PSY 1101 Midterm Review: Research Methods, Neuroscience, Sensation and Perception

Terms in this set (31)

1. Hypothesis vs theoryA hypothesis is a specific, testable prediction. A theory is a broader, well-supported explanation that organizes many observations and generates new hypotheses.
2. Operational definitionA precise statement of how a variable will be measured or manipulated in a study, such as defining aggression as the number of times a child hits a doll in 10 minutes.
3. Independent vs dependent variableThe independent variable is the factor the researcher manipulates. The dependent variable is the outcome that is measured to see whether it changed.
4. Why can experiments show causation when correlational studies cannot?Experiments manipulate the independent variable and use random assignment, which controls for other factors. Correlational studies only measure variables as they occur, so other explanations remain possible.
5. Interpreting a correlation coefficient (r)r ranges from -1 to +1. The sign gives direction and the absolute value gives strength, so r = -0.80 is a stronger relationship than r = +0.50.
6. Third-variable problemA correlation between two variables may be caused by an unmeasured third variable. Ice cream sales and drownings both rise in summer because of hot weather, not because one causes the other.
7. Random sampling vs random assignmentRandom sampling selects participants so the sample represents the population (helps generalize). Random assignment places participants into conditions by chance (helps establish causation).
8. What is a double-blind procedure and why use it?Neither participants nor the researchers collecting data know who is in which condition. It reduces placebo effects and experimenter bias.
9. Reliability vs validityReliability is consistency: the measure gives similar results across time or raters. Validity is accuracy: the measure actually assesses what it claims to. A measure can be reliable without being valid.
10. Main parts of a neuron and their rolesDendrites receive signals, the cell body (soma) integrates them, the axon conducts the action potential, the myelin sheath speeds conduction, and axon terminals release neurotransmitters.
11. Describe the action potentialAt rest the inside of the neuron is about -70 mV. When threshold is reached, Na+ channels open and Na+ rushes in (depolarization); then K+ flows out (repolarization). It is all-or-none: it fires fully or not at all.
12. What is the refractory period?A brief time after an action potential when the neuron cannot fire again (absolute) or needs stronger stimulation to fire (relative). It keeps signals moving in one direction and limits firing rate.
13. How is a signal passed across a synapse?The action potential triggers release of neurotransmitter into the synaptic cleft. It binds to receptors on the next neuron, producing excitatory or inhibitory effects, and is then cleared by reuptake or enzymes.
14. Match the neurotransmitters: dopamine, serotonin, acetylcholine, GABA, glutamateDopamine: reward and movement. Serotonin: mood, sleep and appetite. Acetylcholine: muscle contraction and memory. GABA: main inhibitory transmitter. Glutamate: main excitatory transmitter.
15. Agonist vs antagonistAn agonist mimics or enhances a neurotransmitter's effect at its receptor. An antagonist blocks or reduces the neurotransmitter's effect.
16. Sympathetic vs parasympathetic nervous systemBoth are parts of the autonomic nervous system. Sympathetic: fight or flight (raises heart rate, dilates pupils). Parasympathetic: rest and digest (slows heart rate, promotes digestion).
17. Main functions of the four cerebral lobesFrontal: planning, decision making, movement (motor cortex). Parietal: touch and body position (somatosensory cortex), spatial attention. Temporal: hearing and language comprehension. Occipital: vision.
18. Broca's area vs Wernicke's areaBroca's area (left frontal lobe) supports speech production; damage causes slow, effortful speech. Wernicke's area (left temporal lobe) supports comprehension; damage causes fluent but meaningless speech.
19. Roles of the hippocampus, amygdala and hypothalamusHippocampus: forming new explicit memories. Amygdala: emotion, especially fear. Hypothalamus: regulating hunger, thirst, body temperature and hormones through the pituitary gland.
20. What did split-brain studies reveal?When the corpus callosum is cut, information shown only to the right hemisphere (left visual field) cannot be named aloud, because speech is usually controlled by the left hemisphere. The hemispheres can operate somewhat independently.
21. Sensation vs perceptionSensation is detecting physical energy with sense receptors and converting it into neural signals (transduction). Perception is the brain organizing and interpreting those signals.
22. Absolute threshold vs difference thresholdAbsolute threshold: the minimum stimulus intensity detected 50 percent of the time. Difference threshold (just noticeable difference): the smallest change in a stimulus that can be detected 50 percent of the time.
23. Weber's lawThe just noticeable difference is a constant proportion of the original stimulus, not a fixed amount. If you can detect 1 g added to 50 g, you would need about 2 g added to 100 g.
24. Signal detection theoryDetecting a stimulus depends on both its strength and the observer's decision criterion. Outcomes are hits, misses, false alarms and correct rejections.
25. Rods vs conesRods are more numerous, very sensitive to dim light, concentrated in the periphery and do not detect colour. Cones work in bright light, detect colour and fine detail and are concentrated in the fovea.
26. Trichromatic vs opponent-process theory of colour visionTrichromatic: three cone types sensitive to short, medium and long wavelengths (roughly blue, green, red). Opponent-process: later neural channels code red vs green, blue vs yellow and black vs white, explaining afterimages.
27. Place theory vs frequency theory of pitchPlace theory: different pitches stimulate different locations on the basilar membrane, best for high frequencies. Frequency theory: neurons fire at the rate of the sound wave, best for low frequencies.
28. Bottom-up vs top-down processingBottom-up processing builds a perception from raw sensory features. Top-down processing uses expectations, knowledge and context to interpret sensory input.
29. Name four Gestalt grouping principlesProximity (near things group together), similarity (alike things group), continuity (smooth continuous patterns), and closure (we fill in gaps to see whole figures). Figure-ground separation is also basic.
30. Monocular vs binocular depth cuesBinocular cues need both eyes: retinal disparity and convergence. Monocular cues work with one eye: linear perspective, relative size, interposition, texture gradient and motion parallax.
31. Circadian rhythm and REM sleepThe circadian rhythm is a roughly 24-hour cycle regulated by the suprachiasmatic nucleus of the hypothalamus. REM sleep features rapid eye movements, vivid dreams, an active brain and near-paralysis of skeletal muscles.