Doctrine of Concordance
= concerns the degree of similarity between individuals and their psychological characteristics
–> there is concordance between consciousness (phenomenal consciousness/qualia), awareness (psychological consciousness), and behavior
–> disorders dissociate this concordance
Korsakoff’s Syndrome
- the most common form of amnesia
- concerns anterograde amnesia and retrograde amnesia
- caused by the toxic effects of alcohol, as well as thiamine deficiency caused by malnutrition in heavy drinkers
Anterograde Amnesia
= the inability to form new long-term memories
–> STM memory remains intact, but as soon as thought or perception leaves working memory, they are gone
Retrograde Amnesia
= loss of LTM that stretches back into the past
–> also occurs after accidents, concussion, or trauma, in which case there is usually a period of blank memory for the accident itself, and for a variable time before
No complete loss of memory
amnesic patients can still:
- perform classical conditioning
- perform procedural learning
- retain and learn skills
Consciousness in Amnesia
Amnesics are conscious because:
- they are aware, responsive, able to converse, laugh, and show emotions
- BUT: they have lost the interaction between current and stored information that normally enables the ‘commentary’ that underlies conscious experience
–> amnesics create no memory of a continuous self who lives their life
Anosognosia (form of Neglect)
= a condition in which a person with the condition is unaware of having it (deficit of self-awareness)
- damage to the right parietal lobe
- leaving ‘core consciousness’ intact while damaging ‘extended consciousness’
–> the connections between autobiographical memory and the body representation based in the right parietal lobe are destroyed and this affects the core self
Anton’s Syndrome
= patients are blind and still insist that they can see
- when parts of the visual system are gone there may be no neurons calling for information from the eyes or able to notice that none is coming in
–> there would be an absence of information rather than information about absence
Hemifiled/Unilateral Neglect
= patients seem not to realize that the left-hand side of the world even exists
- occurs only with right brain damage
- can partly be explained as a deficit of attention, in that patients simply do not attend to, or have their attention drawn to, the left-hand side of the world
–> emotional stimuli shown in the neglected field can influence attention, and stimuli that are not consciously seen can prime later responses
Hemianopia
= the removal of V1 on one side of the brain leaves a person blind on the other
–> if a person looks straight ahead and an object is placed on the blind side, it cannot be seen
Blindsight
= cases in which people deny having conscious sensory experiences and yet behave as though they can see
“The most obvious interpretation of Blindsight”
The blind seer has vision without consciousness. He is an automaton or a partial zombie who can “see” functionally but has none of the visual qualia that go with normal seeing. This proves that consciousness is something separate from the ordinary processes of vision.
–> invalid
Objections to this interpretation: Blindsight does not really exist
- light might have strayed from the blind field into the seeing filed
Objections to this interpretation: Blindsight is nothing more than degraded normal vision
- blindseers have several restricted visual functions and severely degraded qualia to match
- blindseers have been shown to respond very accurately while claiming no awareness at all
- blindseers are just overly cautious about saying they can see something
Objections to this interpretation: Blindsight might depend on residual islands of cortical tissue
- true blindsight occurs when V1 is destroyed and other pathways from the eye to different parts of the brain remain intact
–> about 85% of cells take the major route through the lateral geniculate to primary visual cortex
–> the rest goes via the superior colliculus to various other cortical and subcortical areas and are not affected by the destruction of V1
How can we detect Blindsight?
While denying consciously seeing anything, subjects can:
- make saccades to stimuli
- point to the location of objects
- mimic the movement of lights or objects in the blind field
- show pupillary and other emotional responses to stimuli they cannot see
–> this ability depends on information in the minor pathway running through the superior colliculus and amygdala
Super Blindsight
Training a blindsight patient by giving him feedback on his guesses, until he comes to realize that he has a useful ability
–> after this training, he should spontaneously be able to talk about, act upon, and use the information from his blind field just as well as from his seeing field
Evidence against the Super-Blindseer: Blindsight is impoverished
- in spite of their remarkable ability to detect stimuli and simple features without awareness, blindseers generally cannot recognize forms or identify familiar objects
- they cannot use their blindsight in ordinary life
–> they have to be prompted, and even pushed
–> the hypothetical super-blindseer has abilities way beyond those of actual blindsight
Evidence against the Super-Blindseer: Awareness in the blind field
- blindseers are sometimes aware of certain kinds of stimuli in their blind field, especially fast-moving, high-contrast ones
- motion perception in the blind field is the same as that in the seeing field –> patients would not identify the experience as ‘seeing’
–> blindsight should be seen as action without perception
Evidence against the Super-Blindseer: Sensory Substitution
= substituting one sense from another
- the residual functions in blindsight are banned from consciousness because the neural activity does not reach the conscious centers
–> blindsight is visual processing in the absence of phenomenal vision
Evidence against the Super-Blindseer: Access Consciousness vs. Phenomenal Consciousness
Access Consciousness: the availability of information for use in reasoning, speech, and action
Phenomenal Consciousness: experience, or ‘what it is like’ to be in a given state
–> stimuli in blindsight are both phenomenally and access-unconscious
–> the super-blindseer would be a partial zombie who has A-consciousness but no P-consciousness
Somatoparaphrenia (Feinberg)
= a condition in which a person denies ownership of their body parts of attributes them to someone else
–> hypothesized to be a more extreme form of neglect
Neural Basis of Somatoparaphrenia
- damage to the right hemisphere of the brain
- parietal cortex = integrating sensory information from various modalities
–> this integration is disrupted: lack of awareness/recognition of one or more body parts
Behavior of Patients with Somatoparaphrenia
- patients are still able to perform complex tasks with the affected limb
–> often in combination with other symptoms of neglect
–> often in combination with anosognosia
