🧠 AP Psychology Unit 1: Biological Bases of Behavior

heredity

genetic characteristics passed down to us through biological ancestors.

environment

our surroundings/external factors we experience, such as family interactions and education.

epigenetics

the study of how our environment and behaviors can change the way our genes work without changing DNA.

nature-nurture issue

the longstanding controversy over the contribution that genes and environment have on our psychological traits and behaviors.

natural selection

the principle that inherited traits enabling an organism to survive and reproduce in a particular environment will be passed on to succeeding generations.

evolutionary psychology

the study of the evolution of behavior and mind, using principles of natural selection.

phrenology

an outdated belief that the shape of bumps on our skull determines personality traits and mental abilities.

monozygotic twins

identical twins who developed from a single fertilized egg that split into two.

dizygotic twins

fraternal twins who developed from separate fertilized eggs, sharing 50% of genetic makeup.

mutations

random errors in gene replication.

interaction

the interplay that occurs when the effects of one factor depends on another factor.

genes

biochemical units of heredity.

genome

a common set of genes.

behavior genetics

the study of the relative power and limits of genetic and environmental influences on behavior.

nervous system

the body’s speedy, electrochemical communication network consisting of all nerve cells in peripheral and central nervous systems.

central nervous system

includes the brain and spinal cord, responsible for transmitting information throughout the body.

peripheral nervous system

relays messages from the central nervous system to the rest of the body.

somatic nervous system

controls voluntary movements and enables sensations.

autonomic nervous system

governs involuntary processes like heartbeat and digestion.

parasympathetic nervous system

promotes a state of calm and relaxation, facilitating rest and digestion.

sympathetic nervous system

prepares the body for 'fight or flight' response in time of stress.

sensory neurons

neurons that carry information from sensory receptors to the CNS.

motor neurons

neurons that carry signals from the CNS to muscles and glands.

interneurons

neurons within the brain and spinal cord; connect sensory inputs and motor outputs.

reflex

a simple, automatic response to a sensory stimulus.

neurons

nerve cells; the basic building blocks of the nervous system.

cell body

the part of the neuron that contains the nucleus; the cell’s life support center.

dendrite

the neuron’s bushy branching extensions that receive and integrate messages.

axon

the segmented neuron extension that passes messages to other neurons or muscles.

myelin sheath

a fatty tissue layer that encases the axons of some neurons.

glial cells

support, nourish, and protect neurons; play a role in learning and memory.

action potential

a neural impulse; an electrical charge that travels down an axon.

threshold

the level of stimulation required to trigger a neural impulse.

refractory period

a brief resting pause that occurs after a neuron has fired.

all-or-none response

a neuron’s reaction of either firing or not firing.

synapse

the junction between the sending neuron and the receiving neuron.

neurotransmitters

chemical messengers that cross the synaptic gaps between neurons.

reuptake

the reabsorption of a neurotransmitter by the sending neuron.

endorphins

natural neurotransmitters linked to pain control and pleasure.

agonist

a molecule that increases a neurotransmitter's action.

antagonist

a molecule that inhibits or blocks a neurotransmitter's action.

endocrine system

the body’s slow chemical communication system; a set of glands that secrete hormones.

hormones

chemical messengers that travel through the bloodstream and affect other tissues.

psychoactive drugs

chemical substances that alter the brain, causing changes in mood and perceptions.

substance use disorder

disorder characterized by continued substance use despite significant life disruption.

depressants

drugs that reduce neural activity and slow body functions.

barbiturate

drugs that depress central nervous system activity.

opioids

opium and its derivatives that depress neural activity.

stimulants

drugs that excite neural activity and speed up body functions.

hallucinogens

psychedelic drugs that distort perceptions and evoke sensory images.

near-death experience

an altered state of consciousness after a close brush with death.

biological psychologists

scientific study of the links between biological and psychological processes.

biopsychosocial approach

an integrated approach that incorporates biological, psychological, and social levels of analysis.

levels of analysis

differing complementary views for analyzing a phenomenon.

neuroplasticity

the brain's ability to change, especially during childhood.

lesion

tissue destruction in the brain.

EEG (electroencephalogram)

technique that records electrical activity of the brain.

MEG (magnetoencephalography)

a brain-imaging technique that measures magnetic fields produced by neuronal activity.

CT (computed tomography) scan

a specialized x-ray technique that produces cross-sectional images of the brain.

PET (positron emission tomography)

an imaging technique that visualizes metabolic processes in the brain.

MRI (magnetic resonance imaging)

non-invasive imaging technique using strong magnetic fields.

fMRI (functional MRI)

measures and maps brain activity by detecting changes in blood flow.

hindbrain

contains the medulla, pons, and cerebellum; directs essential survival functions.

midbrain

connects hindbrain with forebrain; regulates movement and certain reflexes.

forebrain

includes cerebral cortex, thalamus, and hypothalamus; responsible for higher-order functions.

brainstem

central structure connecting the brain to the spinal cord.

medulla

regulates autonomic functions such as breathing and heart rate.

thalamus

sensory control center of the brain.

reticular formation

a nerve network that plays an important role in controlling arousal.

cerebellum

responsible for coordination, balance, and fine muscle control.

limbic system

neural system associated with emotions and drives.

amygdala

linked to emotion; part of the limbic system.

hypothalamus

regulates maintenance activities; linked to emotion and reward.

hippocampus

helps process explicit memories for storage.

cerebral cortex

the body's ultimate control and information-processing center.

frontal lobes

involved in reasoning, planning, and movement.

parietal lobe

processes sensory information related to touch and spatial orientation.

occipital lobe

primarily responsible for processing visual information.

temporal lobe

involved in processing auditory information and emotions.

motor cortex

controls voluntary movements.

somatosensory cortex

registers and processes body touch and movement sensations.

association areas

involved in higher mental functions such as learning and speaking.

neurogenesis

the formation of new neurons.

corpus callosum

connecting neural fibers between the two brain hemispheres.

split brain

condition resulting from surgery that isolates the brain's two hemispheres.

consciousness

our subjective awareness of ourselves and our environment.

cognitive neuroscience

the interdisciplinary study of brain activity linked with cognition.

dual processing

the principle that information is processed on separate conscious and unconscious tracks.

blindsight

condition where a person can respond to visual stimuli without consciously experiencing them.

parallel processing

processing multiple aspects of a stimulus simultaneously.

sequential processing

processing one aspect of a stimulus at a time.

sleep

a periodic, natural loss of consciousness.

circadian rhythm

our biological clock; regular bodily rhythms on a 24-hour cycle.

REM (rapid eye movement) sleep

a recurring sleep stage during which vivid dreams commonly occur.

alpha waves

relatively slow brain waves of a relaxed, awake state.

NREM (non-rapid eye movement)

encompasses all sleep stages except for REM sleep.

hallucinations

false sensory experiences.

hypnagogic sensations

bizarre experiences occurring while transitioning to sleep.

delta waves

large, slow brain waves associated with deep sleep.

suprachiasmatic nucleus (SCN)

cell clusters in the hypothalamus that control circadian rhythm.