PSYC 100: Chapter 4 09/22/2013
Chapter 4: The Mind and Consciousness
HOW IS THE CONSCIOUS MIND EXPERIENCED?
The conscious mind is difficult to study scientifically.
Conscious vs. unconscious is easy to determine, while the state of being conscious (neural activity in the
brain giving rise to our subjective experience of the world) is not.
Contents of consciousness: what we are conscious of.
Level of consciousness: coma, sleep, wakefulness.
What is conscious? Choosing a shirt to wear vs. scratching an itch.
Consciousness = awareness.
Dualism: the mind is distinctive from the brain.
The view that the mind and body are separate yet intertwined
Dualism is no longer scientifically rejected (they are seen as inseparable).
The activity of neurons produce the contents of conciousness
Natural variation (e.g. Sleep), natural manipulation (e.g. Meditation), artificial manipulation (e.g. alcohol).
Consciousness is a subjective experience
We can’t know if people experience the world in the same way (colours, tastes, smells, etc.)
Qualia: the properties of our subjective experiences.
Scientists cannot ‘read your mind’ by looking at brain activity, but can determine which object you are
looking at by studying the brain activity.
Brain imaging such FMRI can determine what type of image you are looking at
Different types of sensory information are processed by different areas of the brain. There are variations in conscious experience
Your level of consciousness varies naturally throughout the day in your sleep/wake cycle.
It can also be affected by actions, and substances.
Conscious thought is a unified and coherent experience – but there is a limit (multitasking).
In general, we can execute routine or automatic tasks (driving, walking, catching, etc.) that are so well
learned that we can do them without much conscious effort.Automatic processing.
Difficult or unfamiliar tasks require greater conscious effort (e.g. driving during a storm).Controlled
Consciousness and Coma
Serious brain injuries lead to comas.
Some comas last days, while others last weeks or even longer.
In this state, the person still experiences a sleep/wake cycle (open/close eyes) but are unable to respond to
Evidence indicates that the brain can process information during this state.
If the coma is longer than a month, it is considered a persistent vegetative state. The longer this lasts, the
less likely the person will recover.
Between the vegetative state and full consciousness is the minimally conscious state: deliberate
movements (can follow objects with eyes, attempt communication, etc.).
Splitting the brain splits the conscious mind
Studying people who have undergone brain surgery to treat disorders has given researchers a better
understanding of the conscious mind.
Epilepsy patients have undergone surgery to remove the part of the brain where the seizure originates,
causing the seizures to end.
Other times, brain connections have been cut to isolate the area. If the epilepsy doesn’t respond to
medication, sometimes the corpus callosum will be cut, separating the brain into the two hemispheres
causing a condition called split brain.
It was thought that splitting the brain might split the mind, but the patients seemed very normal.
Gazzinga and Sperry performed tests on splitbrain participants and concluded that just as the brain had
been split in two, the mind had, too.
The left side of the brain controls speech and the right side of the body.
The right side of the brain controls spatial relationships. Two pictures were shown, one to the right eye and one to the left eye. When asked, the
participants could only talk about the picture on the right, even though they saw both
pictures. They could vocalize/pick up what the picture on the right was with their left
hand, but their right brain (which controls the left side of the body) did not know what
their left brain had seen.
A left hemisphere process that attempts to make sense of events.
In a similar experiment, two pictures were flashed (a chicken claw to the right eye/left
hemisphere, and a snowcovered house to the left eye/right hemisphere) and the
participants were asked to point to related pictures (the right hand/left hemisphere would
point to a chicken, and the left hand/right hemisphere would point to a shovel). When
asked to explain why they picked the related pictures, the reasoning was that the
chicken claw belonged to a chicken and the shovel was related because you need a
shovel to clean out the chicken shed. (Remember, the left hemisphere controls speech
and did not know what the right hemisphere saw).
The left hemisphere attempts to make sense of the actions conducted by the right
hemisphere after the action has been performed
The Interpreter Speculates
The interpreter strongly influences the way we view and remember the world
The left brain tends to “compress” its experiences into a comprehensible story and to reconstruct
remembered details based on the gist of that story.
The right brain seems to simply experience the world and remember things in a manner less distorted by
The interpreter sometimes makes life difficult for us in that it attempts to look for patterns where there are
Unconscious processing influences behaviour
Subliminal perception: information processed without conscious awareness.
Subliminal messages have very little influence on complex actions, such as buying something, but do have
an effect on simple actions.
Freudian slip: when an unconscious thought is suddenly expressed at an inappropriate time and/or in an
inappropriate social context.
Much of our behaviour occurs without or awareness or intention.
The Smart Unconscious Participants were given two options. One was clearly the better choice. Some people were given time to
consciously think about a decision while others were made to choose immediately.Those who had
unconscious thought made the best decisions.
Consciously reflecting on somethingcan impair performance.
Consciously thinking about something can undermine good decisions, known as verbal overshadowing, the
main message is that we are not very good at describing perceptual experiences and when we are forced
to do so it alters our memories;thinking toomuch can impair judgment and memory
Brain activity produces consciousness
During the past few decades, researchers have worked to identify the brain regions most important in
different forms of awareness.
By studying awareness in individuals with damage to specific regions of the brain researchers hope to link
selective losses of awareness to the damaged brain areas.
o A condition in which people who are blind have some spared visual capacities in the
absence of any visual awareness. They experience some visual stimulation but are
unaware of it.
The global workspace model suggests that consciousness arises as a function of which brain circuits are
active. You experience your brain regions’ output as conscious awareness.
If you experience damage to the eye and suffer from vision loss, you would be aware of this. However, if
you experience damage to the brain’s visual areas so that they stop delivering output, you might not notice
a gap in visual experience, though.
WHAT IS SLEEP?
Many brain regions are more active during sleep than during wakefulness.
It is even possible that some complex thinking, such as working on difficult problems, occurs in the sleeping
Most researchers believe sleep serves some important (but so far unknown) biological purpose.
Sleep is an altered state of consciousness
When you are asleep, you are not conscious, but your brain still processes information and, to some extent,
remains aware of your environment.
Invented in the 1920’s, the electroencephalograph (EEG), a machine that measures the brain’s electrical
activity, revealed that a lot goes on in the brain during sleep.
When people are awake, their brains’ neurons are extremely active, as evidenced by short, frequent,
desynchronized brain signals known as beta waves. When people close their eyes and relax, brain activity slows and becomes more synchronized, a pattern
that produces alpha waves.
Stages of Sleep
Evidenced by changes in EEG readings.
Alert wakefulness: Beta waves
Just before sleep: Alpha waves
Stage 1: theta waves, aroused easily, sensation of falling, jerking limbs, very light sleep.
Stage 2: breathing becomes more regular, less sensitive to external stimulation, theta waves but also bursts
of activity called kcomplexes and sleep spindles.
Stage 3 and 4: delta waves, slowwave sleep, hard to wake them up, disoriented if woken up.
After about 90 minutes of sleep, the sleep cycle reverses, returning to stage 3 and then stage 2.
At this point, there is a flurry of beta waves (this would usually indicate an awake and alert mind during the
‘alert wakefulness’ stage). The eyes dart back and forth rapidly beneath eyelids (Rapid Eye Movement =
Sometimes called paradoxical sleep because of the paradox of a sleeping body but active mind.
While the brain is active during REM sleep, most of the body’s muscles are paralyzed. However,
sometimes the body shows signs of genital arousal.
About 80% of the time people awake during REM, they recall dreaming, compared to less than half who
awaken during nonREM sleep.
As morning approaches, the sleep cycle shortens and the sleeper spends more time in REM sleep.
About half the population reports difficulty getting to sleep or staying asleep.
Insomnia is a sleep disorder in which people’s mental health and ability to function are compromised by
their inability to sleep.
Chronic insomnia is associated with diminished psychological wellbeing, including feelings of depression.
Pseudoinsomnia is when people dream they are not sleeping, their EEG indicate that they are sleeping but
they would claim to have been awake if you woke them
Sleep apnea is a disorder in which a person stops breathing while asleep.
Narcolepsy is a sleep disorder in which people fall asleep during normal waking hours (muscle paralysis
during REM sleep may occur and cause the person to go limp or collapse).
Narcolepsy is believed to be a genetic condition that affects the neural transmission of a specific
neurotransmitter in the hypothalamus.
REM behaviour disorder is when the muscle paralysis does not occur and people act out their dreams.
Sleepwalking (somnambulism), which is relatively common, occurs during Stage 4 of sleep.
Sleep is an adaptive behaviour Sleep must do something important, but the biological purpose is unknown.
Restoration and Sleep Deprivation
Restorative theory: sleep allows the body and brain to rest and repair themselves.
Growth hormone is released during sleep to repair damaged tissue.
Short term sleep deprivation does not seem to have an effect on physical performance.
Cognitive performance was affected: very difficult to complete quiet, boring or mundane tasks.
Over time, sleep deprivation causes mood problems, decreased cognitive performance, attention lapses
and reduced shortterm memory.
Increases the likelihood of microsleeps (brief, unintended sleep episodes, ranging from a few seconds to a
However, it has been shown that sleep deprivation can help people overcome depression due to increased
activation of serotonin receptors.
The regulation of biological cycles into regular patterns (circadian = day).
The circadian rhythm theory suggests that sleep has evolved to keep animals quiet and inactive during
times of the day when there is greatest danger (dark).
Humans depend greatly on vision for survival, and they adapted to sleeping at night because the lack of
light increased the dangers around them.
Facilitation of Learning
Proposes that sleep is important because it is involved in the strengthening of neural connections that serve
as the basis of learning.
Circuits wired together during the