Chapter 4 Summary

Understanding Consciousness

• Definition: Consciousness can be defined as a state of being aware of oneself, one's thoughts, and the environment.

• Components: Aspects to consider include:

  • Content of Consciousness: What is held within and outside our awareness.

  • States of Consciousness: Includes both conscious experiences (e.g., being awake) and unconscious experiences (e.g., being under anesthesia).

Automatic Processing

• Our sensory systems process large amounts of information without our awareness.

• The brain filters this information to determine importance, immediate attention, and future relevance for storage.

Selective Attention

• Definition: The ability to focus on a limited portion of available information.

• Our attention is typically directed towards:

  • Sudden and unexpected changes in the environment.

  • Unfamiliar, rewarding, or strong stimuli.

Circadian Rhythm and Sleep

• Definition: Predictable daily patterns influencing behaviors, alertness, and activity.

• Cycle: Circadian rhythms follow a 24-hour cycle based on daylight and darkness.

• Sleep Patterns: Strongest desire for sleep occurs:

  • Early Morning: Between 2:00 AM and 6:00 AM.

  • Afternoon: Around 2:00 PM to 3:00 PM.

Stages of Sleep

• Sleep is categorized into Non-Rapid Eye Movement (Non-REM) and Rapid Eye Movement (REM).

  • Non-REM Stages:

    • Stage N1: Lightest sleep, lasts a few minutes; may involve imaginary sensations.

    • Stage N2: More difficult to awaken; leads to deeper stages.

    • Stage N3: Known as slow-wave sleep; the deepest stage of non-REM sleep.

  • REM Sleep: Characterized by closed eyes moving rapidly and altered brain activity; often associated with vivid dreams.

• Cycle Duration: One complete cycle (N1 to REM) lasts about 90 minutes; adults experience approximately five cycles per night.

Sleep Disorders

• Narcolepsy: Excessive daytime sleepiness with disturbances.

• REM Sleep Behavior Disorder: Individuals act out dreams due to failure in REM paralysis.

• Obstructive Sleep Apnea Hypopnea: Blocked breathing during non-REM sleep.

• Insomnia: Difficulty falling or staying asleep, leading to poor sleep quality.

Theories of Dreaming

• Freud's Theory: Dreams consist of:

  • Manifest Content: The storyline of dreams.

  • Latent Content: Hidden meanings linked to unconscious conflicts.

• Activation Synthesis Model: Dreams are responses to random neural activity without inherent meaning.

• Neurocognitive Theory: Dreaming results from cognitive processes similar to waking thought.

Psychoactive Drugs

• Effects: Alter psychological activities such as sensation, perception, and emotion.

  • Can depress CNS activity (e.g., barbiturates, opioids, alcohol) or increase it (e.g., cocaine, methamphetamine, caffeine).

Dependence on Drugs

• Physiological Dependence: Development of tolerance and withdrawal symptoms.

• Psychological Dependence: Craving for the drug due to perceived emotional benefits rather than physical needs.

Hypnosis

• Definition: An altered state of consciousness induced by suggestions from a hypnotist.

• Effects: Can change perceptions and behaviors, often utilized for pain management.