Sensation: Detection of stimuli by sensory receptors (bottom-up)
Perception: Brain's interpretation of sensory information (top-down)
Sensory Thresholds
Concept
Definition
Absolute threshold
Minimum stimulus detectable 50% of the time
Difference threshold (JND)
Minimum change in stimulus detectable 50% of the time
Weber's Law
ΔI/I=k (JND is proportional to stimulus intensity)
Signal detection theory
Detection depends on signal strength AND decision criteria (hits, misses, false alarms, correct rejections)
Sensory Adaptation
Decreased sensitivity to constant stimuli over time
Example: You stop noticing the smell of your own house
Does NOT apply to pain (for survival reasons)
Gestalt Principles of Perception
Principle
Description
Proximity
Near objects grouped together
Similarity
Similar objects grouped together
Closure
Brain fills in gaps to complete shapes
Continuity
Prefer smooth, continuous patterns
Figure-ground
Distinguish object from background
Signal Detection Theory (SDT) — The 2×2 Outcome Matrix
SDT separates sensitivity (how well you discriminate signal from noise, d′) from response bias (your willingness to say "yes," criterion β).
Signal present
Signal absent
Said "yes"
Hit
False alarm
Said "no"
Miss
Correct rejection
A conservative criterion (only respond when very sure) → fewer false alarms but more misses.
A liberal criterion → more hits but more false alarms.
Changing payoffs/expectations shifts the criterion WITHOUT changing true sensitivity — this is why SDT data, not raw hit rate, reveals perceptual ability.
Sensory Transduction Pathways (Know the Receptor → Brain Map)
Modality
Receptor
Primary cortical target
Vision
Rods/cones → retina
Occipital lobe (V1)
Hearing
Hair cells (cochlea, organ of Corti)
Temporal lobe (A1)
Touch/pain
Mechanoreceptors / nociceptors
Parietal lobe (somatosensory)
Smell
Olfactory receptors
Olfactory bulb → cortex (bypasses thalamus)
Taste
Taste buds
Gustatory cortex
Place theory (high-frequency pitch coded by WHERE on basilar membrane) vs. frequency/temporal theory (low-frequency pitch coded by rate of firing). High yield for hearing.
Vision: trichromatic theory (3 cone types) explains the receptor level; opponent-process theory (red–green, blue–yellow, black–white) explains afterimages and downstream processing. Both are correct at different stages.
Bottom-Up vs. Top-Down and Perceptual Constancies
Bottom-up: data-driven, builds percept from raw features.
Constancies (size, shape, color) keep objects stable despite changing retinal images — a top-down contribution and the source of many size-illusion questions.
Sensation & Perception 🎯
Worked Examples — Sensation & Perception
<details>
<summary><b>Example 1: Apply Weber's Law to a new modality</b></summary>
Question: A wine taster can just detect a difference when sugar rises from 200 mg/L to 210 mg/L. What is the smallest detectable change at a baseline of 500 mg/L?
Solution:k=IΔI=
</details>
<details>
<summary><b>Example 2: Interpret a signal-detection data table</b></summary>
</details>
<details>
<summary><b>Example 3: Bottom-up vs. top-down in an experiment</b></summary>
</details>
Part 6 of 7 — Neuroscience & Biological Bases of Behavior
Brain Regions
Region
Functions
Frontal lobe
Executive function, planning, personality, motor cortex, Broca's area (speech production)
Parietal lobe
Somatosensory cortex, spatial processing
Temporal lobe
Auditory processing, Wernicke's area (language comprehension), memory
Occipital lobe
Visual processing
Cerebellum
Motor coordination, balance
Brainstem
Vital functions (breathing, heart rate, sleep)
Limbic System
Structure
Function
Hippocampus
Memory formation (declarative/explicit)
Amygdala
Emotion (especially fear)
Hypothalamus
Part 7: Review & MCAT Practice
Psychology & Behavior for the MCAT
Part 7 of 7 — Development & Identity
Erikson's Psychosocial Stages
Stage
Age
Crisis
Trust vs. Mistrust
0-1
Infant depends on caregiver reliability
Autonomy vs. Shame
1-3
Toddler develops independence
Initiative vs. Guilt
3-6
Child explores and leads
Industry vs. Inferiority
6-12
Competence in school and social
Identity vs. Role Confusion
12-18
Adolescent finds self
Intimacy vs. Isolation
18-40
Young adult forms close relationships
Generativity vs. Stagnation
40-65
Contributing to society
Integrity vs. Despair
65+
Reflecting on life's meaning
Kohlberg's Moral Development
Level
200210−200
=
20010=
0.05
ΔI=k⋅I=0.05×500=25 mg/L✓
Key idea: The JND is a constant FRACTION (5%) of the baseline, not a constant absolute amount. At higher intensities you need a larger absolute change to notice it.
Question: Over 100 trials with a signal present and 100 with it absent, an observer scores 80 hits and 30 false alarms. Another observer scores 60 hits and 5 false alarms. Who is more sensitive, and who has the more conservative criterion?
Solution:
Observer A: hit rate 0.80, false-alarm rate 0.30. Observer B: hit rate 0.60, false-alarm rate 0.05.
Sensitivity (d′) reflects the SEPARATION between hit and false-alarm rates. A: 0.80 − 0.30 = 0.50 gap; B: 0.60 − 0.05 = 0.55 gap → B is slightly more sensitive. ✓
Criterion: B says "yes" far less often (low false alarms) → B is the more conservative responder; A is more liberal. ✓
MCAT lesson: You cannot judge ability from hit rate alone — a high hit rate paired with a high false-alarm rate just means a liberal criterion.
Question: Subjects shown a degraded image of an animal identify it faster if they were first told "you'll see a farm animal." Naming this effect and the process involved.
Solution:
The verbal cue creates an expectation/schema that guides interpretation → top-down processing (specifically, priming). ✓
The raw degraded pixels alone would be bottom-up; the cue supplies context that fills the gaps.
Connection: This is the same mechanism behind perceptual set and the word-superiority effect — expectation shapes what we perceive, not just what hits the retina.
Decrease (add unpleasant)
Speeding ticket
Negative punishment
Decrease (remove pleasant)
Phone taken away
Memory Types
Type
Duration
Capacity
Example
Sensory
<1 second (iconic) to ~3-4s (echoic)
Large
Flash of image
Short-term/Working
~30 seconds
7±2 items
Phone number
Long-term
Unlimited duration
Unlimited capacity
Life events
Reinforcement Schedules (ULTRA HIGH YIELD)
Schedule
Rule
Response pattern
Real-world example
Fixed ratio (FR)
Reward after set # responses
High rate, brief post-reward pause
Piecework pay (per 10 units)
Variable ratio (VR)
Reward after unpredictable # responses
Highest, most resistant to extinction
Slot machines, gambling
Fixed interval (FI)
Reward after set time
Scalloped — responding ramps before deadline
Studying right before a weekly quiz
Variable interval (VI)
Reward after unpredictable time
Steady, moderate
Checking for a text reply
Key rule:Ratio schedules (based on # of responses) produce faster responding than interval schedules; variable schedules resist extinction better than fixed. VR is the gold standard for persistence.
Encoding effects: spacing effect (distributed > massed practice), serial position (primacy from LTM rehearsal + recency from STM), depth of processing (semantic > acoustic > visual), and state/context-dependent retrieval.
Memory failures: proactive interference (old disrupts new) vs. retroactive interference (new disrupts old); source monitoring errors; misinformation effect (Loftus).
Biological Basis: Long-Term Potentiation (LTP)
LTP — the cellular model of learning — is strengthening of synaptic transmission via the NMDA receptor, which requires both presynaptic glutamate release AND postsynaptic depolarization to expel its Mg2+ block, allowing Ca2+ influx. The hippocampus is essential for forming new explicit memories (cf. patient H.M., who lost his hippocampi and could form no new declarative memories but could still learn motor skills).
Learning & Memory 🎯
Worked Examples — Learning & Memory
<details>
<summary><b>Example 1: Distinguish negative reinforcement from punishment in data</b></summary>
Question: A rat presses a lever; this turns off a loud noise. Over sessions, lever-pressing increases in frequency. A second rat presses a lever and receives a shock; pressing decreases. Classify each.
Solution:
Rat 1: an aversive stimulus (noise) is removed after the behavior, and the behavior increases → negative reinforcement (escape/avoidance learning). ✓
Rat 2: an aversive stimulus (shock) is added and behavior decreases → positive punishment. ✓
MCAT trap: "Negative" describes removal, not "bad." Whether something is reinforcement or punishment is judged ONLY by whether the behavior goes up (reinforcement) or down (punishment).
</details>
<details>
<summary><b>Example 2: Interpret a serial-position curve</b></summary>
Question: Subjects recall a 20-word list immediately. A U-shaped recall curve appears (best for first and last items). A second group recalls after a 30-second distractor task. What changes, and why?
Solution:
The immediate curve shows primacy (early items rehearsed into long-term memory) and recency (last items still in short-term/working memory).
The 30-second distractor task fills working memory and prevents rehearsal → the recency effect disappears while primacy remains. ✓
Why it matters: This double dissociation is classic evidence for SEPARATE short-term and long-term memory stores — a favorite experimental-reasoning question.
</details>
<details>
<summary><b>Example 3: Apply classical-conditioning terminology to a novel scenario</b></summary>
Question: A chemotherapy patient feels nauseated (response) after infusions. Soon, merely entering the clinic waiting room triggers nausea. Identify the UCS, UCR, CS, and CR.
Solution:
UCS = the chemotherapy drug (naturally causes nausea)
UCR = nausea caused by the drug
CS = the waiting room (a previously neutral stimulus paired with the drug)
CR = nausea triggered by the waiting room alone ✓
Extension: This "conditioned taste/place aversion" can occur after a SINGLE pairing and over long delays — an exception to the usual rule that conditioning needs many closely-timed pairings (biological preparedness).
</details>
Key Takeaways — Part 2
Classical conditioning: association between stimuli (involuntary responses)
Performance is best at moderate arousal → inverted-U.
Simple/well-learned tasks: optimal arousal is HIGHER.
Complex/novel tasks: optimal arousal is LOWER (high arousal disrupts them).
Intrinsic vs. Extrinsic Motivation & the Overjustification Effect
Intrinsic: doing something for its inherent satisfaction. Extrinsic: for an external reward/avoiding punishment.
Overjustification effect: giving an extrinsic reward for an already-intrinsically-enjoyed activity can REDUCE intrinsic motivation (the person re-attributes their behavior to the reward).
"I'm afraid BECAUSE I tremble"; bodily state comes first
Cannon–Bard
Stimulus → arousal AND emotion simultaneously
Thalamus relays both at once
Schachter–Singer (two-factor)
Stimulus → arousal → cognitive label → emotion
Same arousal + different label = different emotion
Lazarus (cognitive-appraisal)
Stimulus → appraisal → arousal + emotion
Appraisal can precede/define the emotion
The three components of emotion: physiological, behavioral (expression), and cognitive (subjective experience/appraisal).
Neurobiology of Emotion
Amygdala: rapid detection of threat/fear; "low road" (thalamus → amygdala) is fast and crude; "high road" (thalamus → cortex → amygdala) is slower and accurate.
Limbic system (amygdala, hippocampus, hypothalamus) + prefrontal cortex (regulation, especially left/right valence).
<details>
<summary><b>Example 1: Distinguish the emotion theories on one scenario</b></summary>
Question: A hiker sees a snake, her heart pounds, and she feels fear. State what each major theory claims about the ORDER of these events.
Solution:
James–Lange: snake → bodily response (pounding heart) → THEN fear. The emotion is the perception of the bodily state. ✓
Cannon–Bard: snake → pounding heart AND fear arise simultaneously and independently (thalamic relay). ✓
Schachter–Singer: snake → arousal → she labels the arousal as "fear" using context (a snake!) → fear. Same arousal labeled differently in another context could be excitement. ✓
Lazarus: snake → cognitive appraisal ("danger!") → arousal + fear; appraisal can come first.
MCAT note: The discriminating question is always: does the bodily response, the cognition, or both-at-once come first?
</details>
<details>
<summary><b>Example 2: Apply Yerkes–Dodson to task difficulty</b></summary>
Question: Two students take exams under high pressure (high arousal): one faces a simple multiplication drill, the other a novel proof-based problem set. Predict who performs better and why.
Solution:
Yerkes–Dodson: performance vs. arousal is an inverted-U, and the optimal arousal level DEPENDS on task complexity. ✓
Simple/well-learned task (multiplication): optimal arousal is HIGH, so high pressure helps or is neutral → that student does fine.
Complex/novel task (proofs): optimal arousal is LOW, so high pressure pushes past the peak → performance DROPS. ✓
Conclusion: the multiplication student is least harmed by the high arousal.
Key idea: "Moderate arousal is best" is shorthand — the true peak shifts with task difficulty.
</details>
<details>
<summary><b>Example 3: Map a stress response onto GAS and physiology</b></summary>
Question: A medical resident works grueling shifts for months, then develops frequent infections and exhaustion. Trace the General Adaptation Syndrome stages and the dominant hormone in each.
Amygdala drives rapid fear detection; cortisol is the chronic-stress hormone.
Complex sentences
Consciousness & Sleep
Sleep Stages:
Stage
Features
Brain Waves
NREM 1
Light sleep, hypnagogic hallucinations
Theta
NREM 2
Sleep spindles, K-complexes
Theta
NREM 3
Deep/slow-wave sleep, hard to wake
Delta
REM
Dreams, muscle atonia, rapid eye movement
Beta (like awake!)
Problem Solving
Algorithm: Step-by-step guaranteed solution
Heuristic: Mental shortcut (faster but error-prone)
Confirmation bias: Seeking evidence that confirms existing beliefs
Functional fixedness: Can't see new uses for familiar objects
Piaget — Assimilation vs. Accommodation (High Yield)
Piaget argued that children build schemas (mental frameworks) and update them by two complementary processes:
Process
Definition
Example
Assimilation
Fitting NEW information into an EXISTING schema
A child who knows "dog" calls a cat a "dog"
Accommodation
MODIFYING the schema to fit new information
The child creates a new "cat" schema
Equilibration
The drive to balance assimilation and accommodation that propels stage transitions
Resolving the dog/cat conflict
Trap: Assimilation does NOT change the schema; accommodation does. Vygotsky offers a contrasting sociocultural view — the zone of proximal development (ZPD) and scaffolding emphasize that cognition is built through guided social interaction, not solitary stage-by-stage maturation.
Heuristics & Biases (Tversky & Kahneman)
Heuristic / Bias
Description
Classic finding
Availability heuristic
Judge frequency by how easily examples come to mind
People overestimate plane-crash deaths after media coverage
Representativeness heuristic
Judge probability by similarity to a prototype
The "Linda problem" — conjunction fallacy (bank teller + feminist judged more likely than bank teller)
Anchoring
Over-rely on the first piece of information
Estimates pulled toward an arbitrary starting number
Belief perseverance
Clinging to beliefs after they are discredited
Distinct from confirmation bias (which is about evidence search)
Consciousness-Altering Substances & Theories of Dreaming
Activation-synthesis hypothesis (Hobson & McCarley): dreams are the cortex's attempt to make sense of random pontine (brainstem) signals during REM — contrast with Freud's wish-fulfillment view. The continual-activation / information-processing model holds that REM consolidates memories.
Cognition 🎯
Worked Examples — Cognition & Consciousness
<details>
<summary><b>Example 1: Apply a Piagetian stage to a behavior</b></summary>
Question: A 9-year-old can correctly reason that if all the water in two identical glasses is equal, pouring one into a taller glass does not change the amount. However, the child struggles to reason about a purely hypothetical scenario ("If you could be invisible, what would you do?") in abstract terms. Which stage is the child in?
Solution:
Mastery of conservation rules out preoperational; the child has the logical operations of the concrete operational stage (ages 7–11). ✓
Difficulty with purely abstract/hypothetical reasoning rules out formal operational (12+), which is exactly where such reasoning emerges.
Conclusion: concrete operational. The child reasons logically about concrete, present objects but not yet about abstractions.
Key idea: Conservation = concrete operational; abstract/hypothetical reasoning = formal operational. The presence of one and absence of the other pins the stage.
</details>
<details>
<summary><b>Example 2: Identify the sleep stage from EEG data</b></summary>
Question: A sleep-lab EEG shows low-amplitude, high-frequency activity resembling the awake state, the EMG shows near-complete loss of skeletal muscle tone, and the participant's eyes are darting under closed lids. When woken, they report a vivid narrative dream. What stage is this?
Contrast: NREM 2 would show sleep spindles and K-complexes; NREM 3 would show high-amplitude delta waves and is the hardest stage to wake from.
MCAT lesson: REM is "paradoxical" because the brain looks awake while the body is paralyzed — the atonia prevents acting out dreams.
</details>
<details>
<summary><b>Example 3: Classify a reasoning error</b></summary>
Question: An investor refuses to sell a failing stock and instead seeks out only news articles predicting the stock will rebound, ignoring analyst downgrades. Classify the dominant cognitive bias and contrast it with a related one.
Solution:
Selectively SEEKING evidence that supports a pre-existing belief = confirmation bias. ✓
Contrast with belief perseverance — that would describe clinging to the belief even AFTER the supporting evidence is directly refuted. Here the investor is actively filtering incoming information, so confirmation bias is the better fit.
Connection: Both protect existing beliefs, but confirmation bias is about biased search/interpretation of evidence, whereas belief perseverance is about resistance to disconfirmation.
Dopamine hypothesis — excess dopamine activity in mesolimbic pathway
OCD
Obsessions (intrusive thoughts) + compulsions (ritualized acts that reduce anxiety)
Now classed separately from anxiety disorders in DSM-5
PTSD
Re-experiencing, avoidance, hyperarousal after trauma
Hyperactive amygdala, hippocampal changes
Positive vs. negative symptoms trap: "Positive" means a behavior is ADDED (hallucination), NOT that it is desirable; "negative" means a normal function is LOST (flat affect). Positive symptoms respond better to typical antipsychotics (D2 blockers).
Personality Theories — Deeper Contrasts
Freud (psychoanalytic): behavior driven by unconscious conflict among id, ego, superego; psychosexual stages; defense mechanisms reduce anxiety.
Trait theorists & the Big Five (OCEAN): describe personality on continuous dimensions; the person-situation controversy (Mischel) questioned whether traits predict behavior consistently across situations.
Social-cognitive (Bandura):reciprocal determinism — behavior, personal/cognitive factors, and environment all influence one another. Locus of control (internal vs. external) and self-efficacy are key constructs.
Humanistic (Maslow, Rogers): people strive toward self-actualization; Rogers stressed unconditional positive regard and congruence between the real and ideal self.
Personality & Disorders 🎯
Worked Examples — Personality & Disorders
<details>
<summary><b>Example 1: Identify the defense mechanism</b></summary>
Question: A man who is deeply attracted to a coworker but considers the feeling unacceptable becomes convinced, without evidence, that the coworker is constantly flirting with HIM. Which Freudian defense mechanism is this, and how does it differ from displacement?
Solution:
The man takes his OWN unacceptable impulse (attraction) and attributes it to another person → projection. ✓
Displacement would instead redirect the emotion onto a safer target (e.g., snapping at a subordinate), not reassign the impulse's ownership to someone else.
Key idea: Projection = "the feeling is yours, not mine." Displacement = "I'll aim my feeling at a safer target."
</details>
<details>
<summary><b>Example 2: Distinguish two mood disorders from a vignette</b></summary>
Question: A patient reports a one-week period of needing only 3 hours of sleep, racing thoughts, grandiose plans to start five companies, and reckless spending — followed by weeks of depressed mood and anhedonia. What is the most likely DSM-5 diagnosis?
Solution:
The decreased need for sleep, grandiosity, flight of ideas, and impulsive spending define a manic episode. ✓
A single full manic episode is sufficient for bipolar I disorder, even with intervening depressive episodes.
Major depressive disorder is ruled out precisely because mania has occurred — the presence of a manic episode is the deciding criterion.
MCAT lesson: One manic episode = bipolar I. Don't be distracted by the depressive phase; mania is the diagnostic key.
</details>
<details>
<summary><b>Example 3: Match a personality construct to its theorist</b></summary>
Question: A therapist offers a client acceptance and warmth regardless of what the client discloses, aiming to close the gap between the client's real self and ideal self. Name the construct and the theorist.
Solution:
Acceptance "regardless of what is disclosed" = unconditional positive regard. ✓
The real-self/ideal-self congruence framework and unconditional positive regard belong to Carl Rogers, a humanistic theorist.
Connection: Contrast with Freud (unconscious conflict) and trait theory (OCEAN dimensions) — humanism is uniquely growth- and self-concept-oriented.
</details>
Key Takeaways — Part 5
Big Five (OCEAN): Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism
Freud: Id (pleasure), Ego (reality), Superego (morality) + defense mechanisms
Trap: EEG wins on timing (millisecond resolution) but is poor at pinpointing location; fMRI is the reverse. Match the question stem's emphasis to the right tool.
Nervous System Organization & the Autonomic Divisions
The neuron's resting membrane potential is about −70 mV, maintained by the Na+/K+ ATPase (pumps 3 Na+ out for every 2 K+ in). Reaching the threshold (~−55 mV) triggers an all-or-none action potential: Na+ influx (depolarization) then K+ efflux (repolarization). The absolute refractory period ensures the impulse travels one direction only.
Neuroscience 🎯
Worked Examples — Neuroscience
<details>
<summary><b>Example 1: Localize a deficit to a brain region</b></summary>
Question: After a stroke, a patient cannot form any new long-term declarative memories but retains older memories and can still learn new motor skills. Which structure is most likely damaged, and which is spared?
Solution:
Loss of NEW declarative (explicit) memory formation localizes to the hippocampus (cf. patient H.M.). ✓
Preserved motor-skill (procedural) learning indicates the cerebellum/basal ganglia are intact — these mediate implicit memory.
Key idea: The hippocampus consolidates new explicit memories; it is not where old memories are permanently stored, which is why remote memories survive.
</details>
<details>
<summary><b>Example 2: Reason from a neurotransmitter to a disorder/treatment</b></summary>
Question: A drug that blocks postsynaptic D2 dopamine receptors reduces a patient's hallucinations and delusions but, over time, produces tremor and rigidity. Explain both effects mechanistically.
Solution:
Blocking dopamine in the mesolimbic pathway reduces the POSITIVE symptoms of schizophrenia — consistent with the dopamine hypothesis (excess dopamine). ✓
The same blockade in the nigrostriatal motor pathway lowers dopamine there, mimicking Parkinsonism (tremor, rigidity) — too little dopamine in a motor circuit.
MCAT lesson: The direction of a neurotransmitter's effect depends on the pathway; one drug can fix one circuit while disrupting another.
</details>
<details>
<summary><b>Example 3: Pick the right imaging method for a study design</b></summary>
Question: Investigators want to identify WHICH cortical region activates when subjects view fearful faces versus neutral faces. Which method best fits, and what is its limitation?
Solution:
The goal is precise spatial localization of activity → fMRI (BOLD signal) is ideal. ✓
Limitation: fMRI has poor temporal resolution (BOLD lags neural activity by seconds) and measures blood flow indirectly, not neural firing itself.
Connection: If instead they needed millisecond timing of the response, EEG/ERP would be chosen, trading spatial precision for temporal precision.
</details>
Key Takeaways — Part 6
Broca's = speech production (frontal). Wernicke's = comprehension (temporal).
Low dopamine → Parkinson's. High dopamine → Schizophrenia.
Reasoning
Example
Pre-conventional
Self-interest (punishment/reward)
"I'll get in trouble"
Conventional
Social norms, law and order
"It's the rule"
Post-conventional
Universal ethical principles
"It's the right thing even if illegal"
Attachment Types (Ainsworth)
Type
Description
Secure
Distressed when parent leaves, happy on return
Avoidant
Little distress, ignores parent's return
Anxious-ambivalent
Very distressed, ambivalent on return (angry + clingy)
Disorganized
No consistent pattern, often from abuse
The Strange Situation (Ainsworth's Classic Study)
Ainsworth's Strange Situation is a structured observation in which a 12–18-month-old experiences a series of separations from and reunions with the caregiver, plus the presence of a stranger. Reunion behavior, NOT separation distress alone, is the key marker:
Secure (~60–65% of infants): uses parent as a secure base to explore; upset at departure; readily comforted on reunion.
Avoidant: explores indifferently; minimal reaction to departure OR reunion.
Anxious-ambivalent (resistant): little exploration; intense distress; on reunion seeks contact yet resists comfort (clingy + angry).
Harlow's monkey studies (cloth vs. wire "mothers") earlier established that contact comfort, not feeding, drives attachment — undermining the behaviorist "cupboard love" view.
Comparing the Stage Theorists (Don't Confuse Them)
Theorist
Domain
Engine of change
Piaget
Cognitive development
Assimilation/accommodation through 4 stages
Erikson
Psychosocial development
Resolving a crisis at each of 8 stages across the lifespan
Kohlberg
Moral reasoning
Pre-/conventional/post-conventional levels
Vygotsky
Sociocultural cognition
Social interaction; zone of proximal development
Trap: Erikson stages are psychosocial CRISES (e.g., identity vs. role confusion); Kohlberg's are about the reasoning behind moral choices, NOT the choice itself. A person can reach the same decision at any Kohlberg level — what matters is the justification.
Theories of Identity & Aging
Marcia's identity statuses (built on Erikson): foreclosure, moratorium, identity achievement, and diffusion — defined by the presence/absence of crisis (exploration) and commitment.
Activity theory vs. disengagement theory of aging: activity theory holds that maintaining social engagement promotes well-being in older adults; disengagement theory (largely discredited) claimed mutual withdrawal is natural.
Development 🎯
Worked Examples — Development & Identity
<details>
<summary><b>Example 1: Match a life situation to an Erikson stage</b></summary>
Question: A 50-year-old reports deriving deep satisfaction from mentoring younger colleagues and volunteering, feeling she is "leaving something behind for the next generation." Which psychosocial crisis is she resolving, and in which direction?
Solution:
Mentoring and contributing to the next generation maps to Generativity vs. Stagnation (middle adulthood, ~40–65). ✓
She is resolving it toward generativity (productive contribution) rather than stagnation (self-absorption).
Key idea: Generativity is specifically about investing in the NEXT generation and society — distinguish it from Integrity vs. Despair, which is end-of-life reflection on whether one's life had meaning.
</details>
<details>
<summary><b>Example 2: Classify a study design / observation</b></summary>
Question: A researcher subjects 12-month-olds to a sequence of caregiver departures, stranger encounters, and reunions, coding behavior at each reunion. What classic paradigm is this, and what is the primary dependent variable?
Solution:
The departure-stranger-reunion sequence is Ainsworth's Strange Situation, a structured-observation paradigm. ✓
The primary measure is reunion behavior (how the infant responds when the caregiver returns), which classifies attachment style — NOT merely how distressed the infant is during separation.
MCAT lesson: Many students wrongly think separation distress is the key variable; it is the reunion response that distinguishes secure from insecure styles.
</details>
<details>
<summary><b>Example 3: Apply Kohlberg's levels to reasoning</b></summary>
Question: A businessman argues he should return a lost wallet "because if word got out that I kept it, my reputation and standing in the community would suffer." Which Kohlberg level is this?
Solution:
The reasoning centers on social approval, reputation, and meeting others' expectations → the conventional level (specifically the "good boy/good girl" orientation). ✓
It is NOT pre-conventional (that would cite direct punishment or personal reward) and NOT post-conventional (that would invoke abstract universal principles like honesty as a moral duty).
Connection: Always classify by the JUSTIFICATION, not the action — returning the wallet is "moral," but the reasoning here is conventional, not principled.
</details>
Psychology & Behavior — Complete! ✅
The Psych/Soc section tests your understanding of how psychological, social, and biological factors influence behavior and health. Master the major theories (Piaget, Erikson, Kohlberg, Freud), neurotransmitters, brain regions, and learning principles.