University of California, Berkeley
Department of Psychology

Psychology 1
Summer 2012

Midterm Examination 1

Scoring Key and Item Analysis

In the scoring key that follows, correct answers are marked with double pound signs (##).

Midterm 1 Exam PerformanceThe average score on the exam, before rescoring, was 33.85 (SD = 6.43), or 68% correct, which was within the historical range of 65-70% correct on exams in Psych 1. The figure shows the distribution of exam scores for the class.

Following procedures outlined in the Exam Information page, the statistical analysis identified no (0) bad items. Accordingly, no items were be rescored.

The exam scores entered into the ANGEL gradebook are final.

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. What makes psychology a coherent science, despite its wide diversity of subject matter?

a. Its focus on emotion as opposed to cognition or behavior.
b. Its adoption of a single perspective on behavior.
c. Its view of the behaving organism as reacting to environmental stimulation.
d. Its view of the organism as an active interpreter of events. ##

45% of the class got this item correct; correlation of item with total score = .37. At psychology’s center is the organism, and its’ participation in and interpretation of surrounding events. This perspective links a wide array of subjects into one cohesive, coherent science, focused on behavior and mental states inclusive. Psychology does not just focus on emotion at the expense of cognition, and definitely does not adopt one single perspective on why we do what we do. We also are not seen as just reacting to the stimuli in the environment, but as active interpreters of the environment, carrying our experiences and abilities with us in that interpretation. Prologue

2. A psychological explanation of behavior is in terms of:

a. the stimuli that impinge on the organism.
b. the individual's thoughts, feelings, and desires. ##
c. the operation of genes, hormones, and neurotransmitters.
d. the influence of other people.

75% correct: item-to-total r = .44. Psychology examines behavior in terms of people’s mental states and their internal experiences, such as thoughts, feelings, beliefs, and desires. While elements of behavior may involve a combination of genetic inheritance, the endocrine system and its function, as well as the brain’s neurotransmitters, this is more the realm of biology’s intersection with psychology than just psychology itself. The influence of other people on behavior is sociological in nature, and while that also has an intersection, it is not strictly a psychological approach. Lecture 1

3. A gene is said to be recessive. What is the likelihood that the trait controlled by that gene will be expressed?

a. The trait has a high likelihood of being expressed.
b. The trait will absolutely be expressed.
c. The trait will be expressed only if the paired gene is identical. ##
d. The trait cannot be expressed.

94%; .43. Genes come in pairs, with one of the pair inherited from the mother and one from the father. Dominant genes are expressed even if there is only one copy present, regardless of the type of the other copy. Recessive genes are genes that won't be expressed if the other gene in that pair is dominant. If both of the inherited genes are recessive, then that trait will be expressed, since there is no dominant copy of the gene taking over expression. Thus, a recessive gene can be expressed, but only if the other copy is recessive, and won't be expressed if the other copy is dominant. Chapter 2

4. Which of the following is NOT a reason for variation in genotypes?

a. the enormous size of an organism’s genome
b. lack of uniformity across individual organisms within a species
c. mutations
d. experiences of an individual organism ##

78%; .43. Genotypes are inherited from parents, and the specific shuffling of the genes to create that genotype is done through reproduction, as the sperm carrying the father’s contribution meets up with the egg carrying the mother’s contribution. Variation occurs because each sperm and each egg has a different assortment, and in coming together they form a unique genotype. A large genome, with many individual genes, offers more opportunity for variation, as there are more factors on which it can vary. Also, since no organism is the same as another, even of the same species, they each are contributing their own diversity to the reproduction process and that propagates variation through reshuffling. Mutations are naturally-occurring changes in genes that are not the result of reproduction, and those changes introduce another factor of variation. The only thing not directly impacting an organism’s genome is the experience an individual has. Experiences do not change the presence of genes in the gametes, the blueprint of which are determined at birth. Chapter 2

5. Why, from an evolutionary perspective, might women show more jealousy regarding emotional loyalty?

a. A female needs resources provided by the male to nourish her young, and emotional loyalty is indicative of a partner’s commitment. ##
b. The female needs the male to create offspring, and emotional connections are critical for female mating.
c. The female has difficulty forgetting emotional hurts more than sexual transgressions and thus is more likely to attend to emotional issues.
d. None of the above; the female does not show more jealousy regarding emotional loyalty.

79%; .31. The female of most species spends much more energy having and raising young, and has less time to gather the increased resources she needs, and so to be successful she needs to secure as many resources as possible from the male she mated with. The best indicator that she and her offspring will be invested in is emotional involvement by her partner, which will keep him around and keep him investing. Females do not need emotional connections in order to mate, and there is no evidence that a female has more difficulty forgetting emotional transgressions than sexual ones, so this would not be a reason to attend to emotional issues. Evolution has shaped humans to have different needs regarding reproduction and each sex has different needs from the other in order to successfully reproduce and raise young. Chapter 2

6. Sam picks up a hot cookie sheet and then quickly drops it as her body begins to respond to the heat sensations. The neurons responsible for sending the signal regarding the pain would be considered __________ neurons.

a. efferent
b. afferent ##
c. parasympathetic
d. somatic

80%; .35. Afferent neurons are those that are sending information from the body into the brain, and the efferent are sending information from the brain to the body. You can think of things as “affecting” you (coming in to your brain) and that you have an “effect” (from your brain outward) on things in the world, if you’d like a pneumonic. The parasympathetic system is a complex system of body regulation that restores and promotes a resting state after a stressor has been responded to, and the somatic system, while that is governing body sensations and movement, is not specific enough to be the answer to this question. Chapter 3

7. An above-threshold depolarizing current is applied to the cell, but it is slightly above the required threshold for the action potential. As a result, __________.

a. the action potential occurs more slowly
b. the action potential will be the same size and propagated at the same speed as if the depolarizing current was applied at threshold levels ##
c. the action potential occurs more quickly and is larger
d. the action potential will be smaller and propagated slightly slower than if the depolarizing current was applied at threshold levels

82%; .39. Action potentials are “all or nothing” events, where once a firing threshold is reached, the neuron fires, whether the threshold is only barely reached or completely exceeded. Action potentials cannot occur slowly, or more quickly, and cannot be small or large, so answers a, c and d cannot be correct. Once a neuron is triggered to fire, it fires the same way every time, at the same speed and intensity. Chapter 3

8. The endocrine system releases __________ into the __________.

a. neurotransmitter; synapse
b. neurotransmitter; bloodstream
c. hormones; synapse
d. hormones; bloodstream ##

92%; .36. Neurotransmitters are found mainly in the brain, specifically the synapse, and do not travel in the blood stream. Since synapses function via neurotransmitters, c cannot be the correct answer. However, hormones are released into the bloodstream for travel throughout the body. The endocrine system is responsible for hormone regulation and production in the body, so answers a and b cannot be correct, leaving only d. Chapter 3

9. Which of the following investigative techniques provide static images of the brain, showing its anatomy but not its neural activity?

a. CT scans and PET scans
b. PET and MRI
c. CT scans and MRI ##
d. none of the above

82%; .33. CT scans examine brain structure by constructing composite X-ray images taken from different angles. These are still images taken of structure, and not of activity. PET scans examine brain function by observing metabolic activity in different brain regions. MRI is an imaging technique that shows the effects of magnetic pulses on the brain tissue, assembling the information into an image of the brain’s structure. Of these 3, only the PET scan examines function, so the answer has to be C. Chapter 3

10. So-called subcortical structures lie underneath the cortex. One of these is the thalamus, which __________.

a. controls speech and verbal reasoning
b. specializes in the processing of emotion
c. acts as a relay station for sensory information ##
d. controls motivated behaviors such as eating, drinking, and sexual activity

93%; .07. The brain area involved in speech and verbal reasoning (Broca’s area) is located in the cortex and is not subcortical. The amygdala is the brain area that specializes in processing emotion, and is subcortical. Motivated behaviors such as eating, drinking and sexual activity are regulated by the hypothalamus. The thalamus is a relay station for all the incoming sensory signals (except olfaction), and it passes those signals on to their appropriate processing areas. This is a memorization question. Chapter 3

11. On which lobe should an electrode be placed to record the most electrical activity in response to a pinch of the left big toe?

a. left parietal
b. right frontal
c. left frontal
d. right parietal ##

72%; .30. The left side of the body sends signals to the right side of the brain, and the right side of the body sends signals to the left side of the brain, with information crossing through the corpus callosum. If the left toe is pinched, the right side of the brain would register that sensation. Secondly, the frontal lobes are responsible for executive function and regulation, while the parietal lobe, near the top of the head, is responsible for somatosensory processing. The right parietal lobe is where a pinch to the left toe would be registering. Chapter 3

12. Tarrence has been blind since birth. When he feels an object, which part(s) of his brain are likely activated, as shown by a recent study examining brain plasticity?

a. his frontal lobe and motor cortex
b. his parietal area
c. both his parietal and his occipital cortex ##
d. his temporal area

63%; .41. The parietal lobe is responsible for processing body sensations, and as such will receive signals from the hands, as Tarrance uses them to feel objects. However, since he has been blind since birth and does not use his occipital cortex for vision processing, that area has been co-opted for use for object recognition through non-visual channels. This is a classic example of brain plasticity, where one area can use different input signals to do its job. Answer b is incomplete, as the occipital, unused for vision processing, still gets incorporated. Tarrance’s frontal lobe controls his executive function and decision making, and isn't likely to be recruited in object recognition, and his temporal area is used for audio production and processing. Chapter 3

13. The hands and feet comprise a relatively small potion of body mass.

a. Accordingly, they have relatively few spinal nerves devoted to them.
b. Nevertheless, they are served by a relatively large segment of spinal nerves. ##
c. For this reason, the spinal nerves that serve them are located at the top of the spinal cord.
d. Because both hands and feet evolved from the limbs of four-footed animals, the spinal nerves that serve both areas are located close together on the spinal cord.

80%; .47. The hands and feet are very sensitive areas of the human body, and as such they convey a lot of information to the brain and have to be capable of fine distinctions. Because of this, they are given a large segment of nerves and are represented by a larger area of the brain than some other comparably-sized parts of the body that aren’t as sensitive. C and D are both tempting answers, but there is nothing special about the place on the spinal cord that determines sensitivity. Lecture 2

14. In the persistent vegetative state:

a. the patient has suffered damage to the pons, excluding the reticular formation.
b. the patient may show some reflex functions and appear to go through the regular sleep cycle. ##
c. remains consciously aware of events in the surrounding environment, despite appearances to the contrary.
d. the patient is unresponsive to stimulation.

58%; .22. People in persistent vegetative states are by definition not conscious, and are not aware of events happening around them. They can, however, be responsive to some physical stimulation, and may have reflexes still intact, as well as show evidence of a sleep-wake cycle (demonstrated by brain activity monitoring), since their nervous system is still conducting signals to limited areas of the brain. Lecture 3

15. The "association area" of the prefrontal cortex is particularly important for:

a. executive functions and problem-solving. ##
b. coordination of hand and eye movements.
c. integrating perception across different sensory modalities.
d. forming links between stimuli and responses

49%; .36. Hand and eye coordination would be handled by communication between the occipital areas that control vision, and the parietal areas that control movement, neither of which are near the prefrontal cortex. Sensory information is processed through the thalamus, or “switching station,” and the respective brain areas for each modality. The prefrontal cortex, both the last to evolve in the human species and the last to develop in each individual person, helps us solve complex problems and is our “executive,” or the area that helps us keep items in working memory, regulate our impulses and our attention, and plan our actions. Lecture 4

16. Specialization of function:

a. is limited to large bundles of neural tissue.
b. occurs for mental functions, but not to particular percepts or memories. ##
c. is contradicted by the fact that the two hemispheres are redundant with each other.
d. is supported by Lashley's Law of Mass Action.

51%; .11. There are specialized functions in the two hemisphere, with language areas located usually in the left hemisphere, along with sequential analyses, mathematical computation and fine motor control (for most of us). The right is more specialized for spatial analysis and pattern perception, generally. The two hemispheres aren't redundant at all, though they do share functions cooperatively, so C cannot be the answer. Specialization of function occurs in functions, but not at the level of very specific concepts or memories, which are stored in a distributed fashion. Lashley’s Law of Mass Action is related to the extent of damage and its effect on memory impairment, and isn’t specific to lateralization. Lecture 5

17. Let’s say you are conducting research to test the idea that regular flossing reduces the incidence of gum disease. In this hypothetical design, what is the independent variable?

a. gum disease
b. flossing frequency ##
c. the severity of the gum disease
d. both a and b are independent variables

86%; .41. Independent variables are the conditions you manipulate in the experiment to see if they have an effect, and the dependent variable is the thing you measure, or the thing that got affected. Gum disease would be what you are measuring, and so would be your dependent variable, and your interest is in whether flossing, or lack thereof, affects that gum disease, so that is your independent variable. The answer A cannot be an independent variable because you are interested in seeing what happens TO the gum disease. Chapter 1

18. If a study’s subjects 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

83%; .41. When a study is said to have external validity, it means that what it is claiming to measure is what it is actually measuring, reflecting the world as it actually is. A researcher can say they are studying intelligence, but it may turn out that the way the question was asked makes it so that she is studying language skills instead, for example. A study that has internal validity is one that is designed carefully and assures that the independent variable and dependent variable indeed do have a relationship and there aren’t other variables that aren't accounted or controlled for. Consistency is a measure of whether a test is constructed well enough that each time you use it it yields the same results. If every time you measure intelligence in the same sample you come up with a different answer, there is a problem with your consistency, or reliability. Chapter 1

19. Which of the following is likely to be a quasi-experimental study?

a. investigating the effects of drug A in rats
b. determining whether pre-exposure to a word set improves retention
c. investigating gender differences in toy play in preschoolers ##
d. examining whether magnitude of reward increases response rates

63%; .41. In an experimental design, subjects are randomly chosen to be in each experimental condition. Answers A, B and D all have that element, where rats are assigned to either drug A or B; subjects are assigned to either of the two word-set conditions; and subjects are assigned to conditions that have different magnitudes of rewards. A quasi-experiment has limits that are determined by the subjects themselves not being able to be randomly assigned. An example would be a study that involved gender, or test scores, or height, or any other variable that a subject cannot be assigned to, and instead comes into the study with. Answer C is about looking at toy play in preschoolers, but it is being looked at across gender, which is not something you can assign to someone. Chapter 1

20. __________ comparisons compare one group to itself in another setting; __________ comparisons compare two groups in the same setting.

a. between-subject; within-subject
b. within-subject; between-subject ##
c. correlational; experimental
d. experimental; correlational

63%; .36. Within-subjects designs are those that take one group of subjects and have them experience two different conditions, measuring their performance in each and seeing how it may or may not change in those two conditions. Between-subjects designs take two (or more) groups and assigning each to a different condition so they can be measured and compared against each other. Correlational studies only measure variables; they do not manipulate them and compare outcomes like experimental studies do. Chapter 1

21. Debriefing must include which of the following?

a. informing the subject about the experiment prior to the onset of the experiment
b. having the experimenter explain any deception or hidden manipulation used in the experiment at the conclusion of the subject’s participation in the experiment
c. If the study involved manipulation of beliefs, mood, or emotion, the investigator must attempt to undo these changes at the conclusion of the subject’s participation in the experiment.
d. both b and c ##

63%; .25. Subjects need to be unaware of the real objective of a given study before they engage in it, ruling out answer A, but an experimenter should explain any deception or manipulation once the subject is done participating in the study, and if there were efforts to persuade or manipulate a subject’s beliefs or change their emotions, efforts must be made to return the subject to his or her previous state. There should be no lasting effects of having participated in an experiment. Chapter 1

22. Considering the following two distributions of scores, which statement is true?

A: 2 3 3 4 5 6 6 7 9
B: 2 2 3 4 5 6 7 7 9

a. A and B have the same mean, but different medians.
b. A and B have the same median, but different means.
c. A and B have the same variance. ##
d. There is a negative correlation between the pairs of variables

58%; .21. In both distributions, the medians are the same (5), and the means are the same (5), ruling answers A and B out. You cannot calculate a correlation with this information. However, distributions A and B do have the same variance, or the degree to which the scores depart from the central value, which is 5. All the scores range from 2 to 9, and are very similar throughout, deviating by only one number above the central value and one number below. If both of the sets had the same mean and median, but their variances were different, we might see a set from 40 to 60 with a central value of 50, and a set from 0 to 100 with a central value of 50. Lecture 6

23. Which of the following is the best example of one of the simplest forms of learning, called habituation?

a. You see something you’ve never seen before and immediately orient toward it.
b. After watching a lot of violent TV, the violence depicted bothers you less and less. ##
c. You work near a stove, accidentally touch a hot burner, and then make the connection: Stoves are hot.
d. If you are involved in a well-rehearsed task, such as washing the dishes, you go through the same steps each time you perform the task.

72%; .37. Habituation is essentially “getting used to” a given stimulus so that you no longer respond to it with the same intensity over time. Watching violent TV may have at one point been shocking, but with repeated exposure, you can become habituated to it and find it bothers you less. The answer C is an example of an association, formed in a single trial, rather than “getting used to” the heat over time. D isn't habituation, because you are not responding less and less, but instead are doing the same thing over and over, identically. Answer A is ruled out because responding immediately to something you’ve never seen before is the opposite of habituation. Chapter 7

24. What is true of backward conditioning?

a. The CS fails to serve as a signal for the onset of the US. ##
b. The CR is presented shortly after the UR.
c. There is a fairly high ratio of unreinforced trials.
d. The CR differs from the UR.

72%; .32. In classical conditioning, the order of events matters. You must have the stimulus you wish to be conditioned come BEFORE the unconditioned one, but close enough in time so it can become a predictor. If the stimulus you wish to be conditioned happens too far from the unconditioned one, it won't get connected in the mind of the subject, and if it comes after the unconditioned one, it won't be a predictor of it at all. Conditioning is said to be backward when the two stimuli do not have a predictive temporal relationship such that the first stimulus can indeed become conditioned by it’s proximity to the unconditioned stimulus. Neither B nor D can be the answer because conditioned RESPONSES are not presented at all, but are performed by the subject, and whether they differ is not relevant. C cannot be right because conditioning is not about reinforcement, but just presentation of stimuli. Chapter 7

25. What would you expect if you were reinforced for selling greeting cards according to a VR 20 schedule?

a. to earn $20 for every major sale
b. to receive payment after every 20th sale on average ##
c. to be paid after every 20 days
d. to be paid after every 20 days on average

72%; .14. VR 20 means that there is a variable-ratio reinforcement schedule centering around 20 trials. It isn't fixed, so the reinforcement doesn’t occur at the 20th trial, thereby ruling answer A out. Answers C and D belong to the time interval rather than ratio category, with C being fixed interval and D being variable interval. Only B fits as an answer because the reinforcement comes after a number of trials, but not a fixed number; it’s a number clustering somewhere around 20, on average. Chapter 7

26. A father is holding his month-old baby as he and the baby look at one another. The father sticks his tongue in and out. Which of the following is a likely response from the baby?

a. The baby should imitate the tongue movements. ##
b. The baby should begin to cry, as the father is showing a frightening facial expression.
c. The baby should turn away, uninterested.
d. The baby should smile but not imitate the father.

63%; .09. Babies even of one month of age are capable of imitating elements of facial expressions, and do so readily. Babies do not find tongue movements scary, and should not cry under normal circumstances. One month old babies are not yet capable of the social smile, so D cannot be the right answer. Lastly, babies are very interested in their caregivers and spend a lot of time observing them. Chapter 7

27. What structural changes occur in the neurons as a result of learning?

a. The neurons develop additional sodium ion gates to allow for faster action potentials.
b. The neurons develop additional Nodes of Ranvier and more myelination.
c. The axon terminals of presynaptic neurons grow new dendritic spines.
d. The dendrites of postsynaptic neurons grow new dendritic spines. ##

44%; .28. Learning involves the development of new dendritic spines on the receiving, or postsynaptic neuron, enabling the creation of new lines of communication with other neurons. Presynaptic axon terminals do not have dendrites; instead, they connect to dendrites (review in chapter 3). Also, the anatomy of an axon, once built, does not change with learning; the length of the axon determines the number of ion gates and Node of Ranvier, not experience. Chapter 7

28. Even though learning varies from species to species, there is one factor that contributes to learning that is shared by all species. What is this one factor?

a. neural plasticity ##
b. visual acuity
c. spatial memory
d. reproduction

61%; .16. Neural plasticity refers to the changes in the brain that occur with learning. Each thing that is stored and recalled when needed (which is what learning essentially is), needs to make a change in the brain that represents it. These changes are necessary, and all species that have brains will have changes in them when they learn. While reproduction is shared, it is not a factor that directly contributes to learning, but instead to the creation of a new generation of offspring. Visual acuity varies species to species, depending on the environments they are suited for, and therefore does not contribute to learning the same way for each species. Furthermore, spatial memory likewise varies according to species challenges, with some having marked advantages in that regard and others not especially so. Chapter 7

29. Instinctual behaviors:

a. are not responsive to environmental stimuli.
b. are acquired through experience during a critical period in the organism's life.
c. interfere with the organism's adaptation to its environmental niche.
d. do not permit the individual to respond to changing circumstances. ##

42%; .37. Instinctual behaviors, by definition, are behaviors that are not decided upon by the organism, but are triggered by stimuli in the environment, whether external or internal. They are “hard-coded” in the organism, and not learned or acquired, and as such are usually thought to contribute to evolutionary fitness, rather than interfere with it. Once triggered, they are carried out without modification, and thus cannot change based on changing circumstances. Lecture 7

30. According to Thorndike's Law of Effect:

a. responses occur to unconditioned stimuli.
b. behavior is shaped by its consequences. ##
c. conditioned responses overcome maladaptive reflexes.
d. the generalization gradient can be prevented by extinguishing spontaneous recovery.

90%; .14. The Law of Effect says that the consequences that follow your actions make those actions more or less likely to occur again, thus shaping behavior. Thorndike’s Law doesn’t address maladaptive reflexes or the generalization gradient. Lecture 8

31. A rat is initially conditioned to respond with fear to a tone paired with footshock. In a subsequent set of trials, the tone follows a brief dimming of the light in the operant chamber, but the animal still gets shocked. Later testing reveals that the animal will show fear in response to:

a. both the tone and the dimming light. ##
b. the tone but not the dimming light.
c. the dimming light but not to the tone.
d. neither the tone nor the dimming light.

65%; -.06. OK, it’s kind of weird that the correlation is negative, but still most of the class got it right. This is an example of second-order conditioning, where one conditioned stimulus (in this case the tone), is preceded predictably by another stimulus (the dimming light) such that that new, second stimulus is connected through the chain to the unconditioned stimulus (the shock). If presented in order – light, tone, shock – then both the light and the tone are predictors of shock and both should elicit fear, as both always lead directly to the feared event. Lecture 9

32. Tolman's experiments on latent learning contradict which assumption of stimulus-response (S-R) learning theory?

a. Associations are formed between stimuli and responses that occur close together in time and space.
b. Given enough reinforcement, associations can be formed between any stimulus and any response.
c. the organism can be treated as if it were a "black box" that collects associations between stimuli and responses.
d. Reinforcement is necessary for learning to occur. ##

55%, .51. Tolman’s experiments on latent learning showed that an animal can get exposure to a stimulus, without receiving reinforcement during that exposure, and still learn about the stimulus. The assumption behind S-R learning theory is that all learning needs reinforcement, and Tolman’s experiments are in direct contradiction to that. The answer A belongs with Pavlov, and classical conditioning, and so does not apply here, and B is in line with S-R theory. Lecture 10

33. According to the empiricists, how do we acquire the ability to interpret the world, given the apparent mismatch between distal and proximal stimuli?

a. This ability is innate.
b. We must learn to ignore the distal and concentrate on the proximal.
c. We acquire this ability through association or learning about the relationship between distal and proximal stimuli. ##
d. We acquire this ability by ignoring the proximal stimuli and concentrating on distal stimuli.

82%, .07. Distal stimuli are those things we are perceiving out in the world, away from us, and proximal stimuli are the elements of that stimuli that reach our sense organs. We may look at an object that is far away, but it is the light waves bouncing off that object that hit our retinas and become proximal stimuli. Sometimes the image that light makes is the same, even if the distal stimuli is different, and how we make sense of that and integrate that into a cohesive sense of the world is to understand the relationship between the properties of stimuli in the environment and how they are perceived by us. We cannot ignore one kind of stimuli and concentrate on the other; the must both be taken into account and learned about through experience. Chapter 4

34. 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.

a. 6
b. 30 ##
c. 50
d. 100

92%, .07. Weber’s law says that the size of the different threshold (of detection) is proportional to the intensity of the stimulus, or, the change in intensity divided by the intensity is the change needed. In this case, the difference is 2% (1 divided by 5), and so 2% of 25 is 5, making the answer 30. 6 makes no sense, 50 is a 100% change, and 100 is a 300% change. Chapter 4

35. To what does transduction refer?

a. the point at which a proximal sensory stimulus impinges on the organism
b. the conversion of a physical stimulus into a neural signal ##
c. the psychological sensation associated with a stimulus
d. the electrical activity in the cerebral cortex associated with the perception of a stimulus

90%, .61. Transduction happens after your sensory organs receive input from the environment (which would be answer A). It is the changing of that received signal into a neural signal that can continue to travel through the nervous system for eventual processing by the brain (which would be answer D). See page 143 in the textbook. Chapter 4

36. Which of the following best explains why humans can detect over 10,000 different scents when they typically only have 1,000 olfactory receptors?

a. Each receptor detects 10 or more individual scents.
b. More than one receptor may be stimulated by an odorant, resulting in a unique pattern of receptors stimulated for each smell. ##
c. Humans think they can smell 10,000 different odors, but in reality we cannot.
d. Only one receptor may be stimulated by an odorant, but it can be stimulated many times or just once, resulting in different qualities of smells.

82%, .51. The way the odor system functions is that each odor has a distinct receptor signature representing it in the olfactory bulb, the combination of which can enable us to detect over 10,000 different odors. This pattern is the source of the great variety, not how often a receptor is stimulated, nor by the receptor itself firing for multiple scents. Chapter 4

37. What does the perceived pitch of an auditory stimulus depend on?

a. The place on the basilar membrane that is maximally deformed by the auditory stimulus is responsible for high-frequency sounds.
b. The frequency of impulses in the auditory nerve that is generated by the auditory stimulus is responsible for low-frequency sounds.
c. It depends on the amount of deformation of the cochlea itself.
d. Both a and b. ##

72%, .02. The auditory system works by vibrations being passed from the oval window to the basilar membrane of the cochlea. As it vibrates, the hair cells bend, triggering a neural response. Some regions vibrate more than others, with higher frequencies vibrating a different region than lower frequencies. This information is part of what the brain uses to interpret sound. The other part is the firing rate of the cells in the auditory nerve, which match the frequency of the sound wave. These two pieces of information are combines and are interpreted by your brain as pitch. Chapter 4

38. What functionally adaptive mechanism would you expect to find in an animal that lives in a cave and is exposed to low-intensity light only?

a. a large number of rods ##
b. very good color vision
c. very good visual acuity
d. both a and c

55%, .29. Vision is initiated by light hitting the rods and cones of the eye, which then pass on this signal. Cones respond to greater light intensities, giving rise to color sensations, and rods respond to lower light intensities, giving rise to colorless sensations. Cones serve day vision well and can discriminate fine detail, while rods are good for night vision but have less ability to discriminate detail. An animal in a cave would be in dim light, and thus would have a large number of rods enabling vision in that environment. Cones would be of little use without higher light intensity, and thus there would be little passing of color information but also little discrimination of detail. An animal in a cave would have very little color vision, and little acuity. Chapter 4

39. 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 Vs next to each other
c. consisting of two crossed diagonal lines ##
d. consisting of four diagonal lines meeting at a central point

78%, .36. Someone who had never seen an X before would most likely see its component parts and describe their spatial relationship, keeping the lines continuous, with the gestalt principle of Good Continuation guiding the perceiver to perceive whole lines rather than pieces of lines. This rules out all other answers, since they all rely on the lines being broken up into pieces, either as V’s or as 4 separate lines. Chapter 5

40. What type of pattern recognition starts with features and gradually builds up to more complex structures, such as letters, words, and phrases?

a. top-down processing
b. knowledge-driven processing
c. bottom-up processing ##
d. both a and b

78%, .29. In processing, we think of things as either top-down or bottom-up. In top-down, we use our knowledge and past experience to interpret and limit what we see, using our perceptions of the whole picture to guide our understanding. In bottom-down, we use our sensory input to assemble what we are seeing into greater and greater wholes until we have understanding. Processing lines into letters into words into phrases is an example of bottom up processing only. Chapter 5

41. A higher-order invariant relationship is a relationship between two or more stimuli that __________.

a. changes frequently
b. changes depending on the size of the objects
c. changes depending on the distance of the objects from the observer
d. does not change ##

59%, .36. An invariant relationship between two stimuli says that their size relationship does not change. If you see the retinal image of one stimuli get larger and smaller (as it gets closer and farther), but the objects near it and the textual elements around it remain in a constant ratio to it, you can gain information about the size of the objects. As an image gets smaller, it could actually be getting smaller or it could be moving further away. If the images around it also get smaller, then you know there is size consistency and that it must be moving further away instead. This is a kind of perceptual constancy. Chapter 5

42. When looking down a rocky beach, you see individual stones nearby, but farther away you can see only a rough-looking terrain. What does this example best illustrate?

a. texture gradients ##
b. interposition
c. linear perspective
d. motion parallax

85%, .34. Uniformly textured surfaces produce texture gradients that give us information about depth: as the surface recedes, the size of the texture elements decreases, becoming less distinct. This is a monocular depth cue. Interposition is when one object blocks another, the linear perspective is when parallel lines seem to converge as they get further away, and the motion parallax is a depth cue based on the fact that as an observer moves, the retinal images of nearby objects move more rapidly than do the retinal images of objects farther away. Chapter 5

43. Which of the following provides the most convincing evidence that there must be a mechanism that serves to stabilize the physical world when one’s eyes move voluntarily?

a. We are able to perceive the difference between an object that is stationary and one that is moving.
b. The world seems to jump to the left if, when your eye muscles are paralyzed, you try to move your eyes to the right. ##
c. When things in your visual field move in one direction, you often feel that you are moving in the opposite direction, even though you are actually stationary.
d. When you move one way, objects in the foreground seem to zoom by, whereas those objects farther away seem to move at a more leisurely pace.

25%, .47. a hard item, but it really discriminates! Since our eyes move constantly, we need a system that stabilizes the images we see and keeps them cohesive. Whenever you turn your head, you unconsciously compute the shift in the retinal image that your own motion will produce and you cancel out this amount of movement in interpreting the visual input. This produces constancy. If your eyes are paralyzed, but you send a signal to move them anyway, your cancelling-out system comes online and moves the retinal image information the opposite way to compensate, but since you didn’t actually move your eyes, you perceive this cancelling out as a jump in the image. This confirms the canceling out theory. Chapter 5

44. Individuals who suffer severe attention deficits because of parietal lobe damage are most likely to only be able to do which task?

a. visual search tasks using complex but not simple stimuli
b. visual search tasks involving movement but not color
c. visual search tasks where the target is defined by multiple features
d. visual search tasks where the target is defined by a single feature ##

58%, .16. People who suffer from parietal damage can do visual search tasks if the target is defined by a single feature, but are deeply impaired if the task requires them to judge how features are conjoined to form complex objects. This is evidence that we are normally bundling the perceptive features into a whole, and that it requires our attention. It suffers when we are distracted, and suffers when our attention capabilities are impaired due to damage. Chapter 5

45. In principle, every sensory modality can be defined by four features. Which feature does not belong with the other three:

a. electromagnetic radiation
b. rods and cones
c. lateral geniculate nucleus
d. temporal lobe ##

37%, .25. Every sensory modality is composed of the four features: they all have a proximal stimulus, a receptor organ (which conveys that stimulus to a neural impulse), a sensory tract (which carries the neural impulse toward central nervous system), and a projection area (area in the brain where the impulse ends). For vision, electromagnetic radiation is the proximal stimulus, the receptors are the rods and cones, the lateral geniculate nucleus is the sensory tract carrying the signal, but it carries it to the occipital lobe, not to the temporal lobe. Lecture 11

46. Which phenomenon is inconsistent with Helmholtz's trichromatic theory of color vision?

a. Purple is seen as a combination of red and blue.
b. Yellow is seen as a primary color. ##
c. The negative afterimage of red is yellow.
d. Color blindness comes in seven basic forms.

52%, .37. Helmholtz’s theory of color vision says that any visible color can be made by mixing any of the three primary colors, which would mean that purple could be made by combining red and blue. Some of the problems in Helmholtz’s theory are that he would say that yellow is made of red and green, but we don’t see it that way; we see yellow as a primary color. Also, that we have afterimages supports the opponent-process system (rather than Helmholtz), where there are cones that are responsive to pairs of colors such that if you tire one color out by staring at it, then when you look away you’ll see an afterimage of the other color of the pair (green tires out and then you see an image of red, for example). Lastly, color blindness comes in two main forms, and likewise demonstrates that you lose colors in pairs of red-green or yellow-blue, but not in green-blue, which supports the opponent-process theory of color vision. Lecture 12

47. In a particular signal-detection experiment, there are a relatively small proportion of "catch trials". This should have the effect on the observer of:

a. induce a liberal bias toward saying "Yes". ##
b. induce a conservative bias toward saying "No".
c. increasing sensitivity.
d. decreasing sensitivity.

51%, .32. A small proportion of catch trials means that the observer has an adequate sensitivity for the stimulus and is detecting when the signal is on, but that he also has a lower criterion for that signal, or a liberal bias toward “yes,” since he sometimes gets caught in the catch trial saying the signal is on when it is off. A conservative bias would lead him to say that he has heard the signal when it is on, and not often saying so when it is off, but because he has set a higher criterion and is “making sure” that the signal is really on, it leads him to also say no when there really was a signal on. Lecture 13

48. As a cue to distance, retinal disparity is:

a. binocular and ocular.
b. binocular and optical. ##
c. monocular and ocular.
d. monocular and optical.

56%, .37. Retinal disparity describes the phenomenon of our eyes being 2-3 inches apart, leading to each eye receiving a different perspective on the object. This difference is compared and fused, and distance is then perceived. Because this requires 2 eyes, this is a binocular phenomenon, ruling out questions C and D. Optical relates to the physical properties of light, while ocular relates to the eye itself. Some distance information is ocular, meaning relating to feedback from the eyes themselves (the position of the muscles, for example), and other distance information is related to the light falling on the retina, not on the eye itself. Retinal disparity involves two different images on the retina, so that makes it optical. Lecture 14

49. In the information-processing view of perception, perception connects to memory at the point of:

a. ecological optics.
b. unconscious inference.
c. feature detection.
d. pattern recognition. ##

52%, .22. Feature detection allows us to analyze a stimulus and extract the basic features it is comprised of. This does not need to connect to our memories at all and is mainly sensory. This is then followed by the “putting together” of the pieces of the stimulus, drawing on memory, permitting the perceiver to recognize patterns, seeing some as meaningful and some as meaningless based on what is in the memory. In the ecological view, everything is contained in the stimulus itself, and perception is direct and needs no individual interpretation. Lecture 15

50. Reversible (or bistable) figures show that:

a. perception can change in the absence of changes in the proximal stimulus. ##
b. perception can remain stable even following changes in the proximal stimulus.
c. unconscious inferences are necessary for veridical perception.
d. in the perceptual cycle, assimilation dominates accommodation.

80%, .27. Bistable figures can support two different interpretations, reversing from one to the other, flipping back and forth. Perception never stabilizes; it changes with nothing in the stimulus changing. This is distinct from perceptual constancies, which remain stable despite changes in the stimuli. In bistable figures, the pattern on the retina never changes, but the perception does. Unconscious inferences are about going beyond the information given, not just seeing what is there in a different way. Lecture 16

A provisional answer key will be posted to the course website tomorrow.

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 after grades are posted.

Requests for rescoring must be received within two (2) days of the posting of grades.
Each request should be accompanied by a paragraph indicating
why the answer given in the key is incorrect or why the answer you chose was better.