Absolute Threshold
The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time.
Abstract Thinking
The ability to think about concepts that are not physically present or directly experienced, such as ideas, possibilities, symbols, and hypothetical situations.
Accommodation
The process of modifying existing schemas or creating new ones in response to new information that does not fit into current understanding
Accommodation (cognition)
The process of modifying existing schemas or creating new ones in response to new information that does not fit into current understanding
Accommodation (vision)
The process by which the eye's lens changes shape to focus near or far objects on the retina.
Acetylcholine
A neurotransmitter that enables communication between neurons and muscles and also plays an important role in learning and memory
Achievement Tests
Tests that measure what a person has already learned in a specific subject or area.
Acquisition
The initial stage of learning in classical conditioning in which a neutral stimulus begins to produce a conditioned response after being paired with an unconditioned stimulus.
Acrophobia
An anxiety disorder characterized by an intense and irrational fear of heights.
Action Potential
A brief electrical impulse that travels down the axon of a neuron, allowing it to transmit information to other neurons, muscles, or glands
Activation-Synthesis
The theory that dreams are the brain's attempt to make sense of random neural activity occurring during sleep.
Active Listening
A core technique in Humanistic Psychology where the therapist carefully listens, reflects, and clarifies the client’s thoughts and feelings to show empathy and help the client feel understood and accepted.
Actor-Observer Bias
A social perception error in which people attribute their own behavior to situational factors but attribute others’ behavior to internal traits or dispositions.
Addiction
Compulsive craving of drugs or certain behaviors (such as gambling) despite known adverse consequences.
Adolescent Egocentrism
A heightened self-focus in adolescence in which individuals have difficulty distinguishing their own concerns from those of others, often leading to beliefs like the imaginary audience and personal fable.
Adrenaline
A hormone released during stress that increases heart rate, breathing, blood pressure, and energy as part of the body’s fight-or-flight response
Adventure Seeking
A component of sensation seeking characterized by a desire for exciting, novel, and physically stimulating experiences.
Adverse Childhood Experiences
Potentially traumatic events that occur during childhood, such as abuse, neglect, or household dysfunction, that can have lasting effects on physical health, mental health, and development.
Adverse Childhood Experiences
Potentially traumatic events that occur during childhood, such as abuse, neglect, or household dysfunction, that can have lasting effects on physical health, mental health, and development.
Affect
The experience or expression of emotion, including feelings and mood states.
Afterimages
Visual sensations that continue after the original stimulus is removed, often appearing in complementary colors due to fatigue in opponent-process color receptors
Ageism
Prejudice, discrimination, or stereotyping based on a person’s age.
Agonists
Chemicals that bind to and activate receptors, increasing or mimicking the effects of a neurotransmitter
Agoraphobia
An anxiety disorder characterized by an intense fear of situations where escape might be difficult or help unavailable, often leading to avoidance of open or crowded places.
Agreeableness
A personality trait in the Big Five model that reflects how cooperative, compassionate, trusting, and friendly a person is toward others.
Alarm Stage
The first stage of General Adaptation Syndrome in which the body recognizes a stressor and activates the fight-or-flight response.
Alcohol
A depressant drug that slows central nervous system activity, impairing judgment, memory, coordination, and reaction time
Algorithms
Step-by-step, logical procedures or rules that guarantee a solution to a problem if followed correctly
All-or-Nothing Principle
A neuron’s reaction of either firing (with a full-strength response) or not firing.
Alpha Waves
Relatively slow brain waves that are most common when a person is awake but relaxed and calm, often occurring just before falling asleep
Altruism
Helping behavior motivated by a genuine desire to benefit another person without expecting personal gain or reward.
Alzheimer’s Disease
A progressive neurological disorder that causes gradual memory loss, impaired thinking, and changes in behavior due to brain degeneration, especially in areas involved in memory and cognition.
Amplitude (sound)
The height or intensity of a sound wave, which determines the loudness of the sound
Amplitude (vision)
The height of a light wave, which determines the intensity or brightness of the light
Amygdala
A structure in the limbic system involved in processing emotions, especially fear and aggression, and in forming emotional memories
Animism
The belief, common in early childhood, that inanimate objects have thoughts, feelings, or intentions (e.g., “the toy is sad”).
Anorexia Nervosa
An eating disorder characterized by severe restriction of food intake, an intense fear of gaining weight, and a distorted body image leading to significantly low body weight.
Antagonists
Chemicals that bind to receptors and block or reduce the effects of a neurotransmitter
Anterograde Amnesia
A type of memory loss in which a person is unable to form new long-term memories after the event that caused the amnesia, while older memories remain intact.
Antianxiety Drugs
Medications (such as Zoloft, Prozac, and Paxil) that reduce symptoms of anxiety by calming the central nervous system.
Antidepressants
Medications that help reduce symptoms of depression and some anxiety disorders by altering the activity of neurotransmitters involved in mood regulation.
Antipsychotic Medications
Medications used to reduce symptoms such as hallucinations and delusions primarily by affecting dopamine activity in the brain.
Antisocial Personality Disorder
A personality disorder characterized by a persistent pattern of disregard for, and violation of, the rights of others, often involving deceitfulness, impulsivity, and lack of remorse.
Anxiety Disorders
A group of psychological disorders characterized by excessive fear, anxiety, or avoidance that interferes with daily functioning.
Anxious Attachment
An attachment style characterized by strong desires for closeness combined with fear of rejection or abandonment, often leading to worry and insecurity in relationships.
Aphasia
A language disorder caused by damage to areas of the brain responsible for language, resulting in difficulties with speaking, understanding, reading, or writing
Applied Behavior Analysis
A therapy based on principles of learning that uses reinforcement and other behavioral techniques to increase helpful behaviors and reduce harmful or disruptive behaviors.
Approach-Approach
A motivational conflict that occurs when a person must choose between two desirable outcomes.
Approach-Avoidance
A motivational conflict that occurs when a single goal or option has both positive and negative aspects, creating mixed feelings about pursuing it.
Aptitude Tests
Tests designed to predict a person’s future ability to learn or perform certain tasks.
Arachnophobia
An anxiety disorder characterized by an intense and irrational fear of spiders.
Arousal Theory
A theory of motivation that suggests people are motivated to maintain an optimal level of alertness or stimulation, seeking activities that increase or decrease arousal as needed.
Assimilation
The cognitive process of incorporating new information into existing schemas without changing the original framework
Assimilation
The cognitive process of incorporating new information into existing schemas without changing the original framework
Association Areas
Areas of the cerebral cortex that are not involved in primary motor or sensory functions; rather, they are involved in higher mental functions.
Ataque de Nervios
A culture-bound syndrome most commonly seen in Latin American cultures, characterized by episodes of intense emotional distress, including shouting, crying, trembling, and sometimes aggression or dissociation in response to stressful events.
Attachment Styles
Characteristic patterns of emotional bonding and relationship behavior that develop from early interactions with caregivers and influence relationships throughout life.
Attention
The cognitive process of focusing awareness on specific stimuli or information while ignoring other competing stimuli
Attention-Deficit/Hyperactivity Disorder (ADHD)
A neurodevelopmental disorder characterized by persistent patterns of inattention, hyperactivity, and impulsivity that interfere with functioning or development.
Attributions
Explanations people make about the causes of behavior or events, which can be internal (dispositional) or external (situational).
Authoritarian Parenting
A parenting style characterized by high demands, strict rules, and low responsiveness, with an emphasis on obedience and discipline over warmth and discussion.
Authoritative Parenting
A parenting style characterized by high expectations combined with warmth, support, and open communication, encouraging both responsibility and independence.
Autism Spectrum Disorder (ASD)
A neurodevelopmental disorder characterized by persistent difficulties in social communication and interaction, along with restricted or repetitive patterns of behavior, interests, or activities.
Autobiographical Memory
Memory for personal life events and knowledge about oneself, combining factual details and emotional experiences that help form one’s identity.
Autokinetic Effect
A perceptual illusion in which a stationary point of light in a dark or featureless environment appears to move due to lack of visual reference points
Automatic Processing
The unconscious and effortless processing of information, such as reading familiar words or walking, that requires little attention or awareness
Autonomic Nervous System
The division of the peripheral nervous system that automatically regulates involuntary body functions such as heartbeat, breathing, digestion, and gland activity
Autonomy and Shame and Doubt
Erikson’s second psychosocial stage (about ages 1–3) in which children develop independence and self-control; successful resolution leads to autonomy, while excessive criticism or control can result in shame and self-doubt.
Availability Heuristic
A mental shortcut where people estimate the likelihood of events based on how easily examples come to mind, often influenced by recent, vivid, or memorable information
Aversion Therapies
A behavioral therapy that reduces unwanted behaviors by pairing them with an unpleasant stimulus to create a negative association.
Avoidance-Avoidance
A motivational conflict that occurs when a person must choose between two undesirable outcomes.
Avoidant Attachment
An attachment style characterized by emotional distance, discomfort with closeness, and a tendency to rely on oneself rather than seek support from others.
Avoidant Personality Disorder
A personality disorder characterized by extreme social inhibition, feelings of inadequacy, and hypersensitivity to negative evaluation, leading to avoidance of social interactions despite a desire for connection.
Axon
The long, slender extension of a neuron that carries electrical impulses away from the cell body to other neurons, muscles, or glands.
Axon Terminal
The end of an axon where neurotransmitters are released into the synapse to communicate with the next cell.
Babbling
A stage of early language development in which infants (around 4–10 months) begin producing repetitive consonant-vowel sounds like “ba-ba” or “da-da,” practicing speech-like sounds.
Basilar Membrane
A membrane in the cochlea that vibrates in response to sound waves and stimulates hair cells to help convert sound into neural signals
Behavioral Perspective
A psychological approach that focuses on observable behaviors and the ways they are learned and shaped through interactions with the environment, especially through conditioning and reinforcement.
Behavioral Perspective
A psychological approach that focuses on observable behaviors and the ways they are learned and shaped through interactions with the environment, especially through conditioning and reinforcement.
Behavioral Perspective
An approach that explains psychological disorders as the result of learned behaviors acquired through conditioning and environmental influences.
Belief Perseverance
The tendency to maintain a belief even after the evidence supporting it has been discredited or contradicted.
Bimodal Distribution
A distribution that has two distinct peaks or most common scores (modes)
Binocular Depth Cues
Depth cues that require the use of both eyes, such as retinal disparity and convergence, to help perceive distance and depth
Biofeedback
A therapeutic technique that uses electronic monitoring to help individuals gain voluntary control over physiological processes such as heart rate, muscle tension, or breathing.
Biological Perspective
A branch of psychology that links biological (genetic, neural, hormonal) and psychological processes.
Biological Perspective
An approach that explains psychological disorders as the result of genetic, neurological, biochemical, or other physiological factors.
Biological Preparedness
The innate tendency for organisms to more easily learn certain associations that have helped survival throughout evolution, such as fear of snakes or heights.
Biopsychosocial Model
An approach that explains health and behavior as the result of interactions among biological, psychological, and social factors.
Biopsychosocial Perspective
An integrated approach that incorporates biological, psychological, and social-cultural levels of analysis.
Bipolar Cells
Neurons in the retina that receive signals from rods and cones and transmit visual information to ganglion cells
Bipolar I Disorder
A mood disorder characterized by at least one full manic episode, which may be preceded or followed by hypomanic or major depressive episodes.
Bipolar II Disorder
A mood disorder characterized by at least one hypomanic episode and at least one major depressive episode, without the presence of a full manic episode.
Blind Spot
The point at which the optic nerve leaves the eye where there are no receptor cells
Blindsight
A condition in which a person can respond to a visual stimulus without consciously experiencing it.
Borderline Personality Disorder
A personality disorder characterized by instability in mood, self-image, and relationships, along with impulsive behavior and intense fear of abandonment.
Boredom Susceptibility
A component of sensation seeking characterized by an intolerance for repetitive or monotonous experiences and a desire for novelty and change.
Bottom-Up Processing
A type of perceptual processing that starts with sensory input and builds up to a complete perception based on incoming data from the environment
Brain Stem
The part of the brain that connects the brain to the spinal cord and controls basic life-sustaining functions such as breathing, heart rate, and blood pressure
Broca’s Area
A region of the left frontal lobe that is involved in speech production and language expression; damage to this area can cause difficulty speaking fluently (Broca’s aphasia)
Bulimia Nervosa
An eating disorder characterized by recurrent episodes of binge eating followed by compensatory behaviors such as vomiting, fasting, or excessive exercise to prevent weight gain.
Bystander Effect
The tendency for individuals to be less likely to help someone in need when other people are present.
Caffeine
A stimulant drug found in coffee, tea, and soda that increases alertness.
Cannon-Bard Theory
A theory of emotion that proposes that physiological arousal and the conscious experience of emotion occur simultaneously and independently.
Case Study
A descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles.
Catatonic Stupor
A state associated with catatonia in which an individual is immobile, unresponsive, and may appear awake but does not react to external stimuli.
Categories
Mental groupings used to organize objects, ideas, or experiences based on shared features or characteristics.
Central Executive
The component of working memory that directs attention, manages cognitive tasks, and coordinates information from other parts of working memory.
Central Nervous System
The division of the nervous system consisting of the brain and spinal cord, which processes information and coordinates the body’s responses
Central Route to Persuasion
A method of persuasion in which people carefully analyze and think about the quality of the arguments being presented before forming an attitude or making a decision.
Cerebellum
A brain structure located at the back of the brain that coordinates balance, movement, and fine motor skills, and is also involved in motor learning
Cerebral Cortex
The outer layer of the brain responsible for higher-level functions such as thinking, perceiving, language, memory, and voluntary movement
Change Blindness
A perceptual phenomenon in which people fail to notice significant changes in a visual scene when their attention is not focused on those changes
Chronological Age
The actual age of a person measured in years, months, and days since birth.
Chronosystem
In Bronfenbrenner’s ecological systems theory, the dimension of time that includes life transitions, historical events, and changes in circumstances that influence an individual's development.
Chunking
A memory strategy that involves grouping individual pieces of information into larger, more meaningful units to improve short-term memory capacity and recall.
Circadian Rhythm
The body’s internal biological clock that regulates the sleep-wake cycle and other physiological processes on a roughly 24-hour schedule
Classical Conditioning
A learning process in which a neutral stimulus becomes associated with a meaningful stimulus and begins to produce a learned (conditioned) response.
Closure
A Gestalt principle of perception in which the brain fills in missing parts of a visual image to perceive it as a complete whole
Cluster A Personality Disorders
A group of personality disorders characterized by odd or eccentric thinking and behavior, including paranoid, schizoid, and schizotypal personality disorders.
Cluster B Personality Disorders
A group of personality disorders characterized by dramatic, emotional, or erratic behavior, including antisocial, borderline, histrionic, and narcissistic personality disorders.
Cluster C Personality Disorders
A group of personality disorders characterized by anxious or fearful thinking and behavior, including avoidant, dependent, and obsessive-compulsive personality disorders.
Cocaine
A powerful stimulant drug that increases dopamine levels in the brain by blocking its reuptake, leading to intense feelings of euphoria, energy, and increased alertness
Cochlea
A fluid-filled, snail-shaped structure in the inner ear that converts sound vibrations into neural signals for the brain
Cocktail Party Effect
The ability to focus one’s attention on a single conversation in a noisy environment while still being able to notice personally relevant information, such as one’s name
Cognitive Appraisal
The process of evaluating and interpreting a situation in order to determine its emotional significance and how one should respond.
Cognitive Dissonance
The psychological discomfort that occurs when a person holds conflicting beliefs, attitudes, or behaviors, often motivating them to reduce the inconsistency.
Cognitive Label
The interpretation or identification of a physiological arousal state that helps determine which emotion is being experienced.
Cognitive Load
The amount of mental effort being used in working memory while processing information or completing a task.
Cognitive Maps
Mental representations of the layout of physical spaces or environments that help an organism navigate and understand relationships between locations.
Cognitive Perspective
A psychological approach that focuses on how people think, perceive, remember, and solve problems, emphasizing the role of mental processes in behavior
Cognitive Perspective
An approach that explains psychological disorders as the result of maladaptive thought patterns, beliefs, and ways of interpreting experiences.
Cognitive Restructuring
A cognitive therapy technique that helps individuals identify, challenge, and replace irrational or negative thought patterns with more realistic and adaptive thoughts.
Cognitive Therapies
A group of therapies that treat psychological disorders by helping individuals identify and change maladaptive patterns of thinking that influence emotions and behavior.
Cognitive Triad
A concept in cognitive therapy describing the pattern of negative thoughts about oneself, the world, and the future that contributes to depression.
Cognitive-Behavioral Therapies
A group of therapies that treat psychological disorders by changing both maladaptive thought patterns and the behaviors that maintain them.
Collectivism
A cultural orientation that emphasizes group goals, cooperation, and the needs of the community or family over individual desires.
Compulsions
Repetitive behaviors or mental acts performed in response to obsessive thoughts, often aimed at reducing anxiety or preventing a feared event.
Concepts
Mental categories or groupings of similar objects, ideas, or events that help the brain organize information and make sense of the world
Concrete Operational Stage
Piaget’s third stage of cognitive development (about ages 7–11) in which children develop logical thinking about concrete events, understand conservation, and can perform mental operations on real, tangible objects.
Conditioned Response (CR)
A learned response that occurs after a neutral stimulus has been associated with an unconditioned stimulus in classical conditioning.
Conditioned Stimulus (CS)
A previously neutral stimulus that, after being associated with an unconditioned stimulus, comes to trigger a learned response in classical conditioning.
Conduction Deafness
Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea
Cones
Photoreceptor cells in the retina responsible for color vision and fine detail, functioning best in bright light
Confederates
People who secretly work with the researcher in a study while pretending to be regular participants
Confidentiality
The ethical principle that personal information obtained from a participant in research or therapy should not be revealed without the individual's permission.
Confirmation Bias
A tendency to search for information that supports our preconceptions and to ignore or distort contradictory evidence.
Confirmation Bias
The tendency to seek out, interpret, and remember information that supports existing beliefs while ignoring or discounting contradictory evidence.
Conformity
The act of changing one’s behavior, attitudes, or beliefs to match those of a group or social norm.
Confounding Variable
A factor other than the independent variable that might produce an effect in an experiment.
Conscientiousness
A Big Five personality trait that reflects how organized, responsible, dependable, and goal-oriented a person is.
Conscious
The level of awareness that contains thoughts, perceptions, and feelings that a person is actively aware of at a given moment.
Consciousness
A person’s awareness of themselves and their environment, including thoughts, feelings, sensations, and perceptions at any given moment
Conservation
The understanding that certain properties of objects (such as volume, mass, or number) remain the same even when their appearance or arrangement changes.
Consolidation Theory
The theory that sleep, especially REM and deep NREM sleep, helps stabilize and strengthen newly formed memories so they can be stored long-term
Construct Validity
The extent to which a test accurately measures the psychological concept it is intended to measure.
Constructive Memory
The idea that memory is not a perfect recording of events, but is actively built and reconstructed using stored information, expectations, and prior knowledge.
Context
The surrounding information, situation, or environment that influences how sensory input is interpreted and perceived
Context Dependent Memory
The tendency to better recall information when the external environment during retrieval matches the environment in which the information was originally learned.
Continuous Development
Development that occurs gradually and smoothly over time, with small incremental changes rather than distinct stages.
Continuous Reinforcement
A reinforcement schedule in which a behavior is rewarded every time it occurs, making learning quick but extinction more likely when reinforcement stops.
Contralateral Organization
The concept that the left hemisphere controls the right side of the body, and the right hemisphere controls the left side.
Control Group
In an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison.
Convenience Sample
A sample of participants selected because they are easy to access or readily available rather than randomly chosen from the population, which can make it less representative of the general population
Convergence
A binocular depth cue in which the eyes turn inward to focus on a nearby object, with greater eye muscle strain indicating closer distance
Convergent Thinking
A type of thinking that focuses on finding a single correct answer or solution to a problem by narrowing down possibilities
Cooing
An early stage of language development in infants (around 2–4 months) characterized by soft, vowel-like sounds such as “oo” and “ah,” often reflecting pleasure and comfort.
Cornea
The transparent, curved outer layer of the eye that helps focus incoming light onto the retina and protects the eye
Corpus Callosum
A thick band of neural fibers that connects the left and right hemispheres of the brain, allowing communication between them
Correlation
A measure of the extent to which two variables change together, and thus of how well either variable predicts the other.
Correlation Coefficient
A statistical measure that quantifies both the strength and the direction between two variables (from -1.0 to +1.0)
Counterconditioning
A behavioral technique that replaces an unwanted response to a stimulus with a more desirable one by repeatedly pairing the stimulus with a new, positive response.
Courage
A signature strength in positive psychology characterized by persistence, bravery, and the willingness to act despite fear or adversity.
Creativity
The ability to produce original and valuable ideas or solutions by thinking in novel and flexible ways
Critical Periods
Specific windows of time in development during which an organism is especially sensitive to certain environmental influences, and certain abilities or traits must develop for normal development to occur.
Cross-Sectional Studies
Research studies that compare individuals of different ages at one point in time to examine developmental differences.
Crystallized Intelligence
The ability to use learned knowledge and experience, such as vocabulary and general information.
Crystallized Intelligence
The ability to use learned knowledge and experience, such as vocabulary and general information.
CT Scan
A medical imaging technique that uses X-rays to create detailed cross-sectional images of the brain and other parts of the body
Cultural Humility
An ongoing approach in therapy that involves self-reflection, openness, and respect for a client’s cultural background, recognizing that the therapist is always learning from the client’s lived experience.
Cycling
The pattern of alternating between episodes of mania, hypomania, and depression in mood disorders such as bipolar I and bipolar II disorder.
Debriefing
The post-experimental explanation of a study, including its purpose and any deceptions, to its participants.
Deep Encoding
The process of encoding information by focusing on its meaning and associations, leading to stronger and longer-lasting memories.
Deindividuation
A state in which individuals lose self-awareness and personal accountability in a group, making them more likely to act in ways they normally would not.
Deinstitutionalization
The movement to replace long-term psychiatric hospitalization with community-based treatment, allowing many individuals with mental disorders to receive care outside of institutions.
Delta Waves
Very slow, high-amplitude brain waves that occur primarily during deep NREM Stage 3 sleep
Delusions
Strongly held false beliefs that persist despite clear evidence to the contrary, commonly associated with psychotic disorders.
Delusions of Grandeur
False beliefs in which a person thinks they have exceptional power, importance, fame, or identity that is not supported by reality.
Delusions of Persecution
False beliefs that one is being harmed, harassed, or targeted by others, despite lack of evidence.
Dementia
A broad category of brain disorders characterized by a gradual decline in memory, thinking, reasoning, and daily functioning that is severe enough to interfere with everyday life.
Dendrites
Branch-like extensions of a neuron that receive incoming signals from other neurons and transmit them toward the cell body (soma)
Denial
A defense mechanism in which a person refuses to acknowledge or accept a painful reality, thought, or feeling.
Dependent Personality Disorder
A personality disorder characterized by excessive need to be taken care of, leading to submissive and clinging behavior, and fear of separation or being alone.
Dependent Variable
The outcome factor; the variable that may change in response to manipulations of the independent variable.
Depolarization
The process during an action potential when a neuron becomes less negative inside due to sodium ions entering the cell, making it more likely to fire an electrical signal
Depressants
Psychoactive drugs that slow down activity in the central nervous system, reducing arousal, anxiety, and bodily functions such as heart rate and breathing
Depressive Disorders
A group of mood disorders characterized by persistent feelings of sadness, loss of interest or pleasure, and related cognitive and physical symptoms that impair functioning.
Descriptive Statistics
Statistical methods used to organize, summarize, and describe data in a meaningful way. This includes measures such as mean, median, mode, range, and standard deviation
Deviation from Social Norms
A criterion for identifying psychological disorders in which an individual’s thoughts, emotions, or behaviors significantly differ from culturally accepted expectations or rules of behavior.
Diagnostic and Statistical Manual of Mental Disorders (DSM)
The primary manual used by mental health professionals to classify and diagnose mental disorders based on standardized criteria.
Dialectical Behavior Therapy
A type of cognitive-behavioral therapy that combines acceptance and change strategies to help individuals regulate emotions, improve relationships, and reduce self-destructive behaviors.
Diathesis-Stress Model
A model that explains mental disorders as the result of the interaction between a biological or psychological predisposition and stressful life experiences.
Dichromatism
A form of color blindness in which only two of the three primary colors can be perceived.
Diffusion of Responsibility
The tendency for individuals to feel less personally responsible for taking action when other people are present.
Directionality Problem
A situation in correlational research where it is known that two variables are related, but it is unclear which variable is causing the other.
Discontinuous Development
Development that occurs in distinct stages, with clear shifts or changes between phases of growth.
Discrimination
Unjustified negative behavior or unequal treatment toward individuals based on their membership in a particular group, such as race, gender, religion, or ethnicity.
Discrimination
Unjustified negative behavior or unequal treatment toward individuals based on their membership in a particular group.
Disinhibition
A component of sensation seeking characterized by a preference for uninhibited, spontaneous, or socially stimulating experiences that provide excitement and arousal.
Disorganized Attachment
An attachment style characterized by a lack of clear attachment behavior, often showing confused or contradictory responses toward caregivers, typically linked to fear, trauma, or inconsistent caregiving.
Disorganized Speech
A symptom of schizophrenia involving incoherent, illogical, or fragmented speech patterns that make it difficult for others to understand the person’s thoughts.
Displacement
A defense mechanism in which a person redirects emotions, especially frustration or anger, from the original source to a safer or less threatening target.
Display Rules
Cultural norms that dictate how and when emotions should be expressed in different social situations.
Dispositional Attributions
Explanations for behavior that focus on internal characteristics of a person, such as personality traits, attitudes, or abilities.
Dissociative Amnesia
A dissociative disorder characterized by an inability to recall important personal information, typically related to traumatic or stressful events, that is inconsistent with ordinary forgetting.
Dissociative Disorders
A group of psychological disorders characterized by disruptions or breakdowns in memory, identity, consciousness, or perception of reality.
Dissociative Identity Disorder
A dissociative disorder characterized by the presence of two or more distinct identity states that control a person’s behavior, along with gaps in memory between these identities.
Distress
A negative form of stress that results from overwhelming or harmful demands and can impair functioning and well-being.
Distress
A state of significant emotional discomfort or suffering that is often used as a criterion for identifying psychological disorders because it impairs daily functioning.
Distributed Practice
A learning strategy in which study sessions are spread out over time, leading to better long-term retention compared to massed practice (cramming).
Divergent Thinking
A type of thinking that generates multiple possible solutions or ideas by exploring many different directions and possibilities
Dizygotic Twins
Fraternal twins formed when two separate eggs are fertilized by two different sperm cells, resulting in twins who share about 50% of their genetic material
DNA (Deoxyribonucleic Acid)
The molecule that carries the genetic instructions for the development, functioning, and inheritance of traits in living organisms
Door-in-the-Face Technique
A persuasion strategy in which a large request is made first and likely rejected, followed by a smaller request that is more likely to be accepted.
Dopamine
A neurotransmitter involved in movement, motivation, reward, and pleasure, and linked to disorders such as Parkinson’s disease and schizophrenia
Dopamine Hypothesis
A theory suggesting that schizophrenia and related psychotic symptoms are associated with excessive dopamine activity in certain brain pathways.
Double-Blind Procedure
An experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo.
Downward Social Comparison
Comparing oneself to others who are worse off or less successful in order to boost self-esteem or feel better about one’s own situation.
Dream Interpretation
A psychodynamic therapy technique that involves analyzing the content of dreams to uncover unconscious thoughts, desires, or conflicts.
Drive-Reduction Theory
A theory of motivation that proposes people are motivated to reduce internal states of tension, or drives, by satisfying biological needs and restoring homeostasis.
Dysfunction
A criterion for psychological disorders referring to thoughts, emotions, or behaviors that interfere with a person’s ability to function effectively in daily life.
Echoic Memory
A brief sensory memory system that stores auditory information for a few seconds after a sound is heard.
Eclectic Approach
An approach to treatment that combines techniques and principles from multiple psychological perspectives or therapies based on the individual’s needs.
Ecological Systems Theory
Bronfenbrenner’s theory that human development is influenced by multiple interacting environmental systems, from immediate relationships (like family and school) to broader cultural and historical contexts.
EEG
Electroencephalogram; an amplified recording of the waves of electrical activity sweeping across the brain's surface.
Effect Size
A measure of how strong or meaningful a relationship or difference is in a study. Unlike statistical significance, effect size shows the magnitude of the result, helping researchers understand how important the finding is in practical terms
Effortful Processing
The encoding of information that requires conscious attention and deliberate effort, such as studying vocabulary or memorizing facts.
Ego
The rational part of personality that operates on the reality principle, balancing the demands of the id, superego, and the real world.
Egocentrism
The inability to see things from another person’s perspective, often seen in young children who assume others think and perceive the world the same way they do.
Elaborative Rehearsal
A memory strategy that involves actively thinking about the meaning of new information and connecting it to existing knowledge to improve long-term retention.
Electroconvulsive Therapy
A biomedical treatment for severe psychological disorders, especially depression, that involves applying controlled electrical currents to the brain to trigger a brief seizure and relieve symptoms.
Elicitors
Events, stimuli, or situations that trigger or cause an emotional response.
Emerging Adulthood
A developmental stage (roughly ages 18–25) between adolescence and adulthood characterized by exploration of identity, relationships, and career paths, as well as increased independence.
Emotion-Focused Coping
A coping strategy that involves managing emotional responses to a stressor rather than changing the stressor itself.
Encoding
The process of converting sensory input into a form that can be stored and later retrieved from memory.
Encoding Failure
A failure to process information into long-term memory, meaning it was never properly stored in the first place.
Endorphins
Literally morphine within—natural, opiate-like neurotransmitters linked to pain control and to pleasure.
Epigenetics
The study of how environmental factors can influence the expression of genes without changing the underlying DNA sequence
Episodic Memory
A type of long-term memory that involves the conscious recollection of personal experiences and specific events, including time and place details.
Ethnocentrism
The belief that one’s own culture or group is superior to others, often leading to judging other cultures based on one’s own cultural standards.
Eugenics
The controversial practice or advocacy of improving the human species by selectively mating people with specific desirable hereditary traits.
Eustress
A positive form of stress that enhances motivation, performance, or well-being.
Evidence Based Interventions
Treatments or therapeutic approaches that have been scientifically tested and shown through research to be effective for specific psychological disorders.
Evolutionary Perspective
The study of the evolution of behavior and the mind, using principles of natural selection.
Evolutionary Perspective
An approach that explains psychological disorders as behaviors or traits that may have developed because they provided adaptive advantages during human evolution.
Excitatory Neurotransmitters
Neurotransmitters that increase the likelihood that the receiving neuron will fire an action potential
Executive Functioning
Cognitive processes that include working memory, flexible thinking, and self-control.
Exhaustion Stage
The final stage of General Adaptation Syndrome in which prolonged stress depletes the body’s resources, reducing its ability to cope effectively.
Exosystem
In Bronfenbrenner’s ecological systems theory, the level of environmental influences that indirectly affect a person’s development, such as a parent’s workplace or community services that impact the child without direct involvement.
Experience Seeking
A component of sensation seeking characterized by a desire for novel experiences through activities such as travel, art, music, or unconventional lifestyles.
Experiment
A research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process
Experimental Group
In an experiment, the group exposed to the treatment, that is, to one version of the independent variable.
Experimenter Bias
The influence of the experimenter's expectations or preferences on the outcome of a research study.
Explanatory Style
A person’s habitual way of explaining the causes of events, especially whether they attribute outcomes to internal vs. external, stable vs. unstable, and global vs. specific factors.
Explicit Memory
Memory of facts and experiences that can be consciously recalled and described, including episodic and semantic memory.
Exposure Therapies
A behavioral therapy that gradually and safely exposes individuals to feared objects or situations to reduce anxiety and avoidance over time.
External Locus of Control
The belief that outcomes are determined by outside forces such as luck, fate, or other people, rather than one’s own actions.
Extinction
In classical conditioning, the gradual weakening and disappearance of a conditioned response when the conditioned stimulus is repeatedly presented without the unconditioned stimulus.
Extraversion
A Big Five personality trait that reflects sociability, assertiveness, talkativeness, and a tendency to gain energy from interacting with others.
Extrinsic Motivation
Motivation to engage in a behavior in order to obtain external rewards or avoid punishment.
Facial-Feedback Hypothesis
The theory that facial expressions can influence emotional experiences, suggesting that expressing an emotion on the face can help generate or intensify that emotion.
Factor Analysis
A statistical method used to identify clusters of related test items that measure underlying abilities or traits.
Factor Analysis
A statistical method used to identify clusters of related variables, helping psychologists discover underlying traits (such as personality factors) that explain patterns in data.
False Consensus Effect
The tendency to overestimate how much other people share our beliefs, attitudes, values, and behaviors.
Falsifiability
The requirement that for any hypothesis, theory, or claim to be considered scientifically valid, it must be testable in a way that allows for the possibility of being proven false
Farsightedness
A condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind the retina.
Fear Hierarchies
A ranked list of feared situations or stimuli, ordered from least to most anxiety-provoking, used to guide gradual exposure during exposure therapy.
Fetal Alcohol Syndrome
A condition caused by prenatal alcohol exposure that can lead to physical abnormalities, cognitive impairments, and behavioral problems in a developing fetus.
Fidelity
An ethical principle requiring psychologists to build trusting professional relationships, keep promises, and uphold responsibilities to clients, colleagues, and society.
Fight Flight Freeze Response
An involuntary physiological reaction to a perceived harmful event, attack, or threat to survival.
Figure and Ground
A Gestalt principle of perception in which the brain organizes visual information by separating a focal object (figure) from its background (ground)
Fine Motor Coordination
The ability to use small muscle movements, especially in the hands and fingers, to perform precise tasks such as writing, buttoning clothing, or using utensils.
Firing Threshold
The level of electrical charge a neuron must reach in order to generate an action potential and send a neural signal
Fixed Interval
A reinforcement schedule in which a response is rewarded after a set amount of time has passed, so responses tend to increase as the time for reinforcement approaches.
Fixed Mindset
The belief that intelligence and abilities are static and cannot be significantly changed.
Fixed Ratio
A reinforcement schedule in which a response is rewarded after a fixed number of correct responses, leading to high rates of responding with a brief pause after reinforcement.
Flashbacks
Vivid, intrusive experiences in which a person feels as though they are reliving a traumatic event
Flat Affect
A negative symptom of schizophrenia characterized by little or no outward expression of emotion through facial expressions, tone of voice, or gestures.
Fluid Intelligence
The ability to solve new problems, think abstractly, and adapt to novel situations.
Fluid Intelligence
The ability to solve new problems, think abstractly, and adapt to novel situations.
Flynn Effect
The observed rise in average IQ scores over time across generations.
fMRI
A brain imaging technique that measures changes in blood flow to show which areas of the brain are active during specific mental task
Foot-in-the-Door Technique
A persuasion strategy in which a person first agrees to a small request, making them more likely to agree to a larger related request later.
Forgetting Curve
A graph showing how quickly information is forgotten over time when it is not reinforced, with the steepest loss occurring soon after learning.
Formal Operational Stage
Piaget’s fourth stage of cognitive development (about age 12 and up) in which individuals develop the ability to think abstractly, reason logically about hypothetical situations, and use systematic problem-solving.
Fovea
A small central area of the retina with the highest concentration of cones, responsible for sharp central vision and detailed color perception
Framing
The way information is presented or “framed,” which can influence how people perceive and respond to it, even when the underlying information is the same
Free Association
A psychoanalytic technique in which clients are encouraged to freely express thoughts, feelings, and memories without censoring them, allowing unconscious conflicts to be explored.
Frequency Theory
The theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
Frontal Lobes
The part of the cerebral cortex involved in decision-making, planning, reasoning, problem-solving, personality, and voluntary movement
Fugue
Unexpected travel away from one’s home or usual environment, accompanied by amnesia for one’s identity or past, sometimes including the assumption of a new identity.
Functional Fixedness
A cognitive bias that limits a person to using an object only in its traditional or familiar way, making it harder to see alternative uses in problem-solving
Fundamental Attribution Error
The tendency to overestimate the influence of personal traits and underestimate situational factors when explaining other people’s behavior.
g (General Intelligence)
A proposed general mental ability that underlies performance on a wide variety of cognitive tasks.
GABA
The brain’s primary inhibitory neurotransmitter, which reduces neural activity and helps regulate anxiety, sleep, and muscle tension
Gambler’s Fallacy
The mistaken belief that past random events influence future independent events, such as thinking a coin is “due” to land on heads after several tails in a row
Ganglion Cells
Neurons in the retina that receive signals from bipolar cells and transmit visual information from the eye to the brain through the optic nerve
Gate Control Theory
The theory that pain is experienced when pain signals pass through a “gate” in the spinal cord, which can be opened or closed by other sensory input or signals from the brain
General Adaptation Syndrome
A three-stage pattern of physiological response to stress that includes alarm, resistance, and exhaustion.
Generalizability
The extent to which research findings can be applied to larger populations, other settings, or different groups beyond the participants in the study
Generalized Anxiety Disorder
An anxiety disorder in which a person is continually tense, apprehensive, and in a state of autonomic nervous system arousal.
Generativity and Stagnation
Erikson’s seventh psychosocial stage (middle adulthood) in which adults focus on contributing to society and guiding the next generation; success leads to generativity, while failure can result in stagnation and a sense of unproductiveness.
Genetic Predisposition
An increased likelihood of developing a particular disease or trait based on a person's genetic makeup.
Gestalt Psychology
A school of psychology that emphasizes how people naturally organize sensory information into meaningful wholes rather than separate parts
Ghrelin
A hormone produced mainly in the stomach that stimulates hunger and signals the brain to increase food intake
Ghrelin
A hormone produced mainly in the stomach that stimulates hunger and signals the brain to increase food intake
Glial Cells
Cells in the nervous system that support, nourish, and protect neurons
Glutamate
The brain’s primary excitatory neurotransmitter, involved in learning, memory, and neural communication
Grammar
The set of rules in a language that governs how words are structured and combined to form meaningful sentences, including syntax and word usage.
Gratitude
A positive emotional response that involves recognizing and appreciating the benefits, kindness, or support received from others.
Gross Motor Coordination
The ability to use large muscle groups to perform broad physical movements such as walking, running, jumping, and balancing.
Group Polarization
The tendency for group discussion to strengthen the initial attitudes of group members, leading them to make more extreme decisions or judgments than they would individually.
Group Therapy
A form of psychotherapy in which a therapist works with several clients at the same time, allowing individuals to share experiences, provide support, and develop social skills.
Groupthink
A phenomenon in which a desire for group harmony and conformity leads members to suppress dissenting opinions and make flawed or irrational decisions.
Growth Mindset
The belief that intelligence and abilities can be developed through effort, learning, and persistence.
Growth Spurt
A rapid period of physical growth in height and weight, typically occurring during puberty.
Gustation
The sense of taste, which allows the detection of chemical substances in food through taste receptor cells on the tongue
Habituation
A simple form of learning in which an organism decreases its response to a repeated or constant stimulus over time.
Hair Cells
Sensory receptor cells in the cochlea that detect sound vibrations and convert them into neural impulses sent to the brain
Hallucinations
A positive symptom of schizophrenia involving false sensory experiences, such as hearing voices or seeing things that are not actually present.
Hallucinogens
Psychoactive drugs that alter perception, mood, and thought processes and can cause hallucinations, or sensory experiences that are not based in reality
Halo Effect
A cognitive bias in which an overall positive impression of a person influences perceptions of their other traits, leading to overly favorable judgments.
Happiness
A general state of well-being characterized by positive emotions, life satisfaction, and a sense of fulfillment.
Health Psychology
The branch of psychology that studies how biological, psychological, and social factors influence health, illness, and overall well-being.
Hemispheres
The two halves of the brain (left and right) that specialize in different functions but communicate with each other through the corpus callosum
Hemispheric Specialization
The tendency of some cognitive functions to be specialized to either the left or right hemisphere.
Heredity
The genetic transfer of characteristics from parents to offspring.
Heritability
A measure of how much differences in a trait among individuals in a population are due to genetic variation
Heroin
An opioid drug that is converted into morphine in the brain and produces intense pain relief and euphoria by activating opioid receptors
Heuristics
Simple, efficient mental shortcuts or “rules of thumb” that speed up decision-making and problem-solving, though they may sometimes lead to errors
Hierarchies
Systems of organization in which information is arranged in levels, from broad general concepts to more specific subcategories, to help structure and simplify understanding.
Higher-Order Conditioning
A process in classical conditioning where a new neutral stimulus becomes a conditioned stimulus by being paired with an already established conditioned stimulus.
Higher-Order Thinking
Complex cognitive processes such as analysis, synthesis, evaluation, and creation.
Highly Superior Autobiographical Memory
A rare condition in which a person can recall an extremely detailed and accurate account of nearly every day of their life, often without conscious effort.
Hindsight Bias
The tendency to believe, after an event has occurred, that you could have predicted the outcome in advance (“I knew it all along” phenomenon)
Hippocampus
A structure in the limbic system that is important for forming new memories and helping with learning and spatial navigation
Histrionic Personality Disorder
A personality disorder characterized by excessive emotionality, attention-seeking behavior, and a strong desire to be the center of attention.
Hoarding Disorder
A disorder characterized by persistent difficulty discarding possessions, regardless of their value, resulting in excessive clutter that interferes with daily living.
Homeostasis
The body’s tendency to maintain a stable internal environment by regulating physiological conditions such as temperature, hunger, and hydration.
Hormones
Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.
Humanistic Perspective
A perspective that emphasizes the growth potential of healthy people and the individual's potential for personal growth.
Humanistic Perspective
An approach that explains psychological disorders as the result of barriers to personal growth, self-acceptance, or the fulfillment of one’s potential.
Humanistic Psychology
A perspective that emphasizes human potential, free will, and the natural drive toward growth, self-actualization, and personal fulfillment.
Humanity
A signature strength in positive psychology that involves caring, valuing close relationships, and showing kindness and compassion toward others.
Hypertension
A condition characterized by chronically elevated blood pressure, increasing the risk of cardiovascular disease and other health problems.
Hypervigilance
A state of heightened alertness and constant scanning for potential threats, commonly associated with Post-Traumatic Stress Disorder.
Hypnagogic Sensations
Vivid, dreamlike experiences (such as falling or seeing flashes of light) that occur during the transition from wakefulness to sleep, especially in NREM Stage 1
Hypnosis
A therapeutic technique involving a focused state of attention and increased suggestibility that can be used to help individuals manage symptoms, explore thoughts, or modify behaviors.
Hypomania
A period of elevated mood, increased energy, and heightened activity that is less severe than full mania and does not significantly impair functioning or require hospitalization.
Hypothalamus
A small brain structure that helps regulate essential body functions such as hunger, thirst, body temperature, and hormone release by controlling the endocrine system
Hypothalamus
A small brain structure that helps regulate essential body functions such as hunger, thirst, body temperature, and hormone release by controlling the endocrine system
Hypothesis
A specific, testable prediction about the relationship between two or more variables
Hypothetical Thinking
The ability to consider possible outcomes, situations, or “what if” scenarios without needing direct experience or concrete evidence.
Iconic Memory
A brief sensory memory system that holds visual information for a fraction of a second after the stimulus is gone.
Id
The primitive and unconscious part of personality that operates on the pleasure principle, seeking immediate gratification of basic drives and desires.
Ideal Self
In humanistic psychology, the person one aspires to be—the image of oneself that reflects personal goals, values, and aspirations.
Identify Achievement
Marcia’s identity status in which an individual has explored different options and made a committed choice about their values, beliefs, goals, or future direction.
Identity and Role Confusion
Erikson’s fifth psychosocial stage (adolescence) in which individuals explore different values, beliefs, and goals to form a stable sense of identity; failure to do so can result in confusion about one’s role, direction, and sense of self.
Identity Diffusion
Marcia’s identity status in which an individual has neither explored different identity options nor made commitments to specific values, goals, or beliefs.
Identity Foreclosure
Marcia’s identity status in which an individual commits to values, beliefs, or goals without exploring other options, often adopting expectations from parents or authority figures.
Identity Moratorium
Marcia’s identity status in which an individual is actively exploring different identities and options but has not yet made a commitment to any particular values, beliefs, or goals.
Illusory Correlation
The perception of a relationship between two variables when no real relationship exists or when the relationship is weaker than it seems
Imaginary Audience
A cognitive bias in adolescence where individuals believe that others are constantly watching, judging, and focusing on their appearance or behavior more than they actually are.
Imagination Inflation
The tendency for imagined events to be remembered as real, or for confidence in false memories to increase after repeatedly imagining them.
Immune Suppression
A reduction in the activity or effectiveness of the immune system, making the body more vulnerable to illness and infection.
Implicit Attitudes
Unconscious beliefs or feelings toward people, objects, or groups that can influence behavior without conscious awareness.
Implicit Memory
A type of long-term memory that operates without conscious awareness, influencing skills, habits, and learned behaviors (like tying your shoes or typing).
Imprinting
A rapid, innate form of learning that occurs during a critical period in early development, in which young animals form strong attachments to the first moving object they see (often a parent).
In-Group Bias
The tendency to favor and give preferential treatment to members of one’s own group over those in other groups.
Inattentional Blindness
A failure to notice a fully visible but unexpected stimulus because attention is focused on something else
Incentive Theory
A theory of motivation that suggests behavior is driven by the desire to obtain rewards or avoid punishments from the environment.
Independent Variable
The experimental factor that is manipulated; the variable whose effect is being studied.
Individualism
A cultural orientation that emphasizes personal independence, individual goals, and self-reliance over group goals or social obligations.
Industrial-Organizational Psychologists
Psychologists who study behavior in workplaces to improve employee productivity, selection, training, and overall organizational effectiveness.
Industry and Inferiority
Erikson’s fourth psychosocial stage (about ages 6–12) in which children develop competence and confidence through mastering skills and tasks; success leads to a sense of industry, while repeated failure or criticism can lead to feelings of inferiority.
Infantile Amnesia
The inability of adults to remember early childhood experiences, typically before age 3 or 4, due to the ongoing development of brain structures involved in memory.
Inferential Statistics
Statistical methods used to make conclusions or predictions about a larger population based on data from a sample
Information Processing Model
A model of memory that compares the mind to a computer, describing memory as a process of encoding, storing, and retrieving information.
Informational Social Influence
The tendency to conform because we believe others have accurate information, especially in ambiguous or uncertain situations.
Informed Assent
Agreement from a minor or someone who cannot legally give full consent to participate in a study after the research has been explained in a way they can understand
Informed Consent
The process of giving participants enough information about a study—such as its purpose, procedures, risks, and benefits—so they can voluntarily decide whether or not to participate
Inhibitory Neurotransmitters
Neurotransmitters that decrease the likelihood that the receiving neuron will fire an action potential
Initiative and Guilt
Erikson’s third psychosocial stage (about ages 3–6) in which children begin to assert power through play and exploration; success leads to initiative and confidence in leadership, while excessive restriction or criticism can lead to feelings of guilt.
Insecure Attachment
A pattern of emotional bonding in which a child does not feel consistently safe and supported by a caregiver, often leading to anxiety, avoidance, or disorganized behavior in relationships.
Insight Learning
A sudden realization of how to solve a problem without trial-and-error, often described as an “aha” moment when the solution becomes clear.
Insomnia
A sleep disorder characterized by persistent difficulty falling asleep, staying asleep, or getting restful sleep despite adequate opportunity to do so
Instinctive Drift
The tendency for an animal to revert to innate, natural behaviors that interfere with learned conditioned behaviors.
Instincts
Inborn, automatic behaviors that are biologically determined and do not require learning.
Institutional Review Board
A committee that reviews research studies to make sure the study is ethical and protects the rights, safety, and well-being of participants before the research can begin
Integrity
An ethical principle requiring psychologists to promote accuracy, honesty, and truthfulness in their professional work, research, and interactions with others.
Integrity and Despair
Erikson’s eighth psychosocial stage (late adulthood) in which individuals reflect on their lives; a sense of fulfillment leads to ego integrity, while regret and dissatisfaction can lead to despair.
Intelligence
The ability to learn from experience, reason, solve problems, and adapt to new situations.
Intelligence Quotient (IQ)
A score derived from standardized tests that is intended to measure general intelligence relative to others.
Internal Locus of Control
The belief that one’s own actions, choices, and efforts are the primary causes of life outcomes.
International Classification of Mental Disorders (ICD)
A diagnostic system developed by the World Health Organization that classifies diseases and health conditions, including mental and behavioral disorders, using standardized criteria.
Interneurons
Neurons located in the central nervous system that connect sensory neurons to motor neurons and help process and interpret information
Interposition
A monocular depth cue in which one object partially blocking another object is perceived as being closer
Intimacy and Isolation
Erikson’s sixth psychosocial stage (early adulthood) in which individuals form close, meaningful relationships; success leads to intimacy and connection, while failure can result in loneliness and isolation.
Intrinsic Motivation
Motivation to engage in a behavior because it is personally rewarding or enjoyable, rather than for external rewards or pressures.
Iris
The colored part of the eye that controls the size of the pupil and regulates the amount of light entering the eye
Macrosystem
In Bronfenbrenner’s ecological systems theory, the broad cultural context that includes societal values, laws, customs, and beliefs that shape development indirectly.
Maintenance Rehearsal
A memory strategy that involves repeatedly reviewing information (such as silently repeating it) to keep it in short-term memory without necessarily encoding its meaning.
Major Depressive Disorder
A depressive disorder characterized by persistent depressed mood or loss of interest or pleasure, along with other symptoms that significantly impair daily functioning for at least two weeks.
Maladaptive Thinking
Thought patterns that are inaccurate, overly negative, or unrealistic and that contribute to emotional distress or psychological disorders.
Mania
A state of abnormally elevated mood, energy, and activity levels that can include impulsivity, decreased need for sleep, and impaired judgment, often significantly disrupting functioning.
Marijuana
A mild hallucinogen that can amplify sensitivity to colors, sounds, tastes, and smells, but also relax and disinhibit.
Massed Practice
A learning strategy that involves studying information in a single, long session (cramming), which often leads to weaker long-term retention compared to spaced practice.
Maturation
The natural, biologically driven process of physical and cognitive development that unfolds over time, largely independent of experience or practice.
Mean
The arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores.
Measure of Central Tendency
A statistical value that represents the center or typical score in a data set. The most common measures are the mean, median, and mode
Measures of Variation
Statistics that describe how much data values differ or spread out in a data set. Common measures of variation include range and standard deviation
Median
The middle score in a distribution; half the scores are above it and half are below it.
Medium Tasters
Individuals with an average number of taste buds and typical sensitivity to basic tastes, falling between supertasters and non-tasters
Medulla
A part of the brainstem that controls vital involuntary functions such as breathing, heart rate, and blood pressure
Melatonin
A hormone that helps regulate sleep and the body’s circadian rhythms
Memory Consolidation
The process of stabilizing and strengthening a memory after it is first formed, often involving the transfer of information from short-term to long-term memory, especially during sleep.
Menarche
The first occurrence of menstruation, marking the onset of female reproductive capability during puberty.
Menopause
The natural biological stage in a woman’s life when menstrual cycles permanently stop, typically occurring in middle adulthood, marking the end of fertility.
Mental Age
The level of cognitive performance typical of a certain age group, based on test performance.
Mental Set
A tendency to approach problems using strategies or solutions that have worked in the past, which can sometimes hinder finding new or better solutions
Mental Symbols
Internal representations (such as images, words, or concepts) that the mind uses to stand for objects, ideas, or experiences in the environment.
Mere Exposure Effect
The tendency for people to develop a preference for things simply because they are familiar with them through repeated exposure.
Mesosystem
In Bronfenbrenner’s ecological systems theory, the interactions between different parts of a person’s microsystem, such as the relationship between family, school, peers, and other immediate environments.
Meta-Analysis
A statistical technique that combines and analyzes the results of multiple independent studies on the same topic to determine an overall trend, conclusion, or effect size
Metacognition
Awareness and understanding of one’s own thought processes, including the ability to monitor, evaluate, and regulate learning and problem-solving strategies.
Method of Loci
A mnemonic device that improves memory by associating information with specific locations in a familiar place, mentally “walking through” those locations to recall the items.
Microsystem
In Bronfenbrenner’s ecological systems theory, the immediate environment a person directly interacts with, such as family, school, peers, and teachers.
Misinformation Effect
The tendency for post-event information to distort or change a person’s memory of an original event.
Mnemonic Devices
Memory aids or techniques that help improve recall by organizing information in more meaningful or easily remembered ways, such as acronyms, rhymes, or imagery.
Mode
The most frequently occurring score(s) in a distribution.
Modeling
A type of learning in which an individual acquires new behaviors by observing and imitating others.
Monochromatism
A rare form of color blindness in which a person sees only shades of one color or only black, white, and gray because of absent or nonfunctioning cone cells
Monocular Depth Cues
Depth cues that can be perceived with one eye alone, helping the brain judge distance and depth in a visual scene
Monozygotic Twins
Identical twins formed when a single fertilized egg splits into two embryos, resulting in twins who share nearly all of the same genetic material
Mood Congruent Memory
The tendency to recall memories that match one’s current emotional state, such as remembering sad events more easily when feeling sad.
More Knowledgeable Other
In Vygotsky’s theory, a person who has a higher level of knowledge or skill in a particular task than the learner, such as a teacher, peer, or expert, who can provide guidance and support.
Morphemes
The smallest units of meaning in a language, including whole words or parts of words (like prefixes and suffixes) that carry meaning, such as “un-” or “-ed.”
Motor Cortex
An area at the rear of the frontal lobes that controls voluntary movements.
Motor Neurons
Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands (Efferent).
MRI
A brain imaging technique that uses magnetic fields and radio waves to produce detailed images of the brain’s structure and other body tissues
Multi-store Model
A theory proposing that memory consists of three separate stores—sensory memory, short-term memory, and long-term memory—with information flowing through them through processes like attention and rehearsal.
Multiculturalism
The recognition, acceptance, and appreciation of cultural diversity within a society, along with the belief that different cultural perspectives should be respected and valued.
Multiple Sclerosis
A neurological disease in which the immune system damages the myelin sheath of neurons, disrupting communication between the brain and the rest of the body
Myasthenia Gravis
An autoimmune disorder in which antibodies block or destroy receptors for acetylcholine at the neuromuscular junction, leading to muscle weakness and fatigue
Myelin Sheath
A fatty insulating layer that surrounds many axons, speeding the transmission of electrical impulses through the neuron.
Narcissistic Personality Disorder
A personality disorder characterized by an inflated sense of self-importance, a need for excessive admiration, and a lack of empathy for others.
Narcolepsy
A sleep disorder characterized by sudden, uncontrollable sleep attacks during waking hours, often including rapid entry into REM sleep and possible loss of muscle control
Natural Selection
The principle that traits leading to increased reproduction and survival will most likely be passed on to succeeding generations.
Naturalistic Observation
Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.
Nature
The influence of our inherited characteristics (genetics) on personality, physical growth, and social interactions.
Nature
The influence of genetic inheritance and biology on development and behavior.
Nearsightedness
A condition in which nearby objects are seen more clearly than distant objects because distant objects focus in front of the retina.
Negative Correlation
A statistical relationship between two variables where they move in opposite (inverse) directions.
Negative Punishment
A type of punishment in which a desired stimulus is removed after a behavior occurs, decreasing the likelihood that the behavior will happen again.
Negative Reinforcement
A process in which a behavior is strengthened because it removes or avoids an unpleasant stimulus.
Negative Skew
A distribution in which most scores are clustered on the high end, with a few unusually low scores creating a long tail to the left
Negative Symptoms
Symptoms of schizophrenia involving a reduction or loss of normal behaviors or emotional functioning, such as flat affect, reduced speech, or lack of motivation.
Neurodevelopmental Disorders
A group of disorders that begin during childhood and involve impairments in cognitive, behavioral, social, or motor functioning due to atypical brain development.
Neurons
Specialized nerve cells that transmit information throughout the body using electrical and chemical signals
Neuroticism
A Big Five personality trait that reflects emotional instability and the tendency to experience anxiety, moodiness, sadness, and negative emotions.
Night Terrors
A sleep disorder involving sudden episodes of intense fear, screaming, and high arousal during deep NREM sleep, typically with little to no recall of the event upon waking
Non-Experimental Methodology
Research methods that do not involve manipulation of independent variables
Nonmaleficence
An ethical principle requiring psychologists to avoid causing harm and to protect the well-being, safety, and rights of clients and research participants.
Nontasters
Individuals who have a relatively low number of taste buds, making them less sensitive to certain tastes, especially bitter flavors
Norepinephrine
A neurotransmitter and hormone involved in alertness, arousal, attention, and the body’s stress response
Normal Curve
A symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean.
Normative Social Influence
The tendency to conform in order to be liked, accepted, or approved of by others, even if we do not privately agree with the group.
Norming
The process of establishing test standards by comparing scores from a representative sample population.
NREM stage 1
A very light sleep stage that occurs as a transition from wakefulness to sleep, marked by slowed brain activity, muscle relaxation, and brief hypnagogic sensations
NREM stage 2
A deeper stage of light sleep characterized by slower heart rate and body temperature, with brain activity showing sleep spindles
NREM stage 3
The deepest stage of non-REM sleep, characterized by delta waves and important for physical restoration, growth, and recovery
Nurture
The influence of environmental factors such as family, culture, and experience on development.
Nurture
The influence of environmental factors, such as experience, culture, and learning, on development and behavior.
Obedience
A form of social influence in which individuals follow direct commands or orders from an authority figure.
Object Permanence
The understanding that objects continue to exist even when they cannot be seen, heard, or directly sensed.
Obsessions
Persistent, intrusive, and unwanted thoughts, urges, or images that cause anxiety or distress, commonly associated with obsessive-compulsive disorder.
Obsessive Compulsive Disorder
A disorder characterized by recurring obsessions and/or compulsions that are time-consuming and significantly interfere with daily functioning.
Obsessive Compulsive Personality Disorder
A personality disorder characterized by a pervasive pattern of perfectionism, rigid orderliness, and a need for control that interferes with flexibility and relationships.
Occipital Lobes
The part of the cerebral cortex located at the back of the brain that is primarily responsible for processing visual information
Olfaction
The sense of smell, which detects airborne chemical molecules through receptors in the nose and sends signals to the brain for interpretation
One-Trial Conditioning
A form of learning in which an association is formed after just one pairing of a stimulus and response, often seen in strong emotional or survival-related experiences like taste aversion
One-Word Speech
A stage of language development in which children use single words to express complete ideas or sentences, such as saying “milk” to mean “I want milk.”
Openness to Experience
A Big Five personality trait that reflects curiosity, creativity, imagination, and a willingness to try new ideas and experiences.
Operant Conditioning
A type of learning in which behavior is strengthened or weakened based on its consequences, such as rewards or punishments.
Operational Definition
A highly specific, precise description of the exact procedures (operations) and measurements used to define a variable in a research study
Opioids
A class of drugs that reduce pain and produce feelings of pleasure by acting on the brain’s opioid receptors, often by mimicking natural endorphins
Opponent-Process Theory
The theory that color vision is controlled by opposing pairs of color receptors (red-green, blue-yellow, black-white), where activation of one color in the pair inhibits the other
Optic Nerve
The nerve that carries visual information from the retina to the brain for processing
Optimistic Explanatory Style
A way of explaining events in which negative outcomes are viewed as temporary, specific, and caused by external factors, while positive outcomes are seen as stable and personal.
Out-Group Homogeneity Bias
The tendency to see members of an out-group as more similar to each other than they actually are, while viewing one’s own in-group as more diverse.
Overconfidence
The tendency to be more confident than correct—to overestimate the accuracy of our beliefs and judgments.
Overgeneralization
A language learning error in which children apply grammatical rules too broadly, such as saying “goed” instead of “went” or “mouses” instead of “mice.”
Oxytocin
A hormone involved in social bonding, trust, childbirth, and breastfeeding
Panic Attack
A sudden episode of intense fear or discomfort that peaks quickly and includes physical symptoms such as rapid heartbeat, shortness of breath, dizziness, or chest pain.
Parallel Play
A stage of early childhood play in which children play near each other but do not directly interact or coordinate their activities.
Paranoid Personality Disorder
A personality disorder characterized by a pervasive distrust and suspicion of others, interpreting their motives as malicious without sufficient evidence.
Parasympathetic Nervous System
The division of the autonomic nervous system that calms the body and conserves energy by promoting “rest-and-digest” functions after a stressful situation
Parietal Lobes
The part of the cerebral cortex that processes sensory information such as touch, temperature, and pain, and helps with spatial awareness and perception
Partial Reinforcement
A reinforcement schedule in which a behavior is rewarded only some of the time, making the behavior more resistant to extinction than continuous reinforcement.
Peer Review
A process in which other experts in the same field evaluate a researcher’s study before it is published to ensure the research is accurate, credible, and scientifically sound
Percentile Rank
The percentage of scores that fall below a specific score in a distribution.
Percentile Rank
A score indicating the percentage of people who scored at or below a particular score on a test.
Perceptual Constancy
The tendency to perceive objects as stable and unchanging (in size, shape, color, or brightness) even when sensory information changes
Perceptual Set
A mental predisposition or expectation that influences how we perceive and interpret sensory information
Peripheral Nervous System
The sensory and motor neurons that connect the central nervous system to the rest of the body.
Peripheral Route to Persuasion
A method of persuasion in which people are influenced by superficial cues such as attractiveness, emotion, or credibility of the source rather than the quality of the arguments.
Permissive Parenting
A parenting style characterized by high warmth and responsiveness but low demands or rules, often allowing children significant freedom with little discipline or structure.
Persistent Depressive Disorder
A chronic form of depression characterized by a depressed mood lasting for at least two years, along with other symptoms such as low energy, low self-esteem, and feelings of hopelessness.
Person Centered Therapy
A humanistic therapy developed by Carl Rogers that emphasizes empathy, unconditional positive regard, and genuineness to help clients achieve personal growth and self-actualization.
Person Perception
The process of forming impressions and making judgments about other people based on their appearance, behavior, and other available information.
Personal Fable
A cognitive distortion in adolescence where individuals believe their thoughts, feelings, and experiences are unique and that others cannot truly understand them.
Personality Disorders
A group of psychological disorders characterized by long-term, inflexible patterns of thinking, feeling, and behaving that deviate from cultural expectations and impair functioning or relationships.
Pessimistic Explanatory Style
A way of explaining events in which negative outcomes are seen as permanent, widespread, and caused by internal factors, while positive outcomes are viewed as temporary or due to external factors.
PET Scan
A brain imaging technique that uses a radioactive tracer to measure activity and energy use in different areas of the brain
Phantom Limb Syndrome
A condition in which a person feels sensations, including pain, in a limb that has been amputated, due to continued brain representation of the missing limb
Pheromones
Chemical signals released by an animal that communicate information and affect the behavior of other animals of the same species.
Phi Phenomenon
An illusion of movement created when two or more lights close to each other blink on and off in succession, causing the perception of motion between them
Phonemes
The smallest units of sound in a language that can be combined to form words and can change meaning when altered (e.g., changing the “b” in “bat” to “c” creates “cat”).
Phonemic Encoding
The process of encoding information based on how words sound, focusing on their auditory qualities rather than meaning.
Phonological Loop
A component of working memory that temporarily stores and rehearses verbal and auditory information, such as spoken words or sounds.
Pituitary Gland
A small gland often called the “master gland” because it releases hormones that control other endocrine glands and regulate growth, metabolism, and reproduction
Pituitary Gland
A small gland often called the “master gland” because it releases hormones that control other endocrine glands and regulate growth, metabolism, and reproduction
Place Theory
The theory that links the pitch we hear with the location where the cochlea's membrane is stimulated
Placebo
An inactive substance, dummy treatment, or fake procedure that has no inherent physiological or therapeutic value
Placebo Efffect
A psychological and physiological phenomenon where a participant experiences real changes in behavior, mood, or health purely due to their expectations of a treatment, rather than the treatment itself
Plasticity
The brain’s ability to change and reorganize itself by forming new neural connections in response to learning, experience, or injury
Pons
A part of the brainstem that helps regulate sleep, breathing, and arousal and acts as a bridge for communication between different parts of the brain
Population
All those in a group being studied, from which samples may be drawn.
Positive Correlation
A statistical relationship between two variables where they move in the same direction
Positive Emotions
Pleasant emotional states such as joy, gratitude, interest, and contentment that contribute to well-being and life satisfaction.
Positive Psychology
A branch of psychology that focuses on the study of strengths, positive emotions, and factors that contribute to happiness, well-being, and human flourishing.
Positive Punishment
A type of punishment in which an unpleasant stimulus is added after a behavior occurs, decreasing the likelihood that the behavior will happen again.
Positive Reinforcement
A process in which a behavior is strengthened by adding a rewarding or pleasant stimulus after the behavior occurs.
Positive Skew
A distribution in which most scores are clustered on the low end, with a few unusually high scores creating a long tail to the right
Positive Symptoms
Symptoms of schizophrenia that involve the presence of abnormal experiences or behaviors, such as hallucinations, delusions, and disorganized speech.
Posttraumatic Growth
Positive psychological change that can occur as a result of struggling with highly challenging or traumatic life experiences.
Posttraumatic Stress Disorder
A trauma- and stressor-related disorder that develops after exposure to a traumatic event and is characterized by symptoms such as flashbacks, avoidance, hypervigilance, and intrusive memories.
Preconscious
The level of awareness containing information that is not currently in conscious thought but can be easily brought into awareness when needed.
Predictive Validity
The extent to which a test accurately predicts future performance or outcomes.
Prefrontal Cortex
The forward part of the frontal lobes responsible for judgment, planning, and processing new memories.
Prejudice
A preconceived negative attitude or belief about a group of people based on characteristics such as race, ethnicity, gender, or religion, often without sufficient evidence or personal experience.
Preoperational Stage
Piaget’s second stage of cognitive development (about ages 2–7) in which children use language and symbols to represent the world but think in a more intuitive and egocentric way, lacking logical operations.
Pretend Play
A form of play in which children use imagination to act out roles or scenarios, using objects or actions to represent something else (e.g., pretending a stick is a sword).
Pretend Play
A form of play in which children use imagination to act out roles or scenarios, using objects or actions to represent something else (e.g., pretending a stick is a sword).
Primacy Effect
The tendency to better remember items at the beginning of a list because they receive more attention and rehearsal.
Primary Reinforcers
Innately satisfying stimuli that naturally reinforce behavior without prior learning, such as food, water, and shelter.
Primary Sex Characteristics
The reproductive organs and structures directly involved in reproduction, such as the ovaries, testes, uterus, and external genitalia, that develop and mature during puberty.
Priming
The activation of specific associations in memory before carrying out a task, which can influence perception, thinking, or behavior without conscious awareness
Proactive Interference
When older memories interfere with the recall of newer information.
Problem-Focused Coping
A coping strategy that involves addressing or changing the source of stress to reduce its impact.
Procedural Memory
A type of implicit long-term memory that stores information about how to perform tasks and skills, such as riding a bike or typing, often without conscious awareness.
Projection
A defense mechanism in which a person attributes their own unacceptable thoughts, feelings, or motives to another person.
Projective Tests
Personality assessments that present ambiguous stimuli, such as images or words, and require individuals to interpret them, revealing unconscious thoughts and feelings.
Prosocial Behavior
oluntary actions intended to benefit others, such as helping, sharing, or cooperating.
Prosopagnosia
A neurological condition, often called “face blindness,” in which a person has difficulty recognizing or distinguishing faces despite normal vision
Prospective Memory
Memory for remembering to perform an intended action in the future, such as remembering to take medication or attend an appointment.
Protection from Harm
The ethical requirement that researchers ensure participants do not suffer undue physical or psychological harm during the study.
Prototypes
The most typical or best example of a concept that helps people quickly recognize and classify new objects or ideas
Proximity
A Gestalt principle of perception in which objects that are close together are perceived as belonging to the same group
Psychoactive Drugs
Chemicals that affect the central nervous system and alter mood, perception, consciousness, or behavior by influencing neurotransmitter activity in the brain
Psychodynamic Perspective
A branch of psychology that studies how unconscious drives and conflicts influence behavior, and uses that information to treat people with psychological disorders.
Psychodynamic Perspective
An approach that explains psychological disorders as the result of unconscious conflicts, unresolved childhood experiences, and internal psychological processes.
Psychodynamic Theory
A psychological perspective that emphasizes unconscious drives, early childhood experiences, and internal conflicts as key influences on behavior and personality.
Psychodynamic Therapies
A group of therapies based on ideas that focus on exploring unconscious thoughts, unresolved conflicts, and early life experiences to improve psychological functioning.
Psychology
The scientific study of behavior and mental processes.
Psychosurgery
A biological treatment that involves surgically altering brain tissue to treat severe psychological disorders when other treatments have not been effective.
Psychotropic Medication
Medications that affect brain chemistry and behavior by altering the activity of neurotransmitters to treat psychological disorders such as depression, anxiety, or schizophrenia.
Puberty
The developmental stage during which a person’s body undergoes physical changes and sexual maturation, becoming capable of reproduction due to hormonal changes.
Punishment
A consequence that follows a behavior and decreases the likelihood that the behavior will occur again in the future.
Pupil
The adjustable opening in the center of the iris that controls how much light enters the eye
Racism
Prejudice, discrimination, or unequal treatment directed toward individuals or groups based on race or ethnicity.
Random Assignment
Assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups.
Random Sample
A sample that fairly represents a population because each member has an equal chance of inclusion.
Range
The difference between the highest and lowest scores in a distribution.
Rational Emotive Behavior Therapy
A cognitive therapy developed by Albert Ellis that helps individuals identify and challenge irrational beliefs to replace them with healthier, more realistic thoughts.
Rationalization
A defense mechanism in which a person creates logical or socially acceptable explanations for behaviors or events that are actually driven by unconscious or unacceptable motives
Reaction Formation
A defense mechanism in which a person behaves in a way that is opposite to their true feelings or impulses in order to hide them from themselves or others.
Real Self
In humanistic psychology, a person's actual thoughts, feelings, behaviors, and characteristics as they currently exist.
Recall
A memory task that requires generating previously learned information from memory, such as answering an essay question without hints or choices.
Recency Effect
The tendency to better remember the last items in a list because they are still present in short-term memory.
Reciprocal Determinism
The idea that a person’s behavior is shaped by the interaction between their thoughts, their environment, and their actions, and each of these factors also influences the others.
Recognition
A memory process that involves identifying previously learned information when it is presented again, often with the help of cues (such as multiple-choice answers).
Reconsolidation
The process in which a retrieved memory is modified before being stored again, resulting in a change of the original memory
Reflex Arc
The neural pathway that controls a reflex action, involving a sensory neuron, interneuron (in most cases), and motor neuron that produce an automatic, rapid response to a stimulus
Reflexes
Inborn, automatic responses to specific stimuli that help protect the body and support survival, such as blinking or withdrawing a hand from a hot surface.
Refractory Period
A period of inactivity after a neuron has fired, during which it cannot fire again until it resets.
Regression
A defense mechanism in which a person reverts to earlier, more childlike patterns of behavior when faced with stress or anxiety.
Regression Toward the Mean
The tendency for extreme or unusual scores to fall back (regress) toward their average.
Reinforcement
Any consequence that increases the likelihood that a behavior will be repeated in the future.
Reinforcement Discrimination
The ability to distinguish between different stimuli and respond only when a specific stimulus is present because that response has been reinforced in that situation but not in others.
Reinforcement Generalization
The tendency for a behavior that has been reinforced in one situation to occur in similar situations or with similar stimuli, even if those new situations have not been directly reinforced.
Relative Clarity
A monocular depth cue in which clearer, sharper objects are perceived as closer than hazy or blurry objects
Relative Deprivation
The perception that one is worse off compared to others or compared to one’s expectations, which can lead to feelings of dissatisfaction or injustice.
Relative Size
A monocular depth cue in which smaller retinal images are perceived as farther away and larger retinal images as closer, assuming the objects are similar in actual size
Reliability
The consistency of a test in producing stable and repeatable results over time.
REM Rebound
An increase in REM sleep that occurs after a person is deprived of REM sleep, causing the body to spend more time in REM during subsequent sleep cycles
REM Sleep
A stage of sleep marked by rapid eye movements, vivid dreaming, high brain activity, and temporary muscle paralysis
REM Sleep Behavior Disorder
A sleep disorder in which the normal muscle paralysis of REM sleep is absent, causing a person to physically act out their dreams, sometimes violently
Replication
The process of repeating a research study to see if the same results can be obtained again, confirming that findings are reliable, accurate, and not due to chance
Representative Sample
A sample that accurately reflects the characteristics of the population as a whole.
Representativeness Heuristic
A mental shortcut where people estimate the likelihood of an event based on how easily examples come to mind, often influenced by recent or memorable experiences
Repression
The unconscious blocking of painful or anxiety-producing memories from conscious awareness.
Repression
A defense mechanism in which distressing thoughts, memories, or impulses are unconsciously pushed out of conscious awareness.
Resilience
The ability to adapt, recover, and maintain functioning in the face of stress, adversity, or trauma.
Resistance Stage
The second stage of General Adaptation Syndrome in which the body adapts to a stressor and continues to cope while remaining physiologically activated.
Respect For People’s Rights And Dignity
An ethical principle requiring psychologists to respect the privacy, confidentiality, autonomy, and cultural differences of all individuals while protecting their rights and welfare.
Resting Potential
The stable, negative electrical charge of a neuron when it is not firing, maintained by the balance of ions inside and outside the cell
Restoration (Sleep)
The theory that sleep serves to repair and rejuvenate the body and brain, helping restore energy, support growth, and maintain overall physical and mental functioning
Reticular Activating System
A network of neurons in the brainstem that regulates alertness, attention, and sleep-wake cycles by filtering incoming sensory information
Retina
The light-sensitive layer at the back of the eye that contains photoreceptor cells (rods and cones) and converts light into neural signals sent to the brain
Retinal Disparity
A binocular depth cue based on the slight difference between the images seen by each eye, which the brain uses to perceive depth
Retrieval
The process of accessing and bringing stored information from long-term memory into conscious awareness.
Retrieval Cues
Stimuli or hints that help trigger the process of retrieving information from long-term memory.
Retrieval Practice
The process of actively recalling information from memory, which strengthens long-term retention and makes future recall easier.
Retroactive Interference
When newer information interferes with the recall of older memories.
Retrograde Amnesia
A type of memory loss in which a person is unable to recall events that occurred before the injury or incident that caused the amnesia, while the ability to form new memories may remain intact.
Reuptake
The process by which neurotransmitters are reabsorbed by the sending neuron after transmitting a signal, helping to clear the synapse and regulate signal strength
Reuptake Inhibitors
Chemicals that block the reabsorption of neurotransmitters by the sending neuron, increasing the amount of neurotransmitter available in the synapse
Reversibility
The ability to mentally reverse an action or process, understanding that objects or operations can be changed and then returned to their original state.
Reward Center
A group of brain structures, including areas of the limbic system, that are activated by pleasurable experiences and reinforce behaviors through dopamine release
Rods
Photoreceptor cells in the retina that are highly sensitive to light and allow for vision in low-light conditions, but do not detect color
Rooting Reflex
An infant reflex in which touching or stroking the cheek causes the baby to turn their head and begin searching for a nipple to help with feeding.
Sample
A subset of individuals chosen from a larger set (a population).
Sampling Bias
A flawed sampling process that produces an unrepresentative sample.
Scaffolding
Temporary support and guidance provided by a teacher, peer, or adult that helps a learner complete a task they could not do alone, with support slowly removed as the learner becomes more capable.
Scatterplot
A graphed cluster of dots, each of which represents the values of two variables. The slope suggests the direction of the relationship.
Schema
A mental framework or concept that helps organize and interpret information based on past experiences.
Schemas
Mental frameworks or cognitive structures that help organize and interpret information based on past experiences and knowledge
Schizoid Personality Disorder
A personality disorder characterized by a persistent pattern of detachment from social relationships and a limited range of emotional expression in interpersonal settings.
Schizophrenic Spectrum Disorders
A group of related psychotic disorders characterized by disruptions in thinking, perception, emotions, and behavior, including conditions such as schizophrenia, schizoaffective disorder, and brief psychotic disorder.
Schizotypal Personality Disorder
A personality disorder characterized by odd beliefs, eccentric behavior, and discomfort in close relationships, often accompanied by unusual perceptual experiences.
Secondary Reinforcers
Stimuli that acquire their reinforcing value through learning or association with primary reinforcers, such as money, praise, or grades.
Secondary Sex Characteristics
Physical traits that develop during puberty but are not directly involved in reproduction, such as breast development, voice deepening, and body hair growth.
Secure Attachment
An attachment style in which children feel safe and supported by their caregiver, use them as a secure base for exploration, and are comforted by their presence when distressed.
Selective Attention
The ability to focus on one specific stimulus while filtering out other distractions in the environment
Self-Actualizing Tendency
According to humanistic psychology, the innate drive to grow, develop, and reach one’s full potential.
Self-Concept
In humanistic psychology, the organized set of beliefs and perceptions a person has about themselves, including their traits, abilities, and identity.
Self-Concept
An individual’s overall understanding and perception of themselves, including beliefs about their abilities, traits, and identity.
Self-Determination Theory
A theory of motivation that emphasizes the role of autonomy, competence, and relatedness in fostering intrinsic motivation and psychological well-being.
Self-Efficacy
A person’s belief in their ability to successfully perform a specific task or handle a particular situation.
Self-Esteem
A person’s overall sense of self-worth or personal value.
Self-Fulfilling Prophecy
A belief or expectation that influences behavior in a way that causes the belief to come true.
Self-Report Bias
An error that occurs when research participants provide inaccurate, distorted, or dishonest answers on surveys, questionnaires, or self-report inventorie
Self-Serving Bias
The tendency to attribute successes to internal factors (such as ability or effort) and failures to external factors (such as luck or circumstances) to protect self-esteem.
Semantic Encoding
The process of encoding information based on its meaning and understanding, which leads to stronger and more durable memories.
Semantic Memory
Semantic Memory – A type of long-term memory that stores general knowledge, facts, concepts, and meanings about the world, independent of personal experience.
Semantics
The part of language that deals with meaning, including how words and sentences convey ideas and how context affects interpretation.
Semicircular Canals
Three fluid-filled canals in the inner ear that help maintain balance by detecting rotation.
Sensation
The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
Sensation-Seeking Theory
A theory of motivation that describes the tendency to seek varied, novel, and intense experiences, even when they involve risk.
Sensitive Periods
Developmental windows of time when the brain is especially responsive to certain experiences, making learning easier, though not absolutely required for development to occur.
Sensorimotor Stage
Piaget’s first stage of cognitive development (birth to about age 2) in which infants learn about the world through their senses and actions, and develop object permanence.
Sensorineural Deafness
A type of hearing loss caused by damage to the inner ear (cochlea) or auditory nerve, often resulting in permanent impairment of sound transmission to the brain
Sensory Adaptation
The diminished sensitivity to a constant or unchanging stimulus over time, allowing the brain to focus on more important changes in the environment
Sensory Interaction
The principle that one sense may influence another, as when the smell of food influences its taste
Sensory Interaction
The principle that different senses can influence and enhance one another, such as how smell and taste work together to create flavor perception
Sensory Memory
Sensory Memory – The very brief storage of sensory information (such as sights or sounds) that lasts only a fraction of a second to a few seconds before it is either processed further or forgotten.
Sensory Neurons
Neurons that carry incoming information from the sensory receptors to the brain and spinal cord (Afferent).
Separation Anxiety
Emotional distress experienced by infants or young children when separated from a primary caregiver or attachment figure.
Serial Position Effect
A memory phenomenon in which people are more likely to remember items at the beginning and end of a list than those in the middle.
Serotonin
A neurotransmitter involved in mood, sleep, appetite, and emotional regulation, with low levels often linked to depression
Sexism
Prejudice, discrimination, or stereotyping based on a person’s sex or gender.
Shallow Encoding
The process of encoding information based on superficial features such as appearance or sound, rather than meaning, which typically leads to weaker memory retention.
Shaping
A learning process in which successive approximations of a desired behavior are reinforced until the full behavior is learned.
Shift Work
Work schedules that take place outside the traditional 9-to-5 day, often disrupting circadian rhythms and sleep patterns.
Short Term Memory
The temporary storage of a small amount of information that is available for immediate use and lasts only a short time without rehearsal.
Similarity
A Gestalt principle of perception in which objects that are similar in appearance are perceived as belonging together or forming a group
Single-Blind Procedure
An experimental procedure in which the research participants are ignorant (blind) about whether they have received the treatment or a placebo.
Situational Attributions
Explanations for behavior that focus on external circumstances or environmental factors rather than a person's traits or characteristics.
Sleep
A naturally recurring state of rest characterized by reduced consciousness, slowed bodily functions, and brain activity that supports restoration, memory consolidation, and overall health
Sleep Apnea
A sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.
Sleep Spindles
Brief bursts of rapid brain activity that occur during NREM Stage 2 sleep and are believed to play a role in memory consolidation and protecting sleep from external disturbances
Social Anxiety Disorder
An anxiety disorder characterized by intense fear or anxiety in social situations due to concerns about being judged, embarrassed, or scrutinized by others.
Social Clock
A culturally shared expectation or “timetable” for when major life events (such as finishing school, getting a job, marriage, or having children) are supposed to happen, which helps shape how individuals judge whether their development is “on time” or “off time.”
Social Comparison
The process of evaluating oneself by comparing one’s abilities, opinions, or characteristics to those of other people.
Social Debt
A psychological feeling of obligation to return a favor or repay someone after receiving help or a benefit, often influencing future behavior in social interactions.
Social Desirability Bias
The tendency for survey participants to answer questions in a manner that will be viewed favorably by others rather than truthfully.
Social Facilitation
The tendency for people to perform better on simple or well-practiced tasks when others are present, but worse on difficult or unfamiliar tasks.
Social Influence Theory
A theory that explains how individuals’ thoughts, feelings, and behaviors are shaped by the real or imagined presence of others through processes such as conformity, obedience, and persuasion.
Social Inhibition
The tendency for the presence of others to reduce performance on difficult, complex, or unfamiliar tasks.
Social Learning Theory
A theory by Albert Bandura that explains learning as a process that occurs through observing others, imitating behaviors, and being influenced by reinforcement, punishment, and cognitive processes.
Social Loafing
The tendency for individuals to put in less effort when working in a group compared to when working alone, especially when individual contributions are not easily identified.
Social Norms
Unwritten rules and expectations about how people should behave in specific situations or within a group.
Social Norms
Shared expectations or rules within a group or culture that guide and influence appropriate behavior.
Social Reciprocity Norm
The expectation that people should respond to positive actions with positive actions, such as returning favors, kindness, or help received from others.
Social Responsibility Norm
The expectation that people should help those who are in need or dependent on others, even when there is no obvious personal benefit for doing so.
Social Traps
Situations in which actions that benefit individuals in the short term lead to negative consequences for the group or society in the long term.
Sociocultural Perspective
The study of how situations and cultures affect our behavior and thinking.
Sociocultural Perspective
An approach that explains psychological disorders as the result of social and cultural factors, such as norms, expectations, and environmental influences.
Soma
The part of a neuron that contains the nucleus and serves as the cell’s life-support center, processing incoming information before passing it to the axon.
Somatic Nervous System
The division of the peripheral nervous system that controls the body's skeletal muscles (voluntary movements).
Somatosensory Cortex
Area at the front of the parietal lobes that registers and processes body touch and movement sensations
Somnambulism
A sleep disorder in which a person walks or performs other complex behaviors while still asleep, usually during deep NREM Stage 3 sleep, with little or no memory of the event
Sound Localization
The ability to identify the origin or direction of a sound by using differences in timing and intensity of the sound reaching each ear
Source Amnesia
The inability to remember where, when, or how a memory was learned, even though the information itself is remembered.
Spacing Effect
The tendency for information to be better remembered when study sessions are spaced out over time rather than crammed into a single session.
Specific Phobia
An anxiety disorder characterized by an intense, irrational fear of a specific object or situation that leads to avoidance and significant distress.
Spermarche
The first ejaculation of sperm in males, marking the onset of sexual maturity and reproductive capability during puberty.
Split Brain Research
Studies of individuals whose corpus callosum has been severed to reduce severe epilepsy, showing how the left and right hemispheres of the brain can function independently and specialize in different tasks
Split-Half Reliability
A measure of reliability in which a test is divided into two halves and scores on both halves are compared.
Spontaneous Recovery
The sudden reappearance of a previously extinguished conditioned response after a rest period, without further conditioning.
Spotlight Effect
The tendency to overestimate how much other people notice and pay attention to our appearance, actions, or mistakes.
Standard Deviation
A measure of how spread out data are from the mean (average). A low standard deviation means most scores are close to the mean, while a high standard deviation means the scores are more spread out
Standardization
The process of administering and scoring a test in a consistent way for all test takers.
State Dependent Memory
The tendency to better recall information when a person is in the same internal state (mood, emotional state, or physiological condition) as when the information was learned.
Statistical Significance
A statistical statement of how likely it is that an obtained result occurred by chance (noted by p-value).
Stereotype
A generalized belief or expectation about a group of people that assumes members of the group share the same characteristics, often oversimplifying reality.
Stereotype Lift
Performance improvement that occurs when positive stereotypes about a group enhance confidence and outcomes.
Stereotype Threat
The risk of underperformance when individuals are aware of negative stereotypes about their group.
Stigma
A negative label or stereotype attached to individuals with psychological disorders that can lead to prejudice and discrimination.
Stimulants
Psychoactive drugs that increase activity in the central nervous system, leading to heightened alertness, energy, and arousal
Stimulus Discrimination
The ability to distinguish between similar stimuli and respond only to the specific conditioned stimulus, not to other similar ones.
Stimulus Generalization
The tendency to respond to stimuli that are similar to the conditioned stimulus with the same conditioned response.
Storage
The stage of memory in which encoded information is held and preserved in the brain over time.
Stress
The physiological and psychological response to demands or challenges that threaten or exceed an individual’s ability to cope.
Stressors
Events, situations, or stimuli that trigger a physiological or psychological stress response.
Stroboscopic Motion
The illusion of continuous movement created when a series of slightly different still images are shown rapidly in succession, as in movies or animation
Structural Encoding
The process of encoding information based on its physical appearance or visual features, such as shape, color, or format, rather than meaning or sound.
Subjective Well-Being
A person’s self-reported evaluation of their own happiness and life satisfaction, including the balance of positive and negative emotions.
Sublimation
A defense mechanism in which socially unacceptable impulses are redirected into socially acceptable or productive activities.
Substance P
A neurotransmitter involved in the transmission of pain messages to the brain.
Sunk-Cost Fallacy
The tendency to continue an endeavor because of previously invested time, money, or effort, even when future costs outweigh the benefits
Superego
The part of personality that represents internalized moral standards and ideals, guiding behavior according to a sense of right and wrong.
Superordinate Goals
Shared goals that require cooperation between groups to achieve, often reducing conflict and increasing positive relationships among group members.
Supertasters
Individuals who have a higher-than-average number of taste buds, making them especially sensitive to certain tastes, particularly bitter flavors
Survey
A technique for ascertaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group.
Sympathetic Nervous System
The division of the autonomic nervous system that activates the body’s “fight-or-flight” response during stress or danger, increasing alertness and preparing the body for action
Synesthesia
A perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to involuntary experiences in another, such as seeing colors when hearing music
Syntax
The set of rules that governs the order and arrangement of words in a sentence to create meaningful and grammatically correct statements.
Systematic Desensitization
A behavioral therapy technique that combines gradual exposure to a feared stimulus with relaxation techniques to reduce anxiety and develop a new response to the fear.
Taijin Kyofusho
A culture-bound syndrome most commonly seen in Japan, characterized by an intense fear of offending or embarrassing others through one’s appearance, body odor, or behavior in social situations.
Tardive Dyskinesia
A movement disorder characterized by involuntary, repetitive muscle movements that can develop as a side effect of long-term use of antipsychotic medications.
Taste Aversion
A learned avoidance of a food or taste after a single experience of illness following its consumption, often occurring after just one pairing.
Telegraphic Speech
Early language use (around age 2) in which children speak in short, simple sentences that include only essential words, usually nouns and verbs (e.g., “want cookie” instead of “I want a cookie”).
Temperament
An individual’s inborn, biologically based patterns of emotional reactivity and self-regulation that appear early in life and influence how a person responds to their environment.
Temperance
A signature strength in positive psychology that involves self-control, moderation, and the ability to regulate impulses and behaviors.
Temporal Lobes
The part of the cerebral cortex involved in processing auditory information, language comprehension, and memory
Tend and Befriend Theory
A theory suggesting that, in response to stress, people may cope by seeking social support and protecting or nurturing others rather than relying solely on the fight-or-flight response.
Teratogens
Harmful substances or environmental agents that can cause birth defects or developmental abnormalities during prenatal development, such as alcohol, certain drugs, or infections.
Test-Retest Reliability
The consistency of test scores when the same test is given to the same people at different times.
Testing Effect
The finding that actively testing oneself on material improves long-term memory more than simply re-studying the information.
Texture Gradient
A monocular depth cue in which coarse, detailed textures appear closer, while smoother, less detailed textures appear farther away
Thalamus
A brain structure that acts as the brain’s main relay station, receiving sensory information and sending it to the appropriate areas of the cerebral cortex for processing
Theory
An explanation using an integrated set of principles that organizes observations and predicts behaviors or events.
Theory of Mind
The ability to understand that other people have their own thoughts, beliefs, intentions, and perspectives that may differ from one’s own.
Therapeutic Alliance
The collaborative, trusting relationship between a therapist and client that supports effective treatment and positive therapeutic outcomes.
Theta Waves
Slow brain waves that are typically seen during light sleep (especially NREM Stage 1 and 2) and are also associated with deep relaxation and early stages of sleep
Third Variable Problem
A situation in correlational research where an unmeasured, outside variable is responsible for the observed relationship between two other variables
Tip-of-the-Tongue Phenomenon
The temporary inability to retrieve a known word or memory, accompanied by the feeling that retrieval is imminent.
Token Economies
An operant conditioning procedure in which people earn a token of some sort for exhibiting a desired behavior and can later exchange the tokens for various privileges or treats.
Tolerance
The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses to experience the effect.
Top-Down Processing
A type of perceptual processing that uses prior knowledge, expectations, and experience to interpret and make sense of sensory information
Touch (Somatosensation)
The sense that allows the body to perceive pressure, temperature, pain, and body position through sensory receptors in the skin and other tissues
Transcendence
A signature strength in positive psychology that involves appreciating beauty, finding meaning, and feeling a connection to something larger than oneself.
Transcranial Magnetic Stimulation
A biological treatment that uses magnetic pulses to stimulate specific areas of the brain, often to treat depression when other treatments have not been effective.
Transduction
The process by which sensory receptors convert physical energy from the environment (such as light, sound, or pressure) into neural signals that the brain can interpret
Trichromatic Theory
The theory that color vision is based on three types of cones in the retina that are sensitive to red, green, and blue light, with all other colors created by combinations of these signals
Trust and Mistrust
Erikson’s first psychosocial stage (infancy) in which infants develop a sense of safety and reliability in the world when caregivers are consistent and responsive; inconsistent care can lead to mistrust and insecurity.
Twin Studies
Research studies that compare identical and fraternal twins to examine the relative influence of genetics and environment on behavior and traits
Two-Factor Theory
A theory of emotion that proposes that emotion is the result of physiological arousal and a cognitive label that interprets that arousal.