David Meyers Psychology Textbook - Chapter 3: Consciousness and The Two-Track Mind

Basic Consciousness Concepts

Defining Consciousness

  • Consciousness: our subjective awareness of ourselves and our environment
    • allows us to reflect on, assemble, and plan info
    • focuses attention when learning complex concepts/behaviors
  • we flit between different states of consciousness
    • spontaneously when we daydream, dream, or are drowsy
    • physiologically when we have hallucinations, are oxygen/food starved, or orgasm
    • psychologically when we go under hypnosis, meditation, sensory deprivation

Studying Consciousness

  • scientists are still figuring out what consciousness is and how it works
  • cognitive neuroscience: interdisciplinary study of brain activity linked with cognition (perception, thinking, memory, language)
  • stronger stimuli leads to more perceived awareness
  • “how matter makes mind” still remains a mystery

Selective Attention

  • selective attention: the focusing of conscious awareness on a particular stimulus
  • things we deem important capture our limited attention
  • texting, calling, and having a conversation while driving all decrease focused attention and can lead to accidents
  • inattentional blindness: failing to see visible objects when our attention is directed elsewhere
  • attention is powerfully selective, the conscious mind can only be in one place at a time (w rapid switching)
  • change deafness can also occur, participants failed to notice a change in the person speaking in an experiment
  • certain stimuli pop out, where change in stimuli are so powerful it’s impossible, basically, for the brain not to notice
    • ex: when someone calls your name

Dual Processing: The Two-Track Mind

  • conscious and unconscious information processed at the same time, alluding to two different mind processes occurring
  • researchers conclude that most of the brain’s work and processing is unconscious, “off stage, out of sight”
  • dual processing: the principle that info is often simultaneously processed on separate conscious and unconscious tracks
  • human brain is a device for converting conscious into unconscious knowledge
  • blindsight: a condition in which a person can respond to a visual stimulus without consciously experiencing it
    • ex: moving around a chair or obstacle on the ground without realizing, happens almost automatically
    • ex: visual perception track vs visual action track
  • brain can make decisions before being conscious of it
  • parallel processing: processing many aspects of a problem simultaneously; generally used to process well-learned info
  • sequential processing: processing one aspect of a problem at a time; generally used to process new info and difficult problems

Sleep and Dreams

  • sleep: a periodic, natural loss of consciousness, as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation
  • while sleeping, our unconscious body and auditory cortex can still be aware of sensations and sounds

Biological Rhythms and Sleep

  • circadian rhythm: our biological clock; regular bodily rhythms (ex: temp and wakefulness) that occur on a 24 hour cycle
  • younger people tend to feel more productive at night and their biological “clocks” send melatonin later in the night, while those who are older often feel energized earlier in the day
  • a sleep cycle goes through distinct sleep stages, each around 90 minutes long
REM Sleep
  • REM sleep: rapid eye movement sleep; a recurring sleep stage during which vivd dreams commonly occur, aka paradoxical sleep, where muscles are relaxed but brain systems are active
  • alpha waves: the relatively slow brain waves of a relaxed, awake state (between sleep and awareness)
  • can experience hallucinations or sensory experiences when falling asleep, ex: “hypnagogic jerk”
  • hallucinations: false sensory experiences, such as seeing something in the absence of external visual stimulus
  • during REM sleep the brain’s motor cortex is active, but the brainstem blocks its messages to the muscles and body to prevent you from acting out your dreams
  • sleep paralysis can occur if you wake from REM sleep but are still unable to move
  • most people can’t remember their dreams, but the average person spends 25% of the night dreaming in REM sleep
Deep Sleep & Patterns
  • delta waves: the large, slow brain waves associated with deep sleep
  • sleep patterns vary depending on the person
    • ex: newborns sleep 2/3 of the day
    • ex: adolescent’s brains produce less melatonin, usually going to bed later at night, often getting too little sleep
  • suprachiasmatic nucleus (SCN): a pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, the SCN causes the pineal gland to adjust melatonin production, modifying feelings of sleepiness

Why Do We Sleep?

  • sleep protects, keeps people safe when its dark (evolutionary advantage)
  • sleep helps us recuperate, restores brain tissues, boosts the immune system, and gives time for the brain to recharge
  • sleep helps restore and rebuild our fading memories of the day’s experiences, consolidating info and strengthening long-term memories, getting rid of unnecessary info
  • sleep feeds creative thinking, gives boost to thinking and learning, finding connections and problem-solving
  • sleep supports growth, pituitary gland releases growth hormones during sleep, helps athletic performance

Sleep Deprivation and Sleep Disorders

  • brain gathers “sleep debt” after not getting enough sleep successive nights in a row
  • getting enough sleep leaves us refreshed, in better moods, and able to perform more efficiently and accurately
  • high school and college students are one of the biggest populations who are chronically sleep deprived
  • sleep depravation leaves us with difficulty studying, diminished productivity, irritability, and fatigue
  • sleep depravation can lead to weight gain and increased hunger
  • more at risk to catch a cold or unable to recover from sickness when sleep deprived
  • attention and reaction times decrease with less sleep
Sleep Disorders
  • insomnia: recurring problems in falling or staying asleep
  • narcolepsy: a sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times
  • sleep apnea: a sleep disorder characterized by temporary cessations of breathing during sleep and repeated awakenings throughout the night
  • night terrors: a sleep disorder characterized by high arousal and an appearance of being terrified; unlike nightmares, night terrors occur during NREM-3 sleep, usually within 2-3 hours of falling asleep, and are seldom remembered

Dreams

  • dream: a sequence of images, emotions, and thoughts passing through a sleeping person’s mind
  • dreams in REM sleep are often vivd, emotional, and bizarre
  • sensory stimuli can be woven into dreams, due to a mind that rationalizes
    • ex: phone ringing, cold air, water splashed on face, etc.
  • manifest content: according to Freud, the remembered story line of a dream (distinct from latent, or hidden, content)
  • latent content: according to Freud, the underlying meaning of a dream (as distinct from its manifest content)
  • many modern scientists agree dreams are nonsensical, and can be symbolic or interpreted uniquely depending on each person
Possible Purposes of Dreams
  • dreams function to file away memories, store, practice, remember, and fix info from the previous day
  • dreams help develop and preserve neural pathways
  • dreams help make sense of random neural static, brain’s attempt to synthesize random neural activity (aka activation-synthesis theory)
  • dreams also help reflect cognitive development
  • REM rebound: the tendency for REM sleep to increase following REM sleep deprivation

Drugs and Consciousness

Tolerance and Addiction in Substance Use Disorders

  • psychoactive drugs: chemical substances that alter mood and perception, often take effect immediately
  • drugs can lead to substance abuse disorder when drug use continues despite significant life disruption

Types of Psychoactive Drugs

  • includes three major categories, depressants, stimulants, and hallucinogens
Depressants
  • depressants: drugs (such as alcohol, barbiturates, and opiates) that reduce neural activity and slow body functions
  • the urges you feel when sober are the ones you will more likely act upon when intoxicated, leads to reduced inhibition
  • alcohol use disorder: (popularly known as alcoholism) alcohol use marked by tolerance, withdrawal, and a drive to continue problematic use
  • extreme brain shrinkage can happen as a result of alcoholism, women are especially susceptible to this
  • alcohol in the body results in slowed neural processing, memory disruption, reduced self-awareness and self-control, and expectancy effects
  • barbiturates: drugs that depress the central nervous system activity, reducing anxiety but impairing memory and judgement
  • opiates: opium and its derivatives, such as morphine and heroin; depress neural activity, temporary lessening pain and anxiety
Stimulants
  • stimulants: drugs (such as caffeine, nicotine, and the more powerful cocaine, amphetamines, methamphetamine, and Ecstasy) that excite neural activity and speed up body functions
  • stimulants can cause heart and breathing rates to increase, blood sugar levels to rise, a drop in appetite, and a rise in energy and self-confidence
  • nicotine: a stimulating and highly addictive psychoactive drug in tobacco
  • nicotine leads to high death tolls, risk of developing lung cancer, heart disease, emphysema, and other serious diseases
  • cocaine: a powerful and addictive stimulant derived from the coca plant; produces temporarily increased alertness and euphoria
  • cocaine can lead to emotional disturbances, suspiciousness, convulsions, cardiac arrest, or respiratory failure
  • amphetamines: drugs that stimulate neural activity, causing accelerated body functions and associated energy and mood changes
  • methamphetamine: a powerfully addictive drug that stimulates the central nervous system, with accelerated body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels
  • Ecstasy (MDMA): a synthetic stimulant and mild hallucinogen. Produces euphoria and social intimacy, but with short-term health risk and longer-term harm to serotonin-producing neurons and to mood and cognition
Hallucinogens
  • hallucinogens: psychedelic (“mind manifesting”) drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input
  • near-death experience: an altered state of consciousness reported after a close brush with death (such as cardiac arrest); often similar to drug-induced hallucinations
  • LSD: a powerful hallucinogenic drug; also know as acid (lysergic acid diethylamide)
  • THC: the major active ingredient in marijuana; triggers a variety of effects, including mild hallucinations