Spring 2001 Final Exam

 

University of California, Berkeley

Department of Psychology

 

Psychology 129/Cognitive Science 102

Scientific Approaches to Consciousness

 

Spring 2001

 

Final Examination

Scoring Guide

 

 

Answer one (1) question within each of the following eight categories (each category offers a choice of two alternatives). Throughout this examination, remember to defend your views by referring to the scientific literature covered in lectures, readings, and discussion.

You are not expected to write extensive essays, but do write complete sentences. Write your examination in ink, and write legibly.

This examination extends over three hours, is worth 100 points total. Spend approximately 1 minute per point. At this rate, you will complete the noncumulative portion in one hour, and the cumulative portion in another hour, leaving you the whole third hour to think and polish.

Write legibly, in ink, and confine your response to the spaces provided. Answers to noncumulative questions probably should not consume more than one side of the paper provided. Answers to the cumulative questions probably will be a little longer, but should not consume more than the other side as well.

The "scoring guide" provided to the GSIs will be posted to the course website shortly after the exam.

We will make every attempt to grade the final exams, and post final grades to the course website and Bear Facts, by Friday, May 18.

If you have questions about your exam, please consult the GSI who graded the item in question. If you believe there was an error in calculating your final grade, please contact the instructor.

 

Noncumulative Portion (50 points)

Answer one (1) question from each of the following five categories.

 

Category 1: Implicit Cognition, Emotion, and Motivation (10 points)

The discovery of hemispheric specialization in the brain has often played a role in theories of consciousness. Describe one theory that seems to identify consciousness with the left hemisphere, and counter with some evidence suggesting that the right hemisphere is conscious as well.

One approach to this question begins with the characterization of the right hemisphere as the "silent" hemisphere, meaning that it generally lacks a capacity for language, but also implying that it is somehow unconscious. Partly this reflects an identification of consciousness with language capacity. In addition, the special capacities of the left hemisphere, such as verbal, sequential, digital, logical, analytical, and rational thinking, are often identified with consciousness, while the special capacities of the right hemisphere, such as nonverbal, visual, spatial, analog, holistic, "Gestalt", and intuitive, thinking, are often identified with unconscious thought.

Another approach is based on the work on "split brain" patients, in which the two cerebral hemispheres are surgically separated by severing the corpus callosum. By virtue of the principle of contralateral projection, in such patients stimuli presented in the right visual field are processed (virtually) exclusively by the left cerebral hemisphere, and vice-versa; and responses made by the right hand are controlled by the left hemisphere, and vice versa. In other words, the left hemisphere is not conscious of what the right hemisphere is doing, and vice-versa.

 

How is priming an example of implicit memory? What evidence is there for dissociations between explicit and implicit perception, analogous to dissociations between explicit and implicit memory? What is the difference between priming as evidence for implicit memory and priming as evidence for implicit perception?

Implicit memory may be defined as any effect of a past experience on a personís subsequent experience, thought, or action, independent of (or even in the absence of) conscious recollection of that experience. Priming exemplifies implicit memory because the presentation of the prime, and event, facilitates (or, in the case of negative priming, inhibits) later processing of a target item: memory for the prime is implicit in the priming effect. There are different kinds of priming, such as repetition and semantic priming, or perceptually based and conceptually based priming. The dissociations between explicit and implicit memory come in two general types: in population dissociations, a group of subjects (e.g., amnesic patients) shows impaired explicit memory but spared implicit memory, compared to controls; in functional (or experimental) dissociations, some experimental variable (e.g., level of processing) affects explicit but not implicit memory. Dissociations come in single and double forms, but single dissociations are the most commonly observed. The same priming effects that provide evidence of implicit memory also provide evidence of implicit perception. The primary difference is that in implicit memory, the prime was consciously perceived at the time it was presented. In implicit perception, the prime was not perceived (e.g., because of brain damage, as in the case of blindsight, or because of masking, as in the case of subliminal perception): in this case, it is not just memory, but perception as well that is implicit in the priming effect.

 

 

Category 2: Sleep and Dreams (10 points)

Distinguish between REM and NREM sleep in terms of brain activity, ocular and muscular activity, and autonomic arousal. What kinds of mental and behavioral activities are associated with the various stages of sleep? What evidence is there for unconscious processing during sleep?

To an observer, sleep appears to be a homogeneous state, but psychophysiological recordings reveal a number of ultradian rhythms within the circadian sleep-wake cycle: Stages 1, 2, 3, and 4 of sleep. These do not have to be individually defined, but a good answer should show some awareness that Stage REM resembles Stage 1 (but with rapid eye movements), while Stage NREM includes Stages 2, 3, and 4. Dreaming occurs most frequently in Stage REM, while mental activity in Stage NREM is more "thoughtlike". Nightmares occur in REM, night terrors in NREM. Sleepwalking in NREM (because REM involves muscle paralysis). Sleeptalking in both REM and NREM, with possible differences in linguistic quality. The research on sleep suggestion, in which subjects respond behaviorally to suggestions administered during Stage REM, with amnesia the next morning, might provide some evidence for unconscious processing during sleep, but careful experiments cast doubt on whether sleep suggestion occurs. Sleep learning might be another example of unconscious processing, but sleep learning doesnít appear to occur either, in terms of either explicit or implicit memory. Another example might be studies of stimulus-incorporation during dreams.

 

Distinguish between Foulkes' and Hobson's theories of dreaming. Of what relevance is the controversy over the occurrence of dreams in various sleep stages? occur. What role does memory play in each theory? What are the implications of each theory for interpreting the "meaning" of dreams?

Foulkesí theory is that dreams are instigated by the diffuse mnemonic (memory) activation, organized by a dream-production system into a more or less coherent, plotlike, narrative. Contrary to Freud, dreams have only indicative meaning, which is to say that they do not require any interpretation of their deep, symbolic content. Dreams are essentially continuous with waking thought, as evidenced by studies of "Piagetian stages" in the development of dreams. Hobsonís theory begins with the activation-synthesis theory of Hobson and McCarley, and ends (for the moment) with Hobsonís own AIM theory. In either version, the dream imagery is essentially the product of random activation, so dreams have no inherent meaning. Foulkesí theory would not be troubled by the finding that dreamlike mentation occurs in Stage NREM, but Hobsonís theory really requires a modulation from aminergic to cholinergic activity. Memories are critical to Foulkesí theory, because itís their activation that produces dreams in the first place; in Hobsonís theory, memory-based activation can combine with random activation to produce occasional day residues. Research on both theories is made difficult by the fact that we have no on-line access to dreams as they occur: dreams reports are essentially memory reports. Therefore, in Foulkesí theory for example, we do not know whether the "Piagetian" stages characterize the dreams themselves, or our waking memories of them.

 

 

Category 3: Anesthesia and Coma (10 points)

What are the common psychedelic drugs, and why are they called psychedelic? Briefly outline the physiological effects, and corresponding psychological effects, of one (1) such substance. What role might expectations and other psychosocial factors play in the "psychedelic" experience?

We didnít discuss the psychedelics in class, so this material comes straight out of Farthing. The psychedelic drugs are a subclass of psychoactive substances, along with CNS stimulants and depressants, narcotic analgesics, antipsychotic drugs, and the like. In the case of the psychedelics, their general result is to produce alterations are changes in perception and imagination (as opposed to sedation, for example). The psychedelics may be further classified as major (e.g., LSD) and minor (e.g., marijuana), based mostly on the strength of their effects. Although neuroscientific theories attribute the effects of the psychedelics to alteration of synaptic transmission and/or neurotransmitter function, it is clear that psychosocial variables, such as expectations, also have an impact on the psychedelic experience. For example, there are both positive and negative placebo effects: believing that an inert substance is cannabis (the active ingredient in marijuana), for example, can produce some of the subjective effects of actual marijuana, while believing that cannabis is actually inert can reduce those same effects.

 

What is meant by "balanced" anesthesia? Which aspects of the anesthetic "cocktail" are most likely to produce loss of consciousness? How does general anesthesia differ from conscious sedation? How does anesthesia differ from coma, the persistent vegetative state, and the "locked in" syndrome? Assume for a moment that both general anesthesia and conscious sedation spare priming on tests such as stem-completion for words presented during the surgical procedure. Would this count as evidence of implicit memory, implicit perception, or both?

Balanced anesthesia is a technique involving four different classes of substances: benzodiazepines to reduce anxiety, analgesics to reduce pain, anesthetics to reduce awareness, and muscle relaxants to reduce reflexive responses to surgical stimuli. It is the anesthetics that produce loss of consciousness: conscious sedation, involving mostly the administration of benzodiazepines, sedates the patient, and induces amnesia, but does not produce loss of consciousness during the operation itself. Anesthesia is often called a controlled coma, because Ė well, itís controlled, whereas coma is something people lapse into and may not come out of. In coma, the patient is apparently unconscious (unresponsive), and the normal sleep-wake cycle is suspended; in the persistent vegetative state, the patient shows a more-or-less normal sleep-wake cycle, but is still unresponsive; PVS is sometimes called wakefulness without consciousness; in the "locked-in" state, the patient is apparently conscious, but unable to respond except by means of eye movements. Priming by items presented during conscious sedation would definitely count as implicit memory, because the patient is aware of the primes as they are presented; thereís no sense in talking about implicit perception in this instance. But priming during general anesthesia arguably counts as evidence of implicit perception as well as of implicit memory, on the assumption that adequate general anesthesia suspends conscious perception: still, perception of the primes is implicit in the priming performance.

 

Category 4: Hypnosis (10 points)

Discuss hypnotic analgesia as an alteration in consciousness. What is the laboratory and clinical evidence that hypnotic suggestion can alter the perception of pain? What is the relevance of Hilgard's "hidden observer" paradigm to the notion that analgesia involves a division in consciousness?

Hypnotic analgesia appears to qualify as an alteration in consciousness, because there is an alteration in perception of a painful stimulus Ė in the classic instance, no awareness of pain at all. Laboratory evidence for hypnotic analgesia comes from studies involving techniques such as ischemic muscle pain or cold-pressor pain, comparing the responses of hypnotizable and insusceptible subjects to the pain stimulus with and without analgesia suggestions. Clinical evidence for hypnotic analgesia comes from the successful use of hypnosis as the sole analgesic agent in both major and minor surgical procedures, as well as the successful use of hypnosis as an adjunct to chemical analgesia and/or conscious sedation. In Hilgardís "hidden observer" technique, discussed at some length by Farthing, it is possible for the hypnotist to contact a "hidden part" of the person that retains awareness of the pain stimulus. In this sense, at least, there is a division of consciousness roughly analogous to what we see in "split-brain" patients (though without the split brain, or any implication that the overt and covert pain are processed, or represented, in different hemispheres).

 

Discuss posthypnotic amnesia as an alteration in consciousness. How is posthypnotic amnesia similar to the "organic" amnesia associated with brain damage? What is the evidence that hypnotic suggestion can enhance memory as well as impair it?

Posthypnotic amnesia is an alteration in consciousness affecting memory rather than perception: the amnesic subject cannot consciously recollect events and experiences that transpired during hypnosis. Posthypnotic amnesia, like the "organic" amnesias associated with brain damage or electroconvulsive therapy, appears to dissociate explicit and implicit memory: recall and recognition of hypnotic events is severely impaired (among hypnotizable subjects), while priming effects are spared. (There are differences, though, too: posthypnotic amnesia is a product of suggestion, and is reversible; it is a disorder of memory retrieval, as opposed to a disorder of memory encoding or storage). There have been some claims that hypnosis can enhance memory as well as impair it, either through direct suggestions for hypermnesia or through suggestions for age regression. However, there is very little evidence, from either the laboratory or the field, that hypnotic hypermnesia improves accurate recollection: mostly, hypnotic suggestions increase false recall, and inappropriately inflate the subjectsí confidence in their memories; it may even increase susceptibility to leading questions (which, like the rest of hypnosis, are suggestive in nature). Similarly, there is no evidence that age regression (e.g., to age 10 or fifth grade) ablates memories encoded after the suggested age, or revives memories encoded before it.

 

Category 5: Meditation and De-Automatization (10 Points)

Discuss similarities and differences daydreaming, "concentrative" meditation, and "mindfulness" meditation. What are the roles of "stimulus bound" and "stimulus independent" thoughts in each state? How does each "state" of consciousness affect intrusive thoughts?

Daydreaming, as defined by Singer or by Klinger (see Farthingís chapter), is stimulus-independent thought, unrelated to current tasks or settings, like thinking of the beach when youíre in a lecture (unless, I suppose, the lecture is on the beach, or about beaches). In concentrative meditation, attention is restricted to only a single stimulus or thought (e.g., oneís mantra): it is stimulus bound thought. Mindfulness meditation is almost the opposite of concentrative meditation, in which the person attempts to maintain awareness of all conscious thoughts and actions: it is not bound to any one stimulus, but because it tries to include all available stimuli in its scope, it canít be described as stimulus-independent either. Almost by definition, daydreaming contradicts concentrative meditation: attention slips away from the stimulus or mantra, and becomes absorbed in the daydream. But daydreaming also contradicts mindfulness mediation, because in daydreaming attention is directed toward the daydream and away from the stimulus or mantra: in true mindfulness, attention would encompass both. In daydreaming, daydreaming is the intrusive thought (or, as Singer would call it, "task-unrelated intrusive thought", or TUIT). In concentrative meditation, the goal is to abolish intrusive thoughts. In mindfulness meditation, the goal is to incorporate the intrusive thoughts, but not at the expense of other, stimulus-bound thoughts. There are lots of examples, from Singerís research, on the study of intrusive thoughts in daydreaming; a really good answer would draw on this literature to discuss how intrusive thoughts could be studied in meditation as well.

What is the relevance of EEG "alpha" activity in meditation? What is the possibility that meditators are actually asleep? Can people achieve psychological effects of meditation through EEG "alpha wave" biofeedback, without practicing a meditative discipline?

Early studies seemed to indicate an increase in EEG alpha activity in meditation, leading some to suggest that the desirable effects of meditation could be achieved by biofeedback training, without the discipline of meditation. However, the relation between meditation and alpha is difficult to interpret, because alpha activity increases in any eyes-closed, resting state Ė leading some skeptics to suggest that meditators might really be in an early stage of sleep (alpha activity increases, then decreases, in descending Stage 1, and disappears in Stage 2). It has also been claimed that different forms of meditation, such as Yoga and Zen, have different effects on the stimulus-induced "blocking" of alpha activity (Yoga inhibiting the blocking response), or on the habituation of alpha blocking (Zen inhibiting the habituation), but later studies have not confirmed these effects. In any event, it is unlikely that alpha-biofeedback training can mimic the effects of meditation, for the simple reason that biofeedback doesnít increase alpha activity above baseline levels. Moreover, the subjective characteristics of the "alpha state" are strongly affected by expectations, along the lines of the placebo effect in drug studies.

 

Cumulative Portion (50 Points)

Answer one (1) question from each of the following three categories.

 

Category 6: Pre-Midterm (15 Points)

What does it mean to study consciousness by means of introspection? What are some of the limitations of introspection for the scientific analysis of consciousness? What can introspection reveal about qualia? About intentionality?

Introspection is the perception of, and reflection on, oneís own internal conscious experiences, as opposed to objects and events in the external world. Introspection comes in a variety of forms: analytic, descriptive, and interpretive (see Farthing). However, introspection is not direct inner observation, because the act of observing, and reflecting on, oneís own thought necessarily changes the thoughts being observed and reflected upon. This "uncertainty principle" is one limitation on introspection. Another is that introspection is more like memory than perception: what we can reflect on, and talk about, are experiences that weíve already had (James: "all introspection is retrospection"). It may be impossible to get rid of memory-based reconstructions, and inferences based on expectations, beliefs, and world knowledge. This problem of introspection is illustrated by Nisbett and Wilsonís finding that peopleís reports of the causes of their behavior rarely correspond to the actual causes, as determined by experimental manipulation. The classical technique of introspection was focused on qualia, on the analysis of the experience of such sensory qualities as "redness" or "sweetness": observers were supposed to avoid the "stimulus error". As such, introspection revealed a great deal about the basic sensory qualities. However, our conscious mental life is not composed of abstract "reds" and "sweets", but rather of red and sweet things. Conscious states are intentional states, which represent the relation between the person and some proposition about the world (e.g., I believe that apples are red and sweet). Avoiding the stimulus error essentially avoids intentionality. For this reason, even if it did not have the kinds of problems outlined above, classical introspection, limited to abstract qualia, cannot give us a full picture of mental life.

 

Distinguish among (1) substance dualism, property dualism (the dual-aspect theory), and interactive dualism; and among (2) epiphenomenalism, the identity theory, and eliminative materialism. (3) Refer to these terms when characterizing Searle's position on the mind-body problem, as you understand it from the reviews and exchanges in Searle's book

The definitions are straightforward, based either on lecture or Farthing. Characterizing Searleís position is a little trickier. The most important thing is that Searle abandons the fundamental categories on which these terms are based: dualism and monism, immaterialistic and materialistic monism. For his stance of biological naturalism, the first thing to be said is that the mind is what the brain does: consciousness is a causal feature of brains that possess certain anatomical properties (like lots of cerebral cortex) and certain physiological properties (like a certain level of activation). In this respect, Searleís position is akin to materialist monism, but he believes that consciousness has causal powers (thus is not merely an epiphenomenon of brain activity), and he doubts that a third-person description can be given of consciousness, because consciousness has a first-person ontology that all third-person descriptions must necessarily leave out. In this respect, Searleís position is akin to dualism, because mind can affect body (the basic position of interactive dualism), and mind has a property (first-person ontology) that brain (which can be completely described in the third person) does not. Thatís what happens when you try to break through received categories. The most important thing is that the student recognizes that Searle does this, and this makes him hard to pin down and categorize.

 

 

Category 7: Post-Midterm (15 Points)

What evidence is there for unconscious processing in either (1) sleep and dreams or (2) general anesthesia and conscious sedation?

Evidence for unconscious processing in sleep and dreams depends on how you define "unconscious". If unconscious means automatic, then dreams, sleepwalking, and sleeptalking seem to qualify as unconscious activities. If unconscious means implicit, then there is little evidence for unconscious perception or memory, as evidenced by studies of sleep suggestion or sleep learning.

Adequately anesthetized patients are unconscious by definition, and experiments using the isolated forearm technique seem to confirm that the anesthetized patient is really unconscious, and not just paralyzed. Still, studies of priming suggest that, at least under some conditions, anesthesia spares implicit memory, suggesting that some unconscious perception is possible in anesthesia, and memories acquired during surgery can unconsciously influence postsurgical experience, thought, and action. By the same token, patients undergoing conscious sedation are, by definition, conscious during the surgery; however, the sedative drugs usually render the patient amnesic for surgical events. Still, studies of priming indicate that conscious sedation spares implicit memory, so that memories of surgical events can influence post-surgical experience, thought, and action even in the absence of conscious recollection.

 

The explicit-implicit distinction had its origins in work on cognitive processes such as perception and memory. Describe how each of these concepts might be applied to our understanding of unconscious emotional or motivational states. In what sense can we, or might we, have unconscious feelings and desires?

We usually think of our feelings and desires as conscious, but thatís also how we usually think of our percepts and memories. Research documents dissociations between explicit and implicit memory, and between explicit and implicit perception, so it is not unreasonable to assume that feelings and desires might not show explicit-implicit dissociations as well. Put in a nutshell, implicit perception occurs when a person behaves as if he or she perceived something, even though s/he is not consciously aware of it; and implicit memory occurs when a person behaves as if s/he has a memory, even though s/he does not consciously remember it. The same point can apply to emotion and motivation, at least in principle. In Langís three-component theory of emotion, for example, the subjective feeling state (conscious or explicit emotion) can be dissociated from the physiological and behavioral expressions of emotion (which together might comprise unconscious or implicit emotion) Ė leading to a state that Rachman and Hodgson labelled desynchrony. The evidence for these particular dissociations or desynchronies is not particularly well developed at present (experiments like the Weinberger experiment are not done frequently), but the work on explicit perception and memory gives us a model for how to do the research.

Category 8: Integrative (20 Points)

Define the concept of "automaticity" in cognitive psychology. Why are automatic processes sometimes called "unconscious" as well? In what sense does cognition during sleep, anesthesia, or coma entail "automatic" processes. How would we know? In what sense might meditation lead to a "deautomatization" of cognition and behavior? How would we know?

Automatic processes are inevitably evoked and incorrigibly executed; they do not consume cognitive capacity, and they do not interfere with, nor are they subject to interference by, other ongoing processes; and they leave no trace of their operation in memory. Thus, automatic processes maybe called unconscious because they are executed independent of conscious intention and outside of conscious awareness. To the extent that any processing goes on during sleep, anesthesia, and coma, it is most likely to be of the automatic nature, precisely because automatic processes donít require conscious intentions (which sleeping, anesthetized, and comatose individuals probably canít form), and donít require much cognitive capacity (which sleeping, anesthetized, and comatose individuals probably donít have much of). Certainly, we donít remember whatever went on during sleep, anesthesia, and coma when we wake up. Still, the properties of automatic processes, discovered through experimental research, allow us (at least in principle) to test for automatic processing in any state of consicousness. For example, if meditation leads to de-automatization, we might expect that formerly automatic processes would lose at least some of the properties that make them automatic in the first place. One example of this idea in practice are Wenkís studies of performance in the Stroop task, which suggests that meditation leads to a reduction in interference from "automatic" word-reading.

 

What is the mind-body problem, so far as consciousness is concerned, and how does research on either (1) sleep and dreams or (2) hypnosis bear on it?

So far as consciousness is concerned, the mind-body problem has at least three aspects: (1) how does a physical system (like the brain) give rise to conscious experience? (2) what are the neural substrates of consciousness? and (3) can conscious experience affect bodily processes? Sleep and dreams give us some insight into the mind-body problem, because sleeping and dreaming are associated with distinctive patterns of neural activity (a good answer should specify what some of those patterns are). Hypnosis bears on the mind-body problem in at least two ways (1) Hypnotic subjects are conscious but not conscious of some things (like certain objects or memories); while this is true of some brain-damaged patients (e.g., the amnesic syndrome or blindsight), hypnosis doesn't entail the kinds of changes in brain structure and function seen in these syndromes. This suggests that there is more to consciousness than the operation of certain brain centers. (2) Hypnotic (and, for that matter, nonhypnotic) suggestions can produce changes in bodily response, as in the studies of allergic response or warts. This prima facie evidence for psychosomatic interactions needs to be firmed up, but if conscious mental states can indeed affect bodily processes, this would count as evidence against certain epiphenomenalist views of mind-body relations.