and thinking and problem-solving. Questions usually present a real-life scenario and ask you to identify or explain a concept, so practice by writing out definitions and then connecting them to examples. Focus on precise vocabulary: terms like elaborative encoding, the serial position effect, and the misinformation effect come up often. Find practice prompts and scoring guidance at AP Psych Unit 2.
The best place to find AP Psych Unit 2 practice questions, including MCQ and practice test sets, is AP Psych Unit 2. That page has resources covering all 8 topics, from perception and thinking to memory, forgetting, and intelligence. For MCQ prep, focus on questions that ask you to apply concepts to new scenarios rather than just recall definitions, since that matches the actual exam format.
Start with perception and work through the memory topics in order, since encoding memories, storing memories, and retrieving memories build on each other. Use spaced repetition flashcards for vocabulary-heavy topics like thinking and problem-solving, forgetting, and intelligence. For each memory concept, create a real-life example, not just a definition. That habit directly prepares you for FRQ scenarios. Review your weak spots using practice questions at AP Psych Unit 2, and revisit forgetting and Other Memory Challenges last since it ties the whole memory sequence together.