University of California, Berkeley

Department of Psychology


Psychology 129 / Cognitive Science 102

Scientific Approaches to Consciousness

Spring 2009


Midterm Examination

Scoring Guide


What follows is the scoring guide prepared for the GSIs to help them grade the exam.  Other answers may also be appropriate, which is why it's called a scoring guide.  Based on the item analysis, I provide the percentage of the class who attempted each item, and the mean score achieved by those students.

Thanks to the GSIs for their quick grading of the midterm exams -- especially given the demands of Spring Break.  

The mean score on the exam, before editing, was 33.14 (SD = 7.23).  That's an average performance of 66%, which is within the range of 65-70% correct, which I like to see as a minimum score on my exams.  However, the mean number of questions answered was 20.49 (SD =3.46), with only eight (8) students answering 25 questions (and nobody answering more than 25!), which suggests that the original 25-question exam was a little too long.  All the more reason to look for "bad" items, employing the criteria described in the Exam Information page.

On average, 59% of students attempted any particular question (SD = 18%).  Applying the "2 SDs" criterion for an outlier, only one item, #32, made the cut -- although four additional items (#s 3, 10, 16, and 30) met a relaxed criterion of lying more than 1 SD away from the mean.
The average score for those attempting each item was 1.60 (SD = 0.29).  Applying the "2 SDs" criterion, no item was identified as an outlier (#18 came close) -- although a total of 8 items (#s 13, 14, 18, 24, 26, 27, 28, and 31) met a relaxed criterion of lying more than 1 SD away from the mean.
No item met the criterion for being a "double outlier", even when applying the relaxed "1 SD" criterion.  

So there weren't any "bad" items as such.  

Still, it was clear that the test was too long.  The most appropriate way to compensate for test length is to give everyone additional points representing the difference between the nominal test length (25 items) and the average number of test items actually answered by students (20.49) items.  Accordingly, I added nine (9) points to everyone's score, and then truncated any revised scores above 50 to the maximum of 50 points. 

MT_S09.jpg (53012 bytes)This resulted in a revised average score of 41.82 (SD = 6.80), or 84% correct, amounting to a solid B average -- pretty good performance.


Why isn't the new mean score 42.14 (33.14 + 9)?  Because scores above 50 were truncated to 50.  That's also why the standard deviation changed.

Why did I lengthen the test, compared to previous exams?  First, there are two kinds of tests, speed tests, which have time limits, and power tests, which don't.  Midterm exams are almost by definition speed tests, because they have to be completed in 50 minutes, and it's fairly common for some students not to finish them in the allotted time.  Final exams are closer to power tests, because the standard is to give students three hours to complete a two-hour exam.  If we had had 80 minutes (which we didn't), I'm sure everybody would have finished early.  

In the past, I have been unhappy with the shortened test formats, because they didn't allow for comprehensiveness of coverage.  With the present format, there was at least one question drawn explicitly from each lecture, and at least one question drawn explicitly from each reading, so what the psychometricians call "content validity" was enhanced.  I knew that 32 questions would be too many, and I was prepared to learn that even 25 questions was too many, but in the end this is an empirical question, and there was no way to find out except to try.  

Still, fewer than 25 questions begins to compromise content validity, so I intend to stick with the 25-question format, allowing for limited choice, in the future.  More details on how that will work out in the future as we get closer to the final exam -- which, because of that extra hour, will give everyone plenty of time to complete both the cumulative and noncumulative portions of the exam.

In the item-analysis below, I provide the percentage of students attempting each question, and the average score they obtained.  

Exams will be returned in discussion section April 2-3.  Students will have until 5:00 PM on Monday, April 6 to request a regrading.  The request for regrading must be in writing, and must provide a written defense of the answer at issue (just one or two sentences will do).   Please don't simply request regrading in the hope that you will get lucky: the GSIs have been strictly instructed to read each answer "fresh", and it is possible that they'll like your answer even less the second time around.  Exams not written in ink are not eligible for regrading.


Answer 25 of the following 32 questions, according to the instructions at the beginning of each section. Do not answer more than the required number of questions in each section. If you do, we will not grade any answers that go beyond the requirement.

Each question is worth 2 points, so that the exam totals 50 points.

Do not provide long-winded answers. You have less than 2 minutes, on average, for each question, and we are grading accordingly. Use only the space provided for your answer. Just one or two sentences will do.

Write your name at the top of every page.

Write your answers in ink. Answers written in pencil will not be eligible for regarding. And write legibly, or we won’t be able to appreciate how wonderful your answers are.

Also, please indicate your Discussion Section # (or time, or GSI) here:_____________


Section 1: Introduction.

Answer Two (2) Questions.

1. Why did the behaviorists abandon the study of consciousness?

84% of students attempted this question; for these students, the average score was 1.92.  Science is objective, and introspection is necessarily subjective, and science depends on public observation, while conscious experience is necessarily private.


2. Why did Cartesian dualism impede the scientific study of consciousness?

61%, 1.82.  Cartesian dualism is substance dualism. By insisting that mind was composed of an immaterial substance, Descartes effectively placed consciousness outside the domain of natural science. (Frith & Rees, Chapter 1)


3. What is the problem of the inverted spectrum supposed to demonstrate?

34%, 1.88.  An observer with an inverted spectrum sees red when other people see green, and vice versa, but has learned to call "red" things "green" and "green" things "red", and behave accordingly. If people with different phenomenal experiences can execute precisely the same functions, then phenomenal experience can’t be understood through a merely functional analysis. (Tye, Chapter 2)


Part 2: Introspection

Answer Four (4) Questions.

4. What did Brentano mean when he said the "Intentionality is the mark of the mental"?

82%, 1.99.  Intentionality means that mental states are "about" things outside the mind – they refer to them, they represent them in some way. Brentano believed that all mental states were intentional in nature, and that only mental states were intentional.


5. What is Helmholtz’s Doctrine of Specific Fiber Energies?

68%, 1.61.  Helmholtz asserted that every sensory quality within a modality, such as red versus green visual hue or high vs. low auditory pitch, was also mediated by a specific neural system. This was an extension of Muller’s Doctrine of Specific Nerve Energies, which asserted that every sensory modality was associated with the activity of specific neural system.


6. "What is it like" to be unconscious?

60%, 1.87.  There’s nothing it’s like to be unconscious because, as Nagel argued, conscious experiences have certain subjective qualities, so that there’s "something it is like" to have them – "something it is like for the organism" that has them. (Clark, Chapter 35)  My favorite answer to this question came from a student who left the space blank -- and then, just to make sure that his/her meaning was clear, drew a bracket and the notation, "This is my answer".


7. What are qualia and what does it mean to say that they are ineffable?

84%, 1.93.  Qualia are the qualities or features or "raw feels" of various conscious experiences. They are ineffable because they cannot be described in terms of other features, so that one who has not had the experience could understand what it is like. (Van Gulick, Chapter 30)


8. What is the distinction between the phenomenal and the intentional aspects of experience?

50%, 1.75.  The phenomenal aspect of experience is "what it’s like" to have that experience. The intentional aspect is what that experience is about, or what the experience refers to. (Graham et al., Chapter 37)


Part 3: Mind and Body

Answer Eight (8) Questions.

9. What is the "Cartesian Impasse"?

80%, 1.87.  The Cartesian Impasse is the problem created by Descartes’ doctrines of substance dualism and interactive dualism: If mind and body are composed of two completely different substances, how can they possibly influence each other?


10. What is intertheoretic reductionism?

34%, 1.66.  Intertheoretic reductionism, as proposed by the Churchlands and others, states that when the propositions and principles of a new theory mirror the propositions and principles of the old theory, and the new theory gives better explanations and predictions than the old one, then the new theory contains the correct description of reality. It is a rationale for replacing the "mentalistic talk" of "folk psychology" in favor of objective descriptions of physiological activity.


11. What would be convincing evidence of a "psychosomatic" interaction?

60%, 1.93.  A psychosomatic interaction is one in which a mental state, such as a belief, expectation, mental stress, or other emotion, affects the physical functioning of the body. The most convincing effects are those observed outside the nervous system, as we assume that any mental state is associated with some pattern of nervous system activity.


12. What is the status of parapsychological or "Psi" phenomena?

44%, 1.85.  Research in parapsychology is subject to a number of methodological difficulties, including sensory leakage and capitalization on chance. The strongest evidence for psi comes from studies with the weakest controls, and when experimental controls are strengthened, the positive evidence disappears.


13. What are John Searle’s primary objections to Daniel Dennett’s explanation of consciousness?

57%, 1.16.  Any two of these will do (The Mystery of Consciousness, pp. 124-125): (1) Of all the authors whose books Searle reviewed, Dennett "is the only one… who denies the existence of the conscious experiences we are trying to explain". (2) He also believes that "it is a fallacy to infer from the fact that science is objective that it cannot recognize the existence of subjective states of consciousness". (3) And "The distinction between appearance and reality, which arguments like his appeal to, does not apply to the very existence of conscious states, because in such cases the appearance is the reality".


14. What are John Searle’s primary objections to David Chalmers’s account of consciousness?

44%, 1.22.  Any two of these will do (Mystery, pp. 168-169): (1) Chalmers thinks that mentalistic words like "belief" have "two completely independent meanings: one where it refers to nonconscious functional processes, and one where it refers to states of consciousness". (2) "Physical events can have only physical explanations, so consciousness plays no explanatory role" in behavior. (3) "Everything in the universe is conscious."


15. What is Chalmers’s distinction between the "easy problems" and the "hard problem" of consciousness?

84%, 1.85.  The "easy problems" concern the mechanisms underlying particular mental abilities and functions, such as the difference between sleeping and waking, and how we discriminate, identify, and categorize objects. The "hard" problem is how neural processes give rise to conscious experience in the first place – or, put another way, why the abilities and functions that constitute the easy problem don’t just go on "in the dark", unconsciously. (Chalmers, Chapter 17)


16. What is Chalmers’s "double aspect" theory of information?

40%, 1.68.  According to the double-aspect theory, information has two aspects, a physical aspect that represents a change in the state of the world, and an experiential aspect that gives rise to conscious awareness. Any physical system that embodies information, whether it is a brain or a computer or a thermostat, will be also be conscious, by virtue of the experiential aspect of information. (Chalmers, Chapter 28)


17. What is the Cartesian Theatre?

68%, 1.64.  In Dennett’s view, the Cartesian Theatre is a sort of screen or stage in which experiences present themselves to the mind. Events appearing on the stage are conscious, while events that do not appear on the stage are not. (Schneider, Chapter 24)


18. Why do Mysterians believe that we’re forever stuck at the Cartesian Impasse?

58%, 1.06.  In Colin McGinn’s view, human cognition is subject to inherent limitations, meaning that there are certain aspects of the world that we are simply incapable of understanding. We are built by evolution to understand things that take up space, and consciousness – like the self, meaning, and free will, is not one of those things. (Rowlands, Chapter 26)


19. Why is Searle’s biological naturalism not dualistic?

71%, 1.62.  Simply put, Searle’s position is not dualistic because he does not accept the traditional dualistic categories of mind and body, and he believes that "it was a mistake to start counting things in the first place", because there’s only one kind of thing: the material universe. Conscious mental states are realized in the brain, which is a part of the physical world, and arise as higher-level or system features of brain activity. (Searle, Chapter 25)


Part 4: Attention and Automaticity

Answer Five (5) Questions.

20. Distinguish between "early-" and "late-" selection theories of attention.

48%, 1.66.  Early-selection theories assume that attentional selection is based on the physical attributes of the object, especially its spatial location, so that physical analysis of the stimulus can occur pre-attentively, and semantic analysis must occur post-attentively. Late-selection theories assume that both perceptual and meaning analyses occur pre-attentively.


21. Define two characteristics of an automatic process.

71%, 1.59.  Any two of these will do, accompanied by adequate one-sentence definitions: inevitable evocation, incorrigible completion (or execution), efficient execution, and parallel processing. Half credit for the characteristics listed by Hasher & Zacks: no improvement with training or feedback, no individual differences, age invariance, independence from arousal.


22. How does the concept of automaticity bear on the notion of fee will?

82%, 1.86.  Automaticity implies that even very complex mental processes can be carried out unconsciously, outside of conscious awareness and conscious control. A more extreme argument, made by some social psychologists, is that our ordinary social behavior is almost exclusively controlled by automatic processes, rendering consciousness epiphenomenal and conscious will an illusion.


23. How does the capacity theory of attention (otherwise known as perceptual load theory resolve the conflict between early- and late-selection views of attention?

53%, 1.37.  There are at least two good responses to this question. One is that the capacity theory of attention allows pre-attentive semantic processing to occur under conditions of low attentional load, or when the semantic processing has been automatized. Another is that the capacity theory of attention impairs processing of distractors under conditions of high load, where there is little or no excess capacity available, but permits processing of distractors under conditions of low load. (Lavie, Chapter 38)


24. What is the significance of "change blindness" and other forms of detail blindness?

64%, 1.16.  In change blindness, observers fail to notice substantial events or changes that take place in their full view of the observer. After that, any one of the following will do: (1) According to the "grand illusion" interpretation, ordinary perceivers are conscious of much less than they think they are, and in further implies that there aren’t really any internal representations of the world for perceivers to be conscious of. (2) According to the "new skepticism" of Daniel Dennett, conscious experience doesn’t consist of a whole, sable, detailed scene, but rather just a few features along with a sketchy background. (3) According to Alva Noe, the phenomena of DB suggest that the details of a visual scene are "out there" in the world, not "in there" inside our heads. (Noe, Chapter 39)


25. What is the significance of the "readiness potential"?

45%, 1.90.  The readiness potential is an event-related potential, measurable in the EEG, that precedes voluntary movements – indicating, as it were, that the person is getting ready to move. Libet found that the RP also precedes the person’s conscious intention to move, suggesting that the subjects’ conscious decisions were not the causes of their action, and limiting "free will" to a kind of veto over behavior that, in fact, is generated unconsciously and involuntarily. (Banks & Pocket, Chapter 51)


Part 5: The Explicit and the Implicit

Answer Six (6) Questions.

26. Distinguish between perceptual and semantic (conceptual) priming.

72%, 1.31.  In perceptual priming, the target is a recapitulation (in whole or in part) of the prime, and the effect is mediated by a perception-based representation, which records information about the physical features of the stimulus. In semantic priming, the target does not physically resemble the prime, but it is semantically or conceptually related, so that the priming requires a representation that goes beyond a physical description, and includes some sort of semantic analysis.


27. Why is semantic priming a critical test for "subliminal" perception?

53%, 1.25.  Ever since the first "early selection" theories of attention, everyone has agreed that at least some physical analysis of stimulus input can be performed preattentively, outside of conscious awareness, so it would surprise nobody if you got repetition priming with a subliminal stimulus. The real test is whether, and how much, semantic analysis can be performed preattentively, and for that you need a test of semantic or conceptual priming.


28. Why should we be skeptical of claims for the effectiveness of subliminal advertising?

62%, 1.17.  Truly subliminal priming effects are relatively weak, and don’t last very long. Moreover, subliminal perception seems to be analytically limited, effectively precluding the kind of extensive analysis that would seem to be required for a persuasive communication.


29. Distinguish between implicit memory and implicit learning.

71%, 1.39.  Implicit memory is implicit "episodic" memory, in which the person has no conscious recollection of some past event – though s/he may retain access to new knowledge acquired during the event covered by the amnesia. In Implicit learning, the person may remember the learning experience perfectly well, but has no conscious awareness of the new "semantic" or "procedural" knowledge acquired during the experience.


30. Distinguish between the objective and subjective thresholds (or measures of awareness).

31%, 1.65.  The subjective threshold is the point below which observers have no conscious awareness of a stimulus, while the objective threshold is the point below which observers can no longer discriminatively respond to a stimulus. Objective threshold measures are more conservative than subjective measures, and "subliminal" perception takes place in the space between them. (Merikle, Chapter 40).


31. What is the significance of blindsight for understanding the neural substrates of vision?

63%, 1.21.  Blindsight patients have lesions in visual cortex, also known as Area V1 in the occipital lobe. The fact that blindsight patients can make certain visual discriminations, in the absence of visual experience, suggests that V1 is necessary for conscious visual experiences, and unconscious vision is mediated by other (perhaps subcortical) neural pathways. (Weiskrantz, Chapter 13)


32. How does memory for novel, unfamiliar information bear on various theories of implicit memory?

8%, 1.38.  "Activation" theories of implicit memory assume that priming reflects the activation of pre-existing knowledge stored in memory, while multiple-systems views do not make this assumption. The fact that priming can occur for novel stimuli is inconsistent with the activation view – though the fact that priming occurs only for "novel" materials composed of familiar components is consistent with a more sophisticated version of the activation view. (Kihlstrom et al., Chapter 41)  At the end of the exam, one of the students remarked that the exam was "about one question too long", and I guess this item proves it.



The scoring guide used to grade the exam

will be posted to the course website as soon as possible after the exam.


Exam grades will be posted on the course website

as soon as possible after March 21.


Exams will be returned in sections April 2-3.