CONSCIOUSNESS

• Consciousness is defined as the awareness that we have of ourselves, our internal states, and the environment.

• A state of consciousness enables us to evaluate the environment and to filter information from the environment through the mind, while being aware of the occurrence of this complex process.

• Alertness and the associated state of arousal involve the ability to remain attentive to our surroundings.

• It is something that we often take for granted; however, many patients who arrive in an emergency room are not alert for various reasons, arriving in a so-called altered state of consciousness.

• William James spoke of a stream of consciousness.

• The cognitive psychologist Robert Sternberg refers to consciousness as a mental reality that we create in order to adapt to the world.

• The unconscious level commonly refers to automatic processes, such as breathing or the beating of the heart.

• The preconscious level contains information that is available to consciousness but is not always in consciousness.

• Consciousness exists on a continuum—starting from controlled processing, where we are very aware of what we are doing, and moving on to automatic processing, where we perform tasks mechanically, such as brushing our teeth.

SLEEP AND DREAMING

• Sleep is an altered state of consciousness.

• Researchers have discovered some neurochemicals, notably melatonin, that play a role in sleep, yet a definitive cause-and-effect relationship between a brain chemical and the control of sleep has not been demonstrated.

• One 24-hour cycle without sleep is tolerable, but the second such cycle is considerably more difficult.

• By the third 24-hour cycle, hallucinations can begin, as well as delusions.

• Four 24-hour cycles of sleep deprivation can lead to paranoia and other psychological disturbances.

• Our body temperature and other physiological markers follow a day-to-night pattern, known as a circadian rhythm.

• Photoreceptors send signals to the brain’s pineal gland, which is the region responsible for the production of melatonin.

• Brain waves are usually measured with electroencephalograms (EEGs), which provide a picture of the electrical activity of the brain.

  • When we are awake and focused, beta wave activity is happening.

  • While still awake but more relaxed, we drift into alpha waves.

    • Then, when we drift off to sleep, theta wave activity takes over.

• In stage 2 sleep, a pattern of waves known as sleep spindles appears.

  • These spindles are occasionally broken up by K complexes, which are large, slow waves.

• In stages 3 and 4, delta waves are most common, with a larger proportion of delta waves occurring during stage 4 sleep.

• The last stage of sleep is called REM (rapid eye movement) sleep.

• Researchers Eugene Aserinsky and Nathaniel Kleitman discovered that the eyes move vigorously during the REM stage.

William Dement

• studied the effects of the deprivation of REM sleep.

• By depriving participants of REM sleep (waking them every time they entered a REM period) and then allowing them to sleep normally after the experimental period, participant’s REM periods increased from the normal 90 minutes of REM per night to 120 minutes of REM sleep in the period immediately following the deprivation.

  • This is known as REM rebound, and it helps reinforce the idea that we need to sleep.

• In psychoanalytic theory, the manifest content, or storyline and imagery of the dream, offers insight into and important symbols relating to unconscious processes.

• The latent content is the emotional significance and underlying meaning of the dream.

• The activation-synthesis hypothesis of dreaming postulates that dreams are the product of our awareness of neural activity due to sensory input while we are sleeping.

• The problem-solving theory of dreaming holds that dreams provide a chance for the mind to work out issues that occupy its attention during waking hours.

• A nightmare is an elaborate dream sequence that produces a high level of anxiety or fear for the dreamer.

• Dyssomnias are abnormalities in the amount, quality, or timing of sleep, and they include insomnia, narcolepsy, and sleep apnea.

• Insomnia is the most common of the sleep disorders and represents the inability to fall asleep or to maintain sleep.

• Narcolepsy is the inability to stay awake.

• Sleep apnea is a disorder in which a person repeatedly stops breathing while sleeping, which results in awakening after a minute or so without air.

• Sudden infant death syndrome (SIDS) may also be linked to sleep apnea.

• Parasomnias involve abnormalities of movement during deep sleep; they include sleepwalking (or somnambulism) and night terrors.

HYPNOSIS

• Hypnosis is an altered state of consciousness in which the hypnotized person is very relaxed and open to suggestion.

• According to Hilgard’s theory of the hidden observer, hypnosis somehow divides or dissociates the mind into two parts.

  • One part obeys the hypnotist, while the other part, referred to as the hidden observer, silently observes everything.

MEDITATION

• Meditation refers to a variety of techniques, many of which have been practiced for thousands of years, and which usually involve learning to train one’s attention.

• Meditators may focus intensely on a single thing, such as their breathing, or they may broaden their attention and be aware of multiple stimuli, such as anything in their auditory field.

PSYCHOACTIVE DRUG EFFECTS

• Dependence occurs when an individual continues using a drug despite overarching negative consequences in order to avoid unpleasant physical and/or psychological feelings associated with not taking it.

  • (This term has generally replaced the term addiction in psychological and health circles.)

• A person has developed tolerance to a drug when increasingly larger doses are needed in order for the same effect to occur.

• Withdrawal refers to the process of weaning off a drug one has become dependent upon; this often involves physical and psychological symptoms of a highly unpleasant nature.

Next Chapter: Chapter 9: Sensation and Perception