PSYC 101 Midterm Review: Research Methods, Biopsychology, Learning, Perception and Memory

Terms in this set (34)

1. Independent variable vs dependent variableThe independent variable is what the experimenter deliberately manipulates; the dependent variable is what is measured to see whether it changed as a result.
2. Why does random assignment allow a causal conclusion in an experiment?It makes the groups equivalent on average on all pre-existing characteristics, so a difference in the dependent variable can be attributed to the manipulation rather than to confounds.
3. Random sampling vs random assignmentRandom sampling chooses who is in the study, which supports generalizing to the population (external validity). Random assignment decides which condition each participant gets, which supports causal inference (internal validity).
4. What is a confounding variable?A variable other than the independent variable that changes systematically along with it, providing an alternative explanation for any difference in the dependent variable.
5. What does a correlation coefficient (r) tell you?r ranges from −1 to +1. The sign gives the direction of the linear relationship and the absolute value gives its strength; r = 0 means no linear relationship.
6. Give two reasons a correlation between X and Y does not prove X causes Y.Directionality: Y might cause X. Third variable: some other factor Z might cause both (e.g., hot weather raises both ice cream sales and drownings).
7. What is an operational definition?A concrete statement of exactly how a variable will be measured or manipulated, e.g., defining aggression as the number of times a child hits a doll in 10 minutes.
8. Reliability vs validityReliability is consistency of a measure across time, raters or items. Validity is whether it measures what it claims to measure. A measure can be reliable but not valid, but it cannot be valid without being reliable.
9. What problems does a double-blind design control for?Because neither participants nor the researchers who interact with them know who is in which condition, it controls for placebo effects and experimenter expectancy effects.
10. Which measure of central tendency is least affected by extreme scores?The median, the middle score when values are ordered. The mean is pulled toward outliers, which is why median income is usually reported instead of mean income.
11. In a normal distribution, what percentage of scores fall within 1 and 2 standard deviations of the mean?About 68% fall within ±1 SD and about 95% fall within ±2 SD.
12. What does p < .05 mean, and what does it NOT mean?If the null hypothesis were true, results at least this extreme would occur less than 5% of the time. It does not mean the effect is large or important, or that the hypothesis is 95% likely to be true.
13. Trace the path of a signal through a single neuron.Dendrites receive input, the cell body (soma) integrates it, the axon carries the action potential away from the soma, and the axon terminals release neurotransmitter into the synapse.
14. Describe the ion movements during an action potential.At threshold, voltage-gated Na+ channels open and Na+ rushes in (depolarization). Then K+ channels open and K+ flows out (repolarization), with a brief hyperpolarization and refractory period.
15. What is the resting membrane potential and what maintains it?About −70 mV inside relative to outside. It is maintained by the sodium-potassium pump (3 Na+ out, 2 K+ in) and the membrane's greater permeability to K+ than Na+.
16. What does the all-or-none principle say about action potentials?A neuron either fires a full-size action potential or does not fire at all. Stimulus intensity is coded by firing rate and by the number of neurons firing, not by the size of each spike.
17. What does myelin do?It insulates the axon so the action potential jumps between gaps called nodes of Ranvier (saltatory conduction), greatly speeding transmission. Myelin loss in multiple sclerosis slows or disrupts signals.
18. Agonist vs antagonist drugsAn agonist mimics or enhances a neurotransmitter's effect; an antagonist blocks or reduces it. SSRIs, for example, increase serotonin's action by blocking its reuptake.
19. Broca's aphasia vs Wernicke's aphasiaBroca's (left frontal lobe): slow, effortful, non-fluent speech with relatively good comprehension. Wernicke's (left temporal lobe): fluent but meaningless speech with poor comprehension.
20. A split-brain patient sees a word flashed only to the left visual field. What happens?The word reaches the right hemisphere, which usually lacks speech, so the patient cannot say it, but can pick out the named object with the left hand (controlled by the right hemisphere).
21. In Pavlov's experiments, identify the US, UR, CS and CR.Food is the unconditioned stimulus (US) causing salivation, the unconditioned response (UR). After pairing, the tone becomes a conditioned stimulus (CS) that triggers salivation, now the conditioned response (CR).
22. Extinction vs spontaneous recovery in classical conditioningExtinction: the CR weakens when the CS is repeatedly presented without the US. Spontaneous recovery: after a rest period, the extinguished CR briefly reappears, showing the learning was suppressed, not erased.
23. Negative reinforcement vs punishmentNegative reinforcement removes an unpleasant stimulus to INCREASE a behaviour (taking aspirin removes a headache). Punishment DECREASES a behaviour. A common mistake is treating negative reinforcement as punishment.
24. Which reinforcement schedule produces high, steady responding and the most resistance to extinction?Variable ratio, where reinforcement comes after an unpredictable number of responses, as with slot machines.
25. What did Bandura's Bobo doll study show?Children who watched an adult act aggressively toward a doll were more likely to copy that aggression. This showed observational learning (modelling) without direct reinforcement.
26. Sensation vs perception, and what is transduction?Sensation is the detection of physical energy by sensory receptors; perception is the brain organizing and interpreting it. Transduction is converting that energy into neural signals.
27. State Weber's law.The just noticeable difference is a constant proportion of the original stimulus: ΔI / I = k. A larger standard stimulus needs a larger change before the difference is noticed.
28. What does signal detection theory separate?It separates sensitivity (how well signal is told apart from noise) from response bias (the criterion for saying 'yes'), using hits, misses, false alarms and correct rejections.
29. Rods vs conesRods are more numerous, very sensitive in dim light, absent from the fovea, and do not code colour. Cones are packed in the fovea, need more light, and support colour vision and fine detail.
30. Describe the Atkinson-Shiffrin (modal) model of memory.Information passes from sensory memory (very brief) to short-term memory (limited capacity, about 7 ± 2 items, roughly 20 to 30 s without rehearsal) and, with encoding, into long-term memory.
31. What is the encoding specificity principle?Retrieval is best when the cues or context at retrieval match those present at encoding. Example: divers recalled word lists better in the same setting (underwater or on land) where they learned them.
32. Proactive vs retroactive interferenceProactive: old learning interferes with recalling new information. Retroactive: new learning interferes with recalling old information.
33. What is the serial position effect?In free recall of a list, items at the beginning (primacy, via long-term memory) and end (recency, still in short-term memory) are remembered better than items in the middle.
34. Availability heuristic vs representativeness heuristicAvailability: judging how likely something is by how easily examples come to mind. Representativeness: judging probability by how closely something matches a prototype, often ignoring base rates.