AP Psych unit 1

Evolutionary Perspective

Definition: Explains behavior and mental processes as traits passed down because they helped survival/reproduction.

Example: Fear of snakes helped early humans avoid danger, so it stayed in the gene pool.

Natural Selection

Definition: Traits that make survival/reproduction more likely get passed on to future generations.

Example: Better memory helps with finding food → those with good memory survive and pass on their genes.

Eugenics

Definition: The false idea that humans can “improve” their species by controlling breeding.

Example: Early 1900s laws tried to stop certain people from having children—used unethically, not real science.

Twin Studies

Definition: Research comparing identical vs. fraternal twins to see how much behavior is shaped by genetics or environment.

Example: Identical twins raised apart still show similar intelligence → evidence for heredity.

Nature/Nurture

Definition: The debate over whether genetics (nature) or environment/experience (nurture) shapes who we are.

Example: A student’s intelligence may be influenced both by inherited genes and by quality of schooling.

Central Nervous System (CNS)

Definition: Brain + spinal cord; controls thinking, decision-making, and communication with the body.

Example: Your brain sends signals to move your hand away from a hot stove.

Peripheral Nervous System (PNS)

Definition: All nerves outside brain/spinal cord; connects CNS to the rest of the body.
Example: Touching ice sends signals through the PNS to the brain.

Autonomic Nervous System (ANS)

Definition: Controls automatic body functions (heartbeat, digestion, breathing).

Example: Your heart races when you’re nervous, without you deciding to make it happen.

Somatic Nervous System

Definition: Controls voluntary muscle movements.

Example: Choosing to raise your hand in class.

Sympathetic Nervous System

Definition: Activates fight-or-flight response (prepares body for action).

Example: Heart races and pupils dilate when you see a bear.

Parasympathetic Nervous System

Definition: Calms the body back down after stress (rest-and-digest).

Example: Heartbeat slows after realizing the “bear” is just a friend in a costume.

Neuron

Definition: Basic nerve cell that sends and receives messages.

Example: Neurons in your brain fire when you answer a test question.

Glial Cells

Definition: Support neurons by providing nutrients, cleaning waste, and forming myelin.

Example: Like “nurse cells” that keep neurons healthy.

Reflex Arc

Definition: Quick, automatic response that skips the brain and goes through the spinal cord.

Example: Pulling your hand away from a hot stove before realizing it’s hot.

Sensory Neurons

Definition: Carry signals from senses to the brain/spinal cord.

Example: Eyes send light signals to brain when reading.

Motor Neurons

Definition: Carry signals from brain/spinal cord to muscles.

Example: Brain tells your legs to move when running.

Interneurons

Definition: Connect sensory and motor neurons, mostly in the brain/spinal cord.
Example: Brain processes “car is coming” → interneurons tell motor neurons to move you off the road.

All-or-Nothing Principle (NT)

Definition: Neuron either fires completely or not at all. No in-between.

Example: Like flipping a light switch on/off.

Depolarization (NT)

Definition: When neuron becomes positively charged inside, starting the firing process.

Example: Domino effect that starts action potential.

Refractory Period (NT)

Definition: Short time after firing when a neuron can’t fire again.

Example: Like a camera flash that needs to recharge before the next photo.

Action Potential (NT)

Definition: Electrical impulse that travels down neuron’s axon.

Example: The “message” telling your hand to wave hello.

Resting Potential (NT)

Definition: Neuron at rest, charged but not firing.

Example: Like a loaded spring waiting to release.

Reuptake (NT)

Definition: When leftover neurotransmitters are reabsorbed by the sending neuron.

Example: Serotonin being taken back up after firing in mood regulation.

Threshold (NT)

Definition: Minimum level of stimulation needed for a neuron to fire.

Example: Enough pressure on your skin must be applied before you feel it as touch.   This is the point at which a stimulus is strong enough to trigger an action potential, leading to neural firing.

Multiple Sclerosis

Definition: Disease where myelin sheath breaks down, slowing signals.

Example: Muscle weakness and vision problems.

Myasthenia Gravis

Definition: Disorder where signals fail between nerves and muscles.

Example: Muscle fatigue when trying to move

Excitatory Neurotransmitter

Definition: Increases chance of neuron firing.

Example: Glutamate helps learning/memory

Inhibitory Neurotransmitter

Definition: Decreases chance of neuron firing.

Example: GABA calms brain activity.

Hormones

Definition: Chemical messengers sent through bloodstream.

Example: Adrenaline increases energy under stress.

Dopamine (E & I)

Definition: Controls movement, reward, learning. Can excite or inhibit.

Example: High dopamine = addiction/reward.Low dopamine = movement issues such as Parkinson's disease.

Serotonin (I)

Definition: Regulates mood, sleep, appetite.

Example: Low serotonin linked to depression.

Endorphins (I)

Definition: Natural painkillers + pleasure boosters.

Example: Runner’s high after exercise.

Substance P

Definition: Neurotransmitter that sends pain signals.

Example: Stub toe → pain travels to brain.

Acetylcholine (ACh) (E)

Definition: Controls muscle movement, learning, memory.

Example: Lack of ACh → Alzheimer’s disease.

GABA (I)

Definition: Major calming neurotransmitter.

Example: Anti-anxiety drugs increase GABA.

Glutamate (E)

Definition: Main excitatory transmitter; helps memory.

Example: Too much glutamate → migraines.

Norepinephrine (I)

Definition: Arousal, alertness, stress.

Example: Increases during fight-or-flight.

Melatonin (H)

Definition: Hormone controlling sleep cycles.

Example: Released at night to make you sleepy.

Oxytocin (H)

Definition: “Love hormone,” linked to bonding + trust.

Example: Released during hugs and childbirth.

Adrenaline (H)

Definition: Hormone for energy + fight-or-flight.

Example: Heart races before public speaking.

Leptin (H)

Definition: Tells body it’s full, regulates hunger.

Example: After a big meal, leptin rises.

Ghrelin (H)

Definition: Stimulates hunger.

Example: Stomach growling before lunch.

Psychoactive Drugs

Definition: Chemicals that change brain activity.

Example: Caffeine, alcohol, marijuana.

Agonist Drugs

Definition: Imitate or boost neurotransmitter activity.

Example: Morphine mimics endorphins.

Antagonist Drugs

Definition: Block neurotransmitter activity.

Example: Botox blocks ACh to prevent wrinkles.

Cocaine

Definition: Stimulant; blocks dopamine reuptake.

Example: Creates intense energy → addictive.

Stimulants

Definition: Speed up nervous system activity.

Example: Caffeine, nicotine, amphetamines.

Caffeine

Definition: Mild stimulant; increases alertness.

Example: Drinking coffee to stay awake

Hallucinogens

Definition: Cause sensory distortions and hallucinations.

Example: LSD makes you “see” things not there

Depressants

Definition: Slow down nervous system.

Example: Alcohol reduces reaction time.

Alcohol

Definition: Common depressant; slows brain function.

Example: Impaired judgment when drunk.

Heroin

Definition: Opioid drug; mimics endorphins → intense euphoria.

Example: Highly addictive with withdrawal.

Marijuana

Definition: Drug with mild hallucinogen + depressant effects.

Example: Alters perception and slows reaction.

Opioids

Definition: Pain-relieving drugs that mimic endorphins.

Example: Prescription painkillers like oxycodone.

Tolerance

Definition: Needing more of a drug to get same effect.

Example: Drinking more coffee daily for same energy

Addiction

Definition: Compulsive craving of a substance/behavior.

Example: Keep smoking despite health risks.

Withdrawal

Definition: Negative symptoms when stopping drug.

Example: Headaches from no caffeine.

Dependence

Definition: Needing a drug to function normally.

Example: Can’t sleep without sleeping pills.