- Classical conditioning
- Learning by association: a neutral stimulus paired with one that triggers a reflex comes to evoke the response on its own. Pavlov's dogs salivated to a bell.
- Operant conditioning
- Learning in which behavior is shaped by its consequences — reinforcement strengthens it, punishment weakens it (Skinner).
- Dopamine
- Neurotransmitter for reward, motivation, and movement; loss in the substantia nigra causes Parkinson's, and excess activity is linked to schizophrenia.
- Serotonin
- Neurotransmitter regulating mood, sleep, and appetite; low levels are linked to depression.
- Acetylcholine
- Neurotransmitter for memory and muscle activation; its loss is associated with Alzheimer's disease.
- GABA
- The brain's main inhibitory neurotransmitter; it calms neural activity and reduces anxiety.
- Glutamate
- The brain's main excitatory neurotransmitter; central to learning and memory.
- Norepinephrine
- Neurotransmitter for arousal and alertness; drives the fight-or-flight stress response.
- Action potential
- The brief electrical impulse traveling down an axon when a neuron fires, following the all-or-none principle.
- Myelin sheath
- The fatty insulation around many axons that speeds the conduction of nerve impulses.
- Synapse
- The junction between two neurons where a neurotransmitter crosses from the axon terminal to the next dendrite.
- Agonist
- A drug or molecule that mimics or boosts the action of a neurotransmitter.
- Antagonist
- A drug or molecule that blocks the action of a neurotransmitter.
- Reuptake
- The reabsorption of a neurotransmitter by the neuron that released it; SSRIs block serotonin reuptake.
- Sympathetic nervous system
- The branch of the autonomic nervous system that triggers fight-or-flight arousal.
- Parasympathetic nervous system
- The branch of the autonomic nervous system that calms the body and conserves energy (rest-and-digest).
- Hippocampus
- The brain structure essential for forming new long-term memories.
- Amygdala
- The brain structure central to fear, aggression, and emotional processing.
- Cerebellum
- The brain structure that coordinates voluntary movement and balance.
- Hypothalamus
- The brain region governing homeostasis — hunger, thirst, temperature — and the endocrine system.
- Thalamus
- The brain's sensory relay station, routing input (except smell) to the cortex.
- Medulla
- The brainstem structure controlling vital autonomic functions like heartbeat and breathing.
- Occipital lobe
- The cortical lobe that processes visual information.
- Temporal lobe
- The cortical lobe that processes hearing and is involved in memory and language.
- Parietal lobe
- The cortical lobe that processes touch and spatial awareness.
- Frontal lobe
- The cortical lobe handling planning, judgment, voluntary movement, and personality.
- Broca's area
- A frontal-lobe region for speech production; damage causes nonfluent (expressive) aphasia.
- Wernicke's area
- A temporal-lobe region for language comprehension; damage causes fluent (receptive) aphasia.
- Corpus callosum
- The band of fibers connecting the two cerebral hemispheres, allowing them to communicate.
- Rods
- Retinal photoreceptors for dim-light and peripheral (black-and-white) vision.
- Cones
- Retinal photoreceptors for color vision and fine detail, concentrated in the fovea.
- Cortisol
- The body's primary stress hormone, released by the adrenal cortex.
- Endorphins
- Endogenous neurotransmitters that reduce pain and produce feelings of pleasure.
- Resting potential
- The negative electrical charge of a neuron at rest, about −70 millivolts.
- Refractory period
- The brief recovery phase after a neuron fires, during which it cannot fire again.
- Reflex arc
- A neural pathway that produces an automatic response without involving the brain.
- Unconditioned stimulus (US)
- A stimulus that naturally and automatically triggers a response (e.g., food).
- Conditioned stimulus (CS)
- A previously neutral stimulus that, after pairing, triggers a learned response (e.g., a bell).
- Positive reinforcement
- Adding a pleasant stimulus to increase a behavior.
- Negative reinforcement
- Removing an aversive stimulus to increase a behavior — it strengthens, not weakens.
- Cognitive dissonance
- The psychological discomfort of holding contradictory beliefs, which motivates a change in attitude or behavior (Festinger).
- Working memory
- The limited-capacity system that holds and manipulates information briefly; Baddeley's model has a central executive, phonological loop, and visuospatial sketchpad.
- Short-term memory
- Memory holding about seven items for roughly 15–30 seconds; expanded by chunking.
- Long-term memory
- Durable memory with effectively unlimited capacity; divided into explicit and implicit.
- Sensory memory
- A very brief, large-capacity store of raw sensory input (iconic for vision, echoic for hearing).
- Chunking
- Grouping individual items into larger meaningful units to expand short-term memory capacity.
- Central executive
- In Baddeley's model, the attentional system that coordinates the phonological loop and visuospatial sketchpad.
- Phonological loop
- The component of working memory that holds and rehearses verbal and auditory information.
- Heuristic
- A mental shortcut that speeds judgment but can cause systematic errors (biases).
- Availability heuristic
- Judging the likelihood of an event by how easily examples come to mind.
- Representativeness heuristic
- Judging probability by how closely something matches a prototype, ignoring base rates.
- Anchoring bias
- Relying too heavily on the first piece of information when making decisions.
- Confirmation bias
- Seeking and favoring information that confirms one's existing beliefs.
- Functional fixedness
- The tendency to see an object as usable only in its customary way.
- Framing effect
- Letting the wording of options (gain vs loss) sway a decision.
- Top-down processing
- Perception guided by prior knowledge, context, and expectations.
- Bottom-up processing
- Perception that builds from raw sensory data without prior expectations.
- Stroop effect
- The slowed naming of an ink color when the word spells a different color — automatic reading interferes with controlled processing.
- Serial position effect
- Better recall of the first (primacy) and last (recency) items in a list.
- Zeigarnik effect
- The tendency to remember incomplete or interrupted tasks better than completed ones.
- Encoding
- The process of getting information into memory.
- Retrieval
- The process of getting information back out of memory.
- Proactive interference
- When old learning disrupts the recall of new information.
- Retroactive interference
- When new learning disrupts the recall of older information.
- Algorithm
- A step-by-step procedure that guarantees a correct solution, though it can be slow.
- Mental set
- The tendency to approach a problem in a way that worked before, even when unhelpful.
- Prospective memory
- Remembering to perform an intended action in the future.
- Semantic memory
- Long-term memory for facts and general knowledge.
- Episodic memory
- Long-term memory for specific personal experiences and events.
- Procedural memory
- Implicit long-term memory for skills and how to do things.
- Spreading activation
- The idea that thinking of one concept primes related concepts in a semantic network.
- Universal grammar
- Chomsky's proposal that humans share an innate, biologically based capacity for language.
- Phoneme
- The smallest distinctive sound unit in a language.
- Morpheme
- The smallest unit of meaning in a language.
- Fluid intelligence
- The ability to reason and solve novel problems, independent of acquired knowledge.
- Crystallized intelligence
- Accumulated knowledge and skills built up over a lifetime.
- Spearman's g
- Charles Spearman's general intelligence factor underlying performance across mental tasks.
- Gardner's multiple intelligences
- Howard Gardner's theory of several distinct intelligences (linguistic, spatial, musical, etc.).
- Fundamental attribution error
- Overestimating dispositional causes and underestimating situational ones when explaining others' behavior.
- Bystander effect
- The more people present at an emergency, the less likely any one helps, due to diffusion of responsibility (Latané & Darley).
- Conformity
- Adjusting behavior or beliefs to match a group standard, demonstrated in Asch's line studies.
- Obedience
- Following the orders of an authority figure; Milgram found ~65% obeyed to the maximum shock.
- Groupthink
- When a group's desire for harmony overrides realistic appraisal of alternatives.
- Self-serving bias
- Crediting successes to oneself and blaming failures on the situation.
- Social facilitation
- Improved performance on simple or well-learned tasks in the presence of others.
- Social loafing
- Reduced individual effort when working in a group than when working alone.
- Diffusion of responsibility
- The reduced sense of personal accountability when others are present.
- In-group bias
- Favoring the group one belongs to over out-groups.
- Out-group homogeneity
- Perceiving members of another group as more alike than they really are.
- Social comparison theory
- Evaluating one's own abilities and opinions by comparing with others, especially similar ones (Festinger).
- Cognitive dissonance theory
- Festinger's theory that holding conflicting beliefs creates discomfort that motivates attitude change.
- Stanford prison experiment
- Zimbardo's study showing how assigned social roles can drive cruel behavior.
- Asch conformity experiment
- A study in which participants gave obviously wrong answers to match a unanimous majority.
- Milgram obedience study
- Milgram's demonstration that ordinary people will obey an authority's order to harm a stranger.
- Robbers Cave experiment
- Sherif's study showing superordinate goals reduce intergroup conflict.
- Superordinate goals
- Shared aims that require cooperation between groups and reduce conflict.
- Foot-in-the-door technique
- Gaining compliance with a large request by first securing a small one.
- Door-in-the-face technique
- Gaining compliance by first making a large request that is refused, then a smaller one.
- Central route to persuasion
- Persuasion through careful evaluation of strong arguments (Elaboration Likelihood Model).
- Peripheral route to persuasion
- Persuasion through surface cues like attractiveness rather than argument quality.
- Mere exposure effect
- Increased liking for stimuli simply from repeated exposure.
- Self-fulfilling prophecy
- When an expectation prompts behavior that makes the expectation come true.
- Actor-observer bias
- Attributing our own behavior to the situation but others' behavior to disposition.
- Just-world hypothesis
- The belief that people get what they deserve, which can lead to blaming victims.
- Deindividuation
- The loss of self-awareness and restraint in groups, often promoting impulsive behavior.
- Stereotype
- A generalized belief about the members of a social group.
- Prejudice
- A negative attitude toward a group and its members.
- Discrimination
- Unjustified negative behavior toward a group or its members.
- Piaget's stages
- Sensorimotor, preoperational, concrete operational, and formal operational — four invariant stages of cognitive development.
- Object permanence
- Understanding that objects exist when out of sight; develops in the sensorimotor stage.
- Conservation
- Understanding that quantity stays the same despite changes in shape; mastered in the concrete operational stage.
- Sensorimotor stage
- Piaget's first stage (birth–2): learning through senses and movement; object permanence emerges.
- Preoperational stage
- Piaget's second stage (2–7): symbolic thought and language, but egocentric and lacking conservation.
- Concrete operational stage
- Piaget's third stage (7–11): logical thought about concrete events; conservation and reversibility.
- Formal operational stage
- Piaget's fourth stage (11+): abstract and hypothetical reasoning.
- Egocentrism
- The preoperational child's difficulty taking another person's point of view.
- Zone of proximal development
- Vygotsky's gap between what a learner can do alone and with guidance.
- Scaffolding
- Temporary guidance from a more knowledgeable other that is withdrawn as the learner improves (Vygotsky).
- Attachment
- The enduring emotional bond between a child and caregiver.
- Harlow's monkeys
- Studies showing infant monkeys preferred a cloth 'comfort' mother over a wire one with food.
- Strange Situation
- Ainsworth's procedure classifying infant attachment as secure, avoidant, or anxious-ambivalent.
- Secure attachment
- An attachment style in which the child uses the caregiver as a safe base and is comforted on reunion.
- Erikson's psychosocial stages
- Eight lifespan stages, each a crisis such as trust vs mistrust or identity vs role confusion.
- Identity vs role confusion
- Erikson's adolescent stage centered on forming a stable sense of self.
- Kohlberg's stages of moral development
- Preconventional, conventional, and postconventional levels of moral reasoning.
- Preconventional morality
- Kohlberg's earliest level: judging right and wrong by rewards and punishments.
- Postconventional morality
- Kohlberg's highest level: reasoning from abstract ethical principles.
- Gilligan's ethic of care
- Gilligan's critique that Kohlberg's model underweighted care and relationships.
- Critical period
- A window in development when a skill is most readily acquired.
- Habituation
- A decrease in response to a stimulus after repeated presentation.
- Temperament
- A child's biologically based, early-appearing style of emotional reactivity.
- Assimilation
- Fitting new information into existing mental schemas (Piaget).
- Accommodation
- Changing existing schemas to incorporate new information (Piaget).
- Schema (Piaget)
- A mental framework that organizes and interprets information.
- Theory of mind
- The understanding that others have beliefs and intentions different from one's own.
- Adolescent egocentrism
- Heightened self-focus in adolescence (the imaginary audience and personal fable).
- Identity foreclosure
- Committing to an identity (often a parent's) without exploring alternatives (Marcia).
- Telegraphic speech
- Early two-word utterances that convey meaning with content words (e.g., 'want cookie').
- DSM-5-TR
- The American Psychiatric Association's standard classification of mental disorders and their diagnostic criteria.
- Cognitive behavioral therapy
- A structured, present-focused therapy that changes distorted thoughts and behaviors (Beck, Ellis).
- Systematic desensitization
- A behavioral therapy pairing relaxation with a hierarchy of feared situations to treat phobias.
- Psychoanalysis
- Freud's therapy aimed at surfacing unconscious conflict through free association and dream analysis.
- Transference
- In psychodynamic therapy, redirecting feelings about important people onto the therapist.
- Big Five (OCEAN)
- Openness, conscientiousness, extraversion, agreeableness, and neuroticism — the trait model of personality.
- Id
- In Freud's model, the unconscious source of basic drives operating on the pleasure principle.
- Ego
- In Freud's model, the reality-oriented mediator between the id and superego.
- Superego
- In Freud's model, the internalized moral standards and conscience.
- Defense mechanism
- An unconscious strategy (e.g., repression, projection) that reduces anxiety from conflict.
- Repression
- The defense mechanism of pushing threatening thoughts out of awareness.
- Projection
- Attributing one's own unacceptable impulses to someone else.
- Maslow's hierarchy of needs
- A five-level motivation model from physiological needs up to self-actualization.
- Self-actualization
- Realizing one's full potential — the top of Maslow's hierarchy.
- Unconditional positive regard
- Rogers's attitude of full acceptance, central to client-centered therapy.
- Client-centered therapy
- Rogers's humanistic therapy emphasizing empathy, genuineness, and acceptance.
- Dialectical behavior therapy (DBT)
- Linehan's therapy combining acceptance and change skills; first developed for borderline personality disorder.
- Major depressive disorder
- A mood disorder marked by persistent sadness, loss of interest, and related symptoms.
- Bipolar disorder
- A mood disorder alternating between depressive and manic episodes.
- Generalized anxiety disorder
- Chronic, excessive worry across many areas of life.
- Obsessive-compulsive disorder
- Intrusive obsessions and compulsive rituals performed to reduce anxiety.
- Schizophrenia
- A psychotic disorder with delusions, hallucinations, and disorganized thought.
- Positive symptoms
- Added experiences in schizophrenia such as hallucinations and delusions.
- Negative symptoms
- Reductions in schizophrenia such as flat affect and social withdrawal.
- Conversion disorder
- Loss of sensory or motor function with no identifiable medical cause.
- Borderline personality disorder
- A disorder marked by instability in mood and relationships, often involving 'splitting.'
- Splitting
- Viewing people or situations as all good or all bad, common in borderline personality disorder.
- Antisocial personality disorder
- A pattern of disregard for others' rights and a lack of remorse.
- Phobia
- An intense, irrational fear of a specific object or situation.
- PTSD
- Post-traumatic stress disorder: flashbacks, hyperarousal, and avoidance after trauma.
- Reliability
- The consistency of a measurement — whether it gives the same result on repeated use.
- Validity
- The degree to which a test measures what it claims to measure.
- Type I error
- A false positive — rejecting a true null hypothesis; its probability is alpha.
- Type II error
- A false negative — failing to reject a false null hypothesis; its probability is beta.
- Confounding variable
- An extraneous variable that varies with the independent variable, offering a rival explanation.
- Independent variable
- The variable a researcher manipulates in an experiment.
- Dependent variable
- The outcome a researcher measures in an experiment.
- Random assignment
- Placing participants into conditions by chance to equalize groups and allow causal inference.
- Double-blind procedure
- A design in which neither participants nor researchers know group assignments, controlling bias.
- Placebo effect
- Improvement from an inactive treatment due to the participant's expectations.
- Correlation coefficient
- A value from −1 to +1 indicating the direction and strength of a relationship.
- Correlation vs causation
- Correlation shows variables relate; only a controlled experiment can establish cause.
- Mean
- The arithmetic average; sensitive to outliers.
- Median
- The middle value of an ordered data set; resists outliers.
- Mode
- The most frequently occurring value in a data set.
- Standard deviation
- A measure of how spread out data are around the mean.
- Normal distribution
- A symmetric, bell-shaped distribution where mean, median, and mode coincide.
- Positive skew
- A distribution with a long right tail; the mean exceeds the median.
- Negative skew
- A distribution with a long left tail; the mean is below the median.
- ANOVA
- Analysis of Variance — a test comparing the means of three or more groups.
- t-test
- A test comparing the means of two groups.
- p-value
- The probability of obtaining results as extreme as observed if the null hypothesis were true.
- Statistical significance
- A result unlikely to be due to chance, conventionally p < .05.
- Null hypothesis
- The default claim that there is no effect or no difference.
- Test-retest reliability
- Consistency of scores when the same test is given to the same people at two times.
- Inter-rater reliability
- Agreement among different observers scoring the same behavior.
- Internal consistency
- The degree to which a test's items measure the same construct (e.g., Cronbach's alpha).
- Construct validity
- Whether a test measures the theoretical trait it intends to.
- External validity
- Whether findings generalize to other settings, people, and times.
- Internal validity
- Whether a study can confidently attribute results to the independent variable.
- Cross-sectional design
- Comparing different age groups at one point in time.
- Longitudinal design
- Following the same participants over an extended period.
