 Hi, and welcome back to this video in the biological psychology video course, and it is video video 6.3 We're going to take a look at consciousness So what is consciousness consciousness is a very difficult Concept to define we all have some subjective idea of what we mean with term consciousness But coming up with a satisfactory definition is very tricky And I think the best people have been able to come up with comes from an essay by Thomas Nagel in which he asked the Question what it is like to be a bad? And I think the best we can say is that consciousness is the what it is like aspect of thought It refers to some kind of first-person perspective that we have on the world It's very hard to define and it is certainly subjective however we define it consciousness is inherently subjective Which makes it the most difficult topic to study? Neuroscientifically or psychologically In a sense consciousness is often phrased as the result of attention so attention would be a selection process and Then consciousness would be the result of this selection process So we are conscious of the things that we attend to and in that sense attention and consciousness are not the same But they are certainly related And as a working definition Because it is so difficult to measure consciousness in most experiments study and consciousness And we will also see that later in this in this in this video We say that we are conscious of something if we are able to verbally report it But that is that that works to some extent but it is very fraught with methodological problems Because what we can report depends very strongly on how we can report it, right? For example making a verbal report of something may require more consciousness You could say they're making a button-press response etc Or making an eye movement response But because we have no other way to objectively say whether you are conscious of something Verbal report or some other form of report is the best that we have in experiments Now most but not all researchers distinguish attention from consciousness in the sense As I just described that consciousness is then the end product of attention, right? That attention is the selection process and consciousness is the result of that selection process And they are certainly related So I would say even even researchers who distinguish attention from consciousness Acknowledge that they are very related concepts Because and I would say we are generally we need to be To pay attention to something to be conscious of it, right? So an example of that is for example the very famous Change blindness experiments in which for example a picture of a picture of some kind of visual scene flashes And then with every With every flash something changes in the picture And then what you find is that generally you don't detect the change until you're attending to it Right? So you really need to attend to the thing that changes in order to be conscious of that thing and in order to detect the change Now a very important distinction that is often made in in research on consciousness Especially by philosophers is that between the easy and the hard problem of consciousness And that was proposed or that that was first done by Dave Chalmers kind of A hippie philosopher that you see on the right there Now an easy problem of consciousness is basically the question. What do neurons do when we are conscious? right, this is A practical problem in principle. We could find out what neurons do when we are conscious of something It is a difficult question Because we don't have that level of neuroscientific insight yet But it is it is a question that I think it is conceivable that at some point we are able to answer it Right? We have some idea of where to start. So in that sense, it is an easy problem Although I think easy it is only easy relative to the hard problem Now so in a hard problem Is the question of how it is possible that the brain or any other material for that matter also? For example a computer an artificial brain Can have some first person insight how it is possible that we have some subjective experience that there is something it is like for us to be us And this is a hard problem because we don't have any idea where even to begin answering this question Right? It is not it may be an unanswerable question We don't know if it is an answerable question Then at least with the current knowledge that we have it seems unanswerable But I'm an optimist and I hope maybe at some point in the future We will be able to answer the hard question about the hard problem But for now I think even the easy problem is already quite challenging Another important thought experiment that you often hear of when we're talking about consciousness is the Chinese room Experiment proposed by John Searle. Now, personally, I don't really like this thought experiment very much I think it is a little bit misleading and actually quite shallow in its in its thinking But because it is so famous, I think it's important to be aware of it And the John Searle proposes the following situation. He says imagine a non-Chinese speaking person in a room When that person receives a line of Chinese text Written text, right? So he receives a note of text That person she looks up the correct Chinese response according to the rules in a manual and then returns this response as written text Right? So the person in that room receives a note of text Has no idea what the note says, but then goes to a manual and based on the rules in that manual says, okay If I see this character, I have to respond in such and such way, etc And then after probably extensively consulting that manual, the person comes up with the with the response Line of Chinese characters and she has no idea what they mean But basically returns them to the person outside of the room Now in that sense if you're outside of the room and you can then you can communicate with the room Right by giving notes to the person in the room and receiving notes back So from the outside these responses seem to seem sensible and they suggest some some level of consciousness, right? Now the question that John Searle then asks is is the man in the Chinese or the woman in this case in the Chinese room Or the room itself consciously speaking Chinese. So is there someone conscious? Is there some conscious? Processing going on in in Chinese in this Chinese room and his his answer to the question is no Right that in this case it shows that something namely the Chinese room can Act as though it is conscious But in this case he says clearly there's no nothing and no one that is actually understanding Chinese in this room So so essentially what I'm demonstrating in this thought experiment Is that something can behave as though it is conscious without any actual consciousness taking place That's his point. I think it's a very shallow point to be honest I think what the the most profound answer that you can give to this question is that a it's an impossible situation because there is No such manual But even if we assume that there is a magical manual that allows you to to translate arbitrary Chinese To an arbitrary Chinese answer then what you would have effectively is a room That as an entity as a whole is conscious, right? So the room with the person in it with the manual in it, etc Together as an entity would be a conscious Chinese being in that sense, right? So I think to me that is the most sensible answer that you can give to this thought experiment But I think it's important to be aware of it because you will hear quite often references to the Chinese room experiment When people are talking about consciousness now So there are various various states of consciousness So let's let's get from the from the philosophy and go a little bit back to the neurobiology Where we have much more to say about consciousness So consciousness is a continuum, right? There are you can be alert and wakeful in which case you are maximally conscious I would say you can be kind of drowsy in which case your consciousness is a bit reduced you can be drunken Drunk in which case maybe your consciousness is not reduced as such but it is it is altered this is at least different You can be asleep in which case you may be conscious maybe not but it's certainly a different form of consciousness You can hibernate right some animals hibernate Hibernation is certainly not death. It's also not quite sleep. It's related to sleep, of course But what happens to what happens to consciousness in hibernation is as far as I know unknown You can be in a coma in which case consciousness is presumably absent or or much reduced and you can even be death that right death is a state of absent consciousness You could say right. So consciousness is not one thing that not an all or nothing thing But it is something that can exist in various to various degrees and also in various forms That we do not have many real theories of consciousness, I would say But bernard bars is one of the main consciousness researchers and he proposed a global workspace theory that I think is is it does certainly not explain all aspects of consciousness But at least it explains some aspects and that I think is already quite good The idea of the global workspace theory, and I should say there was also developed quite a lot by standa han in in paris Uh, and according to the global workspace theory consciousness occurs when different brain areas form coalitions, that's what that's the way they describe it Now and that these coalitions communicate to represent one thought one sensation, etc That sounds a bit vague but to make it a bit more Concrete think about it this way So say for example that you see a car somewhere in the distance when that car gives you visual input So your visual brain areas start representing that car That car also makes a sound so your your auditory cortex start represent starts representing that car The sound that the car makes but as long as you're not conscious of the car That sensation of that visual sensation and that auditory sensation is not linked And as soon as you become conscious of the car then essentially we get a global workspace We get a coalition of brain networks that together start to represent the auditory aspect of the car The visual aspect of the car in one coherent whole So the different parts of the brain start working together start forming coalitions to represent that car And according to uh, bernard bars and standa han that that is what happens when When when you become conscious of something and I think that makes a lot of sense I think to some extent that's probably true even though of course it leaves a lot of aspects of consciousness unexplained Now the global workspace theory has supported Received some support from brain research And I want to take a look at in a bit more detail at a study recently published by saltine colleagues from actually standa han's lab Who used blindside to study consciousness Now so and blindside is the phenomenon that people can report something quite accurately While they feel that they're actually not consciously aware of it And it's mostly used to turn blindside is mostly used used in the context of people with brain damage people who have Damaged to their visual cortex in some cases claim that they they are blind that they cannot see anything Right, so they they have no visual awareness But they are nevertheless able to to perform some visually guided actions And they're nevertheless able to for example guess above choice above chance where something is in front of them Right, so they have clearly they have some function some visual functions are remaining But there is no visual awareness company Accompanying those visual functions, and then it's called blindside Now you can also induce something that vaguely resembles blindside in in healthy Participants, which is what saltine colleagues did So here's what they did. I'll walk you through the experiment So, um, this is a trial of the experiment. So they started with fixation dot And then a target appeared and the target was this this line segment here Target was presented very very briefly 33 milliseconds and then masked by these crosses And then there was a retention interval and then participants had to say two things Either did you see a target or not? Right, so for 33 milliseconds that that is very short So in many cases participants will not consciously perceive the target Right, it will be masked by these crosses so quickly that you simply miss it. You don't see it So then you would say not seen whereas if you would see it you would say, okay, I saw it right So and they used this as this report as a measure of whether participants were consciously aware of the target or not And then as a second task participants had to indicate where the target was right And even if they say said, okay, I didn't see the target. They still had to report where it was Which is a bit of a counterintuitive Thing to do for the participants, right? If you if you as a participant you think I didn't see anything then the question Where was the thing that you didn't see doesn't really seem to make a lot of sense But we will see that participants are actually able to do that above chance So in here in part b we have the performance of the participants So on the trials where participants said that they saw the target You see that the diagonal of this this map is quite red meaning that If the the target was at location one then the reported location was almost always one And if it was at location eight the reported location was almost always location eight, right? So participants correctly reported where the target was Now what you see is that even on trials where participants didn't see the target There is still a diagonal clearly present in other words Even if participants didn't see claim that they didn't see the target if the if the target was at position one Then they reported still above chance that the target was at position one, right? In other words, even if participants were unable to report a target Claimed that they were unaware of the target. They were still able to report its location above chance In other words, they exhibited a form of blindside Now and then salty and colleagues measured electrical brain activity with EEG Which is a way to measure electrical activity of the brain And MEG which is a way to measure magnetic activity essentially a different way to measure electric activity of the brain Now what they found was that if participants Claimed that they didn't see a stimulus and also misreported the location of the stimulus That the target was only very briefly represented in the brain In other words, you can see this here at the bottom and what you see here is essentially sort of a you could see You could say the brain activity that corresponds to the presentation of the target Now and more yellowish reddish colors Correspond to to more stronger representation of that target In other words, what you see is that if it was unseen and incorrectly reported There was some representation of the target, but it was quite weak right Now if participants claimed that they did not see the target, but they did report the Location correctly so the unseen correct trials you see that there is the heat map is hotter essentially So the the the target is represented more strongly and also across But you cannot see that in this figure, but across a wider range of brain areas So there seemed to be more of a global workspace going on in that case And if participants saw the target and correctly reported it then the representation was even stronger All right, so there was a gradual you could say a gradual level of representation if participants Claimed they didn't see the target and also did not correctly report where it was The target clearly did was not very well represented represented in the brain If they claimed that they didn't see it, but they did report the location correctly The representation was stronger and if they just claimed that they saw it So they were aware of it and reported it correctly the representation was strongest at all strongest of all Now, what does this show? I think it is somewhat somewhat in line with the idea of a global workspace It also suggests that consciousness is gradual right that stimuli can be almost seen So if you claim that you didn't see a stimulus, but you nevertheless report its location correctly What happens is that that stimulus was on the on the brink of being consciously perceived Um But it's just that the global workspace can be can exist to a stronger or a weaker extent right There can be the coalitions in your in your brain that Correspond to consciousness can be stronger or looser depending on how consciousness essentially how conscious you are of something I think that's what it shows right and it also shows I think that uh There is not really a qualitative difference between consciousness and non-consciousness But that consciousness is really a gradual process that you can have to uh to different extents Now with that let's move on to the next video video 6.4 in which we're going to take a look at sleep and dreams