Spring 2005 Final Exam


University of California, Berkeley

Department of Psychology


Psychology 129 / Cognitive Science 102

Scientific Approaches to Consciousness

Spring 2005


Final Examination

Scoring Guide and Feedback

Scoring the Exam

Students were asked to answer 10 of 15 questions in each part of the exam.  For the occasional student who answered more than 10 questions, we counted only the first 10 in each section.

On the initial scoring of the exam, each item was scored on a 0-4 scale.  The intention was that the average score would lie somewhere between 3 and 4 points.  There were several items that failed to meet this criterion.  Accordingly, students who attempted these items received additional points, in order to bring the means for these items up to the average for their respective components of the exam.

On the noncumulative Part 1 (average item score = 3.28):

Item #1 (initial mean = 2.92), + .46;

Item #7 (initial mean = 2.81), + .47.

On the cumulative Part 2 (average item score = 3.24):

Item #17 (initial mean = 2.56), + .68;

Item #19 (initial mean = 2.44), + .80;

Item #20 (initial mean = 2.91), + .33.

With 10 responses in each part of the exam, the maximum total of 20 answered questions would yield 80 points.  In order to bring the exam up to 100 points, students received 1 free point for each question they attempted (up to 20 points).  The occasional student who answered fewer than 10 questions in either part, or both, received correspondingly fewer free points.

The average score on the entire exam, before rescoring (but including the free points) was 84.48 (SD = 8.71).

The average score on the final exam, after rescoring (and including the free points) was 86.31 (SD = 8.66).

Note that the mean score on the final exam was just about double the mean for the midterm, 44.2.  

The scoring guide that follows provides the average score on each item (before and after rescoring, as appropriate), plus the number of students who attempted that item.


The noncumulative portion of this exam is worth 50 points. The cumulative portion of the exam is also worth 50 points.

Do not provide long-winded answers. You have less than 5 minutes, on average, for each question, and we are grading accordingly. Use only the space provided for your answer. If you need more space, use the other side of the page.

Write legibly, or we won’t be able to appreciate how wonderful your answers are.

Use pen. Exams completed in pencil may not be eligible for regrading.

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


Note to GSIs: Grade each question on the usual 0-4 scale. Give 1 point if the student writes anything at all, 2 points for a minimally responsive answer, 3 points for something better, 4 points for something really good. The typical response will get 3 or 4 points. I will then add points to bring this portion of the exam up to 50.



Noncumulative Portion

Answer 10 of the following 15 questions. Each question is worth 5 points, so don’t write much. Each of the questions can be addressed satisfactorily in a short paragraph of four or five sentences. There is no bonus for answering all 15 questions, so don’t do it (if you answer more than 10 questions, we will grade only the first 10).


01. Summarize the changes in the EEG observed during sleep.

The waking EEG is characterized by a mix of high-voltage, mid-frequency "alpha" activity (approximately 8-12 cycles per second), and low-voltage, high-frequency "beta" activity, 15-30 cps. The disappearance of alpha activity from the EEG is the criterion for diagnosing "Descending Stage 1" of sleep; the appearance of alpha activity in the EEG is generally taken as a sign that the person is awake. Stages 3 and 4 are characterized by very slow, high-voltage "delta" activity, 0.5-4 cps. Subsequent epochs of Stage 1 resemble the waking EEG, though with an absence of alpha activity.

Mean score = 2.82 (3.28 after rescoring), N = 55.  Some of you were a little confused about alpha activity, saying that it occurs in sleep whereas in fact the absence of alpha is the defining criterion of being asleep.


02. What does it mean to say that dreams are epiphenomenal?

According to Hobson’s "AIM" model of sleep and dreams (and Hobson and McCarley’s earlier "activation-synthesis" theory of dreaming), REM sleep entails a high level of neural activation by aminergic neurotransmitters and neuromodulators. In this view, dreams are simply a byproduct of whatever components of the neural network happen to be randomly activated at any particular time. If REM sleep happens to activate neural networks corresponding to mental representations of dragons and bicycles, then the sleeper will dream of dragons and bicycles. In Dennett’s "retro-selective theory, dreams are constructed retrospectively from whatever fragments of thoughts and images happened to be activated during REM. As Flanagan puts it, "Dreaming came along as a free ride on a system designed to think and to sleep".

M = 3.27, N = 74.


03. What are the implications of the distinction between explicit and implicit memory for sleep learning?

Simon and Emmons famously concluded that "sleep learning is possible to the extent that the subject remains awake". However, all their tests involved explicit memory, or the subject’s conscious recollection of information that had been presented during sleep. This left open the possibility that implicit memories can be acquired during sleep. Studies of memory for information presented as the subject is falling asleep, or during REM sleep, have not found significant priming effects, suggesting that sleep abolishes implicit as well as explicit memory.

M = 3.38, N = 47.


04. How are drug-induced altered states of consciousness classified? Give some examples of each class. Do all psychoactive drugs alter consciousness?

Psychoactive drugs come in basically three categories. CNS stimulants include cocaine, amphetamine, and MDMA ("ecstasy"). CNS depressants include alcohol and barbiturates. Psychedelics include psilocybin, mescaline, cannabis (marijuana), and LSD. It may be useful to distinguish between major and minor psychedelics. Narcotics (like morphine), antipsychotics (like chlorpromazine), and antidepressants (like the SSRIs) are not generally thought to induce altered states of consciousness. Blackmore claims that anesthetics "do not produce interesting ASCs", but surely the loss of consciousness must count as an alteration in consciousness!

M = 3.08, N = 24.


05. What do the dissociative and conversion disorders have in common?

The dissociative disorders entail a loss of conscious memory and identity, as in "hysterical" amnesia, fugue, and multiple personality disorder (also known as dissociative identity disorder). The conversion disorders entail losses of conscious perception (as in "hysterical" blindness), or losses of conscious action (as in "hysterical paralysis). Despite the impairments in explicit memory or perception, there is some evidence for the preservation of implicit memory or perception in these syndromes.

M = 3.45, N = 44.


06. What is the effect of hypnotic suggestions for analgesia?

Both clinical and laboratory research confirm that hypnotic suggestions for analgesia can reduce felt pain substantially. Psychophysical studies indicate that the magnitude of pain reduction is correlated with hypnotizability. Comparative studies show that hypnosis may be superior to common analgesic drugs, such as aspirin and morphine, especially in highly hypnotizable individuals. Hypnotic suggestion affects both sensory pain and suffering. And, in fact, hypnotic suggestions that target the "suffering" component of pain reduce activity in "emotional" parts of the brain, such as the anterior cingulate gyrus, leaving "sensory" parts of the brain, such as the primary somatosensory cortex, unaffected.

M = 3.07, N = 83.


07. What is alpha activity and what is its significance in meditation?

Alpha activity is a component of the waking EEG, consisting of high-voltage waves of 8-12 cycles per second. Initial studies seemed to show that meditating yogis and Zen monks produced high levels of alpha activity while meditating. Further, these studies showed that yogis did not "block" alpha in response to a novel signal, while Zen monks did not show habituation of the alpha blocking response in response to repetitions of that signal. Although both findings were consonant with the spiritual purpose of meditation in the two traditions, later research has not independently confirmed the differences in alpha-blocking response among various forms of meditation.

M = 2.81 (3.28 after rescoring), N = 64.  Again, alpha activity plays a pretty central role in psychophysiological studies of meditation.  The most familiar result is that the density of alpha activity increases in meditation, though this may be an artifact of being relaxed (more or less) with eyes closed.  


08. What role(s) can the self play in conscious experience?

William James asserted that "thought tends to personal form", meaning that every thought is "owned" by its thinker. This is what philosophers mean when they speak of "subjectivity" or "first-person ontology". It’s also what they mean by intentionality, in which mental states represent some relationship between the person who has them and some fact about the world. Linguistically speaking, the self can play four roles: as the agent (do-er) or patient (done-to) of some action, or as the stimulus or experiencer of some state.

M = 3.29, N = 68.


09. What is Sperry’s argument concerning the relationship of consciousness and the self to the two cerebral hemispheres?

Sperry thought that split-brain patients experienced a sort of double consciousness. That is, by virtue of the anatomical principle of contralateral projection, the left hemisphere is consciously aware of events that occur in the right sensory field and consciously controls the actions of the right side of the body, while the right hemisphere is consciously aware of events that that occur in the left sensory field and consciously controls the actions of the left side of the body. Because language is lateralized in the left cerebral hemisphere, though, only the left hemisphere can communicate its awareness through speech. However, the right hemisphere can communicate its awareness through behavior.

M = 3.31, N = 36.


10. How do Libet’s studies of the "readiness potential" in the EEG relate to the concept of conscious will?

The readiness potential is a component of the EEG that occurs roughly 800 milliseconds before an intended action takes place. In a famous experiment, Libet asked subjects to note when they made conscious decisions to flex their wrists. He found that the RP occurred reliably before the subjects consciously decided to act. The implication is that the act is initiated unconsciously. Because the conscious decision occurred after the RP, it could not have been the cause of the action. In Libet’s view, conscious intentions do not initiate actions, though they can terminate actions that are initiated unconsciously.

M = 3.31, N = 36.


11. What are the implications of Gallup’s mirror-recognition paradigm for tracing the evolution of self-awareness.

In Gallup’s experiments, animals are confronted with mirror (or television) images of themselves. Some animals treat their mirror image as if it were another animal, while others appear to recognize themselves in the mirror –by, for example, exploring a spot on their bodies that they can only see with the mirror. In Gallup’s analysis, mirror self-recognition show that animals are aware of what they look like, and of what they are doing. Chimpanzees and orangutans are more likely to show self-recognition than other primates, suggesting an evolutionary continuity with humans. But while all normal human children show mirror self-recognition, only a minority of chimpanzees do so, suggesting that it is not necessarily a universal characteristic of that species.

M = 3.66, N = 65.


12. What are the elements of Baron-Cohen’s theory of mindreading?

Baron-Cohen asserts that the adult’s "theory of mind" consists of four cognitive modules, each hypothetically associated with a different brain module or system. The intentionality detector interprets actions in terms of goals and desires. The eye-direction detector computes the direction in which another person’s eyes are looking. The shared-attention mechanism makes the additional assumption that if the perceiver and the target look in the same direction, they will see the same things. The theory-of-mind mechanism is a system for inferring mental states, particularly cognitive states, from behavior.

M = 3.52, N = 60.


13. How does the false-belief test reveal the "theory of mind"?

In the false-belief test, the subject is given knowledge that is denied to another person. Individuals who lack a theory of mind do not understand that others may have beliefs that are different than their own, and so they will predict that the other person will behave as they themselves would in that situation. Individuals who possess a theory of mind understand that different people will have different beliefs, and they will predict that the other person will behave in accordance with his or her own beliefs. Normal children older than age 5 reliably pass the false-belief test, indicating that they understand that mental states are representations of reality, that beliefs may be right or wrong, and that different people will represent reality differently and behave accordingly.

M = 3.56, N = 78.


14. In terms of the false-belief test, who has a theory of mind and who does not?

Everyone agrees that most children aged five years or older have a theory of mind. Younger children may not pass the standard verbal form of the false-beliefs test, but even infants have been shown to pass a nonverbal version. Autistic children, even those much older than 5 years of age, don’t usually pass the standard verbal test, but it is an open question about whether they might pass a nonverbal test. Chimpanzees don’t appear to pass the false-belief test, though the earliest study by Woodruff and Premack suggests that at least one chimpanzee, Sarah, have a theory of goals and desires, even if chimps in general do not have theories of beliefs.

M = 3.40, N = 78.


15. Distinguish between extrasensory perception and psychokinesis. How do these "paranormal" or "psi" phenomena relate to the mind-body problem?

Extrasensory perception refers to perception or communication that occurs without mediation by sensory mechanisms. It includes clairvoyance, telepathy, and precognition. Psychokinesis refers to "action at a distance" that occurs without mediation by the skeletal musculature or any physical medium. Traditionally, both concepts imply substance dualism – that is to say, the view that minds can exist independent of bodies.

M = 3.31, N = 39.



Cumulative Portion

Answer 10 of the following 15 questions. As before, each question is worth 5 points, so don’t write much. Each of the questions can be addressed satisfactorily in a short paragraph of four or five sentences. There is no bonus for answering all 15 questions, so don’t do it (if you answer more than 10 questions, we will grade only the first 10).


16. According to Varela’s categorization of major theories of consciousness, what do Chalmers and Dennett have in common? Chalmers and Searle? How does Chalmers’ theory differ from Dennett’s? How does Searle’s differ from Chalmers’?

Varela classifies theories of consciousness in a two-dimensional scheme: functionalism vs. mysterianism, and phenomenology vs. reductionism. In Varela’s analysis, Chalmers and Dennett both lean toward functionalism, because they rely on third-person data and validation. Chalmers and Searle both lean toward phenomenology, insisting that some sort of first-person account is essential for the explanation of consciousness. Dennett, of course, rejects the idea that first-person accounts belong in a scientific explanation. Varela claims that Searle verges toward mysterianism – but this must be a mistake, because Searle nowhere asserts that the mind-body problem is insoluble.

M = 3.36, N = 22.


17. How is classical psychophysics a "scientific approach to consciousness"?

Psychophysics attempted to relate the physical properties of stimuli to the corresponding sensory experiences to which they gave rise. By asking observers to assign numbers to the intensity and other qualities of their sensory experiences, it sought to quantify conscious mental states. Relative and absolute thresholds represent the point, on a continuum of intensity, at which we become consciously aware of a stimulus, or consciously aware that it has changed. By examining the correlation between psychological properties such as intensity and quality of sensation to and variability in the physical properties of the corresponding stimulus, psychophysics linked first-person subjectivity with third-person objectivity.

M = 2.56 (3.24 after rescoring), N = 48.  Some of you brought in concepts from physics, like quantum mechanics, which don't have anything to do with the psychophysical principle that every psychological quality of a sensation is related to some physical quality of the stimulus.  Others brought in concepts from philosophy, like psychophysical parallelism, which I guess is a little closer, but parallelism just states that there are brain states correlated with mental states -- whereas psychophysics is really about the relation between stimulus and experience, not body and mind.


18. Distinguish between early-selection and late-selection theories of attention. What are their implications for "subliminal" and masked priming effects?

Early-selection theories of attention propose that information about the physical appearance (perceptual properties) of a stimulus can be processes pre-attentively, but that information about the meaning (semantic properties) of the event requires attention. Late selection theories of attention propose that both the perceptual and semantic properties of a stimulus are analyzed preattentively. According to early-selection theories, these "preconscious" priming effects should be limited to repetition priming, which can be mediated by a perceptual representation of the physical properties of the stimulus. However, late selection theories permit preconscious semantic priming as well. Put another way: preattentive semantic priming effects constitute evidence against early-selection theories of attention.

M = 3.00, N = 54.


19. Distinguish among the various forms of dissociation between explicit and implicit memory.

Dissociations between explicit and implicit memory come in two broad forms. In population dissociations, where a characteristic of a population (such as the presence or absence of hippocampal damage) affects explicit but not implicit memory. In experimental dissociations, an independent variable (such as level of processing at the time of encoding) has differential effects on explicit and implicit memory. In single dissociation, the independent variable affects one expression of memory but not the other. In double dissociation, a single independent variable has opposite effects on explicit and implicit memory.

M = 2.44 (3.24 after rescoring), N = 54.  This wasn't about the dissociative disorders, although there are dissociations between explicit and implicit memory in syndromes like fugue and multiple personality.  It was really just about the various forms that explicit-implicit dissociations can take.


20. What is blindsight, and how is it relevant to the concept of implicit perception?

Blindsight sometimes occurs in cases of cortical blindness. As a result of damage to the striate cortex (in the visual area of the brain), the patient experiences a "blind spot" or scotoma covering some portion of his or her visual field. Nevertheless, when visual stimuli are presented in their blind spots, these patients can make "guesses" about their physical properties that are more accurate than would be expected by chance. By analogy to memory, we can identify the subjects’ inability to see the objects as an explicit expression of perception, and their above-chance performance on the guessing task as an implicit expression of perception.

M = 2.91 (3.24 after rescoring), N = 79. Some of you thought that blindsight was similar to visual conversion disorder or visual neglect.  But blindsight involves an actual brain lesion (in striate cortex) which is absent in hysterical blindness, and the damage in visual neglect is not in the striate cortex. 


21. What is "balanced" anesthesia? Describe two techniques for monitoring the depth of anesthesia during surgery.

Balanced anesthesia is a procedure in which different drugs are administered to achieve four different clinical goals: sedation (reduction in anxiety), muscle relaxation (lack of reflex response to stimulation), analgesia (reduction in pain) and anesthesia (lack of awareness). Any two of the following: (1) Clinical observation of the patient’s lack of response to verbal commands and "surgical stimulation". (2) The "isolated forearm technique", which bypasses the effects of muscle relaxants. (3) Measures of anesthetic concentration, such as the Minimum Alveolar Concentration (MAC). (4) Autonomic indices such as the PRST score (blood pressure, heart rate, sweating, and tears). (5) The auditory, somatosensory or visual event-related (evoked) potential). (6) Measures of the EEG power spectrum, such as Bispectral Analysis (BIS).

M = 3.30, N = 70.


22. What is the relationship between REM and dreaming?

Subjects are more likely to report dreaming if awakened from Stage REM, compared to NREM, but a lot depends on how the question is asked, and how "dreams" are defined. Mental activity in NREM is more likely to consist of thoughts, images, and reveries, compared to the vivid, complex dreams characteristic of REM. Dreams in Stage NREM tend to be shorter than those in Stage REM. Human fetuses spend much of their time in REM, and it is unlikely that they dream at all. The REM "dreams" of older children differ markedly from those of younger children. Taken together, these considerations suggest that REM is neither necessary nor sufficient for dreaming to occur.

M = 3.54, N = 85.


23. How does Gazzaniga’s view of "the interpreter" relate to Sperry’s view of consciousness in split-brain patients?

Sperry thought that split-brain patients experienced a sort of double consciousness, because the stream of mental activity in one hemisphere can be dissociated from that of the other. However, Gazzaniga concluded from the same sorts of experiments on split-brain patients that the left hemisphere interpreted both what it and the right hemisphere "did" – by confabulating reasons for the right hemisphere’s actions, which of course were unknown to it. On this account, the right hemisphere is an automatic, unconscious stimulus-response system, which merely reacts to whatever stimulus information it processes. Only the left hemisphere uses language, organizes beliefs, and attributes intentions – which is to say, only the left hemisphere possesses "high-level consciousness". But Gazzaniga’s position leaves open the possibility that the right-hemisphere interprets the actions of the left hemisphere too, thus performing the functions of consciousness: it just can’t communicate these interpretations via language.

M = 3.22, N = 18.


24. What evidence is there that meditation actually leads to a "de-automatization of thought"?

Automatic processes are inevitably executed upon the appearance of an appropriate stimulus. They are exemplified by the Stroop interference effect, in which the meaning of a color word interferes with the task of naming the color in which the word is printed. There is some evidence that practice in meditation reduces Stroop interference. So, either the Stroop effect isn’t a reflection of automaticity after all, or meditation can permit subjects to gain conscious control over what is normally an automatic result of skilled reading.

M = 3.55, N = 69.


25. Distinguish between the out-of-body experience and the near-death experience. How do these "exceptional human experiences" relate to the mind-body problem?

In the out-of-body experience, people perceive themselves and the world from a location outside their physical bodies. In the near-death experience, people who are on the verge of death (as, for example, following cardiac arrest) experience themselves as passing through a tunnel toward a light. Traditionally, as for example in 19th-century spiritualism, OBEs and NDEs have been taken as support for substance dualism – that is to say, that minds can exist independently of bodies. In the OBE, the mind exists outside the body. In the NDE, the mind survives the body.

M = 3.63, N = 46.


26. Distinguish between the open (or mindfulness) meditation of Zen Buddhism and the concentrative meditation of Yoga. Describe some of the physiological effects of each form of meditation.

In concentrative meditation, the person focuses attention on one thing, such as his or her breathing, or a mantra, to the exclusion of all else. Mindfulness is a mental stance of being fully "in the present", without thinking about the past or the future, paying attention to what is happening without thinking about it or responding to it. Concentrative meditation, like Transcendental Meditation and the Relaxation Response, generally leads to reduced levels of autonomic arousal, such as heart rate, respiration, and blood pressure. Similarly, mindfulness meditation has been promoted as a technique for stress reduction. However, it is not clear that these effects are all that much greater than those achieved by merely resting.

M = 3.20, N = 59.  


27. What are the implications of Darwin’s theory of evolution for consciousness in nonhuman animals? How did behaviorists such as Watson differ from Darwin’s approach?

Darwin’s theory holds that different species have similar traits because they are (and to the extent that they are) descended from common ancestors. This principle of evolutionary continuity applies to mental and behavioral characteristics as well as physical features. Therefore, for Darwin and others (such as Romanes and Washburn), the presence of consciousness in humans implies that consciousness is present in our close neighbors as well. However, the behaviorists sought to account for behavior without invoking conscious thoughts, feelings, desires, and other mental states. To the extent that they were successful, the same principle of evolutionary continuity could be taken as implying that if nonhuman animals are not conscious, then humans aren’t conscious either – or, at least, that human consciousness is epiphenomenal, and plays no role in behavior.

M = 3.52, N = 67.


28. What is Turing’s test of artificial intelligence? Is it also a test of artificial consciousness?

Turing proposed that a machine like a computer would pass a test for artificial intelligence if a person could not distinguish a conversation with a machine from a conversation with another person. Whether the TT is a test of consciousness depends on your definition of consciousness. If you believe that the essence of consciousness lies in first-person subjectivity, the TT is irrelevant to consciousness because it doesn’t test for first-person subjectivity. And besides, a machine might fail the TT test for intelligence and still be aware of its subjective states. However, if you believe, along with the functionalists, that two systems that perform the same functions have the same internal states, though, then any machine that really passed the TT for intelligence would also pass the TT for consciousness.

M = 3.46, N = 37.


29. What is Searle’s primary objection to attempts by Dennett and others to construct an objective, third-person account of consciousness in terms of input-output functions? How would Ralph Messenger and Helen Reed react to this debate?

Dennett, as a functionalist wants to construct an account of consciousness in terms of third-person facts about brain and behavior. Searle insists that consciousness is inherently subjective – that is what he means when he says it has a first-person ontology, and that feeling-states are irreducible. Therefore, any attempt to give a third-person account of consciousness must necessarily leave first-person subjectivity out of the picture. Messenger often seems to agree with Dennett, but he also understands, with Searle, that a proper science of consciousness has to "give an objective, third-person account of a subjective, first-person phenomenon". Helen, for her part, believes that "novelists have been doing that for the last two hundred years" – which is why she recites the passage from Henry James (who, of course, just happened to be William’s brother).

Note: The deep message of Lodge’s book is that the sciences and the humanities are not opposed – they are after the same things, but in different ways.

M = 3.17, N = 70.


30. Can a zombie lose its PalmPilot?

Of course. Philosophers define zombies as creatures who can perform all the same behaviors that humans can, but without accompanying consciousness. Losing is a behavior, and so zombies can do it by definition.

That’s all a student needs to say to get full credit.

Even a "Hollywood zombie", which is defined simply as a human-like creature who lacks consciousness (as in George Romero’s Night of the Living Dead), could lose its PalmPilots – and so could a "Haitian zombie", who lacks a soul. Provided that they had PalmPilots to begin with, there is no reason why they couldn’t lose them while they’re lurching around.

Not that it matters now, but it seems to me that the really interesting approach to the zombie problem is to consider Hollywood zombies, who lack consciousness, and then ask what the behavioral consequences of this deficit might be. Is there anything a conscious person can do that an unconscious zombie can’t? If the answer is yes, that would be proof that consciousness is not epiphenomenal after all – that consciousness exists, and plays a causal function in the world. So, put the question another way: Can a zombie notice that it’s lost its PalmPilot?

But none of this is, or anything else, is required for a full-credit answer.  Still, thanks for listening.

M = 3.73, N = 71.


The scoring guide used to grade the exam

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


The exam scoring guide will be posted on the course website

by 5:00 PM on May 16.


Exam grades and final grades will be available on the course website

by 5:00 PM on May 23.