Psychology definitions

58 psychology terms from Achievable exam prep courses, each defined in plain language with links into the course textbook.

• Absolute thresholdThe absolute threshold is the smallest amount of a stimulus that a person can detect 50% of the time. It marks the lower boundary of sensation for a given sense — anything weaker generally goes unnoticed.
• Agents of socializationAgents of socialization are the people, groups, and institutions — family, school, peers, media, and religion among them — that teach individuals the norms, values, and behaviors of their society.
• Anxiety disordersAnxiety disorders are psychological disorders marked by excessive fear or worry that is out of proportion to the actual threat and interferes with daily functioning. The category includes generalized anxiety disorder, panic disorder, specific phobia, social anxiety disorder, and agoraphobia.
• Attachment stylesAttachment styles are the characteristic patterns of emotional bonding between infants and caregivers, identified through Mary Ainsworth's Strange Situation: secure, avoidant, ambivalent (anxious-resistant), and disorganized attachment.
• Attention (psychology)Attention is the cognitive process of concentrating limited mental resources on some information while filtering out the rest. Because processing capacity is finite, attention determines which stimuli reach conscious awareness and get encoded into memory.
• Attribution theoryAttribution theory explains how people account for the causes of behavior, distinguishing dispositional attributions (blaming personality or character) from situational attributions (blaming circumstances or environment).
• Autism spectrum disorder (ASD)Autism spectrum disorder is a neurodevelopmental condition defined by persistent differences in social communication and interaction along with restricted, repetitive patterns of behavior or interests. Signs appear in early development, and presentation varies widely.
• Belief perseveranceBelief perseverance is the tendency to cling to an initial belief even after the evidence that supported it has been discredited. The belief outlives the information it was built on.
• Classical conditioningClassical conditioning is a form of learning in which a neutral stimulus becomes associated with a stimulus that naturally triggers a response, until the neutral stimulus alone elicits that response. Pavlov's dogs salivating to a bell is the classic example.
• Cognitive developmentCognitive development is the growth of thinking abilities — perception, memory, language, reasoning, and problem-solving — across the lifespan. Piaget's stage theory and Vygotsky's sociocultural theory are the field's foundational frameworks.
• Cognitive dissonanceCognitive dissonance is the mental discomfort felt when a person holds conflicting beliefs, or when their behavior contradicts their attitudes. People are motivated to reduce the tension by changing a belief, changing the behavior, or rationalizing the conflict.
• Cognitive psychologyCognitive psychology is the scientific study of mental processes — how people perceive, attend, remember, think, solve problems, and use language. It treats the mind as an active processor of information.
• Conflict theoryConflict theory is a macro-level sociological perspective that views society as groups competing for scarce resources, with social structures serving the interests of the powerful at the expense of the less powerful.
• Crisis interventionCrisis intervention is short-term, immediate support for a person overwhelmed by an acute event, aimed at ensuring safety, reducing distress, and restoring the person's previous level of functioning.
• Cultural transmissionCultural transmission is the process by which a society's knowledge, values, norms, language, and practices are passed from one generation to the next through learning rather than genetics. It occurs through socialization by family, schools, peers, and media.
• Defense mechanismsDefense mechanisms are unconscious psychological strategies the mind uses to protect itself from anxiety, conflict, or unacceptable thoughts. Classic examples include denial, projection, displacement, and sublimation.
• DeinstitutionalizationDeinstitutionalization is the large-scale movement of psychiatric patients out of long-term mental hospitals and into community-based treatment. It began in the United States in the 1950s and 1960s, driven by new antipsychotic drugs, civil rights concerns, and cost pressures.
• Divided attentionDivided attention is the ability to distribute limited attentional resources across two or more tasks at the same time. It succeeds when at least one task is automatic and breaks down when both require conscious, controlled processing.
• DSM-5 anxiety disordersThe DSM-5 anxiety disorders are the diagnoses defined by excessive fear or worry, including generalized anxiety disorder, panic disorder, specific phobias, social anxiety disorder, agoraphobia, separation anxiety disorder, and selective mutism.
• Eating disordersEating disorders are psychiatric conditions marked by severely disturbed eating behaviors and distorted attitudes toward food, weight, and body shape. The major diagnoses are anorexia nervosa, bulimia nervosa, and binge-eating disorder.
• Encoding (psychology)In psychology, encoding is the process of converting sensory information into a form the brain can store in memory. It is the first stage of memory, followed by storage and retrieval.
• Family as a social institutionIn sociology, the family is a social institution — an organized, enduring pattern of relationships that performs essential functions for society, including socializing children, providing emotional and economic support, and transmitting culture and social status.
• Flynn effectThe Flynn effect is the observation that average scores on intelligence tests rose steadily from one generation to the next throughout much of the twentieth century. Named for researcher James Flynn, the gains ran roughly three IQ points per decade across many countries.
• Functional fixednessFunctional fixedness is a cognitive bias that limits a person to seeing an object only in its usual function, blocking creative problem-solving — like failing to see that a coin could work as a screwdriver.
• Gate control theoryGate control theory proposes that the spinal cord contains a neural "gate" that can block or allow pain signals traveling to the brain. Non-painful input and messages descending from the brain can close the gate, reducing the pain a person feels.
• GentrificationGentrification is the process by which higher-income residents and investment move into a lower-income urban neighborhood, raising property values and rents. The resulting cost increases often displace the original, typically lower-income residents.
• GustationGustation is the sense of taste — the chemical sense that detects dissolved molecules through taste receptor cells on the tongue. It distinguishes five basic qualities: sweet, salty, sour, bitter, and umami.
• HabituationHabituation is the simplest form of learning: a decreased behavioral response to a stimulus that is repeated and turns out to be harmless. It lets organisms ignore familiar, irrelevant stimuli and focus on new or important ones.
• Hidden curriculumThe hidden curriculum is the set of unwritten lessons schools teach beyond the official syllabus — norms, values, and behaviors like obedience, punctuality, and competition that students absorb through everyday school life.
• Implicit memoryImplicit memory is long-term memory that influences behavior without conscious recall, including procedural skills, priming, and conditioned responses. It contrasts with explicit memory, the deliberate recall of facts and events.
• Incongruence (psychology)Incongruence is a mismatch between a person's self-concept and their actual experience, or between who they believe they are and who they want to be. In Carl Rogers's humanistic theory, incongruence produces anxiety and psychological distress.
• Informed consent (psychology)Informed consent is the ethical requirement that research participants agree to take part only after being told what the study involves, including its risks, and that they may withdraw at any time. It is a foundational protection in psychological research.
• Intelligence (psychology)In psychology, intelligence is the capacity to learn from experience, reason, solve problems, and adapt to new situations. Major theories differ on whether it is a single general ability (g) or a collection of distinct abilities.
• MedicalizationMedicalization is the social process by which human conditions and behaviors come to be defined and treated as medical problems, bringing them under the authority of medicine, physicians, and diagnosis.
• Mood disordersMood disorders are psychiatric conditions marked by persistent disturbances in emotional state, chiefly the depressive disorders (such as major depressive disorder) and the bipolar disorders, which add episodes of mania or hypomania.
• NeuronsA neuron is a specialized cell that transmits information through electrical and chemical signals. It is the basic building block of the nervous system, receiving input through dendrites and sending output along its axon.
• Observational learningObservational learning is acquiring new behaviors by watching others (models) rather than through direct experience. Albert Bandura's Bobo doll experiments demonstrated it, and mirror neurons are thought to support it.
• Operant conditioningOperant conditioning is a form of learning in which behavior is shaped by its consequences. Behaviors followed by reinforcement become more frequent, while behaviors followed by punishment become less frequent.
• Personality disordersPersonality disorders are enduring, inflexible patterns of thinking, feeling, and behaving that deviate markedly from cultural expectations and impair functioning. The DSM-5 groups ten disorders into three clusters: A (odd), B (dramatic), and C (anxious).
• Positive psychologyPositive psychology is the scientific study of human strengths, well-being, and what makes life fulfilling. Rather than focusing only on treating mental illness, it examines factors like optimism, gratitude, flow, and resilience that help people thrive.
• Psychological disorderA psychological disorder is a pattern of thoughts, feelings, or behaviors that is clinically significant, causes distress or impairment, and reflects a dysfunction in mental functioning. Diagnosis in the United States follows the criteria set out in the DSM-5.
• PsychophysicsPsychophysics is the study of how physical stimuli relate to the sensations and perceptions they produce. It measures thresholds — the minimum stimulus a person can detect and the smallest change they can notice.
• Psychotic disordersPsychotic disorders are mental disorders characterized by a loss of contact with reality, producing symptoms such as delusions, hallucinations, and disorganized thinking. Schizophrenia is the most prominent example.
• Racial formation theoryRacial formation theory is a sociological framework holding that race is not a fixed biological fact but a social construct that is continually created, transformed, and destroyed through social, economic, and political forces.
• Rational choice theoryRational choice theory holds that people make decisions by weighing the costs and benefits of their options and choosing the one that maximizes personal benefit. Applied to relationships, it becomes social exchange theory, which frames interaction as a trade of rewards and costs.
• Reciprocal determinismReciprocal determinism is Albert Bandura's principle that behavior, personal factors (thoughts, beliefs), and the environment all influence one another continuously — people shape their situations even as their situations shape them.
• Religion as a social institutionReligion is a social institution: an enduring system of beliefs, rituals, roles, and organizations that addresses questions of ultimate meaning and shapes behavior across a society. Sociologists study it not for whether its claims are true but for what it does socially.
• Sensory and short-term memorySensory memory is the fleeting, high-capacity register that holds raw sensory input for a fraction of a second to a few seconds; short-term memory holds a limited amount of attended information — about 7 ± 2 items — for roughly 15 to 30 seconds without rehearsal.
• Signal detection theorySignal detection theory explains how people decide whether a faint stimulus is present amid background noise. It separates true sensory sensitivity from the decision criteria and expectations that bias a person's responses.
• Social loafingSocial loafing is the tendency for people to exert less effort on a task when working in a group than when working alone. It occurs mainly when individual contributions are pooled and cannot be identified.
• Social stigmaSocial stigma is the social devaluation of a person or group based on a characteristic that marks them as different, such as an illness, identity, or behavior. Stigmatized individuals face negative labeling, stereotyping, and discrimination.
• Socioeconomic gradient in healthThe socioeconomic gradient in health is the stepwise pattern in which health outcomes improve at every increase in socioeconomic status — not just between the poor and everyone else, but continuously up the entire social ladder.
• Somatic symptom disorderSomatic symptom disorder is a psychiatric condition in which one or more physical symptoms are accompanied by excessive, persistent thoughts, anxiety, or behaviors related to those symptoms, typically lasting six months or more.
• SomatosensationSomatosensation is the body's sense of touch, encompassing pressure, vibration, temperature, pain, and body position. Specialized receptors in the skin, muscles, and joints convert these physical stimuli into neural signals that travel to the somatosensory cortex.
• Structural functionalismStructural functionalism is a sociological theory that views society as a system of interdependent parts — such as family, education, and religion — that each perform functions to keep the whole stable. It emphasizes social order and equilibrium rather than conflict.
• Substance use disorderSubstance use disorder is a psychiatric condition in which a person continues using alcohol or drugs despite significant impairment or distress. Diagnosis is based on a pattern of impaired control, social problems, risky use, and physical dependence.
• Vestibular senseThe vestibular sense is the sensory system that monitors balance, head position, and movement through space. Its receptors sit in the semicircular canals and vestibular sacs of the inner ear.
• Zone of proximal developmentThe zone of proximal development is the gap between what a learner can do alone and what they can do with guidance from a more capable person. Proposed by Lev Vygotsky, it identifies the range where instruction produces the most learning.