AP Psychology Unit 1 Exam Study Guide
Research Methods & Statistics
Mean: The average of a set of numbers.
Median: The middle value in a sorted set of numbers.
Mode: The value that appears most frequently in a set of numbers.
Range: The difference between the highest and lowest values in a set of numbers.
Standard Deviation: A measure of the amount of variation or dispersion of a set of values. \sigma = \sqrt{\frac{\sum (x_i - \mu)^2}{N}}
Normal Distribution: A symmetrical bell-shaped curve that represents the distribution of many random variables. 68% of data falls within one standard deviation of the mean, 95% within two, and 99.7% within three.
R-score (Correlation): A measure of the strength and direction of a linear relationship between two variables. Ranges from -1 to +1.
Positive Skew: A distribution with a long tail extending towards higher values.
Negative Skew: A distribution with a long tail extending towards lower values.
Experimental Design
Types of Research Methods:
Case Studies: In-depth investigations of a single person, group, event, or community.
Experiments: Research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (dependent variable).
Correlational Studies: Research method that measures the relationship between two or more variables without manipulating them.
Ethics: Principles of conduct governing a person or group, especially in research. Includes informed consent, protection from harm, confidentiality, and debriefing.
Operational Definitions: A specific statement of the procedures used to measure or manipulate a variable in research.
Independent Variable (IV): The variable that is manipulated in an experiment.
Dependent Variable (DV): The variable that is measured in an experiment to see if it is affected by the independent variable.
Random Assignment: Assigning participants to experimental and control conditions by chance, thus minimizing pre-existing differences between those assigned to the different groups.
Random Selection: A way of ensuring that a sample of people is representative of a population by giving everyone in the population an equal chance of being selected for the sample.
Generalizability: The extent to which the results of a study can be applied to other populations or settings.
P-value: The probability of obtaining results as extreme as, or more extreme than, the observed results if the null hypothesis is true. A p-value less than 0.05 (p < 0.05) is typically considered statistically significant.
Heredity
Nature vs. Nurture: The debate over the relative contributions of genetic inheritance (nature) and environmental factors (nurture) to human development.
Twin Studies: Studies that compare identical and fraternal twins to assess the relative contributions of genes and environment to behavior and traits.
Identical Twins (Monozygotic): Twins who develop from a single fertilized egg that splits into two, creating two genetically identical organisms.
Fraternal Twins (Dizygotic): Twins who develop from separate fertilized eggs. They are genetically no closer than ordinary siblings, but they share a prenatal environment.
Drugs
Agonism: When a drug binds to a receptor and activates it, mimicking the effect of the natural neurotransmitter.
Antagonism: When a drug binds to a receptor and blocks it, preventing the natural neurotransmitter from activating the receptor.
Types of Drugs:
Stimulants: Drugs that excite neural activity and speed up body functions (e.g., caffeine, nicotine, cocaine, amphetamines).
Depressants: Drugs that reduce neural activity and slow body functions (e.g., alcohol, barbiturates, opiates).
Hallucinogens: Drugs that distort perceptions and evoke sensory images in the absence of sensory input (e.g., LSD, marijuana).
Opioids: Drugs that reduce pain and induce euphoria; highly addictive (e.g., morphine, heroin).
Tolerance: The diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect.
Addiction: Compulsive drug craving and use, despite adverse consequences.
Withdrawal Symptoms: The discomfort and distress that follow discontinuing the use of an addictive drug.
The Nervous System (NS)
Nervous System: The body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.
Nerves: Bundled axons that form neural cables connecting the central nervous system with muscles, glands, and sense organs.
Neurons: A nerve cell; the basic building block of the nervous system.
Central NS (CNS): The brain and spinal cord.
Peripheral NS (PNS): The sensory and motor neurons that connect the central nervous system (CNS) to the rest of the body.
Parasympathetic NS: The division of the autonomic nervous system that calms the body, conserving its energy.
Sympathetic NS: The division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations.
Autonomic NS: The part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms.
Somatic NS: The division of the peripheral nervous system that controls the body's skeletal muscles.
Sensory (Afferent) Neurons: Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.
Motor (Efferent) Neurons: Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.
Interneurons: Neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs.
Reflexes: A simple, automatic response to a sensory stimulus, such as the knee-jerk response.
Neurotransmitters
Neurotransmitters: Chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse.
Receptors: Protein molecules on the surface of dendrites or cell bodies that have a particular shape to which only certain neurotransmitters fit.
Clearing Neurotransmitters from the Synapse:
Reuptake: A neurotransmitter's reabsorption by the sending neuron.
Enzymatic Degradation: Enzymes break down neurotransmitters in the synapse.
Presynaptic Neuron: The neuron that sends the signal across the synapse.
Postsynaptic Neuron: The neuron that receives the signal across the synapse.
Excitatory Synapses: Synapses where neurotransmitters increase the likelihood of the postsynaptic neuron firing an action potential.
Inhibitory Synapses: Synapses where neurotransmitters decrease the likelihood of the postsynaptic neuron firing an action potential.
Endocrine Communication: The system of glands that secrete hormones into the bloodstream to regulate various bodily functions.
Neurons & Neural Firing
Dendrites: Branching extensions of a neuron that receive messages and conduct impulses toward the cell body.
Axon: The extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands.
Axon Terminals: The endpoint of a neuron where neurotransmitters are stored and released.
Soma (Cell Body): The part of a neuron that contains the nucleus; the cell's life-support center.
Myelin Sheath: A fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next.
Synapse: The junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.
Nucleus: The control center of the neuron, containing DNA.
Action Potential: A neural impulse; a brief electrical charge that travels down an axon.
Parts of an Action Potential: Resting potential, depolarization, repolarization, hyperpolarization, and refractory period.
All-or-None Firing: A neuron either fires completely or does not fire at all. The strength of the action potential is always the same.
Sleep
Consciousness: Our awareness of ourselves and our environment.
Circadian Rhythm: The biological clock; regular bodily rhythms (for example, of temperature and wakefulness) that occur on a 24-hour cycle.
Jet Lag: Disruption of circadian rhythms due to crossing time zones.
Stages of Sleep:
Stage 1: Light sleep characterized by theta waves.
Stage 2: Deeper sleep with sleep spindles and K-complexes.
Stages 3 & 4: Deepest sleep stages characterized by delta waves.
REM Sleep: Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.
Brain Waves:
Beta: Awake and alert.
Alpha: Relaxed and awake.
Theta: Stage 1 sleep.
Delta: Stages 3 & 4 sleep.
Dream Theories:
Activation Synthesis Theory: Dreams are the brain's attempt to make sense of random neural activity during REM sleep.
Information Processing Theory: Dreams help us sort out and process the day's events and consolidate our memories.
Sleep Apnea: A sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings.
Narcolepsy: A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times.
REM Behavior Disorder: A sleep disorder in which the sleeper acts out his or her dreams.
Night Terrors: A sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during Stage 4 sleep, within two or three hours of falling asleep, and are seldom remembered.
Sleepwalking: A sleep disorder characterized by walking or doing other activities while seemingly asleep. Occurs during Stage 4 sleep.
Insomnia: Recurring problems in falling or staying asleep.
Sensation & Perception
Sensation: The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment.
Perception: The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.
Transduction: Conversion of one form of energy into another. In sensation, the transforming of stimulus energies, such as sights, sounds, and smells, into neural impulses our brains can interpret.
Absolute Threshold: The minimum stimulation needed to detect a particular stimulus 50 percent of the time.
Just Noticeable Difference (JND) / Weber’s Law: The minimum difference between two stimuli required for detection 50 percent of the time. The JND is proportional to the magnitude of the initial stimulus. \frac{\Delta I}{I} = k , where \Delta I is the JND, I is the intensity of the stimulus, and k is a constant.
Subliminal Threshold: Below one's absolute threshold for conscious awareness.
Habituation: Decreasing responsiveness with repeated stimulation.
Sensory Adaptation: Diminished sensitivity as a consequence of constant stimulation.
Gate Control Theory: The theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.
Synesthesia: A neurological phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.
Vision
Retina: The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.
Blind Spot: The point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there.
Photoreceptors:
Rods: Retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don't respond.
Cones: Retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. The cones detect fine detail and give rise to color sensations.
Trichromatic Theory: The theory that the retina contains three different color receptors—one most sensitive to red, one to green, one to blue—which, when stimulated in combination, can produce the perception of any color.
Opponent-Process Theory: The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green.
Fovea: The central focal point in the retina, around which the eye's cones cluster.
Afterimages: An image continuing to appear in one's vision after exposure to the original image has ceased.
Color Deficiency: Decreased ability to see color or differences in color.
Audition (Hearing)
Wavelengths (Pitch): The distance from the peak of one light or sound wave to the peak of the next. Wavelength determines the pitch of a sound.
Amplitude (Loudness): The height of a wave. Amplitude determines the loudness of a sound.
Tone (Frequency): The number of complete wavelengths that pass a point in a given time. Frequency determines the pitch of a sound.
Place Theory: In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.
Volley Theory: Neural cells alternate firing. By firing in rapid succession, they can achieve a combined frequency above 1000 waves per second.
Frequency Theory: In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch.
Sound Localization: The process of determining the location of a sound source.
Hearing Loss: Decreased ability to perceive sounds.
Olfaction (Smell)
Olfaction: The sense of smell.
Note: Olfactory information does not pass through the thalamus before reaching the cortex.
Gustation (Taste)
Gustation: The sense of taste.
Types of Tastes: Sweet, sour, salty, bitter, umami.
Taste Receptors: Sensory receptors located on taste buds on the tongue that respond to different chemical compounds to produce taste sensations.
Touch
Touch: The sense of physical contact, involving pressure, temperature, and pain.
Pain: An unpleasant sensory and emotional experience associated with actual or potential tissue damage.
Gate-Control Theory: The theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.
Hot and Cold: Temperature sensations are detected by thermoreceptors in the skin.
Vestibular Sense
Vestibular Sense: The sense of body movement and position, including the sense of balance.
Semicircular Canals: Three fluid-filled canals in the inner ear responsible for detecting head rotation and maintaining balance.
Kinesthesis
Kinesthesis: The system for sensing the position and movement of individual body parts.
The Brain
Brainstem: The oldest part and central core of the brain, beginning where the spinal cord swells as it enters the skull; the brainstem is responsible for automatic survival functions.
Medulla: The base of the brainstem; controls heartbeat and breathing.
Pons: A brain structure that relays information from the cerebellum to the rest of the brain.
Reticular Activating System: A set of connected nuclei in the brains of vertebrates that is responsible for regulating wakefulness and sleep-wake transitions.