Unit 1 AP Psychology Study Guide

Module 1 – Full Term & Definition List

🧬 Nature vs. Nurture, Genetics, and Behavior

• Nature vs. Nurture Issue – The longstanding controversy over the relative contributions that genes (nature) and experience (nurture) make to psychological traits and behaviors. Today’s science views traits and behaviors as arising from the interaction of nature and nurture.

• Evolutionary Psychology – The study of how humans are alike because of shared biology and evolutionary history.

• Natural Selection – The principle that inherited traits that improve survival and reproduction are more likely to be passed to future generations.

• Behavior Genetics – The study of the relative power and limits of genetic and environmental influences on behavior.

• Mutation – A random error in gene replication that leads to a change in the genetic code, potentially creating new traits.

• Environment – Every non-genetic influence, from prenatal nutrition to the people and things around us.

• Heredity – The genetic transfer of characteristics from parents to offspring.

• Genes – The biochemical units of heredity; segments of DNA that code for proteins and affect traits.

• Genome – The complete instructions for making an organism, containing all the genetic material in that organism’s chromosomes.

• Chromosomes – Threadlike structures of DNA molecules containing genes. Humans have 46 (23 pairs).

• DNA – Deoxyribonucleic acid; the molecule carrying the genetic instructions, arranged in a double helix.

• Telomeres – Protective caps at the end of chromosomes that prevent DNA damage.

• Dominant Gene – A gene that is more likely to be expressed when present.

• Recessive Gene – A gene that is less likely to be expressed unless paired with another recessive gene.

• Genotype – The full set of genetic possibilities for a trait.

• Phenotype – The observable traits or characteristics that result from the interaction of genotype and environment.

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👯 Twins, Adoption, and Genetic Studies

• Identical (Monozygotic) Twins – Twins that develop from a single fertilized egg that splits in two, creating two genetically identical organisms.

• Fraternal (Dizygotic) Twins – Twins that develop from separate fertilized eggs. They share a prenatal environment but are genetically no more similar than siblings.

• Separated Twins – Identical twins raised separately after birth. Used in twin studies to measure genetic vs. environmental influence.

• Thomas Bouchard – American psychologist who led the Minnesota Twin Study, which found high correlations in personality traits between separated identical twins.

• Minnesota Twin Study – A large-scale study of identical twins reared apart; showed strong genetic influences on personality, intelligence, religiosity, and preferences.

• Biological vs. Adoptive Relatives – Biological relatives share genes, adoptive relatives share environment. Personality traits are found to be more similar to biological parents.

• Interaction – The interplay between genes and environment, where one factor’s effect depends on the other.

• Epigenetics – The study of molecular mechanisms by which environment can turn genes on or off without altering DNA sequence.

• Gene-Environment Interaction – The combined effect of genetic predispositions and environmental triggers (e.g., a gene for depression activated by trauma).

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🧠 Nervous System

• Nervous System – The body’s speedy electrochemical communication network, consisting of all nerve cells of the peripheral and central nervous systems.

• Central Nervous System (CNS) – Brain and spinal cord.

• Peripheral Nervous System (PNS) – Sensory and motor neurons connecting CNS to the rest of the body.

• Nerves – Bundled axons that connect CNS with muscles, glands, and sensory organs.

• Sensory (Afferent) Neurons – Carry incoming info from tissues/sensory receptors to CNS.

• Motor (Efferent) Neurons – Carry outgoing info from CNS to muscles and glands.

• Interneurons – Neurons in brain/spinal cord that communicate internally and process information.

• Somatic Nervous System – Controls voluntary movements of skeletal muscles.

• Autonomic Nervous System (ANS) – Controls glands and internal organs.

• Sympathetic Nervous System – Arouses the body, mobilizing energy (“fight or flight”).

• Parasympathetic Nervous System – Calms the body, conserving energy (“rest and digest”).

• Reflex – Automatic response to a stimulus, processed in spinal cord.

• Reflex Arc – Pathway involving one sensory neuron, one interneuron, and one motor neuron.

• Cerebrospinal Fluid – Fluid protecting and cushioning the brain and spinal cord.

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🔌 Neurons & Neural Communication

• Neuron – The basic building block of the nervous system.

• Cell Body (Soma) – The life-support center containing the nucleus.

• Dendrites – Branching extensions that receive and integrate messages.

• Axon – Long fiber that passes messages to other neurons, muscles, or glands.

• Myelin Sheath – Fatty tissue layer that insulates axons and speeds transmission.

• Nodes of Ranvier – Gaps in the myelin sheath where action potentials are regenerated.

• Glial Cells (Glia) – Cells that support, nourish, and protect neurons; play a role in learning and memory.

• Action Potential – Neural impulse; brief electrical charge traveling down an axon.

• Threshold – Minimum level of stimulation required to trigger a neural impulse.

• Refractory Period – Short resting pause after a neuron fires.

• All-or-None Response – Neuron fires at full strength or not at all.

• Synapse / Synaptic Gap – Junction between axon tip and receiving neuron’s dendrite.

• Terminal Buttons – Structures at axon ends that release neurotransmitters.

• Neural Network – Interconnected groups of neurons that work together.

• Pruning – The process during adolescence where unused neural connections are eliminated.

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🧪 Neurotransmitters

• Neurotransmitters – Chemical messengers that cross the synaptic gap and influence whether a neuron will fire.

• Reuptake – The reabsorption of a neurotransmitter by the sending neuron.

• Acetylcholine (ACh) – Enables muscle action, learning, and memory; low levels linked to Alzheimer’s.

• Dopamine – Affects movement, learning, attention, emotion, pleasure/reward; too much → schizophrenia, too little → Parkinson’s.

• Serotonin – Regulates mood, sleep, hunger; low levels → depression.

• Norepinephrine – Controls alertness/arousal; low → depression.

• GABA – Main inhibitory neurotransmitter; low → seizures, anxiety.

• Glutamate – Main excitatory neurotransmitter; too much → migraines/seizures.

• Endorphins – Natural painkillers; too little → more pain/stress.

• Substance P – Involved in pain perception and immune response.

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💊 Drugs & Neurochemistry

• Agonist – Molecule that increases neurotransmitter action.

• Antagonist – Molecule that blocks neurotransmitter action.

• Psychoactive Drug – Substance that alters brain function, changing mood/perception.

• Substance Use Disorder – Continued use despite life disruption.

• Tolerance – Diminished effect with regular use, requiring more.

• Withdrawal – Distress following discontinuation.

• Addiction – Compulsive craving despite harmful consequences.

• Blood-Brain Barrier – Membrane protecting brain from harmful substances.

• Synergistic Effect – Two drugs combined create a stronger effect.

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Drug Classes & Examples

• Depressants – Slow neural activity. (Alcohol, barbiturates, opioids)

• Stimulants – Speed up neural activity. (Caffeine, nicotine, cocaine, amphetamines, meth)

• Hallucinogens – Distort perceptions. (LSD, psilocybin, THC)

• Ecstasy (MDMA, Molly) – Stimulant + mild hallucinogen affecting serotonin.

• Opioids – Pain relief, CNS depressants (morphine, heroin).

• Barbiturates – Tranquilizers that impair memory/judgment.

• Nicotine – Highly addictive stimulant in tobacco.

• Cocaine – Powerful CNS stimulant from coca plant.

• THC (Marijuana) – Mild hallucinogen producing relaxation and altered perception.

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🧠 Brain Structures & Imaging

• Biological Psychology – Study of links between biology and behavior.

• Biopsychosocial Approach – Integrates biological, psychological, and social levels of analysis.

• Levels of Analysis – Different perspectives (biological, psychological, social-cultural).

• Neuroplasticity – Brain’s ability to reorganize and form new pathways.

• Lesion – Tissue destruction (natural or experimental).

• EEG – Records brain’s electrical activity.

• MEG – Measures brain’s magnetic fields.

• CT Scan – X-ray images combined to show brain structure.

• PET Scan – Shows brain activity via radioactive glucose use.

• MRI – Produces detailed brain images.

• fMRI – Shows both brain function and structure by measuring blood flow.

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Brain Regions

• Hindbrain – Medulla, pons, cerebellum; controls survival functions.

• Midbrain – Connects hindbrain/forebrain; relays sensory information.

• Forebrain – Cerebral cortex, thalamus, hypothalamus; higher cognitive functions.

• Brainstem – Automatic survival functions.

• Medulla – Controls heartbeat/breathing.

• Thalamus – Sensory relay center.

• Reticular Formation – Filters stimuli, controls arousal.

• Cerebellum – Balance, coordination, nonverbal learning.

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Limbic System

• Amygdala – Emotion (fear, aggression).

• Hypothalamus – Regulates hunger, thirst, body temp; reward center.

• Hippocampus – Memory formation.

• Pituitary Gland – Master endocrine gland.

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Cerebral Cortex & Lobes

• Cerebral Cortex – Outer layer of brain; control center.

• Frontal Lobes – Decision-making, planning, speech production (Broca’s area).

• Parietal Lobes – Touch, spatial reasoning.

• Occipital Lobes – Vision processing.

• Temporal Lobes – Auditory processing, language comprehension (Wernicke’s area).

• Motor Cortex – Voluntary movement control.

• Somatosensory Cortex – Registers body touch/movement sensations.

• Association Areas – High-level thinking, memory, learning.

• Prefrontal Cortex – Personality, decision-making; last brain area to mature.

• Corpus Callosum – Connects brain hemispheres.

• Split Brain – Corpus callosum severed; hemispheres can’t communicate.

• Brain Lateralization – Specialization of left vs. right hemispheres.

• Contralateral Control – Each hemisphere controls opposite body side.

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Disorders, Phenomena, and Examples

• Aphasia – Impaired ability to produce/understand speech.

• Apraxia – Difficulty planning/coordinating voluntary movement.

• Phineas Gage – Famous case showing frontal lobe’s role in personality.

• Alexia – Loss of ability to read due to occipital lobe injury.

• Agnosia – Inability to recognize objects, people, or sounds despite intact senses.

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