constinta Flashcards
what is consciousness
the normal mental condition of the waking state of humans, characterised by the experience of perceptions, thoughts, feelings, awareness of the external world
awareness of things that are happening in our mind and environment
key characteristics of consciousness
subjective and private
dynamic - drift in an out of different states of consciousness - things are constantly changing in- and externally
self-reflective - always the subject of your own conscious experience
linked to selective attention - u are conscious of things u pay attention to
altered states of consciousness
drugs
sleep
hypnosis
drugs
many drugs produce altered states of consciousness
psychedelics - substances that alter a person’s perception
distort conscious sensory experience
LSD - most powerful psychedelic
typical effects of LSD
visual illusions
mood changes
subjective slowing of time
colours heard, sounds seen
depersonalisation - feeling disconnected from themselves
how do psychedelics affect the brain
affect serotonin system
they stimulate serotonin receptors
serotonin has an effect on mood
sleep
wake:
- sensations are vivid and externally generated
- thought is logical
- movement is continuous and voluntary
REM sleep
- conscious experiences can be vivid, internally generated - we can see stuff with our eyes closed
- thoughts are illogically bizarre
-movement is inhibited - u may dream u move but u are stationary
when is dreaming most common
in REM sleep
what happens in the brain during dreaming
during dreaming some parts are activated and some are deactivated
deactivated- prefrontal cortex and visual cortex - leads to disinhibition - why dreams are illogical
are dreams conscious experiences
dreams are a form of consciousness but they are different from full waking consciousness
are we aware in our dreams - do we have self awareness at the time
so dreams lack in self awareness quality
but what about lucid dreams - u seem to have some control abt your dream
hypnosis
a state of heightened suggestibility
change in conscious experience
people may experience imagined situations
is hypnosis an altered state of consciousness - for yes
state theory
hypnosis is a unique conscious state
hypnosis produces a division of awareness - one stream responds to the hypnotist, the other and the other stream of consciousness which monitors our behaviour remains in the background
this division of awareness produces the change in conscious experience associated with hypnosis
is hypnosis an altered state of consciousness - for no
non-state theory
hypnosis is not a unique conscious state
subjects are simply playing a role or faking it
does hypnosis change brain activity
evidence that hypnosis is associated with changes in brain activity
changes in areas of the brain that are typically associated with conscious experience
the more relaxed or absorbed the ppt was during hypnosis, the stronger the changes in frontal parts of the brain
why research on consciousness has taken off: 1. re-conceptualisation of consciousness by Chalmers
2 types of consciousness problems:
easy - neural correlates of conscious perception
hard -how and why does the brain give rise to conscious subjective experience
progress has been slow bc we are hung up on hard problems
- development of new methods for measuring consciousness have been developed
new behavioural paradigms
new ways of investigating brain activity; fmri , eeg, brain stimulation
how do we measure consciousness
most of the research on CS has focused on visual CS
advantage:
+control what is presented
+control if stimuli are consciously perceived - experimentally manipulate CS experience in the visual domain
behavioural measures
those involved in behaviour/ verbal responses
presenting visual stimuli to ppts and ppt have to report if they see - if they can see, they are CS aware of it
masking paradigm - behavioural measure
used to manipulate visual consciousness
present a masking stimulus which are abstract shapes
that’s followed by a target stimulus, followed again by a masking stimulus
if this sequence happens slowly, the target is consciously perceived
if sequence happens quickly, so that person doesn’t have time to process, target stimulus remains unconscious
see what variables affect the conscious perception of a target
post-decision wagering: behavioural measure
rather than saying yes i see target or i dont, ppts also have to place a bet on this decision
ppl have to bet some money some decisions are more reflective of the conscious experience
amount someone bets can reflect the strength of conscious experience they have had
post-decision wagering in blindsight
in blindsight, patient has a lesion in visual cortex - part that processes visual information -
and that produces unawareness of parts of the visual field but patients still able to process items in these parts of the visual field - if u show patient an object and say what’s happening they will say idk i cant see anything. if u force them to say if there is something present or absent, they respond accurately
study of post-decision wagering in blindsight
decide whether item had been presented in affected visual field and place a bet on this decision
patient correctly detected there was an item present on 70% of the trials
but they placed modest bets on these decisions
they are able to process info revealed through their performance at detecting items but they did not have confidence
limitations of behavioural methods
failure to report a CS experience may not mean u do not have it
- could be due to failures of attention or memory
neural correlated of consciousness - to measure consciousness
brain imaging -fmri and eeg to look for correlation between brain activity and conscious experience
recurrent processing - a neural correlated approach
looks for correlations between the types of brain activity u can observe and whats happening in terms of conscious experience
recurrent processing seems to be associated with consciousness
present a visual stimulus to ppt and look at brain activity
there is initial processing in eyes, and this gets sent to early visual areas that gets sent forward in a uni directional flow through higher visual areas
recurrent feedback: if person is consciously aware of the stimulus u present, u observe higher level interaction between more sophisticated parts of the brain and lower level parts of the brain - not all visual stimuli trigger this recurrent so person is not aware of conscious stimulus
recurrent processing can be detected using EEG
observing activation in early visual areas after the visual stimulus is being presented
activity in early visual areas is being triggered by communication coming from higher areas
recurrent activity is correlated with conscious experience of a visual target
showed ppt visual stimuli and detect visual target amongst noisy visual imagery
when ppts detected a visual target, they observed recurrent processing using EEG
specific brain regions involved - a neural correlated approach
what parts are active when someone undergoes a change in consciousness
regions involved are different for different types of conscious experience
there is no single consciousness region of the brain
parts of the brain in visual consciousness
run masking (unconscious) experiments and compare non-masked (conscious)
masking experiment in fMRI
In masked condition activity in the brain was limited (localised) activity in visual areas
un masked condition where ppts consciously detect the target, they observed widespread patterns of activation
conscious experience is associated with distributed patterns of brain activity
explore brain regions involved in consciousness
perform binocular rivalry tasks
presentation of 2 different images to each eye
person’s conscious perception of what they are seeing spontaneously flips throughout a trial between these 2 images
sometimes they consciously perceived left eye image, sometimes right
what changes occur
clustering of activity in frontal regions and parietal regions
pockets of activity elsewhere in the brain
so when brain is undergoing a change in conscious experience you find parietal frontal activation - coupled with widespread activation
