AP Psychology Study Guide

Social psychology explores how individuals are influenced by the presence, actions, or expectations of others. It examines behavior in groups, social interactions, and how attitudes and behaviors are shaped by societal factors.

• Attribution Theory: Explains how we infer the causes of behavior—either attributing it to a person’s disposition (internal factors) or the situation (external factors).
• Fundamental Attribution Error: The tendency to overestimate personality traits and underestimate situational influences when evaluating others' behavior.
• Attitude: Feelings influenced by beliefs that predispose us to react in specific ways.
  • Central Route Persuasion: Persuasion through logical argument and evidence, used when people are motivated to think deeply.
  • Peripheral Route Persuasion: Persuasion based on superficial cues, such as a speaker's attractiveness or tone.
• Cognitive Dissonance Theory: We experience discomfort when our beliefs and behaviors conflict, leading us to adjust either beliefs or behaviors to align them.
• Conformity: Adjusting behavior to match group norms.
  • Normative Social Influence: Conforming to gain approval or avoid disapproval.
  • Informational Social Influence: Conforming because others provide information about reality.
• Social Facilitation: Improved performance on simple tasks in the presence of others.
• Social Loafing: The tendency to exert less effort in a group than when working alone.
• Deindividuation: Loss of self-awareness and restraint in group situations that promote anonymity.
• Group Behavior:
  • Group Polarization: Group discussions lead to more extreme positions than initially held.
  • Groupthink: Desire for group harmony results in poor decision-making by suppressing dissenting viewpoints.
• Prejudice: An unjustifiable negative attitude toward a group and its members.
  • Stereotypes: Generalized beliefs about a group.
  • Discrimination: Unjustifiable negative behavior toward a group.
  • Ingroup vs. Outgroup: The ingroup is seen as “us,” while the outgroup is “them.”
  • Ingroup Bias: Preference for members of one's own group.
  • Scapegoat Theory: Prejudice offers an outlet for anger by blaming others.
  • Other-Race Effect: Tendency to recall faces of one’s own race more accurately.
  • Just World Phenomenon: Belief that people get what they deserve.
• Aggression: Any physical or verbal behavior intended to harm.
  • Frustration-Aggression Principle: Frustration leads to anger, which may result in aggression.
• Altruism: Unselfish concern for the welfare of others.
  • Bystander Effect: People are less likely to help when others are present.
  • Social Exchange Theory: Human interactions aim to maximize benefits and minimize costs.
  • Reciprocity Norm: Expectation to help those who help us.
  • Social Responsibility Norm: Expectation to help those who depend on us.
• Relationships:
  • Mere Exposure Effect: Repeated exposure to a stimulus increases liking.
  • Passionate Love: Intense, positive absorption in another, common in early relationships.
  • Companionate Love: Deep affection for those with whom our lives are intertwined.
  • Equity: Receiving proportional to what one gives in a relationship.
  • Self-Disclosure: Sharing intimate details about oneself.
• Conflict and Cooperation:
  • Social Trap: Conflicting parties harm collective well-being by pursuing individual self-interest.
  • Mirror-Image Perceptions: Mutual views held by opposing sides in a conflict, each seeing the other as bad.
  • Superordinate Goals: Shared goals that require cooperation to achieve.
  • GRIT: Gradual steps to reduce international tensions.

Personality psychology examines individual differences in behavior and the ways in which personality develops. It focuses on the theories of personality structure and measurement.

• Freudian Theory: Freud’s model of personality (id, ego, superego) and his psychosexual stages of development.
  • Id: Unconscious psychic energy operating on the pleasure principle.
  • Ego: Mediates between the id and superego, operating on reality principles.
  • Superego: Represents internalized ideals and standards of judgment.
  • Psychosexual Stages: Oral, Anal, Phallic, Latency, and Genital phases of development.
  • Defense Mechanisms: Strategies to reduce anxiety (e.g., repression, regression, projection).
• Neo-Freudian Perspectives:
  • Collective Unconscious (Carl Jung): Shared, inherited reservoir of memory traces.
  • Projective Tests: Ambiguous stimuli reveal unconscious desires (e.g., Rorschach Inkblot, TAT).
• Humanistic Theories:
  • Maslow’s Hierarchy: Self-actualization is the ultimate psychological need.
  • Roger’s Unconditional Positive Regard: Accepting others without judgment.
• Trait Theories:
  • Big Five Traits: Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism.
  • Personality Inventories: Tools to assess traits (e.g., MMPI).
• Social-Cognitive Perspective:
  • Reciprocal Determinism: Behavior, personal traits, and environment interact.
  • Locus of Control: Internal (control by self) vs. External (control by external factors).

Cognitive psychology focuses on mental processes such as perception, memory, learning, and decision-making, emphasizing how individuals acquire, process, and use information.

• Memory Systems: Models of memory like Atkinson-Shiffrin (sensory memory, short-term memory, long-term memory) and working memory.
  Example: Remembering a phone number long enough to dial it (short-term memory).
• Encoding and Retrieval: The processes by which information is stored and retrieved, including semantic encoding and long-term potentiation.
  Example: Recalling a childhood memory when visiting your hometown.
• Cognitive Processes: Problem-solving strategies, heuristics, and decision-making biases (e.g., availability heuristic, representativeness heuristic).
  Example: Judging an event's likelihood based on vivid memories (availability heuristic).
• Intelligence: Theories of intelligence, such as Spearman’s g factor, Gardner’s multiple intelligences, and Sternberg’s triarchic theory.
  Example: A person with high interpersonal intelligence excels in team collaboration.
• Language: Theories of language acquisition (Chomsky vs. Skinner), linguistic relativity, and language development stages.
  Example: A child saying “goed” instead of “went” shows overgeneralization in language acquisition.

Sensation and perception are fundamental processes that allow us to interpret and react to stimuli in our environment. Sensation involves detecting physical stimuli, while perception refers to how the brain interprets these signals.

• Sensation: The process of detecting environmental stimuli and converting them into neural signals.
  Example: Feeling warmth from sunlight on your skin.
• Perception: The interpretation of sensory information to make sense of the world.
  Example: Recognizing a friend's face in a crowded room.
• Vision and Hearing: How the eye and ear process sensory data, including the anatomy of each, color vision theories, and auditory processing.
  Example: Hearing your name in a noisy environment (cocktail party effect).
• Depth Perception and Constancy: Cues like monocular and binocular depth perception, size, shape, and color constancy.
  Example: Knowing a door is rectangular even when it looks like a trapezoid from an angle.
• Perceptual Set: How expectations and context influence our sensory experiences.
  Example: Interpreting a blurry figure as a ghost after hearing spooky stories.

This unit explores the biological mechanisms that underpin behavior, including the structure and function of the brain, neurons, and the endocrine system.

• Neural Communication: The role of neurons, neurotransmitters, and action potentials in transmitting information across the nervous system.
  • Dendrites: Receive messages.
  • Axon: Sends messages.
  • Myelin Sheath: Speeds neural impulses.
  • Synapse: Gap between neurons.
  • Neurotransmitters: Chemicals transmitting signals (e.g., dopamine, serotonin).
    • Dopamine: Influences movement, learning, attention, and emotion. Imbalances linked to schizophrenia and Parkinson’s.
    • Serotonin: Affects mood, hunger, sleep, and arousal. Low levels associated with depression.
    • Acetylcholine (ACh): Enables muscle action, learning, and memory. Deterioration linked to Alzheimer’s.
    • GABA: A major inhibitory neurotransmitter. Undersupply linked to seizures and anxiety.
    • Glutamate: A major excitatory neurotransmitter involved in memory. Excess can cause migraines or seizures.
    • Norepinephrine: Helps control alertness and arousal. Undersupply can depress mood.
    • Endorphins: Natural painkillers; released during exercise and linked to feelings of euphoria.
• Brain Structure and Function: Key brain structures and their roles.
  • Brainstem: Includes the medulla (controls heartbeat and breathing) and reticular formation (regulates arousal).
  • Limbic System: Includes the amygdala (processes emotions), hippocampus (memory formation), and hypothalamus (regulates drives like hunger and thirst).
  • Cerebral Cortex: The brain's outer layer, responsible for higher-order functions.
    • Frontal Lobe: Decision-making, planning, and voluntary movement.
    • Parietal Lobe: Processes sensory input.
    • Occipital Lobe: Vision processing.
    • Temporal Lobe: Auditory processing.
  • Motor Cortex: Controls voluntary movements.
  • Sensory Cortex: Processes touch and movement sensations.
  • Language Areas: Includes Broca's Area (speech production) and Wernicke's Area (language comprehension).
• Endocrine System: Hormonal communication system.
  • Adrenaline (Epinephrine): Triggers fight-or-flight response.
  • Cortisol: Stress hormone regulating metabolism and immune response.
  • Oxytocin: Influences bonding and trust.
  • Testosterone: Associated with aggression and secondary male characteristics.
  • Estrogen: Regulates female reproductive cycles.
• Plasticity: The brain's ability to adapt and reorganize itself in response to learning or injury.
• Split-Brain Research: Studies on the hemispheric specialization of the brain, often following surgical separation of the corpus callosum.

This section includes a comprehensive list of various psychological concepts and their explanations.

• Experimental Psychology: The study of behavior and thinking using the experimental method.
• Behaviorism: The view that psychology should be an objective science that studies behavior without reference to mental processes.
• Humanistic Psychology: A perspective that emphasizes the growth potential of healthy people and individual's potential for fostering personal growth.
• Cognitive Neuroscience: The interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language).
• Psychology: The science of behavior and mental processes.
• Nature-Nurture Issue: The controversy over the relative contributions that genes and experience make to the development of psychological traits and behaviors.
• Natural Selection: The principle that inherited variations contributing to reproduction and survival are most likely passed on to succeeding generations.
• Levels of Analysis: Complementary views, from biological to psychological to social-cultural, for analyzing any given phenomenon.
• Biopsychological Approach: An integrated approach that incorporates biological, psychological, and social-cultural levels of analysis.
• Biological Psychology: A branch of psychology that studies the links between biological and psychological processes.
• Evolutionary Psychology: The study of the roots of behavior and mental processes using the principles of natural selection.
• Psychodynamic Psychology: A branch of psychology that studies how unconscious drives and conflicts influence behavior.
• Behavioral Psychology: The scientific study of observable behavior and its explanation by principles of learning.
• Cognitive Psychology: The scientific study of all the mental activities associated with thinking, knowing, remembering, and communicating.
• Social-Cultural Psychology: The study of how situations and cultures affect our behavior and thinking.
• Psychometric: The scientific study of the measurement of human abilities, attitudes, and traits.
• Basic Research: Pure science that aims to increase the scientific knowledge base.
• Developmental Psychology: The scientific study of physical, cognitive, and social change throughout the life span.
• Educational Psychology: The study of how psychological processes affect and can enhance teaching and learning.
• Personality Psychology: The study of individual's characteristics pattern of thinking, feeling, and acting.
• Social Psychology: The scientific study of how we think about, influence, and relate to one another.
• Applied Research: Scientific study that aims to solve practical problems.
• Industrial Organization (I/O) Psychology: The application of psychological concepts and methods to optimizing human behavior in workplaces.
• Human Factors Psychology: The study of how people and machines interact and the design of safe and easily used machines and environments.
• Counseling Psychology: A branch of psychology that assists people with problems in living and in achieving greater well-being.
• Clinical Psychology: A branch of psychology that studies, assesses, and treats people with psychological disorders.
• Psychiatry: A branch of medicine dealing with psychological disorders; practiced by physicians who sometimes provide medical treatments as well as psychological therapy.
• SQ3R: A study method incorporating five steps: survey, question, read, rehearse, review.
• Hindsight Bias: The tendency to believe, after learning an outcome, that one would have foreseen it.
• Critical Thinking: Thinking that examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.
• Theory: An explanation using an integrated set of principles that organizes observations and predicts behaviors or events.
• Hypothesis: A testable prediction, often implied by a theory.
• Operational Definition: A statement of the procedures used to define research variables.
• Replication: Repeating the essence of a research study to see whether the basic finding extends to other participants and circumstances.
• Case Study: An observation technique in which one person is studied in depth.
• Survey: A technique for ascertaining the self-reported attitudes or behaviors of a particular group.
• Population: All the cases in a group being studied, from which samples may be drawn.
• Random Sample: A sample that fairly represents a population because each member has an equal chance of inclusion.
• Naturalistic Observation: Observing and recording behavior in naturally occurring situations without trying to manipulate and control the situation.
• Correlation: A measure of the extent to which two factors vary together.
• Correlation Coefficient: A statistical index of the relationship between two things.
• Scatterplot: A graphed cluster of dots, each representing the values of two variables.
• Illusory Correlation: The perception of a relationship where none exists.
• Experiment: A research method in which an investigator manipulates one or more factors to observe the effect on some behavior or mental process.
• Random Assignment: Assigning participants to experimental and control groups by chance.
• Double-Blind Procedure: An experiment procedure in which both the research participants and the research staff are ignorant about whether the participants have received the treatment or a placebo.
• Placebo Effect: Experimental results caused by expectations alone.
• Experimental Group: The group that is exposed to the treatment in an experiment.
• Control Group: The group that is not exposed to the treatment in an experiment.
• Independent Variable: The experimental factor that is manipulated.
• Confounding Variable: A factor other than the independent variable that might produce an effect in an experiment.
• Dependent Variable: The outcome factor that may change in response to manipulations of the independent variable.
• Mode: The most frequently occurring score(s) in a distribution.
• Mean: The arithmetic average of a distribution.
• Median: The middle score in a distribution.
• Range: The difference between the highest and lowest scores in a distribution.
• Standard Deviation: A computed measure of how much scores vary around the mean score.
• Normal Curve: A symmetrical, bell-shaped curve that describes the distribution of many types of data.
• Statistical Significance: A statistical statement of how likely it is that an obtained result occurred by chance.
• Culture: The enduring behaviors, ideas, attitudes, and traditions shared by a group of people and transmitted from one generation to the next.
• Informed Consent: An ethical principle that research participants be told enough to enable them to choose whether they wish to participate.
• Debriefing: The postexperimental explanation for a study, including its purpose and any deceptions, to its participants.
• Neuron: A nerve cell; the basic building block of the nervous system.
• Sensory Neurons: Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.
• Motor Neurons: Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.
• Interneurons: Neurons within the brain and spinal cord that communicate internally and intervene between sensory inputs and motor outputs.
• Dendrite: The bushy, branching extensions of a neuron that receive messages and conduct impulses toward the cell body.
• Axon: The extension of a neuron, ending in branching terminal fibers through which messages pass to other neurons or to muscles or glands.
• Myelin Sheath: A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses.
• Action Potential: A neural impulse; a brief electrical charge that travels down an axon.
• Threshold: The level of stimulation required to trigger a neural impulse.
• Synapse: The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
• Neurotransmitters: Chemical messengers that cross the synaptic gaps between neurons.
• Reuptake: A neurotransmitter's reabsorption by the sending neuron.
• Endorphins: Natural, opiate-like neurotransmitters linked to pain control and pleasure.
• Nervous System: The body's speedy electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.
• Central Nervous System (CNS): The brain and spinal cord.
• Peripheral Nervous System (PNS): The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
• Nerves: Bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.
• Somatic Nervous System: The division of the peripheral nervous system that controls the body's skeletal muscles.
• Autonomic Nervous System: The part of the peripheral nervous system that controls the glands and the muscles of the internal organs.
• Sympathetic Nervous System: The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.
• Parasympathetic Nervous System: The division of the autonomic nervous system that calms the body, conserving its energy.
• Reflex: A simple automatic response to a sensory stimulus.
• Endocrine System: The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.
• Hormones: Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues.
• Adrenal Glands: A pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress.
• Pituitary Gland: The endocrine system's most influential gland. Under the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glands.
• Lesion: Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue.
• Electroencephalogram (EEG): An amplified recording of the waves of electrical activity that sweep across the brain's surface.
• CT (Computed Tomography) Scan: A series of X-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body.
• PET (Positron Emission Tomography) Scan: A visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given task.
• MRI (Magnetic Resonance Imaging): A technique that uses magnetic fields and radio waves to produce computer-generated images of soft tissue.
• fMRI (Functional MRI): A technique for revealing blood flow and, therefore, brain activity by comparing successive MRI scans.
• Brainstem: The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; is responsible for automatic survival functions.
• Medulla: The base of the brainstem; controls heartbeat and breathing.
• Reticular Formation: A nerve network in the brainstem that plays an important role in controlling arousal.
• Thalamus: The brain's sensory switchboard, located on top of the brainstem; it directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medulla.
• Cerebellum: The "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance.
• Limbic System: A doughnut-shaped neural system (including the hippocampus, amygdala, and hypothalamus) located below the cerebral hemispheres; associated with emotions and drives.
• Amygdala: Two lima bean-sized neural clusters in the limbic system; linked to emotion.
• Hypothalamus: A neural structure lying below the thalamus; it directs several maintenance activities, helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward.
• Cerebral Cortex: The intricate fabric of interconnected neural cells covering the cerebral hemispheres; the body's ultimate control and information-processing center.
• Glial Cell: Cells in the nervous system that support, nourish, and protect neurons.
• Frontal Lobes: Portion of the cerebral cortex lying just behind the forehead; involved in speaking and muscle movements and in making plans and judgements.
• Parietal Lobes: Portion of the cerebral cortex lying at the top of the head and toward the rear; receives sensory input for touch and body position.
• Occipital Lobes: Portion of the cerebral cortex lying at the back of the head; includes areas that receive information from the visual fields.
• Temporal Lobes: Portion of the cerebral cortex lying roughly above the ears; includes the auditory areas, each receiving information primarily from the opposite ear.
• Motor Cortex: An area at the rear of the frontal lobes that controls voluntary movements.
• Sensory Cortex: Area at the front of the parietal lobes that registers and processes body touch and movement sensations.
• 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 such as learning, remembering, thinking, and speaking.
• Aphasia: Impairment of language, usually caused by left hemisphere damage either to Broca's area (impairing speaking) or to Wernicke's area (impairing understanding).
• Broca's Area: Controls language expression - an area, usually in the left frontal lobe, that directs the muscle movements involved in speech.
• Wernicke's Area: Controls language reception - a brain area involved in language comprehension and expression; usually in the left temporal lobes.
• Plasticity: The brain's ability to change, especially during childhood, by reorganizing after damage or by building new pathways based on experience.
• Neurogenesis: The formation of new neurons.
• Corpus Callosum: The large band of neural fibers connecting the two brain hemispheres and carrying messages between them.
• Split Brain: A condition resulting from surgery that isolates the brain's two hemispheres by cutting the fibers (mainly those of the corpus callosum) connecting them.
• Consciousness: Our awareness of ourselves and our environment.
• Dual Processing: The principle that information is often simultaneously processed on separate conscious and unconscious tracks.
• Behavior Genetics: The study of the relative power and limits of genetic and environmental influences on behavior.
• Environment: Every nongenetic influence, from prenatal nutrition to the people and things around us.
• Chromosomes: Threadlike structures made of DNA molecules that contain the genes.
• DNA (Deoxyribonucleic Acid): A complex molecule containing the genetic information that makes up the chromosomes.
• Genes: The biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing a protein.
• Genome: The complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes.
• Identical Twins: Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.
• Fraternal Twins: Twins who develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment.
• Heritability: The proportion of variation among individuals that we can attribute to genes.
• Interaction: The interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).
• Molecular Genetics: The subfield of biology that studies the molecular structure and functions of genes.
• Evolutionary Psychology: The study of the evolution of behavior and the mind, using principles of natural selection.
• Mutation: A random error in gene replication that leads to a change.
• Sensation: The faculty through which the external world is apprehended.
• Perception: The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
• Bottom-Up Processing: Analysis that begins with the sensory receptors and works up to the brain's integration of sensory information.
• Top-Down Processing: Information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations.
• Selective Attention: The focusing of conscious awareness on a particular stimulus.
• Inattentional Blindness: Failing to see visible objects when our attention is directed elsewhere.
• Change Blindness: The tendency to fail to detect changes in any part of a scene to which we are not focusing our attention.
• Psychophysics: The study of relationships between the physical characteristics of stimuli and our psychological experience of them.
• Absolute Threshold: The minimum stimulation needed to detect a particular stimulus 50 percent of the time.
• Signal Detection Theory: A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation.
• Subliminal: Below one's absolute threshold for conscious awareness.
• Priming: The activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.
• Difference Threshold: The minimum difference between two stimuli required for detection 50 percent of the time.
• Weber's Law: The principle that, to be perceived as different, two stimuli must differ by a constant minimum percentage.
• Sensory Adaptation: Diminished sensitivity as a consequence of constant stimulation.
• Transduction: The conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses our brains can interpret.
• Wavelength: The distance between crests of waves, such as those of the electromagnetic spectrum.
• Hue: The dimension of color that is determined by the wavelength of light.
• Intensity: The amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by the wave's amplitude.
• Pupil: The adjustable opening in the center of the eye through which light enters.
• Iris: A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
• Lens: The transparent structure behind the pupil that changes shape to help focus images on the retina.
• Retina: The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.
• Accommodation: The act or state of adjustment or adaptation, changes in shape of the ocular lens for various focal distances.
• Rods: Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.
• Cones: Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
• Optic Nerve: The nerve that carries neural impulses from the eye to the brain.
• Blind Spot: The point at which the optic nerve leaves the eye, creating a blind spot because no receptor cells are located there.
• Fovea: The central focal point in the retina, around which the eye's cones cluster.
• Feature Detectors: Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.
• Parallel Processing: The processing of several aspects of a problem simultaneously; the brain's natural mode of information processing for many functions, including vision.
• Young-Helmhotz Trichromatic: The theory that the retina contains three different color receptors (blue, green, red).
• Opponent-Process Theory: The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.
• Audition: The sense or act of hearing.
• Frequency: The number of complete waves that pass a given point in a certain amount of time.
• Pitch: A tone's highness or lowness; depends on frequency.
• Middle Ear: The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.
• Cochlea: The fluid-filled, coiled tunnel in the inner ear that contains the receptors for hearing.
• Inner Ear: Structures and liquids that relay sound waves to the auditory nerve fibers on a path to the brain for interpretation of sound.
• Place Theory: In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.
• Frequency Theory: In hearing, 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.
• Conduction Hearing Loss: Hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.
• Sensorieneural Hearing Loss: Hearing impairment caused by lesions or dysfunction of the cochlea or auditory nerve.
• Cochlear Implant: A device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.
• Kinesthesis: The system for sensing the position and movement of individual body parts.
• Vestibular Sense: A sensory system located in structures of the inner ear that registers the orientation of the head.
• Gate-Control Theory: Theory that spinal cord contains neurological gate that blocks pain signals or allows them to pass.
• Sensory Interaction: The principle that one sense may influence another, as when the smell of food influences its taste.
• Gestalt: An organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes.
• Figure Ground: The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground).
• Grouping: The perceptual tendency to organize stimuli into coherent groups.
• Depth Perception: The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance.
• Visual Cliff: A laboratory device for testing depth perception in infants and young animals.
• Binocular Cues: Depth cues, such as retinal disparity and convergence, that depend on the use of two eyes.
• Retinal Disparity: A binocular cue for perceiving depth; by comparing images from the two eyeballs, the brain computes distance.
• Monocular Cues: Depth cues, such as interposition and linear perspective, available to either eye alone.
• Phi Phenomenon: An illusion of movement created when two or more adjacent lights blink on and off in quick succession.
• Perceptual Consistency: The perceptual stability of the size, shape, and brightness, and color for familiar objects seen at varying distances, different angles, and under different lighting conditions.
• Color Constancy: Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.
• Perceptual Adaptation: In vision, the ability to adjust to an artificially displaced or even inverted visual field.
• Perceptual Set: A mental predisposition to perceive one thing and not another.
• Extrasensory Perception: The controversial claim that perception can occur apart from sensory input.
• Parapsychology: The study of paranormal phenomena, including ESP and psychokinesis.
• Circadian Rhythm: The biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.
• REM Sleep: Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur.
• Alpha Waves: The relatively slow brain waves of a relaxed, awake state.
• Sleep: Periodic, natural loss of consciousness--as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.
• Hallucinations: False sensory experiences, such as seeing something in the absence of an external visual stimulus.
• Delta Waves: The large, slow brain waves associated with deep sleep.
• NREM Sleep: Non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.
• Insomnia: Recurring problems in falling or staying asleep.
• Narcolepsy: A sleep disorder characterized by uncontrollable sleep attacks.
• Sleep Apnea: A sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.
• Night Terrors: A sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered.
• Dream: A sequence of images, emotions, and thoughts passing through a sleeping person's mind.
• Manifest Content: According to Freud, the remembered story line of a dream.
• Latent Content: According to Freud, the underlying meaning of a dream.
• REM Rebound: The tendency for REM sleep to increase following REM sleep deprivation.
• Hypnosis: A social interaction in which one person (the hypnotist) suggests to another (the subject) that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur.
• Posthypnotic Suggestion: A suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized.
• Dissociation: A split in consciousness, which allows some thoughts and behaviors to occur simultaneously with others.
• Psychoactive Drug: A chemical substance that alters perceptions and moods.
• Tolerance: The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect.
• Withdrawal: The discomfort and distress that follow discontinuing the use of an addictive drug.
• Physical Dependence: A physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued.
• Psychological Dependence: A psychological need to use a drug, such as to relieve negative emotions.
• Addiction: Compulsive drug craving and use, despite adverse consequences.
• Depressants: Drugs that reduce neural activity and slow body functions.
• Barbiturates: Drugs that depress the activity of the central nervous system, reducing anxiety but impairing memory and judgment.
• Opiates: Opium and its derivatives, such as morphine and heroin; they depress neural activity, temporarily lessening pain and anxiety.
• Stimulants: Drugs that excite neural activity and speed up body functions.
• Amphetamines: Drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes.
• Methamphetamine: A powerfully addictive drug that stimulates the central nervous system, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels.
• Ecstasy (MDMA): A synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risks and longer-term harm to serotonin-producing neurons and to mood and cognition.
• Hallucinogens: Psychedelic ("mind-manifesting") drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input.
• LSD: A powerful hallucinogenic drug; also known as acid (lysergic acid diethylamide).
• Near-Death Experience: An altered state of consciousness reported after a close brush with death (such as through cardiac arrest); often similar to drug-induced hallucinations.
• THC: The major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations.
• Learning: A relatively permanent change in an organism's behavior due to experience.
• Habituation: An organism's decreasing response to a stimulus with repeated exposure to it.
• Associative Learning: Learning that certain events occur together. The events may be two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning).
• Classical Conditioning: A type of learning in which one learns to link two or more stimuli and anticipate events.
• Unconditioned Response: In classical conditioning, the unlearned, naturally occurring response to the unconditioned stimulus, such as salivation when food is in the mouth.
• Unconditioned Stimulus: In classical conditioning, a stimulus that unconditionally-naturally and automatically-triggers a response.
• Conditioned Response: In classical conditioning, the learned response to a previously neutral stimulus.
• Conditioned Stimulus: In classical conditioning, an originally irrelevant stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response.
• Acquisition: In classical conditioning, the initial stage, when one links a neutral stimulus and an unconditioned stimulus so that the neutral stimulus begins triggering the conditioned response.
• Higher-Order Conditioning: A procedure in which the conditioned stimulus in one conditioning experience is paired with a new neutral stimulus, creating a second (often weaker) conditioned stimulus.
• Extinction: The diminishing of a conditioned response; occurs in classical conditioning when an unconditioned stimulus does not follow a conditioned stimulus.
• Spontaneous Recovery: The reappearance, after a pause, of an extinguished conditioned response.
• Generalization: The tendency, once a response has been conditioned, for stimuli similar to the conditioned stimulus to elicit similar responses.
• Discrimination: In classical conditioning, the learned ability to distinguish between a conditioned stimulus and stimuli that do not signal an unconditioned stimulus.
• Learned Helplessness: The hopelessness and passive resignation an animal or human learns when unable to avoid repeated aversive events.
• Respondent Behavior: Behavior that occurs as an automatic response to some stimulus.
• Operant Conditioning: A type of learning in which behavior is strengthened if followed by a reinforcer or diminished if followed by a punisher.
• Operant Behavior: Behavior that operates on the environment, producing consequences.
• Law of Effect: Thorndike's principle that behaviors followed by favorable consequences become more likely, and that behavior followed by unfavorable consequences become less likely.
• Operant Chamber: In operant conditioning research, a chamber containing a bar or key that an animal can manipulate to obtain a food or water reinforcer.
• Shaping: An operant conditioning procedure in which reinforcers guide behavior toward closer and closer approximations of the desired behavior.
• Discriminative Stimulus: In operant conditioning, a stimulus that elicits a response after association with reinforcement.
• Reinforcer: In operant conditioning, any event that strengthens the behavior it follows.
• Positive Reinforcement: Increasing behaviors by presenting positive stimuli, such as food.
• Negative Reinforcement: Increasing behaviors by stopping or reducing negative stimuli, such as shock.
• Primary Reinforcer: An innately reinforcing stimulus, such as one that satisfies a biological need.
• Conditioned Reinforcer: A stimulus that gains its reinforcing power through its association with a primary reinforcer.
• Continuous Reinforcement: Reinforcing the desired response every time it occurs.