Conscious awareness Flashcards
What are the 2 types of consciousness which we can distinguish between?
1) Phenomenal consciousness (qualia) = the contents of our awareness vs. 2) Reflective self- or meta-awareness = our ability to think about mental states
Not everybody believes that we can investigate awareness empirically. What are the 3 views on this?
1) It’s impossible because the mind & brain are different (but interactive) substances (Descartes dualism), 2) It may be possible because the mind & brain are different aspects of the same substance (dual aspect theory) & 3) It’s certainly possible because the brain causes mind (materialism)
What is the hard problem of consciousness and how has it been overcome?
= the problem of how we can go about explaining a state of phenomenological consciousness in terms of its neural basis (Chalmers, 1996). By looking for the NCC (neural correlates of consciousness)
How might we define the NCC?
= the minimal set of neural events which are jointly sufficient for any one aspect of a conscious percept
What 3 methods can we use to identify the NCC?
1) Neuropsychology: are there any lesions which selectively impair phenomenological awareness?, 2) Correlational methods: are there brain areas or types of activity which correlate with a state of awareness independently of stimulus input? & 3) Interference methods: are we able to induce changes in the state of awareness?
What is the problem with looking for deficits of awareness i.e. zombies? The big question is “Why do we need consciousness? Why did it evolve?”
We wouldn’t know they were here even if they were
How do aspirational, unilateral lesions of V1 in macaques demonstrate that vision can guide behaviour unconsciously? Blindsight demonstrates this in humans. The monkey evidence also suggests that normally monkeys have…
A lesion to V1 in macaques does not severely impair visual behaviours but when monkeys are asked to comment on their percepts they report not seeing the targets to which they responded. However, they do in their intact VF. Visual awareness
Lesions to functionally specialised brain areas block awareness of specific traits e.g. in disorders of…but residual colour or motion behaviours remain e.g….
Akinetopsia, achromotopsia & prospagnosia. Moving out of the line of an approaching ball
Another deficit of awareness is characterised by patient _ _…
DF who has visual form agnosia caused by a lesion to area LOC in the ventral visual pathway. DF remains able to visually guide action but cannot perceive or discriminate simple shapes
Neglect is an example of a deficit in awareness because the contralesional side of space is consciously ignored (e.g. patients’ attempts to bisect a line might be right skewed) but not unconsciously ignored e.g….
When forced to make a choice about whether there is a stimulus in the left VF or not they perform above chance. They also show priming effects for stimuli placed in the neglected, usually left VF
Another deficit in awareness is ___ ___:…
Global amnesia: patients have no explicit conscious memory of dot patterns or shapes but unconsciously do. This is shown by their improved ability to mirror draw with practice & recognition of dot patterns earlier on when they have been previously presented
In sum, there are 5 deficits of awareness which are…
1) blindsight, 2) akinetopsia etc, 3) visual form agnosia, 4) neglect & 5) global amnesia
Reflexive behaviour is clearly unconscious. However, other forms of high-level unconscious responses must also exist in order to enable…
Cricket batters to react to the nature of a ball’s approach & people to run away from dangers before they are consciously perceived
Marcel (1983) shocked the psychology world by demonstrating that unconscious high-level semantic processing exists, as shown in…. It is now considered a basic aspect of normal cognition.
Semantic priming
We have already established that V1 and specialised brain areas are necessary for awareness but are they sufficient?
No, Rees (2000) found residual activation of V1 & the FFA to face stimuli which were not consciously perceived by an extinction patient (extinction = cannot perceive X in the contralesional VF when Y is simultaneously presented in the ipsilesional field)
Other evidence that V1 & FFA activity are insufficient for visual awareness comes from the finding that…
even when healthy controls perceive the presentation of nothing plus a mask in the same way as a face plus a mask, there are neural differences between conditions e.g. greater V1 & FFA activity in the latter condition
Voluntary, consciously-mediated perception is used either when…or when…
Cruise control fails or there is a conflict between what cruise control tells us to do
SURs & fMRI recordings show that neural responses in the FFA & PPA correspond to…. How was this demonstrated?
What we consciously perceive at a precise moment. By presenting a (red) face to one (red lens) eye & a (green) house to the other (green lens) eye. Pps did not perceive a merged combination of both stimuli but instead an image which flipped between the house & the face i.e. the two eyes’ input compete with each other. The flipping corresponds to increases/decreases in FFA/PPA activity
The correspondence between neural activity and the content of the conscious percept is greater for…..FR: using MVP(pattern)A, does this correspondence also hold for the dorsal where pathway? Prediction: ___
Higher-level visual areas i.e. those further down the hierarchy e.g. IT cortex. No
The point at which the percept shifts from one stimulus to the other is correlated with activity in ___ & ___ areas
frontal & parietal
The NCC has been investigated using stimuli, the physical stimulation from which remains constant but the phenomenological experience changes e.g….(4 types of stimuli)
1) Ambiguous stimuli e.g. the flipping of the Necker cube activates frontal & parietal areas, 2) Illusions e.g. motion after-effects from non-moving stimuli activate V5, 3) Threshold stimuli activate V1 & LOC more on the 50% of trials in which the object is seen & 4) hallucinations e.g. hallucinated motion activates V5
Is one hemisphere conscious, whilst the other remain phenomenologically mute?
Potentially yes: when split-brain patients with a lesion to the corpus callosum are asked to pick up the item which is suited to the image in the left VF, they select the correct item (e.g. spade for snow scene) but when asked to justify their selection, they relate the item to the right VF presented image
What does Sperling’s (1969) study suggest in terms of the role of the left vs. right hemispheres?
The LH provides the conscious, phenomenological experience, whereas RH-based actions appear less verbally accessible
Give 3 problems with the NCC approach
1) Conditions compared (aware vs. unaware) are often not equated for task difficulty = comparing a hard-working vs. not revved-up brain, 2) Successful performance does not reliably indicate subjective experience & 3) Frontoparietal activity likely just indicates decision making or reporting
Given the problems with the traditional NCC approach what alternative measures could we use?
1) Tasks of awareness which do not require decisions or reporting? 2) Tasks which include subjective reports e.g. commentary keys (see Lau & Passingham, 2006) or confidence ratings, though these tap into a different type of consciousness: meta-awareness
Lau & Passingham (2006) equated task difficulty by comparing conditions in which discrimination performance was equal but subjective awareness was not i.e. they used separate measures for awareness & performance. Describe the study & its findings
In an fMRI scanner Pps were briefly presented with stimulus A or B followed by a mask, asked to judge which it was and then state whether they had seen it consciously or not. Only PFC activity differentiated the “aware condition” from the “unaware condition”
We have not found the NCC, yet theories re: its location do exist. Using already covered and new material, give 4 opinions re: where the NCC lies
1) Pineal gland = the interface between brain & mind (Descartes), 2) ventral visual stream (& to account for neglect) under the influence of the dorsal stream (Milner), 3) PFC (Lau) & 4) subcortical associative areas (Crick & Koch)
According to Rees & Frith (2007) awareness relates to the integration of…
activity across neural populations through top-down attentional control of competing object representations
The idea of binding underlying awareness concurs with Milner’s belief that the ventral stream (sensory areas)…. TSB…(3 things)
under the control of the dorsal stream (PPC, FEF) brings about awareness. 1) Frontoparietal involvement in shifts of awareness, 2) Awareness deficits in neglect & 3) Frontoparietal involvement in mediating long-range coupling between sensory areas
Koch & Crick argue that ___ of neurons oscillating in synchrony in posterior (sensory) & ___ (___) areas underlie awareness
coalitions. Frontal (executive)
