psych unit1

Nature vs. nurture

The interaction between heredity (genetic/predisposed traits) and environmental factors (family, education, experiences) in shaping behavior and mental processes.

Evolutionary perspective

Natural selection shapes behavior and mental processes to increase survival and reproductive success.

Eugenics

The misapplication of evolutionary principles to selectively breed humans — an attempt to discriminate against others based on evolutionary ideas.

Twin studies

Research comparing identical vs. fraternal twins to estimate the relative contributions of genes and environment to behavior and mental processes.

Adoption studies

Research comparing adopted children to their biological vs. adoptive families to disentangle genetic and environmental influences on behavior.

Family studies

Research examining patterns of traits or disorders across family members to assess hereditary influence.

Central nervous system (CNS)

The brain and spinal cord — processes all information and interacts with all body processes.

Peripheral nervous system (PNS)

The network of nerves outside the CNS that relays messages between the CNS and the rest of the body

Autonomic nervous system

Controls involuntary body processes (heart rate, digestion, glands)

Sympathetic nervous system

Activates the body's fight-or-flight response — increasing heart rate, dilating pupils, and redirecting blood to muscles.

Parasympathetic nervous system

Returns the body to a calm resting state after arousal — slowing heart rate and stimulating digestion (rest-and-digest).

Somatic nervous system

Controls voluntary body movements — governs skeletal muscle actions.

Neuron

A neural cell that transmits information in the nervous system

Glial cells

Non-neural cells that provide structure, insulation (myelin), communication support, and waste transport for neurons.

Reflex arc neurons

Three types work together in the spinal cord: sensory neurons (carry signals from body to CNS), interneurons (process within CNS), and motor neurons (carry signals from CNS to muscles).

All-or-none principle

A neuron either fires completely (action potential) or not at all — the strength of the stimulus does not change the size of the impulse.

Resting potential

The state of a neuron when not firing — the inside of the cell is negatively charged relative to the outside.

Depolarization

When a neuron's membrane becomes less negative as sodium ions rush in, triggering an action potential.

Refractory period

The brief period after firing when a neuron cannot fire again, allowing it to reset to resting potential.

Reuptake

The process by which a sending neuron reabsorbs excess neurotransmitters from the synapse after transmission.

Threshold (neural)

The minimum level of stimulation needed to trigger an action potential in a neuron.

Dopamine

Involved in reward, motivation, movement, and learning. Associated with Parkinson's disease (low levels) and schizophrenia (excess activity).

Serotonin

Regulates mood, sleep, and appetite. Low levels are associated with depression.

Norepinephrine

Involved in alertness, attention, and the fight-or-flight response. Plays a role in mood disorders.

GABA

The brain's main inhibitory neurotransmitter — reduces neural firing. Low GABA is linked to anxiety and seizures.

Glutamate

The brain's main excitatory neurotransmitter — increases neural firing. Involved in learning and memory.

Endorphins

Natural pain-relieving neurotransmitters released during stress or vigorous exercise — produce feelings of euphoria.

Substance P

A neurotransmitter involved in transmitting pain signals from the body to the brain.

Acetylcholine

Enables muscle contractions, learning, and memory. Deficits linked to Alzheimer's disease

Agonist vs. antagonist drugs

Agonists mimic or enhance neurotransmitter activity (encouraging neural firing). Antagonists block neurotransmitter binding (discouraging neural firing).

Reuptake inhibitors

Drugs that block the reabsorption of neurotransmitters back into the sending cell, increasing their availability in the synapse (e.g., SSRIs).

Stimulants

Drugs (e.g., cocaine, caffeine) that increase neural activity — producing heightened alertness, energy, and heart rate.

Depressants

Drugs (e.g., alcohol) that decrease neural activity — producing relaxation, slowed reaction time, and lowered inhibitions.

Hallucinogens

Drugs (e.g., marijuana, LSD) that distort perception and/or cognition, causing hallucinations or altered sensory experiences.

Opioids

Drugs (e.g., heroin, morphine) that primarily act as pain relievers by binding to opioid receptors.

Tolerance and addiction

Tolerance = needing more of a drug for the same effect. Addiction = compulsive drug use with withdrawal symptoms upon stopping.

The 5 CED hormones

Adrenaline (stress response), leptin (fullness signal), ghrelin (hunger signal), melatonin (sleep regulation), oxytocin (bonding and trust).

Brain stem / medulla

Controls basic life-sustaining functions: breathing, heart rate, and blood pressure.

Reticular activating system (RAS)

Controls alertness, some voluntary movement, eye movement, and some forms of learning, cognition, and emotion.

Cerebellum

Controls coordination of muscle movement, balance, and some forms of procedural learning.

Limbic system structures

Thalamus, hypothalamus, pituitary gland, hippocampus, and amygdala — involved in emotion, memory, and motivation.

Thalamus

The brain's sensory relay station — routes incoming sensory information (except smell) to the appropriate cortical areas.

Hypothalamus

Regulates hunger, thirst, body temperature, sexual behavior, and the stress response. Links the nervous and endocrine systems.

Hippocampus

Critical for forming new explicit/declarative memories and spatial navigation.

Amygdala

Processes emotional responses, especially fear and aggression. Involved in emotional memory formation.

Occipital lobes

Control visual information processing — located at the rear of the brain.

Temporal lobes

Control auditory and linguistic processing — located on the sides of the brain.

Parietal lobes

Contain the somatosensory cortex (touch) and association areas that process/organize sensory information — located near the back crown.

Frontal lobes

Control higher-order thinking, executive functioning, linguistic processing (prefrontal cortex), and voluntary skeletal movement (motor cortex).

Broca's area

Located in the left frontal lobe — controls speech production. Damage causes Broca's aphasia: difficulty producing speech while comprehension remains intact.

Wernicke's area

Located in the left temporal lobe — controls speech comprehension. Damage causes fluent but meaningless speech.

Contralateral hemispheric organization

Each hemisphere controls the opposite side of the body — exploited in split-brain research by showing stimuli to one visual field at a time.

Corpus callosum

The thick band of nerve fibers connecting the two brain hemispheres, enabling communication between them.

Split-brain research

Severing the corpus callosum (for severe epilepsy) reveals that each hemisphere may specialize in different functions — language mostly in the left hemisphere.

Brain plasticity

The brain's ability to rewire itself and form new connections throughout life, allowing undamaged areas to assume functions of damaged ones.

Brain research methods

EEG measures electrical activity

Consciousness

Varying levels of awareness of thoughts, feelings, behavior, and internal/external events. Sleep and wakefulness are both states of consciousness.

Circadian rhythm

A roughly 24-hour biological cycle regulating the sleep/wake pattern. Jet lag and shift work disrupt it.

NREM sleep (Stages 1–3)

Non-rapid-eye-movement sleep. Stage 1 involves hypnagogic sensations. Stage 3 is deep slow-wave sleep. NREM duration decreases as the night progresses.

REM sleep

Paradoxical sleep — brain waves resemble wakefulness but the body is most relaxed/paralyzed. Dreaming typically occurs here

REM rebound

When deprived of REM sleep, the body compensates with increased REM on subsequent nights.

Dream theories (CED only)

Activation-synthesis theory: random brain activation is interpreted as dreams. Consolidation theory: dreams help organize and store memories.

Why we sleep

Memory consolidation (organizing memories from the day) and restoration (replenishing depleted resources used during waking hours).

Insomnia

Persistent difficulty falling or staying asleep, leading to impaired daytime functioning.

Narcolepsy

A disorder involving sudden, uncontrollable sleep attacks during the day, sometimes with loss of muscle tone (cataplexy).

Sleep apnea

Breathing repeatedly stops during sleep, causing frequent arousals and daytime fatigue.

REM sleep behavior disorder

Normal muscle paralysis of REM sleep is absent, causing a person to physically act out their dreams.

Somnambulism

Sleepwalking — a NREM disorder where a person performs actions while remaining asleep.

Sensation

The process of detecting environmental stimuli that meet a threshold and transducing them into neurochemical signals for brain processing.

Absolute threshold

The minimum stimulus intensity detectable at least 50% of the time.

Just-noticeable difference (JND)

The minimum difference in stimuli needed to detect a change — also called the difference threshold.

Weber's Law

The JND is a constant proportion of the original stimulus — larger stimuli require proportionally larger changes to notice a difference.

Sensory adaptation

Diminished sensitivity to a constant, unchanging stimulus over time.

Transduction

Converting a physical stimulus (light, sound, pressure) into a neurochemical signal the brain can process.

Sensory interaction

The constant collaboration of sensory systems — one sense can influence another (e.g., smell shaping taste).

Synesthesia

A sensory experience in which stimulation of one sense triggers an experience in another (e.g., hearing colors).

Rods

Photoreceptors in the eye's periphery that detect shape and movement but not color — most active in low-light environments.

Cones

Color-detecting photoreceptors in the fovea. Three types: blue (short wavelengths), green (medium), red (long wavelengths).

Accommodation (visual)

The lens changing shape to focus light from near or far objects onto the retina.

Blind spot

Where the optic nerve exits the eye — no photoreceptors exist there, so the brain fills in the gap.

Trichromatic theory

The retina has three cone types (red, green, blue) whose combined activation produces all perceived colors.

Opponent-process theory

Color vision is explained by opposing ganglion cell pairs (red/green, blue/yellow, black/white) — explains afterimages.

Color vision deficiency

Damage to one or more cone types or ganglion cells. Includes dichromatism (2 functioning cone types) and monochromatism (1 or none).

Prosopagnosia

Face blindness — inability to recognize faces, caused by occipital lobe damage.

Blindsight

The ability to respond to visual stimuli without conscious awareness, caused by occipital lobe damage.

Pitch and loudness

Pitch is determined by sound wave frequency (wavelength)

Pitch perception theories

Place theory: different cochlea locations detect different pitches. Frequency theory: neural firing rate matches sound frequency. Volley theory: neuron groups alternate firing for higher frequencies.

Conduction vs. sensorineural deafness

Conduction: mechanical problem in outer/middle ear. Sensorineural: damage to the cochlea or auditory nerve.

Olfaction (smell)

The only sense not first relayed through the thalamus — connects directly to emotion and memory areas. Pheromones produce chemical signals for the olfactory system.

Gustation (taste)

The sense of taste: sweet, sour, salty, bitter, umami, and oleogustus (fatty). People with more taste receptors are called supertasters.

Chemical senses interaction

Smell and taste interact — without smell, taste sensations are muted or absent entirely.

Gate-control theory

Pain signals can be blocked ("gated") in the spinal cord by competing signals — explains why rubbing a wound reduces pain.

Phantom limb sensation

People who have lost a limb report sensations (including pain) in the area where the limb used to be.

Vestibular sense

The sense of balance and spatial orientation, primarily detected by the semicircular canals in the inner ear.

Kinesthesis

The sense of one's own body movement and position, allowing coordinated motion without visual feedback.