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Chapter 5

Psychology -Chapter 5 Variations in consciousness.docx

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Department
Psychology
Course
PSY100Y5
Professor
Dax Urbszat
Semester
Winter

Description
Chapter 5 Variations in consciousness The nature of consciousness -Conscious –the awareness of internal and external stimuli -Consciousness is continuously changing => William James describe this continuous flow as the stream of consciousness -Almost every human behaviours comes from a mixture of conscious and unconscious processing Variation in awareness and control -Mind wandering –refers to people’s experience of task-unrelated thoughts, thoughts that are not related to what they are intentionally trying to do at a given moment -Mind wandering is associated with less need of awareness of external information, and may be connected to creativity in some contexts -Controlled process – judgement, or thoughts that we exert some control over, that we intend to occur -Automatic processing – its effects happen without our intentional control or effort Unconscious thought effect -Dijksterhuis suggests that if people are distracted or diverted from “conscious deliberation,” some decisions may actually be enhanced -Conscious thought is thought with attention; unconscious thought is thought without attention Consciousness and brain activity -The electroencephalograph (EEG) – a device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp. -Human brain-wave activity is usually divided into four principal bands, based on the frequency of the brain waves: beta (13-24cpts), alpha (8-12 cps), theta (4-7 cps), and delta (under 4 cps) -EEG patterns associated with states of consciousness: Beta (Waking/alert problem solving) Alpha (Deep relaxation, blink mind, and meditation) Theta (Light sleep) Delta (Deep sleep) Biological rhythms and sleep -Variations in consciousness are shaped in part by biological rhythms -Biological rhythms – periodic fluctuation in physiological functioning (Organism have internal “biological clocks” that somehow monitor the passage of time) The Role of circadian rhythms -Circadian rhythms – the 24 hour biological cycles found in human and many other species -Researcher concluded that circadian rhythms can leave individual physiologically primed to fall asleep most easily at a particular time of day -daily exposure to light readjusts people’s biological clocks (When exposed to light, some receptors in the retina send direct inputs to a small structure in the hypothalamus called the suprachiasmatic nucleus. (SCN)) -Circadian rhythms in humans actually appear to be regulated by multiple internal clocks with a central peacemaker located in the SCN Ignoring circadian rhythms -When you ignore the circadian rhythms and not get enough sleep, you’ll accumulate “sleep debt” -Getting out of sync with your circadian rhythms also causes “jetlag”. (Speed of readjustment of circadian rhythms depends on the direction travelled. Generally readjustment is easier when you fly westward and harder when you fly eastward) Melatonin and circadian rhythms -Studies suggest that melatonin can reduce the effects of jet lag by helping traveller resynchronize their biological clocks, but the research results are inconsistent. -Bright light administration and circadian-friendly rotation schedules can sometime reduce the negative effect of rotating shift work Sleep and waking cycle -In addition to an EEG, the other two crucial devices are: electromyography, and Electrooculogrpay -Electrolmyography (EMG) – records muscular activity and tension -Electrooculogrpay (EOG) – records eye movement Cycling through the stages of sleep -during sleep, people cycle through a series of five stages Stage 1-4 -Stage 1 is a brief transitional stage of light sleep that usually last a few minutes (Hypnic jerks, those brief muscular contractions that occur as people fall asleep, generally occur during stage 1 drowsiness) -As the sleeper descends through stage 2, 3, and 4 of the cycle, respiration rate, heart rate, muscle tension and body temperature continue to decline. -During stage 2, which typically last about 10-25min, brief bursts of higher-frequency brain waves, called sleep spindle, spear against a background of mixed EEG activity. -Gradually brain waves become higher in amplitude and slower in frequency, as the body moves into a deeper form of sleep, called slow-wave sleep Slow wave sleep – consist of sleep stages 3 and 4, during which high amplitude, low frequency delta waves become prominent in EEG recordings -the cycle then reverses itself and the sleeper gradually move back to light sleep Rem sleep -When sleepers reversed back to stage 1, they usually enter in fifth stage of sleep, which is most widely known as REM sleep. -REM stage tends to be a deep stage of sleep in the conventional sense that people are relatively hard to awaken from it (Marked by irregular breathing and pulse rate. Muscle tone is extremely relaxes- virtually paralyzed) -Although it is a stage of deep sleep, EEG activity is dominated by high-frequency beta waves that resemble when people are awake - REM sleep is a relatively deep stage of sleep marked by rapid eye movements; high-frequency, low amplitude brain waves and vivid dreaming - Non- REM sleep consists of sleep stage 1 through 4, which are marked by an absence of rapid eye movements, relatively little dreaming, and varied EEG activities Repeating the cycle -The REM sleeps usually off the course 4 times in a course of night, and is usually short at the start and longer after. On the other hand, NREM sleeps are longer in the beginning and shorter at the end and REM sleep gets longer. Age trends in sleep -age alters the sleep cycle -As you get older, the level of REM sleep gradually decreases, as the level of NREM sleep increase slightly (the trend of men is stronger than women) -researcher conclude that elderly may simple need less sleep than adult The neural bases of sleep -One brain structure that is important to sleep and wakefulness is the reticular formation in the core of the brainstem -The ascending reticular activating system (ARAS) – consist of the afferent fibres running through the reticular formation that influence physiological arousal -Many other brain structures are also involved in the regulation of sleeping and waking; for example, Pons and adjacent areas in the midbrain (Hypothalamus, medulla, thalamus, basal forebrain..) Sleep restriction -partial sleep deprivation, or sleep restriction when people make do with substantially less sleep than normal over a period of time - Sleep is important for both cognitive activities and emotional regulations Selective deprivation -A special type of partial sleep deprivation- selective deprivation (REM-sleep deprivation) -Without REM sleep, it has little impact on day-time function and task performance, but it does have interesting effect on the subject’s pattern of sleeping -transition of R
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