AP Psychology Vocabulary! | Unit 1: Biological Bases of Behavior

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Absolute Threshold

The minimum stimulation needed to detect a particular stimulus 50% of the time.

Accommodation

The process by which the eye’s lens changes shape to focus near or far objects on the retina.

Acetylcholine

A neurotransmitter that enables learning, memory, and muscle action.

Activation Synthesis Theory

A theory that dreams are the brain's attempt to make sense of random neural activity.

Afterimages

Visual images that remain after the stimulus is removed, often in complementary colors. (Example: American flag in teal, black, and yellow, after removed from white screen we can see it in red, white and blue!)

Alpha Waves

Slow brain waves of a relaxed, awake state.

Amygdala

A brain structure involved in emotion, particularly fear and aggression.

Antagonist

A chemical that blocks or inhibits the action of a neurotransmitter.

Barbiturates

Depressant drugs that reduce anxiety but impair memory and judgment.

Biological Psychology

The scientific study of the links between biological and psychological processes.

Biopsychosocial Approach

An integrated perspective that incorporates biological, psychological, and social-cultural levels of analysis.

Blind Spot

The point at which the optic nerve leaves the eye; no receptor cells are located there.

Blindsight

A condition where a person can respond to a visual stimulus without consciously experiencing it.

Bottom-up Processing

Analysis that begins with sensory receptors and works up to the brain's integration of sensory information. (What you see is what you perceive)

Brain Plasticity

The brain’s ability to change, especially during childhood, by reorganizing after damage or building new pathways.

Caffeine

A mild stimulant that increases alertness and decreases fatigue.

Central Nervous System

The brain and spinal cord, which process and send information throughout the body.

Cerebellum

A brain structure that coordinates movement and balance.

Cerebral Cortex

The outermost layer of the brain, responsible for higher cognitive functions such as thinking, memory, perception, and decision-making. It is divided into two hemispheres (left and right) and four lobes: frontal, parietal, temporal, and occipital. The cerebral cortex processes sensory information, controls voluntary movements, and is involved in complex thought processes.

Circadian Rhythm

The biological clock; regular bodily rhythms that occur on a 24-hour cycle.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear that transduces sound vibrations into neural impulses. (Cochlea = Coachella!)

Cognitive Neuroscience

The interdisciplinary study of brain activity linked with mental processes.

Consciousness

Our awareness of ourselves and our environment.

Consolidation Theory

A theory that proposes REM sleep helps strengthen new memories.

Contralateral Hemispheric Organization

The concept that the left hemisphere controls the right side of the body and vice versa.

Cornea

The eye's clear, protective outer layer that bends light to help focus images.

Cortex Specialization

The idea that different areas of the cerebral cortex are specialized for different functions.

Delta Waves

The large, slow brain waves associated with deep sleep.

Depolarization

A change in a neuron's charge that leads to the firing of an action potential.

Depressants

Drugs that reduce neural activity and slow body functions. Examples: Alcohol, benzodiazpines.

Dichromatism

A type of color blindness in which one of the three color systems is missing or not functioning.

Dopamine

A neurotransmitter involved in movement, learning, attention, and the brain’s reward system.

Dream

A sequence of images, emotions, and thoughts passing through a sleeping person's mind.

Ecstasy

A synthetic stimulant and mild hallucinogen that produces euphoria and social intimacy.

Embodied Cognition

The influence of bodily sensations, gestures, and other states on cognitive preferences and judgments.

Endocrine System

The body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream.

Epigenetics

The study of how environmental influences and other factors can alter gene expression without changing the underlying DNA sequence.

Evolutionary Perspective

A psychological approach that explains mental and behavioral traits as adaptations from natural selection.

Excitatory Neurotransmitter

Chemicals that increase the likelihood that the receiving neuron will fire.

Feature Detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Forebrain

The largest and most complex brain region, involved in emotions, memory, and higher-level cognitive functions.

Fovea

The central focal point in the retina, around which the eye’s cones cluster.

Frequency

The number of complete wavelengths that pass a point in a given time.

Frontal Lobe

The portion of the cerebral cortex involved in planning, judgment, movement, and problem-solving.

Ganglion Cells

Neurons in the retina that receive visual information from photoreceptors and transmit it to the brain.

Ghrelin

A hormone produced in the stomach that stimulates appetite.

Glutamate

A major excitatory neurotransmitter involved in memory and learning. (Glutamate = Glucose, sugar makes you excited!)

Hallucinogens

A class of drugs that alter perception, mood, and consciousness, often inducing vivid sensory experiences, visual and auditory hallucinations, and altered thinking. These substances can cause users to perceive reality in distorted ways.

Examples: MDMA (Ectasy), Psilocybin (Magic Mushrooms)

Heredity

The genetic transmission of characteristics from parents to offspring.

Hippocampus

A neural center in the limbic system that helps process explicit memories for storage.

Hormones

Chemical messengers produced by endocrine glands that travel through the bloodstream and affect other tissues. (Slow messengers)

Hypothalamus

A neural structure below the thalamus; directs eating, drinking, body temperature to keep homeostasis in the body, and is linked to emotion and reward.

Identical (Monozygotic) Twins

Twins who develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

Inhibitory Neurotransmitters

Neurotransmitters that decrease the likelihood that the receiving neuron will fire.

Insomnia

Recurring problems in falling or staying asleep.

Interaction

The interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

Interneurons

Neurons within the brain and spinal cord that communicate internally and intervene between sensory inputs and motor outputs.

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.

Jet Lag

A disruption of circadian rhythms due to crossing time zones, often causing sleep disturbances and fatigue.

Just-Noticeable Difference (Difference Threshold)

The minimum difference between two stimuli required for detection 50% of the time.

Kinesthesis

The system for sensing the position and movement of individual body parts.

Lateralization

The specialization of function in one hemisphere of the brain or the other.

Leptin

A hormone produced by fat cells that signals the brain to reduce appetite and increase energy use.

Lesions

Tissue destruction; a brain lesion is a naturally or experimentally caused destruction of brain tissue.

Limbic System

A doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheres; associated with emotions and drives.

MEG (Magnetoencephalography)

A brain imaging technique that measures magnetic fields from the brain’s natural electrical activity. MEG allows researchers to map brain activity in real-time, providing insights into brain function, including sensory processing, motor control, and cognitive processes.

MRI (Magnetic Resonance Imaging)

A non-invasive imaging technique used to create detailed pictures of the inside of the body, particularly the brain and soft tissues. MRI uses strong magnetic fields and radio waves to generate images, which help diagnose conditions related to the brain, spinal cord, muscles, and other internal structures.

Melatonin

A hormone that regulates sleep-wake cycles; produced by the pineal gland.

Midbrain

A small central part of the brainstem involved in vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Monozygotic Twins

Another term for identical twins, developed from a single fertilized egg.

Motor Cortex

An area at the rear of the frontal lobes that controls voluntary movements.

Motor (Efferent) Neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Mutation

A random error in gene replication that leads to a change.

Myasthenia Gravis

A chronic autoimmune disease that causes weakness in the voluntary muscles of the body. It occurs when the body's immune system attacks the receptors for acetylcholine (a neurotransmitter) at the neuromuscular junction, impairing communication between the nerve and the muscle. Symptoms often include muscle weakness, difficulty speaking, swallowing, and breathing.

Myelin Sheath

A fatty substance that covers the axon of some neurons and helps speed neural impulses.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks.

Natural Selection

The principle that inherited traits that better enable an organism to survive and reproduce will most likely be passed on.

Nature

The influence of genetic inheritance on behavior.

Near-Death Experience

An altered state of consciousness reported after a close brush with death, often involving out-of-body sensations.

Nervous System

The body’s electrochemical communication network, it is a complex network of cells and structures that coordinates and controls actions, thoughts, sensations, and processes in the body. It consists of two main parts: the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system (PNS), which consists of nerves outside the CNS that connect to the body’s organs and tissues.

Neurogenesis

The formation of new neurons in the brain.

Neurological Disorders

Disorders of the nervous system such as epilepsy, Parkinson’s, or Alzheimer’s.

Neurons

Specialized cells in the nervous system that transmit electrical and chemical signals. Neurons are the basic building blocks of the brain and nervous system, responsible for communication between the brain, spinal cord, and the rest of the body. They consist of the cell body, dendrites, and axon, and communicate via electrical impulses and neurotransmitters.

Neurotransmitters

Chemical messengers that transmit signals across synapses (gaps between neurons) to communicate with other neurons, muscles, or glands. Neurotransmitters play a key role in mood regulation, cognition, and various bodily functions. Common neurotransmitters include dopamine, serotonin, acetylcholine, and norepinephrine.

Norepinephrine

A neurotransmitter involved in arousal and alertness; also associated with mood regulation.

Nucleus

The central structure in a neuron that contains DNA.

Nurture

The influence of environmental factors on behavior and mental processes.

Occipital Lobe

The portion of the cerebral cortex lying at the back of the head; includes areas that receive visual information.

Oleogustus

A proposed basic taste sensation for fatty substances.

Olfactory System

The sensory system used for smelling (olfaction).

Opponent-Process Theory

A theory of color vision that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

Opioids

Natural or synthetic drugs that act on opioid receptors to relieve pain. Examples: Heroin, Fentanyl, Morphine

Oxytocin

A hormone released by the pituitary gland that plays a role in social bonding, sexual reproduction, and childbirth. (The love/cuddle hormone).

Parasympathetic Nervous System

The division of the autonomic nervous system that calms the body and conserves energy.

Parietal Lobe

A region of the cerebral cortex whose functions include processing information about touch.

Peripheral Nervous System

The part of the nervous system that includes all the nerves outside the central nervous system (CNS), which consists of the brain and spinal cord. It connects the CNS to the limbs and organs, and is divided into two main parts: the somatic nervous system and the autonomic nervous system.

Phantom Limb Sensation

The perception of sensations, including pain, in a limb that has been amputated.

Pheromones

Chemical signals released by organisms to communicate with others of their species.

Photoreceptors

Specialized cells in the retina that convert light into electrical signals (rods and cones).

Pitch

A tone’s experienced highness or lowness; depends on frequency.