Department of Psychology
Midterm Examination 1
Scoring Key and Item Analysis
In the scoring key that follows, correct answers are marked with an asterisk (*).
Following procedures outlined in the Exam Information page, the statistical analysis identified one (1) bad item, #12, and another item, #43, which had been keyed incorrectly. Item #43 was corrected. Item #12 was rescored correct for all responses. Students who got this item wrong, in terms of the preliminary scoring key, should give themselves one (1) additional point (do not give yourself the additional point if you got the bad item "right"). No other items will be rescored.
The average score on the exam, before rescoring, was 35.06, with a standard deviation of 6.63 -- 70% correct, which is pretty good by the standards of my exams in Psych 1, in which my usual mean (before scoring) is somewhere between 65-70% correct..
The average score on the rescored exam was 37.20 (SD = 6.90), or approximately 74% correct. The median score was 38. This is right in line with historical experience, in which rescoring typically raises the mean to more than 70% correct. The scores entered into the gradebook reflect this rescoring.
In what follows, I provide the percentage of the class that got each item correct, as well as the item-to-total correlation (rpb)for each item. The next iteration of this feedback will include commentary on why the right answer is right, and the others wrong.
Choose the best answer to each of the following 50 questions. Questions are drawn from the text and lectures in roughly equal proportions, with the understanding that there is considerable overlap between the two sources. Usually, only one question is drawn from each major section of each chapter of the required readings; again, sometimes this question also draws on material discussed in class. Read the entire exam through before answering any questions: sometimes one question will help you answer another one.
Most questions can be correctly answered in one of two ways: (1) by fact-retrieval, meaning that you remember the answer from your reading of the text or listening to the lecture; or (2) inference, meaning that you can infer the answer from some general principle discussed in the text or lecture. If you cannot determine the correct answer by either of these methods, try to eliminate at least one option as clearly wrong: this maximizes the likelihood that you will get the correct answer by chance. Also, go with your intuitions: if you have actually done the assigned readings and attended the lectures, your "informed guesses" will likely be right more often than they are wrong.
Be sure you are using a red Scantron sheet.
Fill in the appropriate circles with a #2 pencil only.
Be sure you put your name on the front of the red Scantron sheet.
Be sure you put your Student ID# on both sides of the red Scantron sheet.
Indicate Exam 001 (use all three digits) on the reverse side of the red Scantron sheet.
Retain this exam, along with a record of your answers.
1. A hypothesis is testable if
a. it can be confirmed.
b. it can be disconfirmed.*
c. it is sufficiently vague.
d. virtually any set of circumstances could support it.
66% of the class got this item correct, item-to-total rpb = .36.Technically, scientists are supposed to look for evidence that would disconfirm their hypothesis, not confirm it. At the very least, they ought to be at least as interested in findings that disconfirm their hypotheses as in findings that confirm them. But if all we do is seek evidence that is consistent with our hypotheses, we might never find out when they're wrong. Not everybody does this all the time, but that's what we're supposed to do.
2. In correlational studies, investigators seek to observe the relationship (or degree of correlation) between two variables -- say, height and level of depression. Such studies differ from experimental studies in several important respects. For instance,
a. in correlational studies, it is difficult to determine what is causing what.
b. correlational studies can suffer from what is called the third-variable problem.
c. random assignment is not an option in correlational studies.
d. All of the above are correct.*
80% correct, rpb = .27. In experimental studies, the investigator deliberately manipulates one or more independent variables to determine the effect of the manipulation on the dependent variable. Therefore, cause-and-effect relations are built into the very design of the study. In correlational studies any relation between the two variables might reflect the fact that one causes the other, but it might also reflect the fact that both effects are caused by some third variable. Moreover, experimental studies typically employ some kind of random assignment of subjects to conditions, so as to avoid the influence of unmeasured confounding variables. Correlational studies, by contrast, make use of natural variation, and so are more susceptible to various confounds.
3. If a study's participants are representative of the population as a whole and its stimuli are representative of stimuli encountered in the real world, then the study is said to have
a. internal consistency.
b. internal validity.
c. external validity.*
d. external consistency.
93%, .33. Internal validity has to do with the influence of third, confounding variables. External validity has to do with the degree to which the experimental situation is representative of the world outside the laboratory.
4. Psychology explains human behavior in terms of the individual's
a. evolved biochemical, genetic, and hormonal structures and processes.
b. neural structures and processes.
c. beliefs, feelings, and goals.*
d. sociocultural factors such as ethnicity and high vs. low status
5. Why is the phrase "survival of the fittest" misleading when it comes to understanding Darwinian theory?
a. Survival of the fittest applies only to humans, not to other organisms.
b. What really matters for evolution is not personal survival, but the survival of one's genes.*
c. Genetic survival and reproductive success are two very different things.
d. All of the above are correct.
90%, .23. "Survival of the fittest" applies to biological evolution in general, not just human evolution, but it's a little misleading because the survival in question is of the individual's genes, not the individual him- or herself, because it's through genes that genetic variations are passed down from one generation to the next.
6. In terms of motivation, what occurs in a negative feedback system?
a. The feedback weakens, stops, or even reverses the response that produces it.*
b. The feedback strengthens the response that produces it.
c. The feedback may either stop or strengthen the response that produces it depending upon the level of the setpoint.
d. The feedback will stop the response that produces it if the stimulus is below a particular setpoint and will strengthen it if the stimulus is above a particular setpoint.
85%, .39. Positive feedback increases whatever process generated the feedback. Negative feedback reduces or terminates whatever process generated the feedback. Most biological motives reflect homeostatic self-regulation, and therefore involve negative feedback. Don't confuse positive feedback with reward and negative feedback with punishment.
7. Let's say, hypothetically, that you inject the hypothalamus with a chemical making its cells insensitive to glucose. What would most likely result?
c. ravenous eating*
75%, .39. The hypothalamus is a subcortical structure involved with homeostatic regulation and biological motives such as hunger and thirst. In hunger, the hypothalamust monitors blood-sugar levels, and instigates eating behavior when these get too low, and terminates eating behavior when they get too high. So making the hypothalamus insensitive to glucose would likely instigate eating, because the hypothalamus would "think" that blood sugar levels were too low.
8. Meditation involves a slowing of respiration and heart rate. In order to effect these changes, the activity of the _____ increases.
a. parasympathetic nervous system*
b. sympathetic nervous system
89%, .38. Remember that the sympathetic nervous system becomes active in response to stress, and that the parasympathetic nervous system acts as an antagonist to sympathetic activation. So, meditation would increase the activity of the parasympathetic branch of the autonomic nervous system.
9. Hormonal influences on sexual behavior are evident in the fact that women's preferences and behavior change as they move through their menstrual cycle. For example:
a. women prefer more "feminine" looking men when in a fertile phase.
b. women have almost zero sex drive when not in a fertile phase.
c. women prefer men with a stronger chin and a more prominent brow when in a fertile phase.*
d. injections of hormones have no effect on women during menses.
77%, .31. It's one of those evolutionary holdovers. Even though sexually active women are receptive to sex at times other than the fertile phase of their menstrual cycle, they are particularly attracted to stereotypically masculine partners at this time. So, hormones have an effect of human sexual behavior.
10. Compared to the parasympathetic nervous system, the sympathetic nervous system
a. has slow onset and slow offset.
b. has slow onset and rapid offset.
c. has rapid onset and rapid offset.*
d. has rapid onset and slow offset
55%, .30. The sympathetic nervous system mediates flight or fight, tend and befriend, and in order to do so it's got to act quickly -- and also respond quickly when the stressor has gone away.
11. A patient shows no fear while climbing a high, unstable ladder. This patient likely has damage to his
a. reticular formation.
d. fusiform gyrus.
70%, .41. The reticular formation is important for general arousal and alerting; damage produces coma. The hippocampus is important for memory, as indicated by Patient H.M. The amygdala is important for emotion, especially negative emotions, especially fear. The fusiform gyrus is involved in face recognition (and similar functions).
12. Research by Karl Lashley showed that specific memories were distributed widely through the:
a. prefrontal cortex.
b. association cortex.
c. white matter of the brain.
d. gray matter of the brain.*
26%, .15. A bad item. I don't know why, the whole point of Lashley's Law of Mass Action is that particular memories are represented in a manner that is distributed widely across the cerebral cortex, which is the gray matter of the brain. This contrasts to the situation for functions, like language and voluntary motor control, that are localized in particular brain "centers". Maybe it was the reference to gray matter. Anyway, the statistical analysis rules, so we rescored this item correct for all responses.
13. The word reflex has its origin in
a. Descartes' belief that the energy from the outside is reflected back by the nervous system to an animal's muscles.*
b. Descartes' belief that animals act as automatons whereas people are rational and have souls.
c. Descartes' desire to explain coughing and sneezing without reference to the soul.
d. Descartes' idea that the pineal gland mediates the relationship between the nonmaterial mind and the material brain.
81%, .40. Think "reflects". Descartes didn't know how the nervous system worked, but he figured that animals, which lacked free will, simply "reflected" stimulus energy back out into the environment. In this way, he thought, nonhuman animals never initiate any activity -- they simply respond to environmental events. Only humans, in his view, with minds and souls and free will, had the ability to initiate activity in the absence of an environmental stimulus.
14. One technique used by neuroscientists to determine whether two distinct processes -- say, X and Y -- are served by different brain areas is called "double dissociation. Here brain researchers try to show that
a. X can be disrupted while sparing Y, and Y can be disrupted while sparing X.*
b. X depends on the smooth functioning of Y, and Y on X.
c. X can perform the functions of Y, and Y of X.
d. both X and Y perform multiple functions in the brain, not just one function exclusively.
80%, .40. This is a term you'll see a lot if you continue your studies in psychology. In a single dissociation, some experimental manipulation can impair X while having no effect on Y. In a double dissociation, Y can also be impaired while sparing X. Double dissociations are theoretically important, because they indicate strong modularity -- that the two processes, X and Y, are mediated by separate and independent systems.
15. The limbic system is involved in the control of
a. sensory functions.
b. the skeletal musculature.
c. such higher mental processes as thinking and language.
d. emotional and motivational activities.*
69%, .43. Both the hypothalamus (which is involved in biological motives and homeostatic regulation) and the amygdala (which is involved in negative emotions like fear, at least) are part of the limbic system, nestled underneath the cerebral cortex.
16. A general characteristic of the primary motor area is that
a. the amount of tissue devoted to a specific area is related to that area's function.*
b. the primary motor area contains the sensory area that corresponds to the same area of the body.
c. primary motor areas are localized in only two lobes of the cerebral hemispheres.
d. the location of a neuron in the primary motor area depends on the importance of the body area to which that neuron corresponds.
62%, .58. Remember the motor homunculus. More cortical mass is devoted to those parts of the body, such as the hands, feet, and face, that require fine motor control. Similarly, in the sensory homunculus of the parietal lobe, more cortical mass is devoted to those parts of the body, including the hands and feet and face, but also the genitalia, that require more acute tactile sensitivity.
17. In observing receptive and expressive aphasics one finds that
a. neither expressive nor receptive aphasics can produce speech.
b. neither expressive nor receptive aphasics can comprehend speech.
c. expressive aphasics can comprehend but not produce speech.*
d. receptive aphasics can comprehend but not produce speech.
42%, .30. Expressive aphasia is also called Broca's aphasia and nonfluent aphasia, because the patient's speech isn't very fluent -- there are lots of speech dysfluencies: it's associated with damage to Broca's area in the left frontal lobe. In receptive aphasia, also called Wernicke's aphasia and fluent aphasia, the speech may be fluent but it tends to be meaningless: it's associated with damage to Wernicke's area in the temporal lobe, near the border with the parietal lobe. Expressive aphasics have no difficulty understanding what's said to them -- they have difficulty getting speech out. Receptive aphasics can't make themselves understood, but they have problems understanding -- receiving -- speech as well.
18. What major part of the brain development takes place after a human infant is born?
a. The brain is split into separate lobes.
b. Twenty to eighty percent of neurons in the brain die off (depending on the brain region).
c. Connections between various neurons are wired.*
d. Neutrophic factors cause brain cell differentiation.
66%, .26. Current neuroscientific theory holds that, for all intents and purposes, we're born with all the neurons we're going to have, and the basic structures of the brain are also present at birth. What happens after birth, as the infant begins to have experiences in the world, is that the pattern of neural interconnections changes -- as, for example, in long-term potentiation, which is the physiological mechanism of learning.
19. _____ is a process by which used neurotransmitters are ejected from the postsynaptic receptors, sucked back into presynaptic axon terminals, and repackaged into new synaptic vesicles.
a. Synaptic reuptake*
b. Neurotransmitter recycling
c. Synapse renewal
d. Neurotransmitter destruction
77%, .36. The three processes of synaptic transmission are: (1) discharge of neurotransmitter into the synapse by the presynaptic neuron; (2) depolarization of the postsynaptic neuron; and (3) reputake of unused neurotransmitter by the presynaptic neuron. Selective serotonin reuptake inhibitors, drugs frequently used in the treatment of depression, work by inhibiting the reuptake of serotonin, so that it stays in the synapse longer.
20. What is the adaptive significance of habituation?
a. It greatly intensifies the effects of sensitization.
b. It allows organisms to ignore familiar but harmless stimuli.*
c. It paves the way for associative conditioning.
d. It keeps neurons active when they might otherwise degenerate.
88%, .44. Habituation is a primitive learning process that acts on the reflexive orienting response to novel stimuli. As a stimulus is repeated, it becomes less novel, and the organism is less likely to orient to it.
21. A(n) _____ is elicited by a stimulus regardless of an animal's history of experiences.
a. unconditioned response*
b. unconditioned stimulus
c. conditioned reflex
d. conditioned response
95%, .16. Remember that reflexes are innate, part of the organism's biological endowment, and not acquired through learning. So an unconditioned response is the reflexive response to some unconditioned stimulus.
22. Which of the following phenomena demonstrates conclusively that an extinguished CR is not forgotten?
a. the presence of higher-order conditioning
c. spontaneous recovery
d. both b and c*
70%, .16. This one was a little tricky, but it didn't meet the statistical criterion for a bad item. The fact that an extinguished CR is not lost or forgotten is shown by both spontaneous recovery of the CR after a period of rest, and by savings in relearning after reinforced presentation of the CS resumes.
23. A dog is conditioned so that it secretes ten drops of saliva to a 1,000 hertz tone. Knowing what you do about the phenomenon of generalization, hypothetically, how many drops of saliva should you expect if you then present the dog with a tone of 750 hertz and 500 hertz respectively?
a. about 7 drops; about 7 drops
b. about 3 drops; about 7 drops
c. about 7 drops; about 3 drops*
d. about 2 drops; about 3 drops
91%, .30. This is about the generalization gradient, where the magnitude of the response to a test stimulus depends on the similarity of the test stimulus to the original conditioned stimulus. A tone of 750 hertz (cycles per second) is closer to 1,000 hz than is a tone of 500 hz, so it should elicit a stronger generalized CR -- in this case, 7 drops compared to 3 drops. By the way, students who have training in music theory will see a problem with this example, but that's beyond the scope of this course.
24. In determining whether two events are contingent, what must one consider?
a. the number of times the two events have co-occurred
b. the number of times the two events have not co-occurred
c. how closely paired in time the two events are
d. both a and b*
67%, .19. Contingency is determined by both the number of times the CS is followed by the CR and the number of times the CS is not followed by the CR. Put mathematically, conditioning occurs when the probability of the US, given the CS, is greater than the probability of the US given the absence of the CS. Conditioning occurs only when the CS is a reliable predictor of the US, and if the US occurs even in the absence of the CS, then the CS is not a particularly reliable predictor. A lot of you went for C, but that would reflect association by contiguity, not association by contingency.
25. According to Thorndike, what determines whether a response will be strengthened or weakened?
a. the latency of the response
b. the goal of the animal
c. the consequences of the response*
d. whether or not the animal noticed the connection between act and consequence
80%, .35. This is about the Law of Effect: responses to a stimulus that are rewarded will be strengthened, responses to a stimulus that are not rewarded will be weakened. So, the conditioning of a response to a stimulus will depend on the consequences of that response.
26. In classical conditioning, the animal must learn about the relationship between _____; in instrumental conditioning, it must learn about the relationship between _____.
a. CR and US; stimulus and response
b. CS and UR; stimulus and response
c. CR and UR; response and reinforcement
d. CS and US; response and reinforcement*
77%, .44. Remember that instrumental conditioning is learning by consequences. In classical conditioning, the animal learns the relationships between events, such as the CS (bell) and US (food). In instrumental conditioning, the animal learns the relationships between its actions and events, such as whether a response will be followed by reinforcement.
27. Working as a car mechanic for a taxi company, Jay receives a paycheck every two weeks. Which type of reinforcement schedule is Jay on?
66%, .55. A good item, but maybe made harder by the acronyms: FI and FR refer to fixed-interval and fixed-ratio schedules of reinforcement, while VI and VR refer to variable-interval and variable-ratio schedules. Jay gets paid every two weeks, so there's a fixed interval of time -- 2 weeks, 14 days -- between reinforcing paychecks. If Jay were paid every time he had accumulated 80 hours of work, even if it took him only 4 days, or even 4 months, to do so, that would be a fixed-ratio schedule. If Jay were paid on the first and 15th of the month, that would be a variable-interval schedule, because while there are 14 days between the 1st and the 15th of the month, there can be as few as 13 days (like February) between the 15th of the month and the 1st of the next month, and as may as 16 days (as in November 15 and December 1). If Jay were paid sometimes after he had accumulated 40 hours, and on other occasions had to wait for his pay until he had accumulated 80 hours, that would be a variable-ratio schedule.
28. An investigator plans to use Seligman's (1975) procedures to study the effects of learned helplessness in rats. Which control group should be included to allow for an unambiguous interpretation of the results?
a. a group of rats that are exposed to a pleasant event instead of an aversive event
b. a group of rats that are put in the same aversive situation, but who are allowed some control over the aversive situation*
c. a group of rats that are exposed to the CS but given neither a pleasant nor an aversive stimulus
d. a group of rats that are given some kind of virus that impairs behavioral response time
60%, .28. Learned helplessness results when animals are exposed to uncontrollable shocks prior to entering the avoidance-learning apparatus. Uncontrollable shocks have two features: they're shocks and they're uncontrollable. Therefore, if you just have one group of animals exposed to uncontrollable shocks, and another group of animals that's not shocked at all (which is what C is all about), you wouldn't know whether learned helplessness was due to the shock or the fact that it's uncontrollable. So, you need to have a control group that gets the same number of shocks as the experimental group, but has some control over them. In his classic experiment, Seligman did just this by having two groups of animals, both of which got the same number of shocks, but one group could escape the shocks, turn the off, but not avoid them entirely, while the other group had no control over the shocks.
29. The normal defense reaction of species paracelsus obsidianus involves freezing in the face of danger. For these animals, according to the principle of preparedness, which of the following responses would be easiest to learn?
a. pressing a bar in order to avoid shock
b. staying immobile in order to avoid shock*
c. turning a wheel in order to avoid shock
d. All of the above would be equally easy to learn.
91%, .38. The species name of course is bogus: there's no such animal. But the preparedness principle simply states that, by virtue of their evolutionary history, each species finds it easy to learn some responses, and hard to learn others. So, if an animal is built in such a way as to reflexively freeze in the presence of danger, than it will be able to capitalize on this innate response when learning how to escape or avoid some new stressful event.
30. What is the main effect of long-term potentiation (LTP)?
a. LTP decreases sensitivity of the postsynaptic neuron in response to repeated stimulation.
b. LTP increases sensitivity of the postsynaptic neuron in response to repeated stimulation.*
c. LTP stimulates sympathetic activation.
d. LTP stimulates parasympathetic activation.
60%, .36. LTP is a change in the properties of the post-synaptic neuron. By virtue of repeated stimulation of the postsynaptic neuron by the presynaptic neuron, the postsynaptic neuron has a lowered threshold for firing. It's not that the presynaptic neuron is squirting more neurotransmitter into the synapse. It's that the post-synaptic neuron needs less neurotransmitter from the presynaptic neuron in order to depoloarize and fire -- put another way, it's more sensitive to whatever neurotransmitter is there.
31. Innate responses to stimulation, such as "instincts" or "fixed action patterns"
a. are ubiquitous in nature.
b. are universal within the species.*
c. enable individual species members to rapidly adapt to environmental change.
d. permit species members to respond to novel stimuli.
52%, .30. Many of you went for A, but nnate responses aren't ubiquitous, in that the same reflexes, taxes, and instincts aren't found in all animal species. (Yes, all behaving organisms have reflexes, but they don't all have the same reflexes, so they're not ubiquitous). But they are universal within a species, just like any other adaptations are. Because evolution changes the characteristics of species, not of individual species members, if some instinctual pattern of behavior has evolved, because it aids adaptation to a particular environmental niche, all species members will have that adaptation.
32. According to the stimulus-response theory of learning:
a. organisms acquire adaptive behaviors through the experience of success and failure.
b. given enough reinforcement, any stimulus can be paired with any response.*
c. organisms actively seek to predict and control events in their environment.
d. understanding the biochemistry of reward is critical to understanding the learning process.
59%, .32. Remember the arbitrariness assumption: by virtue of reinforcement, any arbitrarily selected stimulus can be paired with any arbitrarily selected response. We know this is wrong because there are both biological and cognitive constraints on what associations organisms will form. Rats learn to associate nausea with taste but not sight and sound. And, in Kamin's blocking experiment, they won't learn that the tone predicts shock if they already have light as a perfectly good predictor. Option A refers to the Law of Effect, but that doesn't apply to classical conditioning, which is also covered by the S-R theory of learning. And others went for Option C, but remember the assumption of the passive organism, which holds that animals are not actively trying to learn -- learning just happens by virtue of events in the external world.
33. Kamin's experiment on "blocking" differs from sensory preconditioning in that:
a. in blocking, the redundant CS predicts the informative CS.
b. in sensory preconditioning, neither CS is reinforced on early trials.*
c. in blocking, both CSs are reinforced on early trials.
d. in sensory preconditioning, the CS- is given more reinforcement than the CS+.
29%, .20. A difficult item, but statistically it doesn't meet the criterion for a bad one. In sensory preconditioning, two CSs, like tone and light, are paired before one of these, such as the light, is paired with shock. On the preconditioning trials, neither the tone nor the light is paired with shock, and so neither is reinforced. In this situation, some conditioning will accrue to the tone, because it predicts the light, which predicts the shock. But in the blocking experiment, the tone is paired with the shock before the tone and light, presented together, are paired with the shock. So, on early trials of the blocking experiment, the tone is reinforced by the shock. Under these circumstances, the animal will show a CR to the tone, because it predicts shock, but not to the light, because it doesn't predict anything except what the animal already can predict from the tone.
34. The philosophical viewpoint called empiricism takes the position that
a. the mind contains innate categories of space and time.
b. the mind is like a computer, always actively processing information.
c. we are born with a soul that is different from the mind and outlasts the body.
d. our senses passively receive experiences.*
46%, .36. Nativism, sometimes called rationalism, says that some knowledge is innate (either a gift from God, as in Descartes' view, or a product of biological evolution). Empiricism says that all knowledge comes through the senses -- either directly, in terms of sensory experience, or indirectly, in terms of our reflections on our sensory experience. But whether its direct or reflected-upon, all knowledge comes through the senses. The mind is a blank slate (tabula rasa), written on by experience.
35. A woman is looking at a tree. What is the distal stimulus?
a. the tree*
b. the light waves reflected by the tree
c. the image cast by the tree on the woman's retina
d. the pattern of nerve impulses triggered by the retinal image and conducted by the optic nerve to the brain
74%, .32. The tree is the distal stimulus. The proximal stimulus is the pattern of light waves, or sound waves, or chemical substances, or whatever, that emanate from the tree and fall on the sensory receptors.
36. A research participant can just discern the difference between 50 and 51 candles burning in an otherwise darkened room. According to Weber's law, how many lit candles would have to be added to 300 already-lit candles before a participant could just notice the difference in illumination?
a. one additional candle, for a total of 301 candles
b. three additional candles, for a total of 303 candles
c. six additional candles, for a total of 306 candles*
d. ten additional candles, for a total of 310 candles
86%, .40."Candle" is a unit of illumination in physics, but it doesn't matter. Weber's Law says that the amount of change in a physical stimulus required to produce a just-noticeable difference is a constant fraction. So, of a change of 1 unit from 50 units produces a JND, then Weber's Fraction is 1/50. And it's constant, so you'd need 6 candles' worth of change -- 1/50th of 300) to produce a just-noticeable difference in a stimulus of 300 candles.
37. In a signal detection experiment, Frank, the participant, has a very casual attitude and tends to say, "Yes, I hear the tone" most of the time, even when he is in doubt. What will this lead to?
a. an increase in the number of hits
b. an increase in the number of false alarms
c. It will force the researcher to disregard Frank's data.
d. both a and b*
79%, .26.Frank appears to be one of those liberals who will say "yes" to everything. If he does, he'll say "yes" on a lot of the trials when the stimulus is present, making a lot of hits just by chance, and he won't make many misses. But he'll also say "yes" a lot of times when the stimulus is absent, committing a lot of false alarms as well.
38. Where are the vestibular receptors located?
a. in the muscles, tendons, and joints
b. in the taste buds
c. in the hypothalamus
d. in the inner ear*
63%, .30.Just a little sensory physiology: the vestibular receptors, for the sense of balance, are located in the vestibular sac and semicircular canals of the inner ear, where tiny crystals stimulate hair cells depending on the orientation and motion of the head. The kinesthetic receptors, for bodily motion, are in the muscles, tendons, and joints. The taste buds of the tongue are for the gustatory sense (naturally). We didn't talk about the hypothalamus in this context, but the hypothalamus contains receptors that are sensitive to things like blood--sugar and cell-fluid levels, so you can think of the hypothalamus as part of a sensory system as well, even though it doesn't generate conscious sensory experiences: Sherrington referred to this an interoception, or sensations of the internal environment.
39. According to the Doctrine of Specific Fiber Energies, why does sugar taste sweet and vinegar taste sour?
a. Sugar and vinegar activate different neurons that carry the information to the brain.*
b. The threshold for sour is lower than the threshold for sweet tastes.
c. The size of the JNDs for sugar is smaller than those for vinegar.
d. Sugar and vinegar trigger different patterns of nerve impulses.
60%, .15. Muller's Doctrine of Specific Nerve Energies holds that the modality of a sensation is determined by the activity of specific neurons, specifically those in the sensory projection areas of the brain -- not by the proximal stimulus or the sensory receptor. Helmholtz's Doctrine of Specific Fiber Energies says much the same thing with respect to qualities, like hue and pitch, within a sensory modality. We taste sweet and sour not because particular chemicals have fallen on our taste buds, but because the activity in certain neural structures gives rise to those experiences, even when they are stimulated electrically. Gleitman talks about this as the "specificity" theory, and he prefers the "pattern" theory. But no matter which theory turns out to be correct, both deny that the quality of sensory experience is determined by the proximal stimulus. There's nothing about long-wavelength light that makes us see it as red as opposed to green. Hue is in the brain, not in the world or even in the eye.
40. What happens when a sound stimulus is transmitted to the cochlea?
a. For low-frequency sound, only one place on the basilar membrane vibrates.
b. For high-frequency sound, the whole basilar membrane moves, but one place moves maximally.*
c. The frequency of vibration of the basilar membrane always equals the frequency of the sound wave.
d. The frequency of vibration of the basilar membrane never equals the frequency of the sound wave.
65%, .41. Remember the "frequency" and "place" theories of pitch perception. The frequency theory applies to low-frequency sounds, while the place theory applies to high-frequency sounds. The volley theory is, if you think about it, a variant on the frequency theory.
41. What type of afterimage would you see if you stared at a picture of a red bird in a blue cage?
a. a green bird in a yellow cage*
b. a blue bird in a green cage
c. a yellow bird in a blue cage
d. a yellow bird in a red cage
94%, .34. OK, you got this. There's a red-green opponent process and a yellow-blue opponent process such that the negative afterimage of red is green and the negative afterimage of blue is yellow.
42. Suppose you look out over a football stadium. You can see the people nearby as individuals, but in the distance you see only a solid "sea" of blue and white. This example shows how we use __ to judge distance.
a. shape constancy
b. linear perspective
c. texture gradients*
75%, .35.Never mind that, at Berkeley, you'd see a solid "sea" of blue and gold. The important thing is that fine texture is lost when perceiving objects over long distances, so the gradual change in the texture of a scene is a cue -- a monocular, optical, "pictorial" cue at that -- to which parts of the scene are close to the observer, and which are more distant. Shape constancy isn't a cue to distance. Superposition is a pictorial distance cue used by artists in the medieval period, while linear perspective came to be used in the Renaissance.
43. Why, as we look from left to right, do objects in front of us not seem to move from right to left?
a. There is no relative displacement on the retina.
b. The nervous system compensates for voluntary eye movements.*
c. There is relative displacement on the retina.
d. There is no absolute displacement on the retina.
58%, .43. The exam key originally posted had the correct answer as C, which is of course completely incorrect. That was just a mechanical error. The correct answer, as 58% of you knew, was, of course B. My apologies for any momentary distress this may have caused! Anyway, remember that the cue for motion isn't exactly the movement of a retinal image across the retina -- because the retinal image also moves when the eyes move, even though the object is stationary. So motion is computed from the discrepancy between the movement of the retinal image and the movement of the eyes. In this way, the visual system compensates for voluntary eye movements, and the perceiver sees the object as stationary even though its retinal image is in motion.
44. Let's say that, as we look at a still life, a banana seems to divide the apple behind it in half. Yet what we perceive is an intact apple, not two separate apple slices. The way we organize scenes according to their constituent objects is called
b. binocular disparity.
c. feature detection.
62%, .46.Parsing refers to the process by which the perceiver analyzes the stimulus into its basic features, and notes the relations among those features. It's a term imported from language, where the listener has to parse the speaker's speech into words and sentences in order to understand what's being said. In the same way, the perceiver has to parse the scene into its constituent objects, their features, and their spatial relations, in order to understand what's being seen.
45. Some artists create paintings wherein the figure and the background relations are deliberately reversible and ambiguous. Such ambiguity illustrates which important general point about human perception?
a. Adaptation to steady or repeated stimulation happens in almost all of the senses.
b. Only a few basic perceptual abilities are inborn.
c. Different stimuli can be parsed in the same way.
d. The same stimuli can be parsed in more than one way.*
89%, .32.In the perceptual constancies, perception remains constant even though stimulation changes. In the reversible figures, perception changes even though the stimulation remains constant. Even more than the perceptual constancies, the ambiguous figures show that all the information needed for perception is not provided by the stimulus; some has to be contributed by the perceiver himself.
46. If you tell a research participant that the next word she sees in a visual display is going to concern sports, that information will typically speed up her recognition of words such as soccer and tennis. Priming effects such as these
a. are exceedingly rare.
b. grow less common with age.
c. support the contention that perception is partly knowledge-driven.*
d. All of the above answers are correct.
95%, .28.Priming refers to the fact that performing one task may facilitate performance of another task. In this case, the perceiver already knows that to look for, and this knowledge facilitates perceptual recognition. All the information for perception doesn't come from the stimulus. Some comes from the perceiver, in the form of expectations.
47. A patient suffers from damage to the pathway between her occipital cortex and her temporal cortex. What task will she most likely have difficulty with?
a. identifying an object*
b. reaching for an object
c. seeing an object
d. keeping track of time
63%, .19.Remember the "what" and "where" pathways? Yes, Area V1 9Brodmann's Area 17) is the primary visual cortex, but other areas of the cortex are also involved in various aspects of visual function. The "what" system, involved in object identification, involves the coordinated activities of the occipital and temporal cortex - -especially the inferotemporal cortex, which is where the fusiform area involved in face recognition lies. The "where" system, involved in processing various aspects of spatial relations, involves the coordinated activities of the occipital and parietal cortex.
48. When all is said and done, the modality of sensation is determined by the nature of the:
a. proximal stimulus.
b. receptor organ.
c. afferent tract.
d. projection area.*
40%, .36.Remember the Doctrine of Specific Nerve Energies, and the Doctrine of Specific Fiber Energies. What matters is where the neural impulse goes, not where it started or how it got there. A lot of you went for A or B, whereas the whole point of both doctrines is that neither the proximal stimulus nor the receptor organ is decisive -- not least because sensory experiences can be caused by direct stimulation of the afferent tracts and projection areas.
49. Why is size constancy not a serious problem for the ecological view of perception?
a. Experienced perceivers can identify the objects, so that they know that they don't change size or shape rapidly.
b. Optical cues can compensate for ocular cues.
c. The ratio of the object to its background remains constant, despite changes in absolute size of the retinal image.*
d. Motion cues to distance, such as motion parallax, optic flow, and autokinesis, are the primary cues to size and distance.
73%, .34.Gibson's ecological theory can get around the problem of size constancy easily by asserting that perceived size isn't determined by retinal size. Rather, perceived size is determined by the comparison of the object to its background. If that ratio remains constant, then perceived size remains constant. All the information needed for perception is provided by the stimulus, but "the stimulus" is defined broadly to include the entire stimulus field, including proprioceptive stimuli as well as exteroceptive stimuli.
50. Perceptual illusions
a. occur only in laboratory experiments, and not under conditions of ordinary viewing.
b. often reflect the inappropriate influence of depth cues.*
c. often reflect the inappropriate influence of motion cues.
d. occur only for so-called "bistable" stimuli.
79%, .14.Well, actually, Gibson insists that perceptual illusions are tricks created by psychologists, and don't really occur under normal viewing conditions. Apparently he never saw the moon illusion! Anyway, many -- not all, but certainly illusions like the Muller-Lyer illusion, the Ponzo illusion, and the Ames Room, which I presented in class -- do appear to be generated by inappropriate inferences from depth cues. Like the size-distance rule. In the Muller-Lyer and Ponzo illusions, the perceiver concludes, from the fact that the two lines appear to lie at different distances from the observer, that one line is longer than the other. And in the Ames Room, the perceiver concludes, from the lack of distance cues, that the one target is larger than the other.
Retain this exam, along with a record of your answers.
A provisional answer key will be posted to the course website by 3:00 PM today.
The exam will be provisionally scored to identify and eliminate bad items.
The exam will then be rescored with bad items keyed correct for all responses.
Grades will be posted to the course website.
A final, revised, answer key, and analyses of the exam items,
will be posted on the course website when grades are posted.
Requests for rescoring must be received within one (1) week of the posting of grades