Overview
This lecture is a comprehensive review of AP Psychology Unit 1, covering the biological basis of behavior, nervous and endocrine systems, brain structures, sleep, sensation, and related psychological concepts necessary for exam success.
Nature vs. Nurture & Genetics
- Human behavior is influenced by both heredity (nature) and environment (nurture).
- The evolutionary approach emphasizes heredity and natural selection.
- Epigenetics studies how environment and behavior affect gene expression without altering DNA.
- Twin, family, and adoption studies (e.g., Minnesota Twin Study, Colorado Adoption Project) help separate genetic and environmental influences.
- Plasticity is the brain’s ability to adapt and change through experience.
Nervous System Structure & Function
- Central Nervous System (CNS): brain and spinal cord, sends orders to the body.
- Peripheral Nervous System (PNS): nerves connecting CNS to organs/muscles.
- Afferent (sensory) neurons approach CNS; efferent (motor) neurons exit CNS to muscles.
- Somatic system: voluntary movement and senses; autonomic system: involuntary functions.
- Autonomic system splits into sympathetic (arouses, fight-or-flight) and parasympathetic (calms, rest-and-digest).
Neurons & Neural Communication
- Glial cells support and protect neurons but do not process information.
- Neurons are the functional unit, transmitting information via electrical and chemical signals.
- Reflex arc: sensory neuron → interneuron → motor neuron, enabling rapid responses.
- Action potential: neuron fires when threshold is met (all-or-nothing); followed by refractory period.
- Synapse: space where neurotransmitters cross between neurons.
- Reuptake: process where excess neurotransmitters are reabsorbed.
Neurotransmitters & Drugs
- Common neurotransmitters: acetylcholine (muscles, memory), dopamine (movement, emotion), serotonin (mood, sleep), endorphins (pain), epinephrine & norepinephrine (arousal), GABA (inhibition), glutamate (learning).
- Hormones (e.g., adrenaline, melatonin) are slower-acting and released by the endocrine system.
- Agonist drugs enhance neurotransmitter action; antagonists inhibit it.
- Psychoactive drugs include stimulants (caffeine), depressants (alcohol), hallucinogens (LSD), and opioids (heroin).
Brain Structures & Functions
- Hindbrain: spinal cord (info highway), medulla (vital functions), pons (sleep, movement), cerebellum (coordination).
- Midbrain: processes sensory and motor pathways.
- Forebrain: cerebrum (thinking, split into lobes), corpus callosum (connects hemispheres).
- Frontal lobe: reasoning, movement (motor cortex, Broca’s area for speech).
- Parietal lobe: sensation (somatosensory cortex).
- Temporal lobe: hearing, language (Wernicke’s area), memory (hippocampus), emotion (amygdala).
- Occipital lobe: vision.
- Thalamus: sensory relay station.
- Hypothalamus: homeostasis, drives, works with pituitary gland.
- Brain lateralization: left (language), right (spatial, facial recognition).
Sleep & Consciousness
- Consciousness: awareness of self/environment; includes wakefulness and sleep.
- Circadian rhythm: 24-hour biological clock regulating sleep-wake cycles.
- Sleep stages: NREM 1 (light, alpha waves), NREM 2 (theta waves, sleep spindles), NREM 3 (deep, delta waves), REM (dreams, paralysis, beta waves).
- REM rebound occurs after REM deprivation.
- Theories of dreaming: activation-synthesis, memory consolidation, and restoration.
- Sleep disorders: insomnia, sleep apnea, REM behavior disorder, sleepwalking, night terrors, narcolepsy.
Sensation & Perception Basics
- Sensation: detecting environmental information via sensory neurons (sensory transduction).
- Absolute threshold: minimum stimulation detectable 50% of the time.
- Sensory adaptation: reduced sensitivity to unchanging stimuli.
- Habituation: reduced response after repeated exposure to a stimulus.
- Difference threshold: smallest detectable difference between stimuli (Weber’s Law).
- Sensory interaction: senses work together; e.g., taste relies on smell.
- Synesthesia: condition where stimulation of one sense triggers another.
Vision System
- Light passes through cornea, pupil, lens, and focuses on retina.
- Retina contains rods (dim light, periphery) and cones (color, detail, fovea).
- Optic nerve creates a blind spot, brain fills in gaps.
- Trichromatic theory: color from three cone types (R, G, B); opponent-process theory: color pairs (R/G, B/Y, B/W).
- Wavelength: color; amplitude: brightness.
- Vision disorders: color blindness, prosopagnosia (face blindness), blindsight.
Auditory System
- Sound waves’ frequency determines pitch; amplitude determines loudness.
- Place theory: location of hair cell activation detects pitch; frequency theory: nerve impulses match sound frequency; volley theory: neurons alternate firing.
- Hearing loss: sensorineural (nerve damage) vs. conductive (blockage).
- Cochlear implants and hearing aids restore hearing.
Chemical Senses: Smell & Taste
- Olfactory receptors in nose detect odors, send signals to olfactory bulb (bypassing thalamus).
- Pheromones are chemical signals for communication.
- Taste (gustation): sweet, sour, bitter, salty, umami (savory), and “gustus” (fats).
- Taste buds are on papillae; supertasters, medium tasters, non-tasters.
- Smell and taste combine to create flavor.
Touch, Pain, & Body Senses
- Skin senses: pressure, warmth, cold, pain.
- Mechanoreceptors detect pressure, thermoreceptors detect temperature, nociceptors detect pain.
- Gate control theory: spinal gate modulates pain signals.
- Phantom limb: pain perceived in missing body parts.
- Vestibular sense: balance (semicircular canals); kinesthesis: body position/movement (proprioceptors).
- Cerebellum coordinates movement and balance.
Key Terms & Definitions
- Plasticity — brain’s ability to change and adapt via experience.
- Afferent neuron — sensory neuron bringing info to CNS.
- Efferent neuron — motor neuron carrying info from CNS.
- Action potential — electrical impulse sent down a neuron’s axon.
- Synapse — gap between neurons where neurotransmitters cross.
- Agonist/Antagonist — drugs that enhance/inhibit neurotransmitter effects.
- Corpus callosum — nerve fibers connecting brain hemispheres.
- Circadian rhythm — internal biological 24-hour clock.
- REM sleep — sleep stage with rapid eye movement, dreams, muscle paralysis.
- Trichromatic theory — color vision based on three cone types.
- Gate control theory — theory of how pain is modulated in the spinal cord.
- Proprioception — sense of body’s position and movement.
Action Items / Next Steps
- Review and complete the Unit 1 practice quiz.
- Use the study guide to check your answers.
- Practice with additional resources or videos as needed for weak topics.
- Prepare for Unit 2 by reviewing perception concepts.