Cognition
Unit 2 of AP Psychology, worth 15–25% of the exam. 14 questions below, each with the working. Every answer was checked by a second pass before it was published.
Perception, thinking and problem solving, memory encoding, storage and retrieval, forgetting, intelligence and testing.
How this unit is tested
Start by sorting Unit 2 into its five pieces — perception, thinking/problem solving, memory processes, forgetting, and intelligence — because the AP exam tests each as a distinct cluster of vocabulary and mechanisms rather than one blended topic. For perception, focus on the contrast between bottom-up and top-down processing and be ready to identify Gestalt principles and signal detection outcomes (hit, miss, false alarm, correct rejection) in short scenarios. For thinking and problem solving, know the difference between algorithms and heuristics, and be able to spot representativeness, availability, and confirmation bias, plus obstacles like mental set and functional fixedness, in a described situation rather than just define them. For memory, learn the three-stage model (encoding, storage, retrieval) as a pipeline: something can fail at any one stage, and multiple-choice questions often hinge on knowing which stage a described failure belongs to. Practice applying levels-of-processing, the serial position effect, and encoding specificity to novel examples, since AP rarely asks for a bare definition. For forgetting, memorize the four causes (encoding failure, decay, interference, retrieval failure) and practice telling proactive from retroactive interference by asking which memory — old or new — is doing the damage. For intelligence, know the major theories (Spearman's g, Gardner's multiple intelligences, Sternberg's triarchic theory), the history of testing (Binet, Terman, Wechsler), and the psychometric standards of standardization, reliability, and validity, plus how IQ scores relate to the normal distribution. Throughout the unit, expect scenario-based questions: the exam describes a situation and asks you to name the concept, so practice recognizing concepts in context rather than just reciting definitions.
What you have to know
Weber's Law
The just noticeable difference between two stimuli is a constant proportion (not a constant amount) of the original stimulus's intensity.
Signal Detection Theory
Detecting a faint stimulus depends on both its intensity and the observer's experience, expectations, motivation, and alertness; responses fall into four categories: hit, miss, false alarm, and correct rejection.
Levels of Processing
Information processed more deeply and meaningfully (semantically) is remembered better and longer than information processed shallowly (structurally or phonetically).
Serial Position Effect
Recall is best for items at the beginning of a list (primacy effect, moved to long-term memory) and the end of a list (recency effect, still in working memory), with middle items recalled worst.
Encoding Specificity Principle
Retrieval is most successful when cues, context, or internal state present at encoding are reinstated at retrieval (context-dependent and state-dependent memory).
Reliability and Validity
Reliability is the consistency of a test's results across time, forms, or scorers; validity is the degree to which a test actually measures the construct it claims to measure. A test can be reliable without being valid, but not valid without being reliable.
14 practice questions
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A radiologist who has read thousands of X-rays notices a subtle fracture that a novice would miss, because she expects to find abnormalities in certain locations. Which type of processing best explains her perception?
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Answer. Top-down processing
Top-down processing uses prior knowledge, experience, and expectations to interpret sensory input. The radiologist's expertise shapes what she perceives, rather than her perception being built purely from raw visual data. -
A weightlifter can tell the difference between a 10 lb and 11 lb weight, but not between a 100 lb and 101 lb weight. What principle explains this?
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Answer. Weber's Law
Weber's Law states the just noticeable difference is a constant proportion of the stimulus, not a fixed amount. A 1 lb change is a large enough proportion to notice at 10 lb but too small a proportion to notice at 100 lb. -
A quality-control inspector correctly identifies a defective part on the assembly line. In signal detection theory terms, what is this response called?
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Answer. A hit
A hit occurs when a real signal (the defect) is present and the observer correctly detects it. If the inspector missed it, that would be a miss; if she flagged a good part as defective, that would be a false alarm. -
When shown a series of dots arranged to suggest an incomplete circle, most people perceive it as a complete circle. Which Gestalt principle is this?
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Answer. Closure
Closure is the tendency to fill in gaps in a pattern to perceive a complete, whole object, even when part of the image is missing. -
Solving a Rubik's Cube by trying every single possible combination in sequence until one works is an example of which problem-solving strategy?
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Answer. An algorithm
An algorithm is a methodical, step-by-step procedure guaranteed to eventually produce a correct solution, even though it may take a long time. A heuristic would instead use shortcuts (like solving by color patterns) that are faster but not guaranteed to work perfectly. -
After hearing a description of a quiet, detail-oriented person, someone assumes the person is more likely to be a librarian than a farmer, ignoring that far more people work as farmers. This is an example of which heuristic and its associated error?
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Answer. The representativeness heuristic, leading to base-rate neglect
The representativeness heuristic judges likelihood based on how well something matches a prototype, which here causes the person to ignore the actual base rate (how common each occupation is) in the population. -
A person needs to prop open a door but doesn't think to use a heavy book because they only think of a book as something to read. What cognitive obstacle is this?
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Answer. Functional fixedness
Functional fixedness is the tendency to think of objects only in terms of their typical use, which blocks creative solutions like using a book as a doorstop. -
On a list of 20 words read aloud, participants recall the first few and last few words much better than the words in the middle. The improved recall of the last few words specifically is called the:
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Answer. Recency effect
The recency effect is the tendency to recall the most recently presented items best, because they are still active in working memory at the time of recall. The improved recall of early items is the primacy effect, caused by those items having been rehearsed into long-term memory. -
A student who studied for an exam while chewing mint gum performs better on the exam when she chews the same mint gum during testing than when she doesn't. This illustrates which memory principle?
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Answer. Encoding specificity (context/state-dependent memory)
The encoding specificity principle holds that retrieval improves when cues or conditions present during encoding (like the taste and smell of mint gum) are reinstated at retrieval. -
A student who learned Spanish in high school later struggles to recall Spanish vocabulary because the French she is learning in college keeps popping into her mind instead. What type of interference is this?
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Answer. Retroactive interference
Retroactive interference occurs when newly learned information (French) disrupts the retrieval of older information (Spanish). Proactive interference would be the reverse: old Spanish knowledge disrupting new French learning. -
After being asked leading questions about a car accident they witnessed, several eyewitnesses later report false details that were never actually present in the accident. This phenomenon is called the:
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Answer. Misinformation effect
The misinformation effect occurs when exposure to misleading information after an event distorts a person's memory of the original event, demonstrating that memory is reconstructive rather than a perfect recording. -
A newly designed personality test gives a person very similar scores every time they retake it, but the scores don't actually predict anything about their real personality traits. This test is:
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Answer. Reliable but not valid
Reliability refers to consistency of results across repeated administrations, which this test has. Validity refers to whether the test measures what it claims to measure, which this test lacks since scores don't correspond to actual personality traits. -
Howard Gardner proposed that intelligence is not one general ability but consists of several independent abilities, such as musical, spatial, and interpersonal intelligence. This theory is called:
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Answer. Theory of multiple intelligences
Gardner's theory of multiple intelligences argues against a single general intelligence (Spearman's g), instead proposing several distinct, independent types of intelligence that are not necessarily correlated with one another. -
On a standardized IQ test with a mean of 100 and standard deviation of 15, a student scores 70. Approximately what percentage of test-takers score higher than this student?
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Answer. About 97.5%
A score of 70 is 30 points below the mean, or 2 standard deviations below (30 ÷ 15 = 2). By the empirical rule, about 2.5% of scores fall below −2 SD, meaning roughly 97.5% of the population scores higher than this student.
What people get wrong
- Treating recall and recognition as interchangeable — recall requires retrieving information with no cues (fill-in-the-blank), while recognition only requires identifying it among options (multiple choice); always check which the question describes before naming a memory failure.
- Assuming a reliable test must be valid — a bathroom scale that's off by 10 pounds every time is perfectly reliable (consistent) but not valid (accurate); evaluate the two criteria separately.
- Mixing up proactive and retroactive interference — proactive interference is OLD memories disrupting NEW learning, retroactive is NEW memories disrupting OLD ones; a memory trick is 'retro' looks backward, so it reaches back and damages older memories.
- Believing heuristics guarantee a correct or optimal answer — heuristics are fast mental shortcuts that are often right but systematically produce errors (e.g., the representativeness heuristic causing base-rate neglect); don't call a heuristic 'wrong' or 'right,' call it 'fast but bias-prone.'
- Attributing all forgetting to decay (memories simply fading) — the exam expects you to distinguish encoding failure, decay, interference, and retrieval failure as four separate mechanisms, so match the scenario's details to the specific cause rather than defaulting to decay.
Drill this unit until it sticks
These questions come back on a schedule built from what you get wrong, alongside the rest of AP Psychology. Free, and no account needed to start.