Transcript Introduction to Biological Psychology

Psychological Science,
Third Canadian Edition
Michael Gazzaniga
Todd Heatherton
Diane Halpern
Steven Heine
The Mind and
Consciousness
4
Questions to Consider:
How Is the Conscious Mind Experienced?
What Is Sleep?
What Is Altered Consciousness?
How Do Drugs Affect Consciousness?
How Is the Conscious Mind
Experienced?

Consciousness Is a Subjective Experience

There Are Variations in Conscious Experience

Splitting the Brain Splits the Conscious Mind

Unconscious Processing Influences Behaviour

Brain Activity Produces Consciousness
Learning Objectives
Define consciousness.
Summarize research findings on
the role played by the
interpreter in split-brain and
normal people.
Consciousness Is a Subjective
Experience

Subjectivity and “qualia”: each of us experiences
consciousness subjectively

We cannot know if any two people experience the world in
exactly the same way

Two components: the contents of consciousness
and level of consciousness

Access to information
One difficult question related to consciousness
is how people experience qualia, the
phenomenological percepts of the world. For
instance, does red look the same to everyone
who has normal colour vision?
Consciousness Is a Subjective
Experience

Brain imaging research has shown how particular
regions of the brain are activated by particular types
of sensory information

Miguel Nicolelis and his research on rhesus
monkeys

John Donoghue and BrainGate
There Are Variations in
Conscious Experience

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Consciousness and coma

The persistent vegetative state

Full consciousness

Between these two is the minimally vegetative state
Ethical issues surround the use of brain evidence for
end-of-life decisions
There Are Variations in
Conscious Experience

Conscious experience is a continuous stream
of thoughts that often floats from one thought
to another

Consciousness is a unified and coherent
experience—there is a limit to how many
things you can be conscious of at the same
time
Splitting the Brain Splits the
Conscious Mind

When you split the brain, do you split the
mind?

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
the corpus callosum connects the brain’s
hemispheres
severing the corpus callosum produces split
brain
Differences in right and left hemisphere
function
Splitting the Brain Splits the
Conscious Mind

Left hemisphere: dominant for language

Right hemisphere: dominant for spatial relationships

Splitting the brain splits the mind: the brain halves
contain independent perceptions, thoughts, and
consciousness

Gazzaniga: split-brain experiments and research
Splitting the Brain Splits the
Conscious Mind

The Interpreter: a left hemisphere process that
strives to make sense of events

Hemispheres work together to reconstruct
experiences

Split brain research: left hemisphere / right
hemisphere actions and explanations do not
correlate
Unconscious Processing
Influences Behaviour


The case for unconscious influence:

Priming effects

Subliminal perception

The “Freudian Slip”
The smart unconscious: research by Dijksterhuis
and Nordgren shows unconscious processing
valuable for complex decisions where pros and cons
are difficult to weigh
Brain Activity Produces
Consciousness
 “Blindsight”
 Global
Workspace Model
A central theme emerging from cognitive neuroscience is that awareness of
different aspects of the world is associated with functioning in different parts of the
brain.
What Is Sleep?

Sleep Is an Altered State of Consciousness

Sleep Is an Adaptive Behaviour

Sleep and Wakefulness Are Regulated by
Multiple Neural Mechanisms

People Dream while Sleeping
Learning Objectives
List and describe the stages of
sleep.
Explain why we sleep and dream.
Sleep Is an Altered State of
Consciousness


The difference between being awake and being
asleep has as much to do with conscious
experience as with biological processes.
Using an EEG, researchers have measured the
patterns of electrical brain activity during the
different stages of normal sleep:

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Stage 1 is characterized by theta waves
Stage 2 is characterized by k-complexes
Stages 3 and 4 are characterized by delta waves
REM sleep occurs after approximately 90 minutes of
sleep
Using an EEG, researchers measured these examples of the patterns of
electrical brain activity during different stages of normal sleep.
This chart illustrates the normal stages of sleep over the course of the night.
Sleep Is an Adaptive Behaviour

Researchers have proposed three general
explanations for sleep’s adaptiveness:

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Restoration
Circadian cycles
The facilitation of learning
Sleep Is an Adaptive Behaviour

Restoration: restorative theory suggests
sleep allows the brain and body to rest and
repair themselves

Sleep deprivation causes mood problems and a
decrease in cognitive performance

Microsleeps result from sleep deprivation
Sleep Is an Adaptive Behaviour

Circadian cycles: brain and other physiological
processes are regulated into patterns

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Body temperature
Hormone levels
Sleep/wake cycles
Sleep is an evolutionary adaptation to avoid
danger
Sleep Is an Adaptive Behaviour

The facilitation of learning: sleep is part of the
process of strengthening neural connections
that serve as the basis of learning

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Slow-wave sleep
REM sleep
Sleep and Wakefulness Are
Regulated by Multiple Neural
Mechanisms

Multiple neural mechanisms are involved in
producing and maintaining circadian rhythms of
sleep

A tiny structure in the brain called the pineal gland
secretes melatonin, a hormone that travels through
the bloodstream and affects various receptors in
both the body and the brain
The biological clock signals the
pineal gland to secrete
melatonin, which affects bodily
states related to being tired.
Sleep and Wakefulness Are
Regulated by Multiple Neural
Mechanisms

Researchers have identified a gene that
influences sleep, called SLEEPLESS

This gene regulates a protein that, like many
anaesthetics, reduces action potentials in the
brain
People Dream while Sleeping

Dreams occur in REM and non-REM
sleep, although the dreams’ contents differ
in the two types of sleep:
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REM sleep: bizarre, emotion-filled,
visual/auditory hallucinations, often
illogical
Non-REM sleep: dull, mundane content
and activities
People Dream while Sleeping
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What do dreams mean?
Freud: dreams have hidden content
that represent unconscious conflicts
Manifest content
 Latent content

People Dream while Sleeping
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What do dreams mean?

Alan Hobson: the activation-synthesis
hypothesis

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Random neural stimulation activates
mechanisms that normally interpret visual
input
The mind synthesizes activity in visual/motor
neurons with stored memories
People Dream while Sleeping

What do dreams mean?

Antti Revonsuo: evolved threat-rehearsal
strategies

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Dreams simulate threatening events to allow
people to rehearse coping strategies
Dreams are the result of evolution — providing
solutions to adaptive problems
What Is Altered Consciousness?

Hypnosis Is Induced through Suggestion
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Meditation Produces Relaxation
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People Can Lose Themselves in Activities
Learning Objective
Understand how different states
of consciousness influence
behaviour.
Hypnosis Is Induced through
Suggestion

Hypnosis involves a social interaction
during which a person, responding to
suggestions, experiences changes in
memory, perception, and/or voluntary
action

Psychological scientists generally agree
that hypnosis affects some people, but
they do not agree on whether it produces a
genuinely altered state of consciousness
Hypnosis Is Induced through
Suggestion

Theories of hypnosis:

Sociocognitive theory of hypnosis: hypnotized
people behave as they expect hypnotized
people to behave

Dissociation theory of hypnosis: the hypnotic
state is an altered, trance-like state where
conscious awareness is dissociated from other
aspects of consciousness
This PET image from one of Stephen Kosslyn’s studies shows that areas in the
visual cortex associated with colour perception are activated more when
hypnotized participants are told to imagine colour—a finding that suggests the
brain follows hypnotic suggestions.
Hypnosis Is Induced through
Suggestion

Hypnosis for pain:

Hypnotic analgesia is pain reduction through
hypnosis

Effective for immediate and chronic pain

Self-hypnosis for post-surgical pain
Meditation Produces Relaxation

Meditation is a mental procedure that focuses
attention on an external object or on a sense of
awareness

Through intense contemplation, the meditator
develops a deep sense of calm tranquility
 Concentrative meditation
 Mindfulness meditation
People Can Lose Themselves in
Actvities

A person’s level of conscious awareness
changes as a result of the time of day as well
as the person’s activities

Exercise (runner’s high), religious prayer
(ecstasy), and flow are areas where levels of
conscious awareness shift or change
How Do Drugs Affect
Consciousness?

People Use—and Abuse—Many
Psychoactive Drugs

Alcohol Is the Most Widely Abused Drug

Addiction Has Psychological and Physical
Aspects
Learning Objective
Describe the effects of
marijuana, of stimulants, of
MDMA, and of opiates.
People Use—and Abuse—Many
Psychoactive Drugs

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Many of the same psychoactive drugs
used for medical treatment are also used
for “recreational” purposes
Drug use alters physical sensations, levels
of consciousness, thoughts, moods, and
behaviours in ways that users believe are
desirable
Recreational drug use sometimes can
have negative consequences
People Use—and Abuse—Many
Psychoactive Drugs

Marijuana

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Most widely used illegal drug
THC (tetrahydrocannibinol) produces relaxed
mental state, uplifted/contented mood, and
perceptual/cognitive distortions
Concentration of cannabinoid receptors in the
hippocampus (memory impairment)
Medicinal properties are controversial
People Use—and Abuse—Many
Psychoactive Drugs

Stimulants

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Activate sympathetic nervous system (increased
heart rate and blood pressure)
Improve mood
Cause restlessness and disrupt sleep
Cocaine
Amphetamines (speed, meth, etc.) block reuptake
and increase release of dopamine
People Use—and Abuse—Many
Psychoactive Drugs

MDMA
 Known commonly as “ecstasy”
 Similar effects as stimulants, with slight hallucinations
 Less dopamine release, more serotonin release

Opiates
 Heroin, morphine, codeine
 Increased dopamine activation in the nucleus
accumbens, binding with opiate receptors
 Highly addictive due to dual activation of dopamine and
opiate receptors
Alcohol Is the Most Widely
Abused Drug

Canadians have a love/hate relationship with
alcohol

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On the one hand, moderate drinking is an
accepted aspect of normal social interaction and
may even be good for health
On the other hand, alcohol is a major contributor
to many of our societal problems, such as spousal
abuse and other forms of violence
Alcohol Is the Most Widely
Abused Drug
Gender Differences in Alcohol Consumption
across Cultures
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Men twice as likely to report binge drinking,
chronic drinking, recent alcohol intoxication
Four key factors:
1.
2.
3.
4.
Power
Sex
Risks
Responsibilities
Alcohol Is the Most Widely
Abused Drug
Expectations

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Alcohol reduces anxiety
Alcohol increases social skills, sexual pleasure,
confidence, power
Reality
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Large doses of alcohol result in negative moods and
focus on problems and anxieties
Alcohol impairs motor processes, information
processing, mood, sexual performance
Learned beliefs about intoxication influence behaviour
Addiction Has Psychological
and Physical Aspects

Addiction is a physiological state in which failing to
ingest a substance leads to symptoms of
withdrawal, a state characterized by anxiety,
tension, and craving

Physical dependence is associated with tolerance,
so that a person needs to consume more of the
substance to achieve the same subjective effect

Dopamine activity in the limbic system is central to
addiction and rewarding properties of drugs
Addiction Has Psychological
and Physical Aspects

Psychological dependence refers to habitual and
compulsive substance use despite the
consequences

People can be psychologically dependent without
showing tolerance or withdrawal

Individuals can be psychologically dependent on
behaviours like gambling or shopping