Introduction to Psychology

Introduction to Psychology

Chapter Four: Consciousness Learning Objectives After completing this unit, you should be able to: 1. Discuss the characteristics of consciousness 2. Discuss circadian rhythms and biological rhythm, REM sleep and dreaming 3. Discuss different types of sleep disorders 4. Discuss hypnosis states and theories of hypnosis 5. Discuss the physical and psychological effects of psychoactive drugs and the different classes of drugs 4.1 Biological Rhythms In psychology, consciousness is often defined as our moment to moment awareness of ourselves and our environment. Consciousness is: subjective and private; dynamic and ever changing; self- reflective and central to our sense of self; and intimately linked to selective attention. Selective attention is the process that focuses awareness on some stimuli to the exclusion of others. In humans and other species, hormone levels, body temperature, and wakefulness rise and fall in predictable ways during the course of a day. These are known as circadian rhythms. Circadian rhythms are 24-hour biological cycles that help regulate bodily processes and influence our alertness. Most circadian rhythms are regulated by the brain’s suprachiasmatic nuclei (SCN), located in the hypothalamus, and known as the master circadian clock. Free running circadian rhythms are about hours. The day-night cycle and other environmental factors reset our daily clocks to a 24-hour cycle. Circadian rhythms influence our tendency to be a morning or a night person. Cultural factors may also play a role. In general, our alertness is lowest in the earlymorning hours. Job performance errors, major industrial accidents, and fatal auto accidents peak during these hours. Jet lag, night shift work, and seasonal affective disorder involve circadian disruptions. Treatments include controlling one’s exposure to light, taking oral melatonin, and regulating one’s daily activity schedule. 4.2 Sleep Circadian rhythms promote a readiness for sleep by decreasing alertness, but they do not regulate sleep directly. Roughly every 90 minutes while asleep, we cycle through different stages in which brain activity and other physiological responses change in a generally predictable way. As sleep begins, our brain wave patterns become more irregular. Stages of Sleep- Sleep has five main stages. Stage one is a light sleep fromwhich we can easily awaken. We spend just a few minutes in this stage, often characterized by vivid images, sudden body jerks,

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