AP Psychology Unit 1 - All Terms

Heredity (Nature)

Traits passed from parents to children through genes. Ex: A child has the same eye color as her mom.

Environment (Nurture)

All outside influences on development, such as family, culture, and experiences. Ex: A child learns Spanish because it's spoken at home.

Genetic predisposition

An inherited tendency to develop a trait or condition, which the environment may or may not trigger. Ex: Someone with a family history of anxiety develops it only after very stressful events.

Evolutionary perspective

The view that behaviors exist because they helped our ancestors survive and reproduce. Ex: Fear of snakes helped early humans avoid danger.

Natural selection

Traits that improve survival and reproduction become more common in a population over generations. Ex: Faster rabbits escape foxes and have more babies, so rabbits get faster over time.

Eugenics

The discredited, unethical movement to improve humanity by controlling who reproduces. Ex: Past forced sterilization laws.

Twin studies

Compare identical twins (100% shared genes) with fraternal twins (about 50%) to estimate genetic influence. Ex: If identical twins both have depression more often than fraternal twins, genes likely matter.

Family studies

Examine how often a trait appears among relatives to see if it runs in families. Ex: Schizophrenia is more common in siblings of people who have it.

Adoption studies

Compare adopted children to their biological and adoptive families to separate genes from environment. Ex: An adopted child's personality matches her birth parents more than her adoptive parents, suggesting genetic influence.

Central nervous system (brain and spinal cord)

The brain and spinal cord, which process information and make decisions. Ex: Your brain decides to answer a question in class.

Peripheral nervous system

All nerves outside the brain and spinal cord that carry messages to and from the CNS. Ex: Nerves in your hand send "hot!" to your brain.

Somatic nervous system

Controls voluntary skeletal muscle movement and carries sensory information. Ex: Raising your hand.

Autonomic nervous system

Controls involuntary functions like heartbeat, digestion, and breathing. Ex: Your stomach digests lunch without you thinking about it.

Sympathetic nervous system

Part of the autonomic system that arouses the body for "fight or flight." Ex: Your heart pounds before a big test.

Parasympathetic nervous system

Calms the body and conserves energy ("rest and digest"). Ex: Your heart rate slows after the test is over.

Glial cell

Support cells that nourish, insulate, and clean up around neurons. Ex: Glia act like helpers that keep neurons healthy.

Neural cell (neuron)

A nerve cell that sends and receives messages. Ex: Neurons carry the signal when you touch a hot stove.

Reflex arc

A fast, automatic response using a simple path of sensory neuron, interneuron, and motor neuron, often through the spinal cord. Ex: Pulling your hand off a hot pan before feeling pain.

Sensory neurons

Carry information from the body and senses to the CNS. Ex: Neurons in your skin report that the water is cold.

Motor neurons

Carry commands from the CNS to muscles and glands. Ex: A signal tells your leg to kick a ball.

Interneurons

Connect neurons within the CNS, linking sensory input to motor output. Ex: They relay the "cold" message to the "pull away" command in your spinal cord.

Neural transmission

The process of a neuron firing an electrical signal and passing it on chemically to the next neuron. Ex: A message moving from your eye to your brain.

All-or-none principle

A neuron either fires completely or doesn't fire at all. Ex: Like a light switch, it's either on or off, never half-on.

Depolarization

Positive ions rush in and the neuron's charge shifts toward positive, starting the action potential. Ex: The neuron's "gate" opens and charge floods in so it can fire.

Refractory period

A brief rest after firing when the neuron can't fire again. Ex: Like a toilet that needs a moment to refill after flushing.

Resting potential

The neuron's stable negative charge (about -70 mV) when it's not firing. Ex: A loaded slingshot waiting to be released.

Reuptake

Neurotransmitters are reabsorbed by the sending neuron after they do their job. Ex: A vacuum sucking leftover messengers back up.

Threshold

The minimum level of stimulation needed to trigger a neuron to fire. Ex: You must press a doorbell hard enough for it to ring.

Multiple sclerosis

An autoimmune disease that damages the myelin sheath, slowing messages and causing muscle and movement problems. Ex: A person has numbness and trouble walking because signals travel poorly.

Myasthenia gravis

An autoimmune disease that blocks acetylcholine receptors, causing muscle weakness and fatigue. Ex: Someone's eyelids droop and their muscles tire quickly.

Neurotransmitters

Chemical messengers that cross the synapse to pass signals between neurons. Ex: A chemical carries a message from one neuron to the next.

Location in NS

Where a neurotransmitter works (brain, spinal cord, muscles) affects its role. Ex: Acetylcholine works at muscles, while dopamine works in reward pathways in the brain.

Excitatory

A neurotransmitter effect that makes the next neuron more likely to fire. Ex: A "go" signal.

Inhibitory

A neurotransmitter effect that makes the next neuron less likely to fire. Ex: A "stop" signal.

Dopamine

Involved in movement, motivation, and reward; too little is linked to Parkinson's, too much to schizophrenia. Ex: The good feeling of getting a high score.

Serotonin

Affects mood, sleep, and appetite; low levels are linked to depression. Ex: Feeling calmer after getting enough sleep.

Norepinephrine

Helps with alertness and arousal. Ex: Feeling focused and wired during an emergency.

Glutamate

The main excitatory neurotransmitter, involved in learning and memory. Ex: Helps you form a memory while studying.

GABA

The main inhibitory neurotransmitter, which calms neural activity. Ex: Helps you relax and fall asleep.

Endorphins

Natural painkillers that also create pleasure. Ex: "Runner's high" after a long run.

Substance P

Transmits pain signals. Ex: The sharp sting when you stub your toe.

Acetylcholine

Involved in muscle movement and memory. Ex: Lets your muscles contract when you wave.

Hormones

Chemical messengers released by endocrine glands into the bloodstream, slower than neurotransmitters. Ex: Puberty hormones change your body over months.

Adrenaline

A hormone that boosts heart rate and energy during stress. Ex: A surge of energy when you're startled.

Leptin

Hormone from fat cells that signals fullness and suppresses hunger. Ex: You stop eating because you feel full.

Ghrelin

Hormone from the stomach that triggers hunger. Ex: Your stomach growls before lunch.

Melatonin

Hormone from the pineal gland that regulates sleep. Ex: You feel sleepy when it gets dark.

Oxytocin

Hormone involved in bonding, trust, and attachment. Ex: Hugging a loved one or a mother nursing her baby.

Psychoactive drugs

Chemicals that change brain function, mood, or perception. Ex: Caffeine in coffee changes how alert you feel.

Agonist

A drug or chemical that mimics a neurotransmitter and activates its receptors. Ex: Morphine mimics endorphins to reduce pain.

Antagonist

A drug or chemical that blocks a neurotransmitter's receptors. Ex: Botox blocks acetylcholine, so muscles can't contract.

Reuptake inhibitors

Drugs that block reuptake so more neurotransmitter stays in the synapse. Ex: Antidepressants (SSRIs) keep more serotonin available.

Stimulants (caffeine, cocaine)

Drugs that speed up body and brain activity. Ex: Coffee makes you feel more awake.

Depressants (alcohol)

Drugs that slow body and brain activity. Ex: Alcohol slows reaction time and slurs speech.

Hallucinogens (marijuana)

Drugs that distort perception and cause sensory experiences without real stimuli. Ex: Colors or sounds seem unusually intense.

Opioids (heroin)

Drugs that mimic endorphins, reducing pain and creating euphoria. Ex: Prescription painkillers like morphine.

Tolerance

Needing larger doses of a drug to get the same effect. Ex: One cup of coffee no longer wakes you up, so you need two.

Addiction

Compulsive drug use despite harmful consequences. Ex: Someone keeps using even though it hurts their grades and friendships.

Withdrawal symptoms

Unpleasant physical or psychological effects when someone stops using a drug they depend on. Ex: Headaches and irritability after quitting caffeine.

Brainstem

The base of the brain that controls basic survival functions. Ex: Keeps you breathing while you sleep.

Medulla

Part of the brainstem that controls heartbeat and breathing. Ex: Keeps your heart beating without thought.

Reticular activating system

A brainstem network that controls arousal and alertness. Ex: Wakes you up when your alarm goes off.

Reward center

Brain circuits (like the nucleus accumbens) that release dopamine for pleasurable experiences. Ex: Feeling good after eating your favorite dessert.

Cerebellum

Controls balance, coordination, and movement, and helps with procedural memory. Ex: Riding a bike without falling.

Cerebral cortex

The brain's wrinkled outer layer, responsible for higher thinking. Ex: Solving a math problem.

Hemispheres

The left and right halves of the brain. Ex: The left side handles language for most people.

Limbic system

Brain structures involved in emotion, memory, and drives. Ex: Feeling scared and remembering why.

Thalamus

The sensory relay station that sends information to the proper cortex area (except smell). Ex: Routes the sound of a bell to your auditory cortex.

Hypothalamus

Regulates hunger, thirst, body temperature, and sex drive, and controls the pituitary. Ex: Makes you sweat when you're hot.

Pituitary gland

The "master gland," which releases hormones that control other glands. Ex: Releases growth hormone during childhood.

Hippocampus

Forms new explicit (conscious) memories. Ex: Remembering what you did yesterday.

Amygdala

Processes emotions, especially fear and aggression. Ex: Your heart jumps when you see a spider.

Corpus callosum

The band of fibers connecting the two hemispheres so they can communicate. Ex: Lets your right brain share what your left eye sees with your left brain.

Lobes of the cortex

The four regions of each hemisphere: frontal, parietal, temporal, and occipital. Ex: Each lobe handles different jobs, like vision or movement.

Occipital lobes

Located at the back of the brain; process visual information. Ex: Recognizing a friend's face.

Temporal lobes

Located above the ears; process hearing, language comprehension, and some memory. Ex: Understanding a song's lyrics.

Parietal lobes

Located at the top and back of the head; process touch and spatial awareness. Ex: Feeling a tap on your shoulder.

Somatosensory cortex

Strip at the front of the parietal lobe that registers touch, pressure, temperature, and pain. Ex: Feeling a cold drink in your hand.

Association areas

Cortex areas that integrate information rather than handle basic sensory or motor tasks. Ex: Combining what you see and hear to understand a conversation.

Frontal lobes

Located at the front of the brain; involved in planning, judgment, speech, and movement. Ex: Deciding to study instead of go out.

Prefrontal cortex

The front part of the frontal lobes; handles decision making, self-control, and personality. Ex: Resisting the urge to blurt out an answer.

Motor cortex

Strip at the back of the frontal lobes that controls voluntary movement. Ex: Moving your fingers to type.

Split brain research

Studies of people whose corpus callosum was cut, showing how each hemisphere functions on its own. Ex: A patient can't name an object shown only to the right hemisphere.

Specialization of hemispheres

Each hemisphere is better at certain tasks (left: language, logic; right: spatial skills, faces). Ex: The left hemisphere helps you speak, while the right helps you recognize faces.

Broca's area

Left frontal lobe area that controls speech production. Ex: Damage means you understand speech but can't speak fluently.

Wernicke's area

Left temporal lobe area that handles language comprehension. Ex: Damage means you speak fluently but your words make no sense.

Aphasia

Impairment of language caused by brain damage. Ex: A stroke patient can't find the right words.

Test with split-brain patients

Information is flashed to one visual field so only one hemisphere sees it. Ex: A word flashed to the left visual field can be drawn by the left hand but not spoken.

Cortex specialization

Different cortex areas are specialized for different functions. Ex: The occipital lobe handles vision, while the motor cortex handles movement.

Contralateral organization

Each hemisphere controls and receives information from the opposite side of the body. Ex: The left hemisphere moves your right hand.

Brain plasticity

The brain's ability to change and reorganize itself after experience or injury. Ex: After a stroke, other brain areas take over lost functions.

EEG

Records the brain's electrical activity using electrodes on the scalp. Ex: Used to measure brain waves during sleep.

fMRI

Uses blood flow to show which brain areas are active during a task. Ex: Shows which areas light up when you solve a math problem.

Case studies

In-depth studies of one individual, often used for rare brain conditions. Ex: Phineas Gage's injury showed the frontal lobes affect personality.

Lesioning procedure

Destroying or removing part of the brain to see how behavior changes. Ex: Researchers damage a rat's hypothalamus to see its effect on eating.

Varying levels of consciousness

Awareness ranges from fully alert to unconscious. Ex: You're alert in class, drowsy at bedtime, and unaware during deep sleep.

Sleep/wake cycle

The daily pattern of sleeping and being awake, controlled by the body's internal clock. Ex: Feeling sleepy at night and awake in the morning.

Circadian rhythm (disruptions)

The roughly 24-hour biological clock; disruptions throw off sleep and alertness. Ex: Staying up all night makes you feel off the next day.

Jet lag

Circadian disruption from traveling across time zones. Ex: Flying from Michigan to Europe and feeling wide awake at 3 a.m.

Shift work

Working schedules that go against the natural circadian rhythm, leading to poor sleep. Ex: A night-shift nurse struggles to sleep during the day.