Hey you! Yes, you! Are you conscious right now? Of course you are, right? But what does this actually mean?
Consciousness is an extremely intuitive, yet mysterious phenomenon: for scientists, philosophers and really anybody else. It quite literally entails everything we experience; yet nobody is sure how it really occurs. Maybe you have asked yourself before if the way you perceive the color orange is the same way that other people do. Or maybe you have asked yourself how you can be sure that other people are conscious at all. While in everyday life it mostly helps to assume that people have similar conscious experiences to you, these are actually questions to which we have no clear answers …
Generally, consciousness can be thought of as having two aspects: functional and phenomenal. Functional consciousness includes all the data we can collect about someone’s conscious experience; for example, we can measure neuronal firing. So this is pretty objective, but often doesn’t tell us all that much about someone’s direct experience: You can’t tell how Petra perceives the color orange from her EEG scan. Phenomenal consciousness is where it gets juicier: It is the subjective nature of experience of a person. Thus, we can say that a person, animal or other life form is conscious if there is ‘something it is like’ to be them. For example, there is something it is like to see the color orange, to feel happy or to think a thought. These ‘what-it-is-like’s’ are also called qualia and they are arranged into larger (‘eidetic’) structures, e.g. what it is like to see an orange at the market.
Picture: The quale (singular of ‘qualia’) of the color orange (left) is included in the eidetic structure of seeing oranges at the market (right).
So what about the brain then? Assuming that consciousness originates here (which neuroscientists tend to do), how does this work?
Well, it’s a bit complicated: Researchers have thought of all sorts of different experiments to learn about consciousness in the brain. One example is the use of ‘binocular rivalry’. Essentially, when you show different images to the left and right eye of someone, the visual perception of the person will switch between the left and right picture. So the visual input stays the same, while only the conscious experience (what you actually see) changes. (Importantly, in this experiment the participant cannot control which image they see, since both stimuli are competing to be perceived. So there is a difference between attention and your conscious perception, and here we are measuring the latter.) Now we can use an fMRI machine to localize a brain area that is more active when this perceptual switch occurs. Multiple studies have reported a whole network of areas, mostly in the right hemisphere being involved. Some researchers are especially interested in the role of frontal regions* in this switching process.
A study from 2014 investigated what areas are involved in the change of perception in a new way: Unlike other studies that made participants report when a switch would take place, the researchers also added a condition where they inferred this switch from the pupils and eye movements. Comparing these conditions, interestingly frontal areas were only more active than usual when participants were asked to report switches, but not when these were inferred. Thus, frontal activation seems to be linked more to the active report and not to the actual change in perception. Other areas were still associated with the switch though, namely parietal and occipital regions*…
While this is pretty cool research in itself, it still begs the question of what this really tells us: Even if we find one or several areas where consciousness is located, we still don’t really know how consciousness is produced there in the first place. Obviously, much more research needs to be (and is being) done to figure this all out.
As you can see, consciousness remains an exciting topic! We will soon feature more articles on other neuroscientific methods to investigate it, and what they mean for the philosophy of consciousness.
*Not sure what the frontal, occipital and parietal cortex do? Check out our Brain Basics 1.01 article, where you can learn some brain basics!
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Author: Melanie Smekal