The Nature of Consciousness

The Nature of Consciousness

• Consciousness involves awareness of internal and external stimuli.

• To be conscious includes awareness of: external events, internal sensations, your self as unique, and your thoughts about experiences.

• The contents of consciousness continuously change; William James called it the "stream of consciousness."

Variations in Levels of Awareness

• Sigmund Freud viewed consciousness as having depth, with conscious and unconscious processes at different levels of awareness.
• Research suggests some awareness persists during sleep and anesthesia.
• Some stimuli can still penetrate awareness even during sleep such as a parent hearing a baby's cry.

Consciousness and Brain Activity

• Consciousness arises from distributed neural network activity, not one brain structure.

• An electroencephalograph (EEG) monitors the brain's electrical activity over time using electrodes on the surface of the scalp.

• EEG summarizes cortical activity rhythm as brain waves, varying in amplitude and frequency.

• Brain-wave activity consists of beta(13-24 cps), alpha (8-12 cps), theta (4-7 cps), and delta (under 4 cps) bands.

• Beta waves dominate during problem-solving; alpha waves increase during relaxation.

• Delta waves become prevalent during deep, dreamless sleep.

The Evolutionary Roots of Consciousness

• Consciousness likely evolved to aid ancestor's survival and reproduction.
• Consciousness assists in thinking through actions and choosing the best outcomes instead of acting on ill-advised actions.

Biological Rhythms and Sleep

• Biological rhythms are periodic physiological fluctuations tied to planetary rhythms.

• Organisms possess internal “biological clocks” to monitor the passage of time.

The Role of Circadian Rhythms

• Circadian rhythms are the 24-hour biological cycles found in humans.

• Humans' circadian rhythms regulate sleep, blood pressure, urine production, hormonal secretions, cognitive performance, and alertness.

• The body temperature varies rhythmically daily, peaking in the afternoon and bottoming at night.

• People generally fall asleep as body temperature drops and awaken as it rises.

• The suprachiasmatic nucleus (SCN) in the hypothalamus receives light inputs from the retina.

• The SCN sends signals to the pineal gland, whose secretion of melatonin adjusts biological clocks.

Ignoring Circadian Rhythms

• Ignoring the biological clock and going to sleep at an unusual time impairs sleep quality.

• Jet lag occurs when circadian rhythms are out of sync due to crossing time zones.

• Adjusting from jet lag can take about a day for each time zone crossed.

• It is easier to fly westward, lengthening the day, than eastward to shorten it.

• Rotating work shifts disrupts biological rhythms, leading to less and poorer-quality sleep.

• This leads to decline in productivity, poor employee work-life balance, and health challenges.

Realigning Circadian Rhythms

• Melatonin supplements potentially reduce jet lag effects by resynchronizing biological clocks.

• Bright light exposure helps align circadian rhythms in rotating shift workers.

• Work schedules are carefully planned and rotated to reduce circadian disruption.

The Sleep and Waking Cycle

• Sleep consists of various physical and mental activities throughout the night.

• Sleep research occurs in labs where participants sleep while connected to equipment that records physiological changes.

• Equipment used includes EEG, EMG (muscular activity/tension), EOG (eye movements), and EKG (heart contractions).

Cycling Through the Stages of Sleep

• People cycle through five distinct sleep stages.

• Stage 1 is a brief, transitional stage of light sleep, lasting a few minutes with slowed breathing, heart rate, and muscle tension.

• Stages 2–4 are characterized by declines in respiration, heart rate, muscle tension, and body temperature.

• Brain waves become higher in amplitude and slower in frequency as one moves into slow-wave sleep.

• Slow-wave sleep includes stages 3 and 4, during which delta waves are prominent.

REM Sleep

• REM (rapid eye movement) sleep is the fifth stage of sleep, marked by rapid eye movements and high-frequency brain waves.

• The REM stage is characterized by irregular breathing, pulse rate, minimal bodily movements, and muscle paralysis.

• Although REM is a relatively deep stage of sleep characterized by higher arousal thresholds, EEG activity is dominated by high-frequency brain waves.

• During REM sleep, researchers systematically awaken subjects that report they were dreaming.

Repeating the Cycle

• People repeat the sleep cycle about four times a night.
• REM periods get longer (40-60 minutes), NREM intervals get shorter, and descents into NREM stages become more shallow.
• Slow-wave sleep occurs early in the sleep cycle; REM sleep piles up in the second half.
• Young adults spend about 20% of their sleep time in slow-wave sleep and 20% in REM sleep.

Age, Culture, and Sleep

• Age alters the sleep cycle with trends including children display different patterns than adults.

• Newborns sleep six to eight times a day, up to 16 hours total and in the first few months of first year a long nighttime unified sleep cycle develops.

• Infants spend about 50% of their sleep time in REM sleep compared to the adults 20%.

• During the rest of the first year the REM sleep time in infants reduces to about 30%, and onto the average age during adolescence of 20% and similar trends are seen during adulthood.

• A large number of shifts to towards lighter sleep are seen amongst the elderly.

Cultural Variations

• Psychological and physiological experiences of sleep don't significantly vary across cultures.

The Evolutionary Bases of Sleep

• Sleep has considerable adaptive value.

• Theorists disagree about how precisely sleep is adaptive, but offer the following hypothesis:

  • Sleep evolved to conserve energy
  • Sleep helps avoid predators.
  • Sleep helps restore energy and bodily resources.

Doing Without: Sleep Deprivation

• Studies suggest that sleep deprivation is detrimental.

• More and more people squeeze additional waking hours, contributing to partial sleep deprivation.

• Sleep restriction impairs individuals' attention, reaction time, coordination, and decision-making and has a negative endocrine and immune system.

Drug Dependence

• Sleep deprivation can cause transportation accidents and mishaps in the workplace.

The World of Dreams

• Dreams have had a dramatic influence on history and culture.

The Nature and Contents of Dreams

• Most dreams are mundane.
• In dreams, people dream of sex, aggression, and misfortune which center on internal conflicts and what is going on in their lives.
• Freud suggestes that the contents of waking life may spill into dreams. He labeled this ‘day residue’.

Culture and Dreams

• Cultural beliefs about the nature and importance of dreams vary striking.
• People in cultures that take dreams more seriously show an increased remembrance of dreams.

Theories of Dreaming

• Sigmund Freud believes the purpose of dreams is wish fulfillment in which people satisfy ungratified needs in dreams and some theories have tried to modernize this.
• Other theorists propose dreams provide an opportunity to go through daily problems and there is considerable continuity between waking and sleeping thought.
• J. Allan Hobson and Robert McCarley argued that dreams are just by-product from subcortical bursting activities.

Hypnosis: Altered Consciousness or Role Playing?

• Hypnosis began with Franz Anton Mesmer in Paris and popularized later on by James Braid.
• Today it has led a curious dual existence.

Hypnotic Induction and Phenomena

• Hypnosis is a systematic procedure that produces a heightened state of suggestibility.

• Hypnotic phenomena includes:

  • Anesthesia
  • Sensory distortions and hallucinations
  • Disinhibition
  • Posthypnotic suggestions and amnesia

Theories of Hypnosis

• Most theories attribute hypnotic effects either to dramatic role-playing or to a special, altered state of consciousness (a trance).
• There is evidence that suggests that in hypnosis people are often acting in a role.

Hypnosis as an Altered State of Consciousness

• Other prominent theorists still maintain that hypnotic effects are attributable to a special, altered state of consciousness.

• It is doubtful playing a role can explain all hypnotic phenomena.

Meditation: Pure Consciousness or Relaxation?

• Meditation refers to a family of practices that train attention to heighten mental awareness.

• The most widely used approaches to meditation that are rooted in Eastern religions involve mental self discipline, that requires a deliberate effort to alter consciousness.

Altering Consciousness with Drugs

• Like hypnosis and meditation, drugs are commonly used in deliberate efforts to alter consciousness and involve moral, political, and legal issues that are not matters for science to resolve.

The factors influencing drug experiences

• Psychoactive drugs are chemical substances that modify mental, emotional, or behavioral functioning such as narcotics, sedatives, stimulants, hallucinogens, cannabis, and alcohol. Alcohol being legal has the most diverse negative effects. Depending on the drug, there are great fatal overdose risks. _