• Consciousness – our moment to moment awareness of ourselves and our environment
    • Has various characteristics:
      • Subjective and Private – reality and experience depend on the individual
      • Dynamic – consciousness experiences are ever-changing and a continuous flow of mental activity
      • Self-reflective and Central to Our Sense of Self – mind is aware of its own consciousness

Levels of Consciousness

  • Freud proposed that the mind consists of three levels:
    • Conscious – contains thoughts, perceptions, and other mental events that we are aware of
    • Preconscious – outside of current awareness, but can be recalled under certain conditions (eg. Reminder is necessary)
    • Unconscious – cannot be brought into conscious awareness under ordinary circumstances (as it would arouse anxiety, guilt, or other negative emotions)
  • The Cognitive Unconscious
    • Reject notion of an unconscious mind driven by instinctive urges and repressed conflicts
    • View conscious mental life as complementary forms of information processing
    • Controlled vs. Automatic Processing
      • Controlled – voluntary use of attention and conscious effort (studying, planning, etc.)
      • Automatic – performed with little or no conscious effort (driving, etc.)
    • Divided Attention – ability to perform more than one activity at the same time
      • More difficult when tasks require similar mental resources
  • The Emotional Unconscious
    • Emotional and motivational processes also operate unconsciously and influence behaviour
  • The Modular Mind
    • Many models propose that the mind is a collection of largely separate but interacting modules
    • Information processing subsystems that perform tasks related to sensation, perception, memory, problem solving, etc.
    • Subjective experience of consciousness arises from the integrated activity of the various modules

Circadian Rhythms: Our Daily Biological Clocks

  • Circadian rhythms – daily biological cycles within the body that occur on a 24 hour cycle
  • Most rhythms regulated by brain’s suprachiasmatic nuclei (SCN) in the hypothalamus
    • Linked to pineal gland, which secretes melatonin (relaxing hormone) at night when SNC is less active to reduce secretion
  • Gradual and sudden environmental changes can disrupt our circadian rhythms
    • Seasonal affective disorder – cyclic tendency to become psychologically depressed during certain months of the year
    • Jet lag caused by change in typical daily time cycle

Sleep and Dreaming

  • Brain’s electrical activity mostly beta waves (high frequency, low amplitude) while awake
  • Alpha waves (lower frequency, slightly higher amplitude) while relaxed and frowsy

Stages of Sleep

  • Stages 1 through 4
    • Stage 1 – alpha waves turn into theta waves
      • Lasts a few minutes, can be easily awakened
    • Stage 2 – sleep spindles in brain-wave activity indicate transition to stage
    • Stage 3 – regular appearance of slow and large delta waves
    • Stage 4 – delta waves dominate brain wave activity
  • Within 60-90 minutes of falling asleep, stages proceed through 1-2-3-4-3-2
  • REM sleep – periods of sleep involving rapid eye movements
    • Periods of REM comes following stage 2 sleep
    • Period where dream occurs
      • Dreams can occur during non-REM sleep, but not as vivid
    • REM sleep paralysis – brain sends signals to make voluntary muscle movements more difficult
      • Body is highly aroused, but little or no muscle movement

How Much Do We Sleep

  • Newborns began by sleeping 16 hours a day, almost half in REM
  • As people age, three important changes occur:
    • Sleep less (19-30 year olds: 8 hours average, elderly: under 6 hours average)
    • REM sleep dramatically decreases during early childhood, but remains stable afterwards
    • Time spent in stages 3 and 4 decline
  • Both genetics and environment can affect length of sleep
  • Sleep deprivation causes negative impact on functioning, mood, cognition, and physical performance

Why Do We Sleep

  • Restoration model – sleep recharges our run-down bodies and allows us to recover from physical and mental fatigue
    • Researchers believe adenosine (decreases alertness, promotes sleep) may play a role in why we sleep
  • Evolutionary/circadian sleep models – sleep’s main purpose is to increase a species’ chances of survival in relation to its environmental demands
    • Those who left shelter at night would be killed by nighttime predators
    • Circadian pattern developed as adaptation to environment
  • REM sleep is vital for mental functioning
    • Memory consolidation – ability to transform short-term memory into long-term memory
      • REM may strengthen neural circuits required for this process

Sleep Disorders

  • Insomnia – chronic difficulty in falling asleep, staying asleep, or experiencing restful sleep
    • Most common sleep disorder
    • Caused by genetics, medical conditions, mental disorders, drugs, stress, poor lifestyle, and circadian disruptions
  • Narcolepsy – extreme daytime sleepiness and sudden, uncontrollable sleep attacks that may last from one minute to one hour
    • Narcoleptics may go right into REM sleep
  • REM Sleep Behaviour Disorder – loss of muscle tone that causes normal REM sleep paralysis is absent
  • Sleep Apnea – disorder characterized by a repeated cycle in which the sleeper stops breathing, momentarily awakens, and then returns to sleep
    • Caused by an obstruction in the upper airways
  • Sleepwalking – typically occurs during stage 3 or 4 sleep
  • Nightmares – frightening dreams that occur often during REM sleep in the hours prior to awakening
  • Night Terrors – sleeper suddenly sits up and screams
    • No recollection of the episode in the morning
    • Most common during stage 3 or 4 sleep

The Nature of Dreams

  • Dreams most common when brain is most active (brain activity highest during REM sleep, and during final hours of sleep)
  • Freud’s psychoanalytic theory
    • Main purpose of dreaming is wish fulfillment (gratification of unconscious desires and needs)
      • Desires are too unacceptable to be consciously acknowledged and fulfilled in real life
    • Manifest content – story the dreamer reports
    • Latent content – the disguised psychological meaning
    • Dream work is the process by which the latent content is transformed into the manifest content
  • Activation-synthesis theory
    • During REM sleep, the brain bombards higher brain centers with random neural activity (activation)
    • Cortex attempts to interpret activity by creating a best fit to the pattern of activation (synthesis)
    • Accounts for the bizarreness of dreams
  • Cognitive approaches
    • Problem-solving dream models – dreams can help us find creative solutions to our problems and conflicts because they aren’t constrained by reality
    • Cognitive-process dream theories – focus on the process of how we dream
      • Propose that dreaming and waking thought are produced by same brain systems
      • Dreaming requires imagery skills and other cognitive abilities that young children have not yet developed
        • Explains why ability to dream develops with age
      • Similar activity between dreaming and waking mental activity
        • Rapid content shifts due to change of thought

Daydreams and Waking Fantasies

  • Involved greater visual imagery than other forms of waking mental activity
  • Less vivid, emotional, and bizarre than nighttime dreams

Drugs and Altered Consciousness

Drugs and the Brain

  • Drugs can pass through the blood-brain barrier and alter consciousness by facilitating or inhabiting synaptic transmission
  • Agonist – drug that increases that activity of a neurotransmitter
    • Activates receptor, enhances production/storage/release, prevents reuptake.
    • Examples:
      • Opiates (pain relievers) – activate endorphin receptors
      • Amphetamines (stimulants) – enhance production and prevent reuptake of dopamine and norepinephrine
  • Antagonist – drug that inhibits or decreases the activity of neurotransmitters
    • Many bind to receptors, but do not affect neuron

Tolerance and Withdrawal

  • Tolerance – the decreasing responsivity to a drug
    • Larger doses required to reach same effects
    • Stems from body’s attempt to maintain a state of optimal physiological balance (homeostasis)
    • Brain produces compensatory reactions to oppose effects of drug (e.g. decrease heart rate)
  • Withdrawal – occurrence of compensatory responses after drug use is discontinued, causing the person to experience physiological reactions opposite to those that had been produced by the drug

Learning, Drug Tolerance, and Overdose

  • Tolerance for drugs partly depends on the familiarity of the drug setting
    • Continued drug use in same setting causes progressively stronger compensatory responses, increasing the tolerance
    • Classically conditions drug users to have compensatory responses while in drug setting, causing withdrawal, and increasing craving for drug
  • If drug user takes typical high dose in unfamiliar setting, compensatory responses don’t respond as strongly à leads to overdose

Facts about Drug Addiction and Dependence

  • Drug tolerance does not always lead to significant withdrawal at typical doses
  • Substance dependence can occur even without tolerance or withdrawal
  • Physiological dependence is not the major cause of drug addiction


  • Decrease nervous system activity
  • Alcohol – most widely used recreational drug in numerous countries
    • Increases activity of gamma-aminobutyric acid (GABA)
    • Alcohol myopia – shortsightedness in thinking caused by inability to pay attention
  • Barbiturates (sleeping pills) and Tranquilizers (anti-anxiety drugs) – used as sedatives and relaxants
    • Depress the nervous system by increasing activity of inhibitory neurotransmitters


  • Increase neural firing and arouse the nervous system
  • Amphetamines – increase dopamine and norepinephrine activity
    • Amphetamine psychosis – schizophrenia-like hallucinations and delusions that occur when the brain’s dopamine activity is artificially increased far beyond normal levels by heavy amphetamine use
    • Ecstasy primarily alters serotonin functioning by causing release and blocking reuptake of it
  • Cocaine – increases activity of norepinephrine and dopamine by blocking reuptake

Other Drugs

  • Opiates (morphine, codeine, heroin) are drugs derived from opium
    • Bind to and stimulate receptors normally activated by endorphins
    • Relieve pain and cause intense euphoria
  • Hallucinogens (LSD) – powerful mind altering drugs that produce hallucinations
  • Marijuana – THC binds to receptors on neurons throughout the brain


  • Hypnosis – state of heightened suggestibility in which some people are able to experience imagined test suggestions as if they were real
  • Hypnotic induction – process by which one person leads another person into hypnosis

Hypnotic Behaviours and Experiences

  • Involuntary Control and Behaving against One’s Will
    • Behaviour seems involuntary
    • Studies show that those pretending to be hypnotized will commit same actions that those truly hypnotized will
  • Physiological Effects and Physical Feats
    • Hypnotized people with allergies can be exposed to certain allergens and, if told that it is harmless, most will not have an allergy
    • Can also be seen without hypnosis
  • Pain Tolerance
    • Hypnosis can act as an anesthetic, producing analgesia (an absence of pain)
  • Hypnosis and Memory
    • Hypnotic amnesia can be temporarily produced

Theories of Hypnosis

  • Dissociation Theories
    • Hypnosis viewed as an altered state involving a division of consciousness
    • Person simultaneously experiences two streams of consciousness that are cut off from one another:
      • One stream responds to hypnotist’s questions
      • Second stream (part of consciousness that monitors behaviour) remains in the background but is aware of everything
  • Social Cognitive Theories
    • Hypnotic experiences result from expectations of people who are motivated to take on the role of being hypnotized
    • People motivated to conform to the role of a hypnotized person develop a readiness to respond to the suggestions and to perceive the hypnosis as real and involuntary
author avatar
William Anderson (Schoolworkhelper Editorial Team)
William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

1 Comment

  1. Cylert (generic: Pemoline) was an exceptionally effective treatment for Excessive Daytime Sleepiness. I used it daily for many years. Unfortunately, it’s no longer on the market.

    Quite by accident, I came across a non-prescription compound which is the only Cylert substitute I’ve found that works for sufferers of Excessive Daytime Sleepiness and, possibly, other narcolepsy symptoms.

    Unlike Cylert, it’s not a stimulant. But it does alleviate the symptoms of EDS without any side effects.

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