PSYCH 104 Exam Review: Research Methods, Brain, Sensation, Learning and Memory

Terms in this set (35)

1. Independent variable vs dependent variableThe independent variable is what the researcher manipulates (for example, hours of sleep). The dependent variable is the outcome that is measured (for example, test score).
2. Why doesn't correlation prove causation?A third variable could cause both (the third-variable problem), and the direction of the effect may be unclear (the directionality problem). Only a true experiment with random assignment supports a causal claim.
3. What does a correlation coefficient (r) tell you?r runs from -1 to +1. The sign gives the direction (positive or negative) and the absolute value gives the strength; r = 0 means no linear relationship. For example, r = -0.8 is stronger than r = +0.3.
4. Random sampling vs random assignmentRandom sampling picks participants from a population so that results generalize (external validity). Random assignment places participants into conditions by chance so that groups are equivalent and causal conclusions are valid (internal validity).
5. What is an operational definition?A precise statement of how a variable will be measured or manipulated in a study, for example defining aggression as the number of times a child hits a doll in 10 minutes.
6. What is a double-blind study for?Neither participants nor the researchers who interact with them know who is in which condition. This controls for placebo effects and for experimenter expectancy bias.
7. Name the main parts of a neuron and what each does.Dendrites receive signals, the soma (cell body) integrates them, the axon carries the action potential away, and the axon terminals release neurotransmitter into the synapse.
8. What happens during an action potential?When the membrane reaches threshold, Na+ channels open and Na+ rushes in (depolarization). K+ channels then open and K+ flows out (repolarization). It is all-or-none: a stronger stimulus raises the firing rate, not the size of each spike.
9. What does myelin do, and what happens when it is damaged?Myelin insulates axons so the action potential jumps between the nodes of Ranvier (saltatory conduction), which speeds transmission. Its loss, as in multiple sclerosis, slows or blocks signals.
10. Match these neurotransmitters to their main roles: dopamine, serotonin, acetylcholine, GABA, glutamate.Dopamine: reward and movement (lost in Parkinson's). Serotonin: mood, sleep and appetite. Acetylcholine: muscle contraction and memory (reduced in Alzheimer's). GABA: main inhibitory transmitter. Glutamate: main excitatory transmitter.
11. Agonist vs antagonist drugsAn agonist mimics or enhances a neurotransmitter's effect (for example, morphine at opioid receptors). An antagonist blocks a neurotransmitter's effect (for example, curare blocks acetylcholine receptors).
12. Give the main functions of the four cerebral lobes.Frontal: planning, decision making and voluntary movement (motor cortex). Parietal: touch and body sense (somatosensory cortex) and spatial processing. Temporal: hearing, language comprehension and memory. Occipital: vision.
13. Broca's aphasia vs Wernicke's aphasiaBroca's area (left frontal) damage causes slow, effortful, broken speech with comprehension largely intact. Wernicke's area (left temporal) damage causes fluent but meaningless speech and poor comprehension.
14. What did split-brain studies reveal?When the corpus callosum is cut, an image shown only to the right hemisphere (left visual field) cannot be named aloud, because language is usually in the left hemisphere, yet the left hand can pick out the object.
15. Sensation vs perception, and what is transduction?Sensation is the detection of physical stimuli by sense receptors. Perception is the brain's organization and interpretation of that input. Transduction is the conversion of stimulus energy into neural signals.
16. Absolute threshold vs difference threshold, and Weber's lawThe absolute threshold is the minimum stimulus detected 50% of the time. The difference threshold (JND) is the smallest detectable change. Weber's law: the JND is a constant proportion of the original stimulus (ΔI/I = k).
17. What does signal detection theory add to the idea of thresholds?Detection depends on both sensitivity and the observer's decision criterion. Outcomes are hits, misses, false alarms and correct rejections, so motivation and expectations shift responses.
18. Rods vs conesRods are concentrated in the periphery, are very sensitive in dim light and do not code colour. Cones are concentrated in the fovea, need brighter light and support colour vision and fine detail.
19. Trichromatic theory vs opponent-process theory of colour visionTrichromatic: three cone types (short, medium and long wavelength, roughly blue, green and red) combine to code colour. Opponent-process: later neurons work in opposing pairs (red-green, blue-yellow, black-white), which explains afterimages. Both are correct at different stages.
20. Place theory vs frequency theory of pitchPlace theory: different frequencies maximally vibrate different locations on the basilar membrane, which best explains high pitches. Frequency theory: neural firing rate matches the sound frequency, which explains low pitches.
21. Name four Gestalt grouping principles.Proximity (nearby items group together), similarity (alike items group), continuity (we see smooth, continuous lines) and closure (we fill gaps to see whole figures). Figure-ground separation is also basic.
22. Bottom-up vs top-down processingBottom-up processing builds perception from raw sensory features. Top-down processing uses expectations, knowledge and context to interpret input, for example reading a messy word correctly from the rest of the sentence.
23. Give examples of binocular and monocular depth cues.Binocular: retinal disparity and convergence. Monocular: relative size, linear perspective, interposition (overlap), texture gradient, relative height and motion parallax.
24. In Pavlov's experiments, identify the UCS, UCR, CS and CR.UCS: food. UCR: salivation to food. CS: the tone, once it has been paired with food. CR: salivation to the tone alone.
25. Define extinction, spontaneous recovery, generalization and discrimination in classical conditioning.Extinction: the CR fades when the CS is presented without the UCS. Spontaneous recovery: the CR reappears after a rest. Generalization: the CR occurs to stimuli similar to the CS. Discrimination: responding only to the CS and not to similar stimuli.
26. Positive and negative reinforcement vs positive and negative punishmentReinforcement increases a behaviour and punishment decreases it. Positive means something is added and negative means something is removed. Taking away a nagging noise when a seatbelt is buckled is negative reinforcement.
27. Which reinforcement schedule produces high response rates and the most resistance to extinction?A variable-ratio schedule (reward after an unpredictable number of responses, as with slot machines). Fixed-interval schedules produce a scalloped pattern with a pause after each reward.
28. What did Bandura's Bobo doll study show?Children who watched an adult act aggressively toward a doll later imitated that aggression, showing observational learning (modelling) without any direct reinforcement.
29. Atkinson-Shiffrin model: name the three memory stores and their limits.Sensory memory: large capacity, lasts under a second (iconic) to a few seconds (echoic). Short-term memory: about 7 plus or minus 2 items, about 20 to 30 seconds without rehearsal. Long-term memory: essentially unlimited and durable.
30. What does the levels-of-processing framework predict?Deeper, meaning-based (semantic) encoding produces better retention than shallow encoding based on appearance (structural) or sound (phonemic).
31. Proactive interference vs retroactive interferenceProactive: old information disrupts recall of new information (your old password intrudes). Retroactive: new information disrupts recall of old information (you learn Spanish and forget French vocabulary).
32. Explicit vs implicit memory, and what patient H.M. showedExplicit memory is conscious recall of facts and events. Implicit memory shows up in skills and priming. After removal of H.M.'s hippocampal regions he could not form new explicit memories (anterograde amnesia) but could still learn motor skills.
33. Availability heuristic vs representativeness heuristicAvailability: judging how likely something is by how easily examples come to mind (fearing plane crashes after news coverage). Representativeness: judging by similarity to a prototype while ignoring base rates.
34. Drive-reduction theory vs the Yerkes-Dodson lawDrive-reduction: physiological needs create drives that motivate behaviour to restore homeostasis. Yerkes-Dodson: performance is best at moderate arousal, and the optimal level is lower for difficult tasks.
35. James-Lange, Cannon-Bard and Schachter-Singer theories of emotionJames-Lange: bodily arousal comes first and the emotion is our perception of it. Cannon-Bard: arousal and emotion happen at the same time and independently. Schachter-Singer (two-factor): arousal plus a cognitive label produces the emotion.