Topic 8 - Consciousness (FPSH1014) PDF

FPSH1014 Understanding Self and Others Topic 8 Consciousness Prepared by: Tony Ooi Presented by: Kelvin Wee  Introduction ❑ What is consciousness? ❑ Many questions about consciousness are unanswerable, at least by present methods. ❑ But...

FPSH1014 Understanding Self and Others Topic 8 Consciousness Prepared by: Tony Ooi Presented by: Kelvin Wee  Introduction ❑ What is consciousness? ❑ Many questions about consciousness are unanswerable, at least by present methods. ❑ But that doesn’t stop us from dealing with some simpler but related questions: ▪ What aspects of brain activity are necessary for consciousness? ▪ How does our conscious experience change when we’re sleeping, dreaming/under hypnosis? Continued…  Introduction ❑ Late 1800s – psychology began as the scientific study of the conscious mind. ❑ However, researchers soon abandoned that effort; reason: ▪ Behaviourists argued that consciousness is an internal, private experience that researchers can’t observe/measure. ❑ They’re not wrong – as they don’t have methods to measure brain activity/anything else that might correlate with private experiences. ❑ As a result, psychologists redefined their field as the study of behaviour. ❑ Many behaviourists agreed that consciousness couldn’t be studied, saying that it wasn’t important. Continued… Operational Definition of Consciousness ❑ Consciousness = subjective experience of perceiving oneself & one’s surroundings & action. ❑ Researchers today have several methods to record brain activity without invading the brain. ❑ Simplest methods: ▪ Electroencephalograph (EEG) ▪ Magnetoencephalograph (MEG) ❑ EEG & MEG uses detectors on the scalp to measure rapid changes in the brain’s electrical/magnetic activity. ❑ fMRI method identifies the location of activity more precisely.  Ways of Controlling Consciousness of a Stimulus 1st Method: Masking ❑ Masking = procedure of preceding/following a stimulus with an interfering pattern that might prevent consciousness of the stimulus. ❑ Participants in a study watched words flash on a screen for just 29 milliseconds (ms) each. ❑ On some trials, a blank screen preceded & followed the word. ❑ Under those conditions, people usually identified the word, even though it flashed so briefly. Stimulus Continued…  Ways of Controlling Consciousness of a Stimulus 1st Method: Masking ❑ On other trials, a masking pattern preceded & followed the word. ❑ Under these conditions, people: ▪ Almost never identified the word; ▪ Almost always insisted that they saw no word at all. Masking Pattern Stimulus Masking Pattern Ways of Controlling Consciousness of a Stimulus 2nd Method: Flash Suppression ❑ Flash Suppression = procedure of blocking consciousness of a stationary visual stimulus by surrounding it with rapidly flashing items. ❑ Example: ▪ A yellow dot is surrounded by blue dots on a screen. ▪ Then the blue dots start moving rapidly in haphazard directions. ▪ Movements of the blue dots grab our attention so strongly yellow dot disappears from our sights for seconds at a time. Ways of Controlling Consciousness of a Stimulus 3rd Method: Binocular Rivalry ❑ Ordinarily, our 2 retinas see almost the same thing. ❑ Binocular Rivalry = alteration between seeing the pattern in the left retina & the pattern in the right retina. Continued… ❑ Find/make tubes like those in a roll of paper towels: ▪ So your left eye can look at the above figure through 1 roll; ▪ Your right eye can look through the other roll. ❑ For a quick shortcut, you could cup both your hands to form viewing tubes. ❑ Adjust your focus until the 2 circles appear to overlap. ❑ At first, you will be conscious of what 1 eye sees (e.g. red & black lines). ❑ Within seconds, that perception fades start seeing green & black lines. ❑ Reason: you can’t see both images at the same time in the same place your brain alternates between the 2 perceptions (red & black lines ⬄ green & black lines). Unconscious Processing of a Suppressed Stimulus ❑ During binocular rivalry, while we’re conscious of 1 stimulus, the brain representation of the other 1 is not lost. ❑ Although the information doesn’t spread enough to become conscious, it does spread enough for the brain to process it to a certain degree. ❑ Example: ▪ Your eyes are viewing different scenes on a screen. ▪ While you’re conscious of 1 eye, the experimenter gradually changes the scene in the other eye to show a face. ▪ A face with an emotional expression captures your attention faster than a neutral face does. Continued… Unconscious Processing of a Suppressed Stimulus ❑ If a word emerges on 1 side, it captures our attention faster if it’s in a language we can read. ❑ Our brain notices that something is meaningful/important even before we become conscious of it.  Reflective Question Is there a degree to consciousness? Are we ever “partly” conscious of a stimulus? Consciousness as an All-or-None Phenomenon ❑ Example: ▪ A blurry stimuli flashes on the screen for a split second each. ▪ Some people would say they were conscious of the stimulus accurately name/describe it. ▪ Some would say they didn’t see the stimulus; use guessing on what they might have saw. ▪ But people almost never say they were “partly conscious” of the stimulus. ❑ Studies using brain scans point to the same conclusion: ▪ A stimulus either reaches a threshold (maximum) necessary for spread in the brain OR it doesn’t. ❑ Hence, consciousness of a stimulus appears to be an all-or-none phenomenon. Consciousness as Construction ❑ Many studies have doubt on the assumption that when we see/hear something, we assume that we see/hear it as it happens. ❑ Example: ▪ A word flashes on a screen for 29 milliseconds (ms) followed by a masking stimulus, so that you are not conscious of the word. ▪ Then the experimenter repeats the procedure but extends the duration to 50 milliseconds (ms). ▪ With this longer presentation, you do see the word. ▪ Question: Does that mean you have an unconscious perception for the first 29 milliseconds conscious perception in the other 21 milliseconds? Continued… Consciousness as Construction ❑ No… Instead, the final part of that 50 milliseconds presentation enabled you to become conscious of the first part that happened earlier. ❑ In some way, our brain constructed an experience of a 50 millisecond stimulus, even though it had to wait until the later part of the stimulus to perceive the first part.  Example – Consciousness as Construction ❑ Suppose you see a display of 2 vertical lines: ❑ After a delay of one- or two-tenths of a second, you see a display of circles like this: ❑ When you report the appearance of the lines, you’ll likely describe it as something like this: Continued… Example – Consciousness as Construction ❑ The lines appear to be displaced partly in the same direction that the circles were displaced. ❑ Reason: ▪ The later stimulus changed our perception of the earlier stimulus. ▪ Evidently, consciousness doesn’t occur at exactly the same time as the actual events. ▪ We construct a conscious perception of events that already happened. ❑ In short, the perception of a 1st stimulus can be altered by a stimulus that follows it. Can We Use Brain Measurements to Infer Consciousness? ❑ Brain death = condition in which the brain shows no activity + no response to any stimulus. ❑ Most people consider it ethical to remove life support for someone who remains steadily in such condition. ❑ Coma = condition caused by traumatic brain damage in which the brain shows a steady but low level of activity + no response to any stimulus. ❑ In nearly all cases, someone in a coma either: ▪ Dies OR ▪ Begins to recover within a few weeks. Continued…  Brain Death https://chainedevie.org/en/read-view/donation-transplanta tion-and-health/understanding-brain-death Can We Use Brain Measurements to Infer Consciousness? ❑ Someone starting to emerge from a coma enters a vegetative state. ❑ Vegetative State = condition marked by limited responsiveness to stimuli (e.g. increased heart rate in response to pain). ❑ Characteristics of Vegetative State: ▪ Person is awake but shows no signs of awareness/any purposeful behaviours; ▪ May open eyes, wake up & fall asleep at regular intervals; ▪ Responsiveness varies between a sleeping state & a waking state; ▪ But even in the waking state, brain activity is well below normal. Continued… Can We Use Brain Measurements to Infer Consciousness? ❑ Minimally Conscious State = condition in which someone has brief periods of purposeful actions + speech comprehension. ❑ A vegetative or minimally conscious state can last for months or years. ❑ Because people in a vegetative state do nothing, it’s easy to assume that they are unconscious. ❑ However, new research methods challenge that assumption in certain cases. Continued… Can We Use Brain Measurements to Infer Consciousness? ❑ Research study: ▪ Used fMRI to record brain activity of a young woman in a persistent vegetative state after a traffic accident. ▪ When instructed to imagine playing tennis increased activity in the same motor areas of the brain (as if she were getting ready to hit a tennis ball). ▪ Instruction to imagine walking through her house activated the brain areas responsible for spatial navigation. ▪ When uninjured people received the same instructions, they showed activity in the same areas that the young woman did. ❑ This result suggest that some patients in a vegetative state are conscious. What Is the Purpose of Consciousness? ❑ Why do we have consciousness at all? ❑ Some theorists argued that consciousness is an epiphenomenon (an accidental by-product with no purpose). ❑ Hypothesis: ▪ Conscious thought is a way of rehearsing possibilities for future actions. ▪ Our conscious thinking modifies our behaviour on some future occasion. ▪ Example: After we do something, we might ponder: ✔ “That didn’t go well.” ✔ “What could I have done differently? Then what would have happened?” ✔ “Next time I’m in this situation, here’s what I’ll do….” Continued… What Is the Purpose of Consciousness? ❑ Many theorists seem to see the role of consciousness as an either–or question. ❑ Either consciousness is useless, or it evolved to serve a special purpose. ❑ We can’t have consciousness without brain activity. ❑ But we also can’t have certain kinds of brain activity without consciousness. ❑ The questions “why is there such a thing as consciousness “ will require more researches to answer.  Circadian Rhythms ❑ Circadian rhythms = rhythms of activity & inactivity lasting approximately 1 day. ❑ Part of the body’s internal clock which runs in the background to carry out essential functions & processes. ❑ Humans have mechanisms that prepare us for activity during the day & sleep at night. ❑ Circadian rhythm controls more than sleeping & waking. ❑ It also controls our hunger, thirst, urine production, blood pressure, alertness, body temperature etc. Continued…  Circadian Rhythms ❑ Sleepiness & alertness depend on the circadian rhythm (not just on how long a person didn’t sleep). ❑ As experienced by most college students, you probably felt very sleepy between 2:00 – 6:00 am. ❑ But in the morning, you began feeling less sleepy. ❑ You became more alert because of your circadian rhythm, even though your sleep deprivation continued. Are you a morning person or evening person? Morning People & Evening People ❑ People vary in their circadian rhythms: ▪ Morning people – awaken easily, become alert quickly; do their best work early. ▪ Evening people – take longer to warm up in the morning; do their best work in the afternoon/evening. ❑ Advantages of morning people (particularly students): ▪ Maintain attention better in the morning; ▪ Do better on tests in the morning; ▪ Get better grades (compared to evening-type students with same cognitive ability & motivation). Continued… Morning People & Evening People ❑ Age differences in circadian rhythms affect behaviour in many ways. ▪ Most young adults are either evening or intermediate people. ▪ Most people over age 65 are morning people. ❑ Researchers’ finding: ▪ Study on memories of young adults (18 to 22 years old) & older adults (66 to 78 years old). ▪ Early in the morning, older adults performed as well as younger people. ▪ Later in the day, younger adults remained steady/improved, whereas older adults deteriorated. Shifting Sleep Schedules ❑ Normally, the light of early morning resets the body’s clock each day to keep it in synchrony with the outside world. ❑ If you travel across time zones, your internal rhythm is temporarily out of phase with your new environment. ❑ Example: ▪ If you travel from Malaysia to Vancouver, Canada, arriving at 8 a.m., it’s time to wake up. ▪ However, your body says it’s 11 p.m. (Malaysia is 15 hours ahead of Vancouver), getting close to bedtime. Continued… Shifting Sleep Schedules ❑ Jet lag = period of discomfort & inefficiency while our internal clock is out of phase with a new surrounding. ❑ Most people find it easier to adjust when flying west (where they go to bed later) > flying east (where they go to bed earlier). ❑ Our circadian rhythm (body clock) is less confused if we travel westward. ❑ Reason: travelling west ‘prolongs’ the body clock’s experience of its normal day-night cycle (normal body clock in most of us is slightly longer than 24 hours).  Stages of Sleep ❑ There are 2 types of sleep: i. Non-rapid eye-movement (NREM) sleep (3 stages) ii. Rapid eye-movement (REM) sleep (1 stage) ❑ Rapid eye movement (REM) = sleep stage characterized by rapid eye movements, high level of brain activity, & deep relaxation of the postural muscles. ❑ REM – eyes move around quickly under closed eyelids. ❑ NREM – eyes remain still under closed eyelids. Continued…  Stages of Sleep Stage Characteristics ✔ Brain, eye movement, heartbeat & breathing slow down. NREM Stage N1 ✔ Muscles begin to relax. (Falling Asleep) ✔ Last for a few minutes. ✔ Less aware of surroundings. ✔ Heartbeat & breathing slow down further/more regular. NREM Stage N2 ✔ Eye movements stop. (Light Sleep) ✔ Body temperate drops. ✔ Last about 25 minutes.  Stages of Sleep Stage Characteristics ✔ Progress into deepest sleep (where any noises/activity in the environment may fail to wake the sleeping person). ✔ Muscles are completely relaxed. NREM Stage N3 ✔ Blood pressure drops, heartbeat & breathing are at the slowest rate. (Slow Wave Sleep) ✔ No eye movements. ✔ Tissue repair & growth & cell regeneration. ✔ Immune system strengthens.  Stages of Sleep Stage Characteristics ✔ Begins approximately 90 minutes after falling asleep. ✔ Brain activity is markedly increased (closely resembles its activity when awake). ✔ Body is temporarily paralyzed (to prevents you from acting out your dreams). Stage 4: REM Sleep ✔ Starts to dream. ✔ Eye movements become rapid. ✔ Breathing & heart rate increases. Topic 8 Consciousness Part 2  Insomnia ❑ Insomnia = condition of not getting enough sleep to feel rested the next day. ❑ 6 hours sleep could be insomnia for someone, but adequate for another. ❑ Insomnia results from causes, including: ▪ Noise; ▪ Worries; ▪ Indigestion; ▪ Uncomfortable temperatures; ▪ Use of alcohol/caffeine; ▪ Medical/psychological disorders etc. Continued…  Insomnia ❑ If you have persistent insomnia, consult a physician, but for occasional/minor insomnia, you can try a few things yourself: ✔ Keep regular schedule for going to bed & waking up each day. ✔ Spend some time in the sunlight to set your circadian rhythm. ✔ Minimize exposure to screens a few hours before bedtime. ✔ Avoid caffeine (especially in the evening). Continued…  Insomnia ❑ If you have persistent insomnia, consult a physician, but for occasional/minor insomnia, you can try a few things yourself: ✔ Don’t rely on alcohol/tranquilizers to fall asleep; after repeated use, you may be unable to sleep without them. ✔ Keep your bedroom cool & quiet. ✔ Exercise daily, but not shortly before bedtime.  Sleep Apnea ❑ Sleep Apnea = condition in which someone fails to breathe for a minute/more during sleep. ❑ People with sleep apnea may lie in bed for 8 – 10 hours but sleep less than half that time. ❑ Most common in overweight middle-aged men whose breathing passages become narrower than usual. ❑ While awake, they compensate by breathing frequently & vigorously, but they can’t keep up this pattern while they are asleep. Continued…  Sleep Apnea ❑ Treatment for sleep apnea includes: ▪ Recommendations to lose weight; ▪ To avoid alcohol & tranquilizers before bedtime; ▪ Surgeons can remove tissue to widen the airways; ▪ Use a device (Continuous Positive Airway Pressure machine) that pumps air into a mask covering the nose & mouth during sleep, forcing the person to breathe.  Narcolepsy ❑ Infants alternate between brief waking periods & brief sleeping periods. ❑ As they grow older, they consolidate into one long waking period during the day & 1 long sleeping period at night. ❑ Narcolepsy = condition characterized by sudden attacks of sleepiness during the day. ❑ A neurotransmitter called orexin is important for maintaining long periods of wakefulness. ❑ People with narcolepsy lose the brain cells that produce orexin return to a pattern resembling infants. Continued…  Narcolepsy https://www.youtube.com/watch?v=e328D6tmlrs  Narcolepsy ❑ People with narcolepsy experiences: ▪ Sudden attacks of muscle weakness/paralysis ▪ Occasional dreamlike experiences while awake. ❑ Treatment for narcolepsy: ▪ Combination of stimulant & antidepressant drugs – maintains wakefulness during day & blocks attacks of muscle weakness. ❑ Future research may develop medications based on orexin, but none are available currently. Some Other Sleep Experiences Sleep Talking ❑ Common experience ranging from a grunted word to a clear paragraph. ❑ Occurs in sleep more often than people realize (don’t remember). ❑ Occurs in all stages of sleep (most common during stage 2). ❑ Facts: ▪ Sleep talkers sometimes pause between utterances (as if they were in a conversation). ▪ It’s possible to engage some sleep talkers in a dialogue. ▪ Sleep talking isn’t related to mental/emotional disorders. Continued… Some Other Sleep Experiences Sleep Walking ❑ Sleepwalking factors may include: ▪ Genetics & family history ▪ Sleep deprivation ▪ Brain injury ▪ Obstructive sleep apnea ▪ Stress etc. ❑ Occurs mostly during the 1st half of the night’s sleep. ❑ Sleep walkers are sort of asleep; the entire brain doesn’t necessarily wake up/go to sleep all at once. ❑ Occurs when motor cortex & a few other areas are active while most of the brain remains asleep. Continued… Some Other Sleep Experiences Lucid Dream ❑ Lucid dreaming – when you’re conscious during a dream. ❑ Typically occurs during rapid eye movement (REM) sleep. ❑ During a lucid dream, you’re aware of your consciousness. ❑ Often, lucid dreaming also lets you control what happens in your dream. Some Other Sleep Experiences Night Terror ❑ Night terror = condition that causes someone to awaken screaming & sweating with a racing heart rate, sometimes flailing with the arms. ❑ Occur during stage 3 or stage 4 sleep. ❑ Common characteristics of night terror: ▪ Sudden awakening from sleep; ▪ Persistent fear/terror that occurs at night; ▪ Screaming & confusion; ▪ Sweating & rapid heart rate; ▪ No recall of bad dreams/nightmares etc. ❑ Treatments include: psychotherapy, antidepressant, antianxiety drugs, & advice to minimize stress.  Dreams ❑ In ancient times, people believed that dreams foretold the future. ❑ Occasionally, they do, either by coincidence. ❑ Today, scientists don’t believe dreams tell us about the future, although many other people do. ❑ If you dream about a plane crash tonight, will you hesitate to take a plane trip tomorrow? ❑ Can we explain/interpret dreams? Freud’s Theory of Dreams ❑ Sigmund Freud (founder of psychoanalysis) – dreams reveal the dreamer’s unconscious thoughts & motivations. ❑ To understand a dream, one must probe for hidden meanings. ❑ Each dream has a: ▪ Manifest content ▪ Latent content Continued… Freud’s Theory of Dreams ❑ Manifest content = content that appears on the surface of a dream. ❑ Latent content = hidden ideas that a dream experience represents symbolically. ❑ Because latent contents are so painful & threatening transformed into more acceptable manifest content. ❑ Many therapists offer dream interpretations that their clients find meaningful: ▪ Try to uncover disguised meanings by studying the symbols in the manifest content of the dream. Continued… Freud’s Theory of Dreams ❑ To uncover meanings of latent content, therapists may ask clients to free associate to some aspect of manifest content of a dream. ❑ Interpreting meanings of the dream elements unlock client’s repression that kept the material from consciousness relate the new insight to their present struggles. ❑ However, there’s no way to check which interpretations are accurate and which ones are not.  Hypnosis ❑ Hypnosis = condition of increased suggestibility that occurs in the context of a special hypnotist-subject relationship. ❑ Comes from the word ‘Hypnos’ = the Greek god of sleep. ❑ In short, it’s a trance-like mental state in which people experience increased attention, concentration & suggestibility. *suggestibility = state where a subject is inclined (willing to accept) the actions/suggestions of others. Continued…  Hypnosis ❑ The similarity between a sleeping person & hypnotized people is superficial. ❑ Hypnotized people: ▪ Lose initiative & accept contradictory information without protest. ▪ Walk around & respond to objects in the real world. ▪ Have brain activity characterized by increased activity in the prefrontal cortex (important for attention). Continued… Way of Inducing Hypnosis ❑ Successful hypnotists need practice (there’s no unusual powers). ❑ 1st step toward being hypnotized ▪ Agreeing to give it a try. ▪ No one can hypnotize an uncooperative person. ▪ When a hypnotist tells a person to sit down & relax, and he/she does so (because he/she would like to experience hypnosis). ▪ The whole point of hypnosis is following the hypnotist’s suggestions. ▪ When a person sits down & relax, he/she is already following a suggestion. Continued… Way of Inducing Hypnosis ❑ Hypnotist might then monotonously repeat something like: ▪ “You are putting everything else out of your mind except what you hear from me.” ▪ “You are starting to fall asleep.” ▪ “Your eyelids are getting heavy.” ▪ “Your eyelids are getting very heavy. They are starting to close.” ▪ “You are falling into a deep, deep sleep.” Continued… Way of Inducing Hypnosis ❑ A bit later, hypnotist might suggest something specific, e.g. ▪ “After you go under hypnosis, your arm will begin to rise automatically.” ❑ Hypnotist encourages the person to relax & suggests that his/her arm is starting to feel lighter (as if it were tied to a helium balloon). Continued… Way of Inducing Hypnosis ❑ Hypnotist might suggest that the person’s arm is beginning to feel strange & is beginning to twitch. ❑ Timing of suggestion is important; when a person stands/sits in one position long enough, the limbs may tingle & twitch. ❑ If hypnotist’s suggestion comes at just the right moment, a person might think: ▪ “Wow, that’s right. My arm does feel strange. This is starting to work!” ❑ Believing that yourself is being hypnotized big step toward actually being hypnotized.  Hypnosis Demonstration to a Non Believer https://www.youtube.com/watch?v=UQG_vcVCeDY Uses & Limitations of Hypnosis ❑ Hypnosis: ▪ Resembles ordinary suggestibility. ▪ Enhances suggestibility a little, but only a little. ❑ People vary considerably in how far they will follow suggestions, either with/without hypnosis: ▪ Someone asked you to imagine a bright, sunny day – you almost certainly would (without being hypnotized). ▪ If you were asked to stand & put your hands on your head, you probably would, (again without being hypnotized). ▪ If someone asks you to stand, flap your arms & cluck like a chicken – you might/might not. What Hypnosis Can Do? ❑ Hypnosis can help to inhibit pain. ❑ Some people undergo medical/dental surgery with only hypnosis & no anesthesia. ❑ Particularly helpful for people who: ▪ React unfavorably to anesthetic drugs; ▪ Developed a tolerance to painkilling opiates. ❑ Although hypnosis can relieve pain cheaply & without side effects, few physicians & hospitals use it. What Hypnosis Doesn’t Do ❑ Hypnosis doesn’t give people special strength/unusual powers. ❑ Hypnosis doesn’t improve memory accuracy: ▪ When asked to report their memories under hypnosis, people report a mixture of correct & incorrect information with much confidence. Other States of Consciousness Meditation ❑ Meditation = systematic procedure for inducing a calm, relaxed state. ❑ Mindfulness meditation involves a person being aware of the sensations of the moment but otherwise remain passive. ❑ While performing mindfulness meditation, one might concentrate on a single image/repeat a sound (e.g. “om”). Continued… Other States of Consciousness Meditation ❑ Research studies suggest that meditation: ▪ Increases relaxation; ▪ Decreases pain; ▪ Decreases anxiety; ▪ Improves health. ▪ Is useful for increasing people’s ability to control their attention & resist distraction. Continued… Other States of Consciousness Déjà vu Experience ❑ Déjà vu experience = feeling that an event is uncannily familiar. ❑ More commonly, people report déjà vu in a familiar setting. ❑ You might be sitting in your room, walking down a familiar road, or having an everyday conversation, when you suddenly feel, “This has happened before!” ❑ Apparently, something is triggering the brain to signal “familiar.” ❑ In some cases (probably not all), déjà vu experience relates to abnormal activity in brain areas responsible for memory.