Unit 1 AP Psychology Study Guide

Evolutionary Psychology

The study of how humans are alike due to 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.

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

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.

Chromosomes

Threadlike structures of DNA molecules containing genes; humans have 46 (23 pairs).

DNA

Deoxyribonucleic acid; the molecule carrying 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

Observable traits or characteristics from the interaction of genotype and environment.

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; genetically no more similar than siblings.

Separated Twins

Identical twins raised separately after birth, used to measure genetic vs. environmental influence.

Thomas Bouchard

Psychologist who led the Minnesota Twin Study, found high correlations in personality traits between separated identical twins.

Minnesota Twin Study

A study of identical twins reared apart that showed strong genetic influences on personality and intelligence.

Biological vs. Adoptive Relatives

Biological relatives share genes, while adoptive relatives share environment. Personality traits align more with biological parents.

Interaction

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

Epigenetics

The study of how the environment can turn genes on or off without altering DNA sequence.

Gene-Environment Interaction

The combined effect of genetic predispositions and environmental triggers.

Nervous System

The body’s speedy electrochemical communication network, consisting of all nerve cells.

Central Nervous System (CNS)

The brain and spinal cord.

Peripheral Nervous System (PNS)

Sensory and motor neurons connecting the CNS to the rest of the body.

Nerves

Bundled axons that connect the CNS with muscles, glands, and sensory organs.

Sensory (Afferent) Neurons

Neurons that carry incoming information from tissues and sensory receptors to the CNS.

Motor (Efferent) Neurons

Neurons that carry outgoing information from the CNS to muscles and glands.

Interneurons

Neurons in the 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 for 'fight or flight' situations.

Parasympathetic Nervous System

Calms the body, conserving energy for 'rest and digest' functions.

Reflex

An automatic response to a stimulus, processed in the spinal cord.

Reflex Arc

Pathway involving one sensory neuron, one interneuron, and one motor neuron.

Cerebrospinal Fluid

Fluid that protects and cushions the brain and spinal cord.

Neuron

The basic building block of the nervous system.

Cell Body (Soma)

The life-support center containing the nucleus of the neuron.

Dendrites

Branching extensions of neurons 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 up transmission.

Nodes of Ranvier

Gaps in the myelin sheath where action potentials are regenerated.

Glial Cells (Glia)

Cells that support, nourish, and protect neurons; involved 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

A neuron fires at full strength or not at all.

Synapse / Synaptic Gap

Junction between the axon tip and the receiving neuron's dendrite.

Terminal Buttons

Structures at the end of an axon that release neurotransmitters.

Neural Network

Interconnected groups of neurons that work together.

Pruning

The process during adolescence where unused neural connections are eliminated.

Neurotransmitters

Chemical messengers that cross the synaptic gap and influence neural firing.

Reuptake

The reabsorption of a neurotransmitter by the sending neuron.

Acetylcholine (ACh)

Neurotransmitter enabling muscle action, learning, and memory; linked to Alzheimer's.

Dopamine

Neurotransmitter affecting movement, attention, emotion; related to schizophrenia and Parkinson's.

Serotonin

Regulates mood, sleep, hunger; low levels are linked to depression.

Norepinephrine

Controls alertness and arousal; low levels are associated with depression.

GABA

Main inhibitory neurotransmitter; low levels can lead to seizures and anxiety.

Glutamate

Main excitatory neurotransmitter; excessive levels can lead to migraines and seizures.

Endorphins

Natural painkillers; low levels can lead to more pain and stress.

Substance P

Involved in pain perception and immune response.

Agonist

Molecule that increases neurotransmitter action.

Antagonist

Molecule that blocks neurotransmitter action.

Psychoactive Drug

Substance that alters brain function and changes mood or perception.

Substance Use Disorder

Continued substance use despite life disruptions.

Tolerance

Diminished effect of a substance with regular use, requiring more for the same effect.

Withdrawal

Distress following the discontinuation of a substance.

Addiction

Compulsive craving for a substance despite harmful consequences.

Blood-Brain Barrier

Membrane protecting the brain from harmful substances.

Synergistic Effect

When two drugs combined create a stronger effect.

Depressants

Substances that slow neural activity (e.g., alcohol, barbiturates, opioids).

Stimulants

Substances that speed up neural activity (e.g., caffeine, nicotine, cocaine).

Hallucinogens

Substances that distort perceptions (e.g., LSD, psilocybin, THC).

Ecstasy (MDMA, Molly)

A drug that is a stimulant and mild hallucinogen affecting serotonin.

Opioids

Pain relief medications that act as CNS depressants (e.g., morphine, heroin).

Barbiturates

Tranquilizers that impair memory and judgment.

Nicotine

A highly addictive stimulant found in tobacco.

Cocaine

A powerful CNS stimulant derived from the coca plant.

THC (Marijuana)

A mild hallucinogen that produces relaxation and altered perception.

Biological Psychology

Study of links between biology and behavior.

Biopsychosocial Approach

Integrates biological, psychological, and social levels of analysis.

Levels of Analysis

Different perspectives from biological to social-cultural.

Neuroplasticity

The brain’s ability to reorganize and form new pathways.

Lesion

Tissue destruction, either natural or experimental.

EEG

A technique that records brain's electrical activity.

MEG

Technique that measures the brain's magnetic fields.

CT Scan

An imaging method using X-ray images combined to show brain structure.

PET Scan

Shows brain activity via the use of radioactive glucose.

MRI

Technique that produces detailed brain images.

fMRI

Technique showing both brain function and structure by measuring blood flow.

Hindbrain

Region controlling survival functions such as heartbeat and breathing.

Midbrain

Connects hindbrain and forebrain; relays sensory information.

Forebrain

Region responsible for higher cognitive functions.

Brainstem

Controls automatic survival functions.

Medulla

Controls heartbeat and breathing.

Thalamus

Sensory relay center.

Reticular Formation

Filters stimuli and controls arousal.

Cerebellum

Controls balance, coordination, and nonverbal learning.