Department of Psychology
Midterm Examination 1
Scoring Key and Item Analysis
In the scoring key that follows, correct answers are marked with double pound signs (##).
Following procedures outlined in the Exam Information page, the statistical analysis identified one (1) bad item, #23, and a couple of other items which had been keyed incorrectly. The incorrectly keyed items were corrected, and Item #23 was rescored correct for all responses. No other items will be rescored.
The average score on the exam, after rescoring, was 34.87, with a standard deviation of 8.33 -- 70% correct, which is pretty good by the standards of my exams in Psych 1, in which my usual mean is somewhere between 65-70% correct.
The scores entered into the ANGEL gradebook reflect this rescoring. Because of the corrected keying, and the rescoring of Item #23, most students will notice that the exam score posted to the gradebook grade is higher than the initial score they received as feedback when they submitted their exam.
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. I also 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.
Correct answers are marked with ##.
____ 1. Humans, like other species, sometimes communicate through built-in displays. One such response, found in all babies, even in those born blind, is
a. the smile. ##
b. the snicker.
c. the good-bye wave.
d. the OK sign.
96% of the class got this item correct; Item-to-total rpb = .24. Evidence suggests that humans rely on built-in displays, such as the smile. The smile is often considered a biologically rooted signal by which humans tell each other: "Be good to me. I wish you well."
____ 2. The control group
a. provides a basis for comparison, allowing the experimenter to assess the effects of the experimental manipulation.
b. must be matched to the experimental group in all respects except for the experimental manipulation.
c. provides a means of reducing demand characteristics.
d. Both a and b are correct. ##
88% correct; rpb = .27. In an experimental study, investigators need both an experimental group, with which the investigator introduces an experimental manipulation (e.g., consuming a sugar cube before a road race), and a control group, which is matched to the experimental group in all respects except for the experimental manipulation (e.g., not consuming a sugar cube before a road race). Having this control group provides a basis for comparison and allows the investigator to assess the causal effect of the experimental manipulation on the outcome of interest (e.g., how does eating sugar, i.e., experimental group, versus not eating sugar, i.e., control group, impact the speed with which participants complete the road race?).
____ 3. There seems to be a correlation between schizophrenia and poverty. It may be the case that neither causes the other. Perhaps a separate factor, such as parental income, accounts best for both schizophrenia and poverty. This illustrates a problem in assessing causality that is specific to correlational research, and is called
a. the third-variable problem. ##
c. random sampling.
d. response bias.
85%; .49. Correlational data raises questions about the direction of causation between two correlated variables (e.g., does schizophrenia lead to poverty or does poverty lead to schizophrenia). In addition, correlational data raises an alternative possibility that a third factor, different from the two correlated variables, is causing both (e.g., parental income). This is the third-variable problem. Both the third-variable problem and ambiguity about causal direction often make it difficult to interpret correlational data, and this leads psychologists to emphasize that correlation does not imply causation.
____ 4. In Descartes' conception, nonhuman animals are machines but humans are not because only humans
a. possess souls or minds. ##
b. have complex enough nervous systems to make it obvious that their actions are not governed only by reflexes.
c. possess senses, nerves, and animal spirits.
d. have a central switching mechanism.
80%, .44. Descartes proposed that the centralized controller of human behavior was not a machine, but rather that what truly governed our behavior, what made reason and choice possible, and what distinguished us from other animals, was the soul -- operating through the brain, choosing among nervous pathways, and controlling our bodies.
____ 5. Detailed pictures of moment-to-moment brain activity can be obtained without exposure to radioactivity by using __________.
a. CT scans
b. fMRI ##
c. PET scans
61%, .25. fMRI scans adapt standard MRI procedures to document relatively fast-changing aspects of brain physiology (tracking blood flow and oxygen use, primarily). The fMRI measures a pattern of increased brain physiology beyond the baseline constant state of brain activity (which enables the maintenance of basic life functions like breathing or circulating the blood or maintaining posture, etc.). In contrast to PET scans, in which participants are injected with a safe dose of radioactive sugar, the fMRI does not use any radioactivity.
____ 6. Throughout evolution, the process of increasing "braininess" is most evident by observing differences in the __________ of various species.
c. cortex ##
70%, .47. The cortex, or the outer surface of the forebrain, constitutes approximately 80% of the human brain. The cortex may get the reputation as the locus of "braininess" in the brain because of its involvement in planning, executive function, reasoning, and higher order organizing. Notably, it has been suggested that the cortex is proportionally larger in humans compared to other primates.
____ 7. Following a stroke, a patient shows grossly diminished sensitivity to touch and other stimulation in the right hand and arm. The probable site of the lesion is the
a. motor homunculus.
b. left somatosensory area. ##
c. right somatosensory area.
d. left frontal area.
81%, .36. Contralateral control is seen in nearly all vertebrate nervous systems and describes the pattern in which movements on the right side of the body are controlled by the left half of the brain (and vice versa). The somatosensory area in the brain is the receiving area for sensory information from the skin senses. Therefore, if a patient show diminished sensitivity to skin senses (i.e. touch and other stimulation) in the right hand/arm, it is likely that the lesion is in the left somatosensory area.
____ 8. Expressive aphasia is to receptive aphasia as __________ is to __________.
a. Broca' s area; the adjacent regions of motor cortex
b. Broca' s area; the adjacent auditory projection area ##
c. agnosia; apraxia
d. minor hemisphere; dominant hemisphere
50%, .42. Expressive aphasias (also known as nonfluent aphasias) typically involve lesions in the region of the left frontal lobe called Broca's area, and typically involve disruptions in the production of speech. Receptive aphasias (also known as fluent aphasias) typically involve lesions in the adjacent auditory projection area, and typically involve disruptions in the comprehension of speech.
____ 9. What happens when wiring errors are produced during brain development?
a. Neurons compete with each other.
b. Some neurons are given a signal to die.
c. Incorrect and redundant connections are changed.
d. All of the above. ##
67%, .28. Inevitably, there are some wiring errors in the developing nervous system -- however, there is a safeguard in place to deal with these. Specifically, many more neurons are created than are needed, and each neuron tries to form far more connections than are required. Therefore, if a neuron's connections are either incorrect or redundant, that neuron can withdraw its connections and find better targets, or it can be given a message to die -- neurons "compete" with each other to live.
____ 10. Transduction is the change of energy from one form to another. Which of the following are transducers?
a. rods and cones in the eye
b. taste buds on the tongue
c. pressure receptors in the skin
d. all of the above ##
91%, .34. Certain cells transduce (or translate) stimuli into electrical changes within the nervous system. In vision, for example, receptor cells (rods and cones in the eye) transduce optical stimulation into electrical changes in the cell, which in turn trigger impulses in sensory neurons that then proceed through the nervous system. Taste buds on the tongue and pressure receptors in the skin are two additional examples of cells that transduce energy from one form to another in this manner.
____ 11. Transmission of information across the synaptic gap occurs by means of
a. electrical charges.
b. movement of synaptic vesicles.
c. fine neurotubules.
d. chemical diffusion. ##
44%, .40. Vesicles, which are like water balloons filled with chemical neurotransmitters, are stored in the terminals of presynaptic neurons. When a presynaptic neuron fires, some of the vesicles literally burst and eject their chemical contents through the terminal's membrane and into the synaptic gap. The chemicals diffuse across this gap and then activate specialized chemical receptors in the postsynaptic membrane. Thus, this process of transmission of information occurs by chemical diffusion.
____ 12. The development of medicines to help people with brain disorders is complicated by the brain's natural defense system, called the __________ barrier.
b. blood-brain ##
79%, .30. The blood-brain barrier is a specialized membrane of tightly joined cells that surround the blood vessels within the brain and that filter toxins and other harmful chemicals, ensuring that brain cells receive a relatively pure blood supply. Some medicines to help people with brain disorders are therefore filtered out by the blood-brain barrier, which filters out the medicine as a "foreign substance." Pharmacologists must develop medicines that are able to bypass this barrier in order for the medicines to reach the brain.
____ 13. Which of the following statements best describes the current status of research concerning treatment of spinal cord injuries and degenerative brain disorders in humans?
a. Neuronal transplantation and the design of growth-promoting chemicals provide hope that effective treatments will be developed in the future. ##
b. The outlook for obtaining regeneration of function in these cases is dismal, with little or no evidence that effective treatments will be developed in the future.
c. Transplantation of adult neuronal tissue into the sites of brain or spinal cord damage in young children has been moderately successful in the treatment of these afflictions.
d. The use of growth-promoting chemicals to treat brain and spinal cord damage has been shown to be effective in children, but not in adults.
63%, .29. The central nervous system appears unable to grow new neurons to replace neurons damaged through spinal cord injuries or degenerative brain disorders, and these limits on neural growth are deeply problematic for patients' treatment. Investigators are seeking new ways to circumvent the brain's limited potential for regeneration by implanting new tissue or by seeking external means of encouraging neuronal growth.
____ 14. When researchers talk about a person's particular genetic "blueprint," they are referring to his/her
a. evolution via natural selection.
c. genotype. ##
d. family history.
87%, .42. The genotype is defined as the genetic blueprint of an organism, which may or may not be overtly expressed by its phenotype (i.e., the overt appearance and behavior of an organism). The reason that the genotype may or may not be overtly expressed is because genes interact with other factors (e.g., presence of nutrients, certain forms of stimulation, toxins) to influence the biochemical processes that eventually lead to the overt characteristics of an individual. Ultimately, the genotype can be understood as setting out the guidelines for the completion of the phenotype.
____ 15. In terms of motivation, what does negative feedback mean?
a. There is an ever-increasing level of activity.
b. There is a decrease in the level of activity.##
c. There is a steady ongoing level of activity.
d. There is a random fluctuation in the level of activity.
82%, .35. Feedback is a system in which an action produces some consequence that affects (feeds back on) the action. In negative feedback, the consequence stops or reverses the action. For example, a thermostat in one's house turns on the heater when the house's temperature falls below a given setting; when the house is heated back up to reach a preset temperature, the thermostat then turns the heater off. The result of this type of negative feedback leads to a decreasing level of activity (of, in this case, the furnace).
____ 16. Stuart is overweight. He goes on a starvation diet in the hopes of slimming down before graduating from college. He starts consuming about 1,000 calories a day. He loses some weight, but not nearly as much as he thought he would. What is the most likely reason for Stuart's failure to lose a great amount of weight?
a. Stuart has a larger number of fat cells.
b. Stuart is probably just losing excess water, which is easily replaced.
c. Stuart' s activity level needs to be greatly increased.
d. Stuart' s body has compensated for this caloric reduction by reducing its metabolism. ##
87%, .40. When individuals dramatically decrease their caloric intake, the body compensates for this loss by reducing its metabolic rate. In other words, the body gets less food but responds by burning less (i.e. slower metabolism) which serves to defend the already-established target weight that our bodies work homeostatically to maintain. The consequence of this is that the decreased eating does not lead to the hoped-for weight loss.
____ 17. With which bodily function is the sympathetic nervous system most concerned?
a. vegetative functions
b. slowing of the heart
c. activation ##
80%, .44. The two branches of the autonomic nervous system -- the parasympathetic and sympathetic nervous systems -- serve two broad and different functions. The parasympathetic branch handles the mundane functions of ordinary life, such as conserving bodily resources and reproduction, and generally manages the organism's operations during times of peace (e.g., a low and steady heart rate, secretions by digestive glands, etc.). In contrast, the sympathetic branch has an activating function, summoning the body's resources in times of crisis and getting the organism ready for vigorous action (such as preparing the body for an emergency reaction).
____ 18. Attractive people are often believed to be more "good" than unattractive people. In fact, people generally associate intelligence, happiness, and good mental health with physical attractiveness. What is this tendency called?
a. self-serving bias
b. the matching hypothesis
c. superego tripping
d. the halo effect ##
65%, .33. "Halo effect" is a term that refers to our tendency to assume that people who have one good trait are likely to have others (and, conversely, that people with one bad trait are likely to be bad in other regards as well).
____ 19. __________ occurs when one fails to respond to stimuli that have become familiar due to repeated exposure.
c. Response control
d. Habituation ##
77%, .56. Habituation may be one of the simplest forms of learning and is certainly shared across species. Habituation describes the decline in an organism's response to a stimulus once the stimulus has become familiar. For example, a sudden noise usually startles us, but the subsequent times the noise is heard the startle response will be diminished and ultimately ignored altogether -- at this point, we will have become fully habituated to it.
____ 20. Injection of an animal with amphetamine leads to heart rate acceleration. With repeated injections, however, the injection procedure alone (i.e., when an inert substance is injected) can elicit heart-rate acceleration. In this situation, which of the following is true?
a. The injection procedure is the CS.
b. Heart rate acceleration is both the UR and the CR.
c. Amphetamine is the US.
d. All of the above answers are correct. ##
77%, .45. An unconditioned response is a product of the organisms' biology and is triggered by a certain stimulus (the unconditioned stimulus) independent of any learning. In this example, the amphetamine (the unconditioned stimulus) leads to heart rate acceleration (the unconditioned response) with no learning necessary. The conditioned response, in contrast, is a product of learning. In this case, the injection procedure is initially a neutral stimulus that does not elicit heart-rate acceleration. However, after some presentations of the conditioned stimulus (injection procedure) followed by the unconditioned stimulus (amphetamine), then the conditioned stimulus (injection procedure) alone comes to elicit the conditioned response (heart-rate acceleration).
____ 21. What do we know about the speed of relearning as compared with the original speed of learning?
a. It begins faster, then slows to a stop.
b. It is slower.
c. It is faster. ##
d. It begins slower, then grows substantially faster.
77.8%, .49. The speed of relearning, after something learned has been extinguished, is faster than the original speed of learning. It appears that extinction does not work by "erasing" the original learning, meaning that the animal does not return to its original "na�ve" state. Rather, the animal retains some memory of the learning, and this memory provides it with a head start in relearning at a later time.
____ 22. In one experiment, rats were exposed to combinations of a tone and a shock. For one group of rats, shocks arrived 40 percent of the time without any warning; the tone therefore really provided no information. For another group of rats, shocks also arrived occasionally with no warning. But the likelihood of a shock was smaller (below 40%) when there was no tone than when there was a tone. What was the finding?
a. The second group of rats became fearful whenever a tone was sounded. ##
b. Both groups of rats feared the sound of the tone the same.
c. Both groups of rats came to fear any sound of any kind.
d. The first group of rats became fearful whenever a tone was sounded.
66%, .37. For the first group of rats, the tone provided no information; the rats' expectation about things to come should have been the same with the tone or without it. Therefore, this situation led to no conditioning; the rats simply learned to ignore the tone. However, for the second group of rats, the tone was an imperfect predictor of things to come but still provided some information: shock was more likely following the tone than otherwise. In this situation, the rats did develop a conditioned response and became fearful whenever the tone was sounded. Thus, it appears that an imperfect predictor is better than no predictor at all.
____ 23. Signaled shock leads to __________, whereas unsignaled shock leads to __________.
a. a CS; a US
b. a UR; a CR
c. anxiety; fear
d. fear; anxiety ##
38%; .19. A bad item, though just barely. In a situation involving signaled shock, wherein the probability of a shock following a tone is greater than the probability of a shock without a tone, the animal becomes fearful when the tone appears because shock is likely to follow, but when there is no tone the animal can relax because the shock is less likely. In contrast, in a situation involving unsignaled shock wherein the probability of a shock following a tone is equal to the probability of a shock without a tone, animals learn that there is danger in this setting and that they can never feel safe. As a result, the animal must be anxious all the time. Put another way: with signaled shock, the animal has something specific to fear; anxiety occurs under conditions of unpredictability.
____ 24. What can be said of conditioned reinforcement?
a. Conditioned reinforcement is typically given after primary reinforcement.
b. Conditioned reinforcement acquires its properties by being paired with primary reinforcement. ##
c. Conditioned reinforcement is more effective than primary reinforcement.
d. Conditioned reinforcement is usually a biologically necessary incentive such as food or water.
74%, .30. Primary reinforcers serve as reinforcement because of their biological significance (e.g., food, water, etc.). In contrast, conditioned reinforcers are initially neutral in value but come to serve as reinforcement because they have, in the experience of the animal, been repeatedly paired with some other, already established reinforcer. For example, a dollar is a conditioned reinforcer. The actual paper bill is not itself reinforcing. However, it can be used to acquire primary reinforces like food. Therefore, the dollar becomes a conditioned reinforcer as a result of pairing with primary reinforcers.
____ 25. Which of the following represents an important fact about punishment as a form of behavior control?
a. Behaviors brought about via punishment do not extinguish.
b. Behaviors brought about via punishment do not generalize.
c. More intense punishers (more painful shock, for instance) are more effective than less intense punishers. ##
d. Extreme surprise is the optimal form of punishment.
59%, .41. Punishment is a powerful means of shaping behavior. If a response is followed by some aversive event, then that response is less likely to occur in the future. More intense punishers (e.g., a more painful shock) are more effective in suppressing behavior than less intense punishers. Notably, punishments introduced in mild form and then gradually intensified turn out to be markedly less effective than punishments introduced at "full strength" from the start.
____ 26. An infant, Betty, has a colorful mobile suspended over her crib. There is a sensing device under her pillow so that when Betty moves her head, the mobile turns and its colorful shapes move enticingly. Betty enjoys making the mobile move and she smiles whenever the mobile is in motion. Betty's twin brother, Frank, has an identical mobile suspended over his crib. However, Frank's mobile moves only when Betty sets hers in motion. Based on what you know about response control, what is the most likely outcome in this situation?
a. Betty will pay less attention to the mobile than Frank because the movements of hers are predictable.
b. Betty will have intelligence scores that are significantly higher than Frank' s when the twins are about two years old.
c. Frank will lose interest in the movements of his mobile while Betty will continue to enjoy hers. ##
d. Frank will attempt to reach out and grasp the colorful shapes in motion above his crib, while Betty will just move her head to set her mobile in motion.
64%, .48. Instrumental conditioning is a form of learning in which a reinforcer (e.g., mobile moving) is given only if the individual performs the instrumental response (e.g., moving the head). In effect, what is learned is the relationship between the response and the reinforcer; what matters is that there is a relationship between responding and getting the reward, such that this relationship actually gives the individual some control over the reward. In the case of Betty and Frank, Betty does experience control over the reward (she makes the mobile move when she moves her head), whereas Frank has no control over the reward. Given that individuals prefer being in control, Betty will continue to enjoy her mobile, whereas Frank will lose interest.
____ 27. According to the principle of preparedness (or belongingness), which of the following would be the most difficult to do?
a. train a pigeon to peck a key to avoid shock ##
b. train a cat to rub your legs to get you to open a can of cat food
c. train a rat to avoid a certain flavor of ice cream with a mild poison as punishment
d. train a rat to jump over a hurdle to avoid shock
48%, .25. Preparedness refers to capabilities that are innately programmed and determine to a large extent what can be learned and the ease with which it can be learned. Depending on this innate programming, for different animals some stimuli/experiences belong together and some do not. For example, for rats the sense of taste goes with illness; there is survival value in rats being able to learn quickly about the connection between a particular flavor and illness. When trying to train an animal to do a certain behavior, it will be easier to train a behavior that is founded upon associations that make biological sense (e.g. for rats, taste and illness), and most difficult to train a behavior that is founded upon associations that do not make biological sense. In this question, consider pigeons pecking a key to avoid shock. Typically, pecking of birds is related to food consumption, not pain. Therefore, the association between these two things does not make much biological sense and, thus, would be most difficult to train.
____ 28. 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.
83%, .39. One form of neural plasticity involves postsynaptic changes, and a particularly important mechanism in this category is long-term potentiation (LTP). LTP is produced when one neuron stimulates another repeatedly. The repeated stimulation causes the postsynaptic neuron to become more sensitive to this input that it was before, and so more likely to respond to this input in the future.
____ 29. We smell a rotten egg only because the hydrogen sulfide molecules in the air flow over the sensory cells in our nasal cavities. In this example, what is the distal stimulus?
a. our nasal cavities
b. the air
c. the rotten egg ##
d. the hydrogen sulfide
66%, .37. In perception, the distal stimulus is the real object in the world outside of us; the proximal stimulus is information about that distal stimulus that actually reaches the sensory receptors. So in this example, the distal stimulus is the rotten egg and the proximal stimulus is the hydrogen sulfide molecules flowing over the sensory cells.
____ 30. Most people can just detect the difference between 5 spoonfuls of sugar in a gallon of water and 6 spoonfuls of sugar in a gallon of water. If Weber's law holds, these same people should be able to just tell the difference between 25 spoonfuls of sugar in a gallon of water and __________ spoonfuls of sugar in a gallon of water.
b. 30 ##
86%, .45. Weber's law suggests that the sensory apparatus is sensitive to percentage changes rather than absolute changes. In other words, if most people can tell the difference between 5 and 6 spoonfuls of sugar in a gallon of water, it indicates that most people are sensitive to a proportional difference of 20% of sugar in a gallon of water. Therefore, most people would be able to distinguish 25 spoonfuls of sugar from 30 spoonfuls of sugar in a gallon of water, because this is also equivalent to a proportional difference of 20%.
____ 31. What is true of signal-detection theory?
a. Signal-detection theory allows one to separate actual perceptual ability from response tendencies. ##
b. Signal-detection theory suggests that, for each observer, there exists a constant stimulus intensity corresponding to a zero stimulus.
c. Signal-detection theory suggests that perceived sensation occurs only in the presence of an external stimulus.
d. Signal-detection theory suggests that confusion about whether a stimulus has been presented or not is most likely to occur when the signal is much greater than the noise.
40%, .31. Signal-detection theory is based on the assumption that, if individuals differ in how sensitive they are to a signal, then they will differ in their proportions of correct and incorrect responses -- i.e., their total number of hits and correct negatives relative to their total number of misses and false alarms. But if they differ in their criterion for responding (e.g., whether they say yes when in doubt, or no), then they will differ in their proportions of yes and no responses. As a result of these assumptions, we can separately assess individuals' sensitivity to signals (or actual perceptual ability) and their criterion for responding (or response tendencies) by looking at all four types of responses and calculating the relative numbers of each to determine exactly why individuals are responding as they are.
____ 32. Vestibular receptors provide information about
a. movements of the head. ##
b. the position of the body in space.
c. the sensation of pressure.
d. the sensation of taste.
52%, .33. The vestibular sense is one among the human sense modalities. The vestibular sense receptors are in a cavity within the inner ear and signal movements of the head.
____ 33. The experiences of blue-green, A-sharp, and sweet-sour clearly have different qualities. According to the doctrine of specific nerve energies, what causes this difference in qualities?
a. differences in the physical energies that serve as the stimuli for vision, hearing, and taste
b. differences in the neural structures excited by stimuli associated with these experiences ##
c. differences in the absolute thresholds for vision, hearing, and taste
d. differences in the jnd' s for vision, hearing, and taste
75%, .48. The doctrine of specific nerve energies indicates that the differences in sensory quality (e.g., the difference between seeing and hearing, between hearing and touch, etc.) are not caused by differences in the stimuli themselves but by the different nervous structures that these stimuli excite. Therefore, given that blue-green (visual), A-sharp (auditory), and sweet-sour (taste) are representative of different sensory modalities, the cause of differences in the qualities of these three experiences is rooted in differences in neural structures excited by stimuli associated with these experiences.
____ 34. Which finding is inconsistent with the place theory of pitch?
a. High-frequency tones cause peak deformations close to the oval window, while low-frequency tones have their peaks farther away from this structure.
b. For high-frequency tones, the site of peak deformation along the basilar membrane does not correspond to stimulus characteristics.
c. Normal adults can discriminate between the frequencies of tones considerably higher than 500 hertz.
d. For low-frequency sounds, the basilar membrane is deformed almost equally along its entire length. ##
25%, .26. A hard item, but not a bad one. The place theory of pitch perception suggests that the nervous system is able to identify a sound's pitch simply by keeping track of where the movement is greatest along the length of the basilar membrane. More specifically, stimulation of hair cells at one end of the membrane leads to the experience of a high tone, while stimulation of hair cells at the other end leads to the sensation of a low tone. Therefore, the finding that low-frequency sounds are associated with the deformation of the entire basilar membrane almost equally is inconsistent with the place theory of pitch.
____ 35. Why are we unable to see colors in very dim light?
a. The receptors for color are not sensitive to dim light. ##
b. Lateral inhibition is activated in very dim light.
c. Opponent processes cannot operate at low levels of light.
d. All of the above.
56%, .54. The rods are sensitive to even low intensities of light, but they're not differentially sensitive to various wavelengths; the cones are sensitive to various wavelengths (short, medium, and long), but they operate only at higher levels of illumination.
____ 36. Which of the following is true about color receptors?
a. Any wavelength will stimulate all four types of color receptors, but will do so unequally.
b. Any wavelength will stimulate all three types of color receptors, but will do so unequally. ##
c. Any wavelength will stimulate only one or two of the four types of color receptors.
d. Any wavelength will stimulate only one or two of the three types of color receptors.
71%, .25. Our color vision is trichromatic, meaning it depends on three different kinds of color receptors. Each type of color receptor responds to a broad range of wavelengths in the visible spectrum, but their patterns of sensitivity differ in that one receptor type is most sensitive to wavelengths in the short-wave region of the spectrum, the second to the middle-range, and the third to the long range. Therefore, any wavelength will stimulate all three types of receptors but some types of color receptors will respond more than others given their different patterns of sensitivity.
____ 37. A is farther away from an observer than is B. What will happen if the observer moves his head from right to left?
a. A will seem to move more quickly than B in a direction opposite to that of the observer.
b. B will seem to move more quickly than A in a direction opposite to that of the observer. ##
c. A will seem to move more quickly than B in the same direction as that of the observer.
d. B will seem to move more quickly than A in the same direction as that of the observer.
63%, .48. Whenever we move our heads, the images projected by the objects in our world necessarily move across the retina. For reasons of geometry, the projected images of nearby objects move more than those of distant ones. The direction of motion across the retinal depends on where we are pointing our eyes. Points closer to us than the target of our gaze appear to be moving in a direction opposite to our own; points farther away appear to be moving in the same direction we are.
____ 38. Why does the world seem to move when you push on your eyeball through the side of your eyelid?
a. The retinal receptors have been stimulated both by what you are looking at and by your finger pressing against your lid.
b. Your eye has moved without being signaled by the brain to do so. ##
c. Your eye has been moved without the corresponding blinking that usually occurs when you put your finger very near your eye.
d. You have moved a part of your body voluntarily rather than involuntarily.
56%, .48. Hermann von Helmholtz showed a century ago that movement is be seen, even with no change in relative positions, if the eyes are moved by muscles other than their own. In other words, the perceptual system can sense "motion" even when there are no changes in the spatial relationships on the retina.
____ 39. Gestalt psychologists take the following position with respect to perception:
a. the whole equals the sum of its parts.
b. perceptual parsing usually results in illusions.
c. how or whether we perceive something depends on the organization of a pattern. ##
d. perception is "bottom-up."
65%, .44. Gestalt psychologists argue that how a form is perceived depends on the organization of the entire pattern, a coherent, intact Gestalt that is different from the sum of its parts. Therefore, the perceiver must take the entire pattern into account, and must organize the pattern appropriately, in order to find anything meaningful.
____ 40. According to the Gestalt grouping factor of good continuation, how would someone who had never before seen an "X" most likely describe it?
a. consisting of a right side up "v" over an upside down "v"
b. consisting of two sideways "v"s next to each other
c. consisting of two crossed diagonal lines ##
d. consisting of four diagonal lines meeting at a central point
72%, .42. Good continuation suggests that our visual system organizes patterns in a fashion that suggests a preference for contours that continue smoothly along their original course. Since it is two crossed diagonal lines that compose an X (i.e. their "original course" is as two distinct lines), someone who had never before seen an "X" would most likely describe it as two crossed diagonal lines.
____ 41. When you first look at a certain painting by Salvador Dal�, you see an archway filled with people fighting. But when you look a bit longer the archway seems to become a horse and many of the people become textures in the landscape. As you continue to look your perception keeps flip-flopping. This phenomenon, known as a "reversible image," exemplifies which general principle about human perception?
a. The same stimulus can be parsed in more than one way. ##
b. Ambiguous figures will gradually fade away as we habituate to them.
c. We attend to the stimulus that is most meaningful at the time.
d. Only a few basic perceptual abilities are inborn.
73%, .61. Reversible image occurs when a perceiver discovers that a given stimulus can be parsed in more than one way (i.e., as a horse/landscape versus as an archway filled with people fighting). The fact that the given stimulus can be perceived in multiple ways makes it clear that the stimulus itself is typically neutral with regard to parsing; the perception is in the eye of the beholder.
____ 42. Objects A and B both cast the same size image on your retina, yet distance cues indicate that A is closer to you. Which of the following will you perceive to be true?
a. A is larger than B.
b. A is smaller than B. ##
c. A and B are objects of the same size, at different distances from you.
d. A and B are objects of the same size, at the same distance from you.
57%, .46. If an object moves to a new distance, the size of the retinal image cast by that object changes. The farther away the object, the smaller the retinal image cast by that object. Therefore, if objects A and B cast the same size image on your retina, but object A is physically closer to you, then you would perceive object A as smaller than object B to result in the same size retinal image.
____ 43. What would happen if we were to use top-down processing only?
a. We would experience only ambiguous figures.
b. We would perceive only the individual features of objects.
c. We would perceive only what we expect to see. ##
d. We would see objects two-dimensionally.
70%, .48. Top-down or knowledge-driven processes are influenced by beliefs and expectations, as well as incoming data (whereas bottom-up or data-driven processes are primarily influenced by incoming stimulus information). Therefore, if we only used top-down processing, our perception would be driven primarily by what we expect to see.
____ 44. The binding problem focuses on how
a. movement is perceived.
b. all the elements of a stimulus detected by separate systems are integrated. ##
c. depth is perceived.
d. an object is identified.
85%, .42. The binding problem is the problem confronted by the brain of recombining the elements of a stimulus, once these elements have been separately analyzed by different neural systems.
____ 45. What is suggested by research in which subjects are asked to take part in a dichotic listening test?
a. The auditory stimulus is received by the receptors in the unattended-to ear, but the information is only partly processed. ##
b. The auditory stimulus is completely blocked out of the unattended-to ear.
c. The auditory stimulus in the unattended-to ear and the attended-to ear are both blocked out.
d. The auditory stimulus in the unattended-to ear and the attended-to ear are both clearly received and attended to.
50%, .33. In dichotic listening tasks, subjects are required to pay attention to a voice arriving (through headphones) in one ear, while another (unattended) voice is presented to another ear. In this set-up, participants grasp virtually none of the content of the unattended message. However, participants are not totally deaf to the unintended message. For example, if the unattended message includes the participant's own names, a substantial number of participants will detect this salient stimulus. This suggests that the information in the unattended-to ear is only partly processed.
____ 46. The 50 students in a class are arranged in order according to height, with the shortest student given the number "1" and the tallest student given the number "50". The resulting scale would be classified as:
b. ordinal. .##
77%, .35. An ordinal scale is a scale in which responses are rank-ordered by relative magnitude but in which the intervals between successive ranks are not necessarily equal.
____ 47. In the following distribution, the value 20 is the _____:
14 15 17 17 18 19 20 21 22 23 23 24 25
b. median. ##
95%, .49. The median is the point that divides the distribution into two equal halves when the scores are arranged in increasing order, i.e., the numeric value separating the higher half of the sample from the lower half of the sample. In this example, there are 6 values smaller than 20 and 6 values greater than 20.
____ 48. A patient has a z-score of 2 on a questionnaire test of depression. This individual scores higher than approximately _____ of the population at large.
c. 98% ##
d. The correct answer cannot be determined without knowing the mean and standard deviation.
47%, .4. Remember the rule of 68, 98, and 99. Assuming that the score on the questionnaire test of depression is a normally distributed variable, then the individual who has a z-score of 2 would have a score higher than approximately 98% of the population at large.
____ 49. Assume that the correlation between anxiety and depression is .50. From this we can conclude that a line drawn around the scatterplot of scores would be:
a. almost circular.
b. shaped like a fat football. ##
c. be parallel to the X-axis.
d. run from the upper left-hand corner to the lower right-hand corner of the plot.
54%, .50. The correlation is positive, which eliminates option (D) because a line from the upper left-hand corner to the lower right-hand corner would reflect a negative correlation. The correlation is greater than 0, which eliminates option (C) because a line parallel to the X-axis would reflect a correlation of 0. If the line drawn around the scatterplot were almost circular, that would indicate an almost null, or 0, correlation, eliminating option (A). That leaves option B, the correct answer -- see the sample scatterplot below:
____ 50. A political opinion poll finds that 55% of the respondents favored gay marriage, with a confidence interval of 5%. From this, you can be reasonably certain that the true percentage of the population favoring gay marriage is:
b. between 50% and 60%.##
c. between 45% and 65%.
d. between 40% and 70%.
87%, .50. The confidence internal is an interval around a sample mean within which the true population mean is likely to fall. In this example, the confidence interval is 5%, indicating that the true percentage of the population mean is likely to fall within 50% and 60%, i.e. +/- 5% from the poll's finding.