Units 1–2: Biological Bases
& Cognition
20 high-yield speed cards — each containing a core definition, key comparison, a timed MCQ, and the most dangerous exam mistake. Built for the final sprint.
Genetics & Environment
Heritability = proportion of variation in a trait within a population attributable to genetic differences. It is not the percentage of a trait caused by genes in an individual.
MZ twins (monozygotic): 100% identical DNA. DZ twins (dizygotic): ~50% shared DNA — same as ordinary siblings.
Twin studies logic: if MZ twins raised apart are more similar than DZ twins raised together, genetics contributes significantly.
Gene × environment interaction: genes set a reaction range; environment determines where within that range an individual lands.
| Feature | MZ | DZ |
|---|---|---|
| DNA overlap | 100% | ~50% |
| Zygotes | 1 (splits) | 2 (separate) |
| Sex | Always same | Can differ |
| Use in research | Genetic baseline | Genetic control |
A researcher finds that the heritability of extraversion is 0.50 in a sample of U.S. adults. This finding is best interpreted to mean that
- (A) 50% of any individual's extraversion score is caused by their genes
- (B) extraversion is 50% genetic and 50% environmental in origin for all humans
- (C) 50% of the variation in extraversion scores among people in this sample is associated with genetic differences
- (D) people with more extraverted genes will always be more extraverted than people with fewer
- Heritability ≠ "caused by genes"Heritability of 0.80 does NOT mean 80% of your height is genetic. It means 80% of height differences in that population are associated with genetic variation. Heritability can change across populations and environments.
- Identical ≠ determinedEven MZ twins raised apart show differences — epigenetics, prenatal environment, and chance all contribute. 100% heritability still does not eliminate environment.
Endocrine System
The endocrine system communicates via hormones released into the bloodstream — slower and longer-lasting than neural signals.
Pituitary gland: "master gland"; controlled by hypothalamus; regulates other glands.
Adrenal glands: adrenal medulla → epinephrine & norepinephrine (fight-or-flight); adrenal cortex → cortisol (chronic stress).
Thyroid: thyroxine → regulates metabolism and energy.
Pineal gland: melatonin → regulates circadian rhythms and sleep onset.
| Feature | Hormones | Neurotransmitters |
|---|---|---|
| Travel via | Bloodstream | Synaptic cleft |
| Speed | Slow (seconds–minutes) | Fast (milliseconds) |
| Duration | Long-lasting | Brief |
| Produced by | Endocrine glands | Neurons |
During a stressful situation, which gland releases epinephrine to prepare the body for a fight-or-flight response?
- (A) Thyroid gland
- (B) Pituitary gland
- (C) Adrenal gland
- (D) Pineal gland
- Pituitary ≠ master of everythingThe pituitary is itself controlled by the hypothalamus. The hypothalamus is the true bridge between the nervous and endocrine systems.
- Cortisol vs. epinephrine timingEpinephrine = immediate/acute stress response (adrenal medulla). Cortisol = sustained/chronic stress (adrenal cortex). Don't mix them up when a scenario specifies acute vs. ongoing stress.
Nervous System & Neuron Structure
CNS: brain + spinal cord. PNS: all other nerves.
Somatic NS: voluntary muscle control. Autonomic NS: automatic, involuntary (heart, glands, digestion).
Sympathetic: fight-or-flight — accelerates HR, dilates pupils, inhibits digestion. Parasympathetic: rest-and-digest — slows HR, constricts pupils, promotes digestion.
Dendrites: receive signals from other neurons.
Cell body (soma): integrates signals; contains nucleus.
Axon: transmits signal away from soma.
Myelin sheath: fatty insulation → speeds transmission; produced by oligodendrocytes (CNS) or Schwann cells (PNS). Degeneration = MS.
Terminal buttons: release neurotransmitters into the synapse.
A person's heart rate increases, breathing quickens, and digestion slows after nearly being hit by a car. Which division of the nervous system is primarily responsible?
- (A) Somatic nervous system
- (B) Parasympathetic nervous system
- (C) Sympathetic nervous system
- (D) Central nervous system
- Dendrites receive; axons transmitNot the reverse. Dendrites receive incoming signals; axons carry the action potential away from the soma toward terminal buttons.
- Autonomic ≠ "automatic"The autonomic NS does operate automatically, but "automatic" is not its technical meaning. Distinguish somatic (voluntary skeletal muscle) vs. autonomic (involuntary organs and glands).
Neural Transmission
Resting potential: −70 mV; neuron polarized, Na⁺ outside.
Depolarization: threshold reached (~−55 mV) → Na⁺ rushes in → spike to +40 mV.
All-or-none law: either fires fully or not at all; intensity coded by firing frequency, not spike size.
Refractory period: brief period after firing when neuron cannot fire again (K⁺ rushes out, repolarization).
Steps: action potential → terminal button → vesicles release NT → NT crosses synapse → binds to postsynaptic receptors → reuptake or enzymatic degradation.
Reuptake: NT recycled back into presynaptic neuron. SSRIs block serotonin reuptake → more serotonin remains in synapse.
Agonist: binds to and activates a receptor, producing effects similar to the natural NT. Antagonist: binds to a receptor without activating it, blocking the NT's effects.
Which best explains why a stronger stimulus (e.g., a loud noise vs. a soft tap) produces a more intense neural response?
- (A) Each action potential has a larger amplitude with stronger stimuli
- (B) Stronger stimuli lower the threshold required to fire an action potential
- (C) Stronger stimuli cause neurons to fire action potentials more frequently
- (D) Stronger stimuli cause longer refractory periods that carry more information
- All-or-none applies to individual neuronsOne neuron either fires or doesn't — no partial action potentials. Intensity is coded by the pattern (frequency + which neurons recruit), not by spike size.
- Reuptake ≠ degradationReuptake = NT recycled back into presynaptic neuron intact. Degradation = NT broken down by enzymes (e.g., MAO breaks down dopamine). SSRIs specifically block reuptake, not degradation.
Neurotransmitters
| NT | Key Roles | Too Little | Too Much |
|---|---|---|---|
| Dopamine | Reward, motivation, movement | Parkinson's (motor tremors) | Associated with schizophrenia (+ symptoms) |
| Serotonin | Mood, sleep, appetite, impulse control | Depression, OCD | Serotonin syndrome (rare) |
| GABA | Main inhibitory NT; reduces neural firing | Anxiety, seizures | Sedation, reduced anxiety |
| Glutamate | Main excitatory NT; learning, memory | Learning/memory impairment | Excitotoxicity, seizures |
| Acetylcholine (ACh) | Muscle movement, attention, memory | Alzheimer's (memory loss), myasthenia gravis | Muscle over-contraction |
| Norepinephrine | Alertness, arousal, fight-or-flight | Depression, low energy | Anxiety, hypertension |
| Endorphins | Pain relief, euphoria (natural opioids) | Pain sensitivity | Rare; opioid drugs mimic these |
A patient with Alzheimer's disease shows dramatically reduced levels of a neurotransmitter critical for memory and voluntary movement. Which neurotransmitter is most likely deficient?
- (A) Dopamine
- (B) GABA
- (C) Acetylcholine
- (D) Serotonin
- Dopamine ↑ → schizophrenia (not Parkinson's)The dopamine hypothesis links excess dopamine activity to positive symptoms of schizophrenia. Low dopamine causes Parkinson's motor symptoms. Keep the direction correct for each disorder.
- GABA is inhibitory, glutamate is excitatoryNot the other way around. GABA slows neural activity (benzodiazepines enhance GABA). Glutamate excites. These are the most abundant NTs in the brain.
Brain Structures & Functions
Frontal: executive function, planning, impulse control, aspects of personality, voluntary motor control (motor cortex), Broca's area (speech production).
Parietal: sensory integration (somatosensory cortex), spatial processing, body awareness.
Temporal: auditory processing, language comprehension (Wernicke's area), memory (links to hippocampus).
Occipital: primary visual processing (visual cortex); damage causes cortical blindness even with intact eyes.
Limbic system: emotion and memory hub.
Amygdala: fear conditioning, threat detection, emotional memory tagging.
Hippocampus: forming new explicit memories; spatial navigation.
Hypothalamus: homeostasis (hunger, thirst, temperature, sex drive); controls pituitary.
Cerebellum: balance, motor coordination, procedural learning.
Medulla oblongata: vital reflexes — breathing, heart rate, swallowing.
Corpus callosum: connects left and right hemispheres.
After a motorcycle accident, a patient can no longer recognize faces or understand spoken language, but can still speak fluently and move normally. The damage is most likely located in the
- (A) frontal and motor cortex
- (B) temporal lobe
- (C) occipital lobe
- (D) corpus callosum
- Broca's vs. Wernicke's aphasiaBroca's area (frontal): damage → non-fluent aphasia, broken speech, comprehension intact. Wernicke's area (temporal): damage → fluent but nonsensical speech, comprehension impaired. Know the location AND the specific deficit for each.
- Hippocampus ≠ amygdalaHippocampus = explicit memory storage (facts, events). Amygdala = emotional memory and fear responses. They are adjacent but distinct — a common confound in MCQs describing memory or emotion scenarios.
Brain Research Methods
| Method | Measures | Best For (AP) | Key Tradeoff |
|---|---|---|---|
| EEG | Electrical activity (neural waves) | Sleep stages, seizure detection | Best temporal resolution; poor spatial |
| fMRI | Blood oxygen (BOLD signal — activity proxy) | Identifying active brain regions during tasks | Best spatial resolution; slower temporal |
| PET | Radioactive glucose metabolism | Metabolic activity; neurotransmitter studies | Moderate on both; requires radioactive tracer |
| Lesion study | Behavior change after brain damage | Inferring structure → function (causal) | Cannot ethically control; natural variation |
CT and MRI show brain structure (anatomy), not activity. EEG/fMRI/PET show function. Know which type each method provides.
A researcher wants to identify which specific brain regions become active while a person solves math problems. The method that would provide the best spatial resolution of active areas is
- (A) EEG, because it captures electrical activity in real time
- (B) PET, because it uses radioactive tracers to map metabolism
- (C) fMRI, because it shows blood oxygen changes with high spatial detail
- (D) CT, because it provides clear three-dimensional images of brain tissue
- EEG = electrical; fMRI = blood flowEEG measures the electrical activity of neurons directly (voltage fluctuations). fMRI measures blood oxygenation as a proxy for neural activity — it does not measure electricity. The distinction matters when a question asks what the method "measures."
- Correlation ≠ causation in brain imagingShowing that region X is active during task Y does not prove X causes Y. Lesion studies are needed to establish necessity, not just correlation.
Sleep
N1: lightest; hypnagogic hallucinations; theta waves; 5–10 min.
N2: sleep spindles and K-complexes; body temperature drops; ~50% of night.
N3: deep slow-wave sleep (delta waves); hardest to wake; physical restoration; sleepwalking and night terrors occur here.
REM: rapid eye movements; vivid dreaming; brain active (like waking); muscle atonia; involved in memory consolidation — REM is especially linked to procedural and emotional memories, while N3 is more associated with declarative memory consolidation. REM increases across the night.
| Disorder | Key Features |
|---|---|
| Insomnia | Difficulty falling/staying asleep; most common |
| Sleep apnea | Airway collapse during sleep; oxygen drops; snoring; daytime fatigue |
| Narcolepsy | Sudden daytime sleep attacks; cataplexy (sudden muscle loss); REM intrusion while awake; orexin deficiency |
| Night terrors | N3; child screams but is not dreaming; no memory next day |
| Sleepwalking | N3; complex behaviors; no memory next day; distinct from REM — no dreaming occurring |
| REM sleep behavior disorder | REM; muscle atonia fails; acts out dreams; risk of injury |
During which sleep stage do sleepwalking and night terrors most commonly occur, and what EEG pattern characterizes this stage?
- (A) REM; sawtooth waves
- (B) N1; theta waves
- (C) N3; delta waves
- (D) N2; sleep spindles
- Dreaming ≠ only in REMWhile vivid, narrative dreams occur primarily in REM, mental activity can occur in NREM stages too. Night terrors in N3 are NOT accompanied by dreaming, which distinguishes them from REM nightmares.
- Narcolepsy is NOT just "falling asleep"The defining features are cataplexy (sudden loss of muscle tone triggered by emotion) and direct transitions into REM from wakefulness. It is linked to orexin (hypocretin) deficiency — sometimes tested in stimulus scenarios.
Sensation
Absolute threshold: minimum stimulus intensity detectable 50% of the time.
Difference threshold (JND): smallest detectable difference between two stimuli.
Weber's Law: JND is a constant proportion of the original stimulus (not a fixed amount). Heavier weights require larger increases to be "just noticeable."
Subliminal perception: stimuli below conscious detection may have limited, subtle effects on perception or behavior; effects are generally small and not a powerful or reliable means of control.
Sensory adaptation: reduced sensitivity to a constant, unchanging stimulus (e.g., no longer noticing your watch).
Detection is not just about stimulus intensity — it involves motivation, expectations, and response bias.
| Signal Present | Signal Absent | |
|---|---|---|
| Respond "yes" | Hit | False alarm |
| Respond "no" | Miss | Correct rejection |
SDT explains why a radiologist reading scans and a soldier watching radar have different detection criteria — not just different sensitivities.
A person can just barely detect the difference between a 50 g weight and a 51 g weight. According to Weber's Law, what would be the minimum weight that could be distinguished from a 200 g weight?
- (A) 201 g
- (B) 202 g
- (C) 204 g
- (D) 251 g
- Weber's Law: proportion, not fixed amountA JND of 1 g for a 50 g weight does NOT mean you can always detect a 1 g difference. For a 500 g weight, the JND would be 10 g. The ratio stays constant; the absolute amount grows.
- Sensory adaptation ≠ habituationSensory adaptation is a peripheral sensory process (the receptors stop firing as intensely). Habituation is a learned behavioral process (you stop responding to a repeated stimulus). They produce similar outcomes but have different mechanisms.
Perception
Bottom-up processing: starts with raw sensory data → builds percept (data-driven). No prior knowledge needed.
Top-down processing: prior knowledge, expectations, and context shape perception (schema-driven). Explains why we "see" incomplete figures as complete.
Perceptual set: mental readiness to perceive a stimulus in a particular way based on expectation.
Perceptual constancy: perception of objects as stable despite changes in sensory input (size, shape, color, brightness constancy).
| Type | Cue | Requires |
|---|---|---|
| Binocular | Retinal disparity | 2 eyes |
| Convergence | 2 eyes | |
| Monocular | Interposition | 1 eye |
| Linear perspective | 1 eye | |
| Texture gradient | 1 eye | |
| Relative size | 1 eye | |
| Motion parallax | 1 eye |
- Figure-ground: separate object from background
- Proximity: nearby items grouped together
- Similarity: similar items grouped
- Continuity: prefer continuous smooth paths
- Closure: fill in gaps to complete a figure
- Common fate: items moving together perceived as a group
A person reads "THE CAT" correctly even though both H and A are represented by an identical visual symbol. This best illustrates
- (A) bottom-up processing
- (B) top-down processing
- (C) retinal disparity
- (D) perceptual constancy
- Retinal disparity: distance mattersRetinal disparity (binocular cue) is greatest for nearby objects and decreases with distance — it becomes useless beyond ~30 meters. At far distances, monocular cues dominate depth perception.
Attention & Consciousness
Selective attention: focusing on one stimulus while filtering others (cocktail party effect — you hear your name in background noise).
Inattentional blindness: failure to notice an unexpected stimulus when attention is engaged elsewhere (gorilla experiment — Simons & Chabris).
Change blindness: failure to detect changes in a scene due to disruption in visual flow.
Divided attention: attempting to attend to two things simultaneously; performance degrades, especially when tasks overlap in modality.
| State | Key Feature |
|---|---|
| Waking | Alert; beta waves (EEG) |
| Daydreaming | Alpha waves; relaxed |
| Hypnosis | Heightened suggestibility; dissociation theory (Hilgard); social influence theory |
| Meditation | Focused attention or open monitoring; stress reduction |
| Drug-altered | Varies by substance |
Participants watching a video of people passing a basketball fail to notice a person in a gorilla suit walking through the scene. This demonstrates
- (A) change blindness
- (B) inattentional blindness
- (C) selective attention failure
- (D) perceptual set
- Inattentional blindness ≠ change blindnessInattentional blindness: fail to notice something already present when distracted. Change blindness: fail to detect a change (substitution or addition) between views. Similar outcomes, different conditions.
Memory: Encoding
Structural (shallow): focus on physical appearance (Is the word in uppercase?). Poorest recall.
Phonemic (intermediate): focus on sound (Does it rhyme with "cat"?). Moderate recall.
Semantic (deep): focus on meaning (Does it fit in the sentence "He ate the ___"?). Best recall.
Elaborative rehearsal: connecting new information to existing knowledge; most effective encoding strategy.
Maintenance rehearsal: simple repetition; keeps info in STM but transfers poorly to LTM.
| Strategy | Mechanism | Effectiveness |
|---|---|---|
| Elaborative rehearsal | Connect to existing knowledge | ★★★★★ |
| Chunking | Group items into meaningful units | ★★★★ |
| Mnemonic devices | Peg word, method of loci, acronyms | ★★★★ |
| Spaced practice | Distribute learning over time | ★★★★★ |
| Maintenance rehearsal | Simple repetition | ★★ |
A student studying for a psychology exam tries to connect each new vocabulary term to a personal experience or existing concept. This strategy best exemplifies
- (A) maintenance rehearsal
- (B) shallow processing
- (C) elaborative rehearsal
- (D) iconic encoding
- Maintenance rehearsal does NOT produce LTMRepeating something over and over (maintenance rehearsal) keeps it in working memory but does not reliably transfer it to long-term memory. Deep, meaningful processing is what drives durable encoding.
Memory: Storage
| Stage | Duration | Capacity |
|---|---|---|
| Sensory | <1 sec iconic; ~3 sec echoic | Large, fades instantly |
| Working (STM) | ~20–30 sec without rehearsal | 7 ± 2 chunks (Miller); active manipulation |
| Long-term | Potentially permanent | Unlimited; requires encoding |
Baddeley's working memory: central executive (manages processing) + phonological loop + visuospatial sketchpad.
Explicit (declarative): conscious recall.
• Episodic: personal events ("my graduation").
• Semantic: facts ("Paris is the capital of France").
Implicit (nondeclarative): unconscious, automatic.
• Procedural: motor skills ("riding a bike") — survives hippocampal damage.
• Priming: prior exposure speeds later processing.
Key exam link: H.M. could learn new procedural skills but could not form new explicit memories → hippocampus critical for explicit, not procedural.
A patient with severe anterograde amnesia can still learn to ride a bicycle during rehabilitation, even though they have no conscious memory of the training sessions. This preserved ability relies on
- (A) episodic memory
- (B) semantic memory
- (C) procedural memory
- (D) working memory
- Working memory ≠ short-term memory (exactly)Working memory is an updated model: it emphasizes active manipulation, not just passive holding. The central executive manages processing across the phonological loop and visuospatial sketchpad. When the AP exam mentions "active processing," think working memory.
- Implicit memory survives hippocampal damageH.M. could form new procedural memories (he improved on mirror tracing tasks) despite being unable to consciously recall doing them. Procedural = cerebellum/basal ganglia, not hippocampus.
Memory: Retrieval
Recall: reproduce from memory with no cues (essay exam, fill-in-the-blank). Most demanding.
Recognition: identify a previously seen item among options (MCQ, "have you seen this face?"). Easier than recall.
Relearning (savings): how much faster you learn material a second time — the most sensitive measure of memory.
Priming: prior exposure speeds recognition of related stimuli, even without conscious awareness.
Encoding specificity principle: retrieval is best when conditions at retrieval match conditions at encoding.
Context-dependent memory: physical environment at retrieval matches encoding context. Divers study underwater, recall better underwater.
State-dependent memory: internal physiological/emotional state matches encoding. Mood-congruent memory: depressed people recall more negative memories.
Tip-of-tongue (TOT): partial retrieval failure; shows memory is stored but retrieval cue is inadequate.
A student who studied for an exam while listening to jazz performs better when jazz is playing during the exam than when silence is required. This finding is best explained by
- (A) the serial position effect
- (B) state-dependent memory
- (C) context-dependent memory
- (D) elaborative rehearsal
- Context vs. state-dependent: external vs. internalContext = external environment (room, smell, background music). State = internal condition (drunk while studying and drunk while recalling; or sad encoding + sad retrieval). Mood-congruent memory is a form of state-dependent memory.
Forgetting & Memory Distortion
Encoding failure: information was never stored (most common "forgetting"). E.g., which way does Lincoln face on a penny?
Storage decay: memory trace fades over time (Ebbinghaus forgetting curve — fastest decay shortly after learning).
Proactive interference: old memories interfere with recalling new ones. (Old phone number blocks new one.)
Retroactive interference: new memories interfere with recalling old ones. (Learning Spanish hurts French recall.)
Motivated forgetting (repression): Freudian; unconscious blocking of threatening memories.
Misinformation effect: misleading post-event information alters memory. Classic: "Did you see the broken headlight?" vs. "Did you see a broken headlight?" — witnesses later "remember" a broken headlight.
Source monitoring error: confusion about where a memory came from (imagined vs. actually seen).
False memories: detailed, confident memories of events that never occurred. People can be implanted with false memories of childhood events.
Eyewitness testimony: susceptible to significant errors; reliability is compromised by leading questions, post-event information, stress, and time delay.
After learning her new locker combination, a student finds she can no longer remember her old combination from last year. This forgetting is best explained by
- (A) proactive interference
- (B) retroactive interference
- (C) encoding failure
- (D) repression
- Proactive vs. retroactive: direction mattersPRO-active = forward; old memories act on new. RETRO-active = backward; new memories disrupt old. Exam questions often present a scenario and ask you to name the correct type — get the direction right.
- False memories can be vivid and confidentPeople with implanted false memories can hold them with high confidence despite being inaccurate. Confidence is not a reliable indicator of memory accuracy — critical point for eyewitness testimony research questions.
Biological Bases of Memory
Hippocampus: critical for forming new explicit (declarative) memories; also spatial navigation. Damage → anterograde amnesia (cannot form new explicit memories). Note: long-term memories are ultimately stored across the cortex, not in the hippocampus itself.
Long-term potentiation (LTP): repeated stimulation strengthens synaptic connections — the neural basis of learning and memory. "Neurons that fire together, wire together."
Stress hormones: epinephrine and cortisol enhance encoding of emotionally significant events (flashbulb memory mechanism; amygdala involvement).
Sleep: memory consolidation occurs during both slow-wave and REM sleep; disrupting sleep impairs retention.
Patient H.M. (Henry Molaison): bilateral hippocampectomy for epilepsy; became landmark case in memory research.
| Preserved | Impaired |
|---|---|
| Old explicit memories (before surgery) | Forming new explicit memories (anterograde amnesia) |
| Procedural learning (mirror tracing improved) | Recalling any new events or facts |
| Intelligence, personality, STM | Knowing he had practiced tasks before |
Long-term potentiation (LTP) is considered the neural basis of learning primarily because it
- (A) reduces the number of synaptic connections to conserve energy
- (B) strengthens synaptic connections through repeated co-activation of neurons
- (C) transfers information from the hippocampus to the prefrontal cortex
- (D) increases the amount of neurotransmitter stored in the cell body
- Anterograde vs. retrograde amnesiaAnterograde = cannot form NEW memories after the injury (the direction is forward in time). Retrograde = cannot recall memories from BEFORE the injury. H.M. had severe anterograde amnesia with relatively mild retrograde amnesia — the classic case. Key precision: the hippocampus is critical for the encoding and consolidation of new explicit memories, not static storage — which is why old memories survive hippocampal damage but new ones cannot form.
Thinking & Problem Solving
Algorithm: systematic, exhaustive procedure that guarantees a solution. Slow but always works (e.g., trying all possible passwords).
Heuristic: mental shortcut — faster, not guaranteed. Works most of the time.
Insight: sudden "aha!" solution (Köhler's apes); no apparent incremental progress before solution.
Incubation: stepping away from a problem allows unconscious processing; often leads to insight.
| Barrier | Definition | Classic Example |
|---|---|---|
| Functional fixedness | Can only see object in its usual function | Duncker candle problem (tack box as shelf) |
| Mental set | Applying old strategies to new problems | 9-dot problem (don't go outside the box) |
| Confirmation bias | Seek evidence that supports prior belief | Only reading news sources you agree with |
| Overconfidence | Overestimate accuracy of own beliefs | "I know I got that right" (on a wrong answer) |
A mechanic keeps trying to fix a squeaking door with lubricant, even after repeatedly failing. She does not consider that the screws might be loose. This best illustrates
- (A) functional fixedness
- (B) mental set
- (C) confirmation bias
- (D) the availability heuristic
- Functional fixedness vs. mental setFunctional fixedness = can't see a new USE for an object. Mental set = can't switch STRATEGY for solving a problem. Both involve cognitive rigidity but in different domains (object perception vs. problem-solving approach).
Cognitive Biases & Heuristics
| Bias / Heuristic | Definition | AP Example |
|---|---|---|
| Availability heuristic | Judge likelihood by how easily examples come to mind | Fear flying after crash coverage; ignores base rates |
| Representativeness heuristic | Judge by how much something resembles a prototype | "She's quiet and orderly — must be a librarian" |
| Hindsight bias | "I knew it all along" — overestimate how predictable a past outcome was | After election: "I always knew he'd win" |
| Confirmation bias | Seek/favor information that confirms existing beliefs | Only read news sources you already agree with |
Also tested: Anchoring (over-rely on first number given), Overconfidence (overestimate accuracy of own judgments), Framing effect ("90% fat-free" vs "10% fat" — same information, different reaction).
After hearing several news stories about shark attacks, a swimmer dramatically overestimates the probability of being attacked by a shark, despite very low statistical rates. This best demonstrates the
- (A) availability heuristic
- (B) representativeness heuristic
- (C) hindsight bias
- (D) anchoring bias
- Availability vs. representativeness: the trigger is differentAvailability = triggered by ease of recall / vividness of examples. Representativeness = triggered by similarity to a prototype or stereotype. A question about judging someone's career from a brief personality description usually signals representativeness.
- Hindsight bias ≠ memory distortion (exactly)Hindsight bias is specifically about overestimating how predictable a past outcome was — "I knew it all along." It's a judgment bias, not the same as a false memory, though both involve reconstructive processes.
Language
Phoneme: smallest unit of sound (~44 in English). "cat" = 3 phonemes: /k/ /æ/ /t/.
Morpheme: smallest meaningful unit. "unhappy" = 2 morphemes: "un-" + "happy".
Syntax: rules for sentence structure (grammar).
Semantics: study of meaning of words and sentences.
Pragmatics: how context shapes language use (social rules of conversation).
| Theorist | View | Key Concept |
|---|---|---|
| Chomsky | Nativist / biological | LAD (Language Acquisition Device); universal grammar; innate |
| Skinner | Behaviorist | Language learned via operant conditioning; reinforcement of babbling |
| Vygotsky | Social-cultural | Language shapes thought; social interaction drives development |
| Whorf | Linguistic relativity | Language shapes/limits thought (Sapir-Whorf hypothesis) |
The fact that children all over the world progress through the same stages of language development at roughly the same ages — from babbling to two-word utterances — is most consistent with which theoretical perspective?
- (A) Behaviorism, because reinforcement schedules are universal
- (B) The Sapir-Whorf hypothesis, because all languages share the same thoughts
- (C) Chomsky's nativist view, because children are biologically primed for language acquisition
- (D) Vygotsky's social-cultural view, because all cultures provide the same scaffolding
- Sapir-Whorf: language influences thought, not eliminates itLinguistic relativity does NOT say that people cannot think about concepts for which they have no word. It says language shapes and influences thought. Strong and weak forms of the hypothesis are distinguished — AP usually tests the general concept, not the strong deterministic version.
- Phoneme vs. morpheme confusionPhoneme = sound unit (no meaning). Morpheme = meaning unit. "Cat" has 3 phonemes but 1 morpheme. "Cats" has 4 phonemes and 2 morphemes (cat + -s). This distinction appears frequently in structure-of-language MCQs.
Intelligence & Achievement
Spearman's g: general intelligence factor underlying all cognitive abilities; supported by factor analysis showing intercorrelations.
Gardner's Multiple Intelligences: 8+ distinct intelligences (linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, naturalist). Each relatively independent.
Sternberg's Triarchic Theory: Analytical (book smart), Creative (novel problems), Practical (street smart). All adaptive in different contexts.
| Concept | Definition |
|---|---|
| Standardization | Uniform procedures + normal distribution of scores (bell curve) |
| Reliability | Consistency — same result on repeated testing |
| Validity | Measures what it claims to measure |
| IQ (historical) | Mental age ÷ chronological age × 100; modern tests use deviation IQ (score relative to age-matched norms), not this ratio |
| Stereotype threat | Awareness of negative stereotype impairs performance (Steele) |
| Flynn effect | Rising IQ scores across generations; likely environmental |
A researcher creates an intelligence test that always produces the same scores when the same person takes it on different days, but the test scores do not correlate with any measure of academic performance. This test is
- (A) valid but not reliable
- (B) reliable but not valid
- (C) both valid and reliable
- (D) neither reliable nor valid
- Reliable ≠ validA bathroom scale that reads 5 kg too heavy every time is reliable (consistent) but not valid (wrong absolute measurement). A test can be consistent without measuring the right thing. Validity requires reliability, but reliability does not guarantee validity.
- Stereotype threat ≠ ability differenceStereotype threat (Steele & Aronson) shows that performance deficits in negatively stereotyped groups can appear under threat conditions and disappear when the threat is removed. It does not reflect real group differences in ability — it reflects how awareness of stereotypes impairs performance.
Unit 1 highest-yield topics: Neurotransmitter–disorder pairs (especially dopamine, serotonin, ACh), brain structure–function (Broca's vs. Wernicke's, hippocampus vs. amygdala), action potential all-or-none law, sleep stage–disorder pairings, and Weber's Law calculations.
Unit 2 highest-yield topics: Memory types (explicit vs. implicit; episodic vs. semantic vs. procedural), interference types (proactive vs. retroactive), Loftus misinformation effect, reliability vs. validity distinction, and cognitive heuristic–scenario matching (availability vs. representativeness vs. anchoring).
Cross-unit connection: Hippocampus connects Unit 1 (brain structures) to Unit 2 (biological bases of memory). H.M. case study bridges both units — always link the structural damage to the specific memory deficit.
When a stimulus presents a person making a judgment error or memory mistake: ① Is the error about estimating probability? → likely a heuristic (availability/representativeness). ② Is it about consistency of recall? → interference or encoding failure. ③ Is a test inconsistent? → unreliable. Is it consistent but wrong? → reliable but invalid. ④ Is an object used in only its conventional way? → functional fixedness. Is an old strategy applied incorrectly? → mental set.