AP Psychology Unit 2 ReviewCognition

AP Psychology Unit 2, Cognition, explains how your mind takes in information, thinks with it, remembers it, forgets it, and gets measured by it. The single biggest idea is that memory and perception are constructive processes. Your brain doesn't record reality like a camera; it builds an interpretation from sensory input, expectations, and stored knowledge, which is why memories can be vivid and wrong at the same time. Unit 2 makes up 15-25% of the AP exam, which makes it one of the heaviest units in the course.

What this unit covers

Perception: how your brain interprets the world (2.1)

• Bottom-up processing builds perception from raw sensory data; top-down processing starts with what you expect to see. Reading a messy doctor's handwriting is top-down at work, since your prior knowledge fills in the gaps.
• Schemas and perceptual sets are internal filters. If you expect to see a snake, an ambiguous shape in the grass looks like a snake. Context, experience, and culture act as external filters on the same input.
• Gestalt principles (closure, figure-ground, proximity, similarity) explain why you perceive organized wholes instead of scattered pieces.
• Depth perception uses binocular cues, which need both eyes (retinal disparity and convergence), and monocular cues, which work with one eye (relative clarity, relative size, texture gradient, linear perspective, interposition). Monocular cues are how flat paintings create the illusion of depth.
• Attention concepts like selective attention explain why you can follow one conversation at a party and completely miss everything else, including things in plain sight (inattentional blindness).

Thinking, judgment, and decision-making (2.2)

• Concepts are the building blocks of thought, and a prototype is your mental "best example" of a concept. A robin matches your bird prototype better than a penguin does.
• Schemas grow through assimilation (new info fits the existing framework) and accommodation (new info forces you to change the framework).
• Algorithms guarantee a solution by trying every possibility; heuristics are mental shortcuts that are fast but error-prone. The representativeness heuristic judges by how well something matches a prototype, and the availability heuristic judges by what comes to mind easily.
• Thinking traps to know by name include mental set (sticking with old strategies), functional fixedness (only seeing an object's usual use), priming, framing, gambler's fallacy, and sunk-cost fallacy.
• Executive functions support planning and flexible thinking, and creativity involves divergent thinking (generating many possible answers) versus convergent thinking (narrowing to one correct answer).

Memory: encoding, storing, and retrieving (2.3-2.6)

• Memory types split into explicit memory (episodic for events, semantic for facts) and implicit memory (procedural, like riding a bike). Prospective memory is remembering to do something in the future.
• The multi-store framework moves information from sensory memory (iconic and echoic, fractions of a second) to short-term memory (limited capacity) to long-term memory (essentially unlimited). Working memory actively manipulates information rather than just holding it.
• Encoding strategies are the testable "how to study" science. Mnemonic devices like the method of loci, chunking information into meaningful groups, building categories and hierarchies, and the spacing effect (distributed practice beats massed practice, also known as cramming) all improve encoding.
• Storage is strengthened by rehearsal. Maintenance rehearsal just repeats information; elaborative rehearsal connects it to meaning, which works far better. Some people show highly superior autobiographical memory, hinting at biological differences in storage.
• Retrieval happens through recall (no cues, like an FRQ) or recognition (cues provided, like multiple choice). Retrieval improves when your situation matches encoding conditions, which gives you context-dependent, mood-congruent, and state-dependent memory.
• The testing effect is the big practical takeaway. Practicing retrieval (quizzing yourself) strengthens memory more than rereading ever will.

Forgetting and memory errors (2.7)

• Ebbinghaus's forgetting curve shows that forgetting is rapid right after learning, then levels off. Time matters most early.
• Retrieval failures come from encoding failure (it never got in), proactive interference (old info blocks new), retroactive interference (new info blocks old), and the tip-of-the-tongue phenomenon.
• Psychodynamic theorists add repression, the idea that distressing memories are pushed out of awareness to protect the ego.
• Memory is reconstructive, not a replay. The misinformation effect shows that post-event information can rewrite a memory, and source amnesia means you remember the fact but forget where it came from. This is why eyewitness testimony is less reliable than it feels.

Intelligence, testing, and achievement (2.8)

• Researchers still debate whether intelligence is one general ability (g) or multiple distinct abilities. There is no settled definition, and that ambiguity opens the door to bias.
• Early IQ tests calculated mental age divided by chronological age, times 100. Modern tests compare you to others your age and are used to identify students for educational services.
• Good tests follow psychometric principles. They must be standardized (uniform procedures, norm-based scoring), reliable (consistent results), and valid (actually measuring what they claim to measure). A test can be reliable without being valid.
• The Flynn effect shows worldwide IQ scores rising over time, driven by societal factors like better nutrition, health care, and socioeconomic conditions. That trend is strong evidence that environment shapes test scores.
• IQ scores vary more within groups than between groups, and poverty, discrimination, and educational inequities can depress scores. Stereotype threat (anxiety about confirming a negative stereotype) and stereotype lift can shift performance during the test itself.
• Achievement tests measure what you already know; aptitude tests try to predict future performance. Believing intelligence is malleable (growth mindset) rather than fixed from birth (fixed mindset) is linked to better academic outcomes.

Unit 2, Cognition at a glance

Why Unit 2, Cognition matters in AP Psych

Cognition is the bridge between the brain (biology) and behavior (everything else in the course). Almost every later unit assumes you can explain how people perceive, think, and remember, and the unit also delivers the course's most direct lesson in applying psychology to your own life.

• The constructive nature of memory and perception is a recurring course theme. Misinformation effects, schemas, and heuristics all show that the mind interprets rather than records.
• Intelligence testing is the course's clearest case of psychology's social impact, since assessments have been used both to identify aptitude and to limit access to opportunities.
• The encoding and retrieval research doubles as study advice you can apply immediately. Spacing, elaborative rehearsal, and the testing effect are evidence-based, not study folklore.

How this unit connects across the course

• Memory processes have a physical basis in the hippocampus, long-term potentiation, and neural plasticity, so Unit 2 is the functional side of the brain anatomy you learned in Biological Bases of Behavior (Unit 1).
• Schemas, assimilation, and accommodation reappear as the engine of cognitive development, and memory concepts underpin how learning is studied (Unit 3).
• Heuristics, framing, and schema-driven thinking explain attribution errors, stereotypes, and biased social judgment in Social Psychology and Personality (Unit 4).
• Stereotype threat, stress effects on cognition, and growth versus fixed mindset connect intelligence and memory to well-being and treatment topics in Mental and Physical Health (Unit 5).

Key thinkers and models

• Hermann Ebbinghaus: Mapped the forgetting curve, showing forgetting is steepest right after learning and then levels off.
• Elizabeth Loftus: Demonstrated the misinformation effect, where leading questions and post-event information distort eyewitness memories.
• George Miller: Found short-term memory holds about seven plus or minus two chunks, making chunking a real encoding strategy.
• Daniel Kahneman and Amos Tversky: Identified heuristics like availability and representativeness, explaining why judgment goes predictably wrong.
• Charles Spearman: Argued for g, a single general intelligence underlying performance across tasks.
• Howard Gardner: Countered with multiple intelligences, the major voice on the "many abilities" side of the debate.
• Alfred Binet: Built the first practical intelligence test, the origin of the mental age concept behind early IQ.
• James Flynn: Documented the worldwide rise in IQ scores over time, evidence that environment shapes measured intelligence.
• Carol Dweck: Distinguished fixed mindset from growth mindset and linked beliefs about intelligence to achievement.
• Sigmund Freud: Proposed repression, the psychodynamic idea that distressing memories are pushed out of awareness.

Unit 2, Cognition on the AP exam

Unit 2 carries 15-25% of the exam, tied for the largest share of any unit, so this content shows up everywhere. On the multiple-choice section, expect scenario-based questions where you identify which concept a short vignette illustrates. A student who can't see a new use for a paperclip is showing functional fixedness; a witness whose memory shifts after a leading question is showing the misinformation effect. Questions also test perception and memory vocabulary precisely, like telling proactive from retroactive interference or recall from recognition.

On the free-response side, the Article Analysis Question often features memory or intelligence research, since these topics lend themselves to studies with operational definitions, reliability, and validity. The Evidence-Based Question can ask you to use research findings to argue about things like study strategies or testing bias. Either way, the move is the same. You apply a named concept to a specific situation and explain the mechanism, not just label it. Practice writing one-sentence applications ("Maya's old locker combination interferes with learning her new one, which is proactive interference") because that's exactly the skill being scored.

Essential questions

• Why do two people perceive the same event differently, and what does that say about how perception works?
• If memory is reconstructive rather than a recording, how much should we trust eyewitness testimony or our own vivid memories?
• What makes a mental shortcut useful in some situations and dangerously misleading in others?
• Can intelligence be measured fairly, and who has been helped or harmed by the attempt?

Key terms to know

• Top-down processing: Perceiving by starting with expectations and prior knowledge rather than raw sensory data.
• Schema: A mental framework that organizes knowledge and filters how you interpret new information.
• Heuristic: A mental shortcut that speeds up judgment but can produce systematic errors.
• Availability heuristic: Judging how likely something is by how easily examples come to mind.
• Working memory: The active system that holds and manipulates information you're currently using.
• Chunking: Grouping pieces of information into meaningful units to expand what short-term memory can hold.
• Spacing effect: Distributed practice over time produces stronger long-term retention than massed cramming.
• Testing effect: Practicing retrieval (self-quizzing) strengthens memory more than rereading.
• Proactive interference: Old information blocks the retrieval of newer information.
• Retroactive interference: New information blocks the retrieval of older information.
• Misinformation effect: Memories change when misleading information is introduced after the event.
• Reliability: A test's consistency, producing similar scores across repeated administrations.
• Validity: Whether a test actually measures what it claims to measure.
• Stereotype threat: Anxiety about confirming a negative stereotype that lowers test performance.

Common mix-ups

• Proactive vs. retroactive interference: Name the blocker. Proactive means prior learning interferes with new material; retroactive means recent learning reaches back and disrupts the old.
• Reliability vs. validity: A bathroom scale that's always 10 pounds off is reliable (consistent) but not valid (inaccurate). A test can be reliable without being valid, but never valid without being reliable.
• Recall vs. recognition: Recall pulls information with no cues (an essay question); recognition just identifies it among options (multiple choice). That's why multiple choice feels easier.
• Assimilation vs. accommodation: Assimilation fits new info into an existing schema unchanged; accommodation rebuilds the schema. A toddler calling a zebra "horsie" is assimilating; learning "zebra" as a new category is accommodating.