Lecture 10: Other Consciousness theories Flashcards
(32 cards)
What alternate theory was first introduced by which handsome man?
Local Recurrency theory
How are these two theories similar?
They both believe that the feedforward sweep isn’t for consciousness and that you can get unconscious behavioural effects driven by this unconscious feedforward sweep. Also that widespread recurrent interactions incorporating fronto-parietal cortices are related to reportable conscious percepts i.e conscious access.
How do these theories differ in terms of conscious experience?
Conscious access reflects a selection of the sensory input, with attention. This means the conscious experience is not very rich, as attention selects from the original input and we only become aware of those (e.g spotlight of attention).
Victor argues that, Dehaene by studying conscious access, very often focuses on this attention-dependent small capacity stable working memory representation of conscious experience. But conscious experience is much richer.
Describe an experiment which could illustrate poor conscious experience as suggested by Dehaene and GNWT
Sperling’s attentional cueing paradigm. In which 12 digits are displayed in rows of 4 and a tone or something else is sounded to inform which row the participant must report after the rows disappear. The participant could not name all 12 but paradoxically could name any row requested. In this paradigm when there is no cue, it suggests that the conscious access to the world is limited as the participant only report one part of it. However, when a cue is presented right after the letters were presented, subjects are actually good at reporting them.
What is an alternate explanation of the results of Sperlings experimental paradigm
The reason why they couldn’t report all might be caused by working memory as it overflows.
What does Lamme attempt to demonstrate in the study provided by the lecturer?
Lamme discusses whether the conscious experience is very rich or very poor, as the GWT suggests
What was the procedure of Lamme’s study?
8 rectangles at different orientations are displayed around a fixation point for 500ms. A grey screen is then shown for 200-1500ms and the rectangles return but some has changed their orientation.
The participant must report whether the cued rectangle changed its orientation. In some trials the rectangle is cued after the orientation has changed (a), others before the orientation has changed (b) and the rest during the grey screen (c).
What were the results of Lamme’s study
(a) had an accuracy of about 60% which was much lower than those cued before (b= 100%) (c = about 90%).
How are these different conditions actually different tasks?
(a) is a working memory task, and shows that the capacity is ~4.
(b) is an iconic memory task, when the inter-stimulus interval is short. (not interesting to what we are talking about).
(c) is visual STM, when the inter-stimulus interval is longer than 500ms.
What consclusions were drawn from these studies?
These results suggest that when we present a screen and then take it off, we have a detailed representation of that information, then when we cue specific stimulus of this display, we can bring that fragile information to our WM. But when we present a second screen afterwards, all that fragile information is washed away, but the item we brought to out WM is robust to being overridden. Therefore we can report the stimulus.
Depending on the types of experience, we could conclude the conscious experience is very limited or not. When we look at ‘a’ it looks very limited, when we look at ‘b & c’ it seems rich.
How does Lamme use this to roast smelly Dehaene
Working memory is working with attention, has small capacity, stable representation, and robust to interference. Visual short term memory (iconic and fragile)is very large but easily overwritten by other stimuli. The transfer from iconic memory to working memory happens with attention.
Victor argues that, Dehaene by studying conscious access, very often focuses on this attention-dependent small capacity stable working memory representation of conscious experience. But conscious experience is much richer.
Summarise the difference between Dehaene’s and Lamme’s views in regards to attention
Dehaene claims that attention gates conscious access and is thus limited. Consciousness depends on attention.
Lamme claims that attention selects from what is already conscious and thus consciousness is rich. Attention and consciousness are independent. Considers the preconscious stage of Dehaene, which is not yet reportable, as already conscious. He thinks we create a memory only for conscious information, so consciousness and memory are strongly related to each other than consciousness and attention (as Dehaene says).
How does Lamme’s views on the brain activation required for consciousness differ to that of Dehaene?
Victor Lamme argues that an involvement of the frontal area isn’t needed, a local recurrent processing is already raising the conscious experience. Information goes from the visual cortex to the dorsal and ventral route, and then comes back as a recurrent feedback. And this is already where we are conscious of something. For example only IT and V1 is sufficient for conscious experience.
Dehaene thinks we need fronto-parietal global ignition for the information to reach conscious access. But Lamme argues only local recurrent interaction between between for example higher level visual cortex and lower level visual cortex, is sufficient for consciousness to arise.
Describe feedforward processing according to Lamme
Imagining we have two different stimuli reaching the visual cortex, Stimulus A and B. And the brain is at a neutral state, meaning there is no memory related to these stimuli or anything like that. Then we get a feedforward of information leading to a specific response, either A or B on the image. Depending on which route was taken by the stimuli. When the feedforward reaches the frontal part of the brain, we can get unconscious responses in the PFC. Although at the same time visual areas engage in recurrent interactions. We get an initial feedforward of information, but at the same time when this reaches higher order areas, we get a response back, a recurrent process. In this case, we have phenomenal awareness of stimulus A and B in this case, and we have a conscious response when also visual AND frontal areas engage in interaction. Then we get access awareness
How do these two theories compare after this feedforward sweep?
Here the views converge again: when we get this fronto-parietal and visual recurrent interactions, then we have conscious access of Stimulus A, but not Stimulus B, as only Stimulus A is engaged in this recurrent interactions. Dehaene would say Stimulus B is in a preconscious state, it didn’t reach global workspace but it was processed.
What is meant by the term non-retinotopic?
Non-retinotopic basically means it’s stable, it’s not dependent on where in the visual field anything is presented and information is in WM. For retinotopic, the stimulus in in iconic memory so it is still accessible if only the attention was present.
Summarise Lamme’s views in a couple of lines
If we have recurrency, so recurrent interaction, we have phenomenal consciousness. If we would add attention to this, then we get conscious access. So then we transfer phenomenal conscious experience to conscious access.
What controversial idea does Lamme’s views raise?
There is such a thing as conscious perception that a human being cannot report, without knowing it we are conscious.
=>When there is local interactions, the frontal isn’t involved, we cannot act on that information. But Lamme says this still counts as conscious experience and calls it phenomenal consciousness. Even if we aren’t aware of the information and can’t act on it. Therefore the debate in the field is whether this actually counts as conscious or not.
How does Lamme claim that there is error in Dehaene’s methodology?
They disagree on the neural signatures of consciousness, so what we should look at when we are looking for consciousness. Lamme says Dehaene focuses on the consequences of consciousness by measuring what the subjects report. And so he misses the true cause of consciousness and mistakenly incorporates the consequences in the NCC.
What have the criticisms of Dehaene’s methodology resulted in?
Now people are looking into ways of measuring consciousness where we don’t have to ask questions to the subjects.
This is called “No-report paradigms” now.
Name two popular experimental paradigms in consciousness research that have been adapted as ‘no report’ versions
Binocular rivalry and inattentional blindness
Describe no report binocular rivalry procedure
They looked at the eye movements of the subjects to predict what they are experiencing without asking them about it. Because when we perceive the green stimulus our eyes respond differently then when we perceive the red stimulus. There are two conditions, one where subjects reported and the other where they didn’t.
Describe the results of the no report binocular rivalry study
The results showed that in the report condition we can see the fronto-parietal activity, but in the no-report condition there is no activity in the frontal area. Even though we know subjects see the images and changes. Showed that the frontal activity was about decision making and reporting, rather than to merely looking at the stimuli and being aware of it.
Describe the stimuli of the no report inattentional blindness study
There are eight large red dots on a red ring, inside is a large group of little rectangles and a fixation point. the circle moves one step clockwise at the same time as all of these little rectangles change their orientation. Occasionally a red circle dims a little and some of the rectangles form a square in the middle but these are subtle enough that if you are focusing on spotting one you likely wouldn’t notice the other.
