Chapter 6: The unity of consciousness

If there is one thing that has not been questioned yet, it is that our consciousness is one thing and certainly not made up out of many parts.

From an outsiders point of view, this seems like a rather illogical assumption. The brain for instance, is made of many parts and processes, all running and functioning simultaneously, without ever having to come together. The same goes for the body. So why not for the consciousness?

It is proven that different processes in the brain and body work at different speeds and cues. This means there isn’t a focal point where they all start or finish. Seeing as we cannot find on specific place the consciousness is housed or located, it would almost make sense to consider that the consciousness might be made of many parts as well.

However, if you stop looking from a biological point of view, you might see where this conscious unity is coming from. After all, you only experience one ‘me’, and the only point your consciousness can ever find itself in is the present. We only see one world around us, not different parts of sound and vision and touch. Thus, a question arises;

How can such unity, experienced right now, arise from such diversity of non-instantaneous processing?

When stating it like that, dualism will look like a very nice, promising option. Dualism, after all, states that there is one, coherent mind that governs consciousness and is completely separate from those neuro-biological processes in the body. There, problem solved.

Many philosophers, such as Descartes and Poppers, chose this solution. As did Benjamin Libet, who proposed to take a part of a person’s cortex from the brain and keep it artificially alive. If his theory was right, then electrical stimulation of the piece of brain should, through central mental fields, provide a sensation with the owner of the brain, and thus prove consciousness is a mental field. (It failed.)

So yeah, like proven in previous chapters, though seeming to hold the answers, dualism seems to run into more trouble than the answers that it offers. Including dualism, there seem to be three options to the unity of consciousness;

• Dualism
• Research the body and brain to find the solution
• Reject the idea of unity.

Doesn’t it seem like the three options every consciousness issue ever offers? That’s right, because they are. These are the three things always to consider when dealing with a consciousness problem.

What is the binding problem?

Toss a coin up, what do you see? You probably see one object, flipping up though the air, showing several sides, and then landing again. Somehow, your visual cortex and brain made sense of all those visual inputs and told you that this is one object, flying through the air.

There are three components to this coinflip; colour, orientation and motion. Colour is the fastest process in the brain. Orientation is a bit slower, your brain needing the time to tell you what side of the coin is up and facing you. Then slowest is the process of recognising motion. And yet somehow, somehow you manage to see all three at the same time, even though their processing speeds vary largely.

The problem described is that of visual binding, but if you look more generally, the ‘binding problem’ applies across many different sensory modalities, and at many levels of description. Some of these levels (most obviously the neural processes) can be studied quite separately from consciousness, but others also seem to be closer related. Towards the more cognitive end, the problem is how combinations of features are represented, ranging from the combining of shape and colour in detecting blue triangles or red squares, to the binding of words and phrases with their roles in sentences. In particular, the problem for consciousness is how this kind of binding happens dynamically at the right time. As the coin flips, what keeps the colour, form, movement, and other attributes of the coin together without producing a distorted image?

This problem seems to be bound with both memory and attention. For example, try remembering entering your own car. To do this successfully, a lot fo features have to be imagined at once: maybe the colour of the car door, the height of the car or the pile of candy wrappers on the passenger seat, probably the key on its ring as you press the button to unlock it.

In Chapter 3, the question of just how detailed this experience really is was discussed. If vision does not actually operate by building up pictures of the world, maybe lots of this information is simply not given. For example, when imagining a face, your imaginative experience may not specify whether or not the person is wearing glasses or a beard. And when you imagine your car, the pile of rubbish may be neither present nor explicitly absent; your imagining may simply not specify. In your mind, that detail may not be important.

But the concept of binding does not commit us to any specifics in regard to the amount of detail; even if all we imagine is stepping into a nondescript car, there are still things that need binding to each other. And as a result of the binding, you experience a more or less unified memory of something you do every day, or an imagination of something you never do at all. All that information is held briefly in working memory and, as we have seen in some theories of consciousness, places as global workspace theories, which relate consciousness to working memory.

Attention, that is what first springs to mind when discussing this topic. And yes, there is evidence that attention is absolutely required for binding. For example, when people’s attention is overloaded or diverted, the wrong features can be bound together to produce illusory conjunctions, such as when you are rushing along the street and see a white cat, only to realise that it was in fact a black cat passing a white wall.

It is thus easy to say that attention is binding, but that cannot be the case. Think of catching a ball someone tosses at your head. Many things must be considered – the height and position of you hand, the speed of the ball, the contraction of muscles to hold it. Do you pay attention to each of these things? Probably not. And how often has it happened that you barely saw and caught the ball on time? Were you properly paying attention to it then?

Binding by synchrony then?

The best-known theory relating binding and consciousness is by two researchers we already know;  Francis Crick and Christof Koch. In the 1980s, they did studies on the cat’s visual cortex and revealed oscillations in the range of 35 to 75 hertz - in which large numbers of neurons all fired in synchrony. Known as ‘gamma oscillations’, the idea was that all the neurons dealing with attributes of a single object would bind these attributes together by firing in synchrony, thus creating a unity. Or, as they hypothesised, the synchronicity of these neurons firing together might be the neural correlate (NC) of visual awareness.

Keeping it in the neural theme, Crick subsequently stated that ‘consciousness exists only if certain cortical areas have reverberatory circuits that project strongly enough to produce significant reverberations’. Think of it like an impulse threshold.

But, other studies have shown that these gamma oscillations are not one hundred percent solely functioning to do neural binding. Others have shown maybe they don’t help feature binding at all. Studies with a dalmatian dog on a black and white spotted background have shown spikes in the gamma oscillations when they discovered the dog alone. This suggest that they might just spike when they see anything noteworthy.

Andreas Engel, Wolf Singer, and their colleagues in Frankfurt, Germany, propose that objects are represented in the visual cortex by assemblies of synchronously firing neuron. This means that the firing isn’t the binding, but the occurrence of multiple gamma oscillations firing. Combinations of these firing patterns are encoded to the recognition of a specific detail. The relationship between these features is then encoded by temporal correlation among the neurons. This means that neurons representing one object fire in synchrony with each other, but out of synchrony with neurons representing other objects at the same time. This means this might be two different object overlapping. The model allows for many kinds of synchronised neural activity apart from that based on oscillations.

What is micro-consciousness?

The main person of this chapter that challenges the unity of consciousness is Semir Zeki, who proposes instead that there are as many micro-consciousnesses as processing nodes in a system.

Zeki states that the many parallel systems of the primate visual system reach their perceptual endpoints at different times. For example, the attributes of an object, such as orientation, depth, facial expression, or shape, are processed separately, and colour be as much as 80 ms ahead of motion. But we are not aware of this perceptual asynchrony. In Zeki’s view, each of these separate cortical systems has its own conscious correlate, and this goes so fast we cannot notice the asynchrony.

Interesting enough, Zeki’s view is not a Cartesian theatre. As he states is, there is no need for a central cortex. Each of these micro-consciousnesses can function on their own.

Experiments show that basic colour perception can occur without the activation of the frontal lobes, which implies phenomenal consciousness without higher processing. This indicates that active participation by V1 is not necessary for visual consciousness, as people (Crick) long believed.

Zeki argues that binding is a post-conscious phenomenon. In other words, there is phenomenal consciousness of visual attributes before those attributes are bound, simple because the micro-consciousnesses all operate with different speeds and times. This sets Zeki apart from Crick and Koch, who argue that consciousness is built up only when stable coalitions form.

Micro-consciousnesses are bound into macro-consciousnesses which correspond to Block’s phenomenal consciousness. Unified consciousness corresponds to Block’s access consciousness and comes about only through language and the awareness of a perceiving self. However, funnily enough it is Zeki himself who said at another time that micro-consciousness might be the wrong name for it because it implies there is some hierarchy, some larger consciousness – so it is unclear whether he believes in a higher consciousness or not.

What is multisensory integration?

Binding, as far as discussed up till now, has only been within the senses, in particular within vision. However, it occurs just as much between senses as within them.

Somehow decisions are made about what to integrate and when. Principles of time, space, and inverse effectiveness have been proposed as guiding the integration process. A more general framework for understanding the likelihood of different levels of segregation and integration in multisensory perception is the Bayesian model, in which new evidence is combined with prior belief to assess probability.

The most important thing is that, within the brain, integration depends on multisensory neurons that respond to input from more than one sense. This integration can lead to illusions, such as ventriloquism or the McGurk effect, but most of the time, we are pretty good at the distinction. When senses cross, a thing such as synaesthesia can occur.

It can be said that the more we learn about interaction between senses, the harder it is to define what a ‘sensory modality’ means: do pain, vestibular awareness, or thermal perception count as separate modalities, and if not, why not? And what about awareness of speech or music compared to general sound perception? Where do we draw the line?

In the end, what we know is that that some combination of sensory distinctness and multisensory integration makes possible a world in which objects can be recognised as whole, and as being touched, seen, tasted, smelled, or heard, and as being the same thing however we perceive them. Many brain areas are known to be involved, but just how this kind of integration gives rise to the subjective sense of being one self in a unified world remains to be seen.

How about the IIT?

Remember the IIT in the last chapter – the integrated information theory? Yeah, let’s go back to that. According to IIT, consciousness reacts to the capacity of a system to integrate information. Information is integrated if it can’t be localised in any singular part of the system or is ‘generated by causal interactions in the whole, rather than the information generated by the parts’. IIT plays with five key parts in relation to consciousness.

1. Intrinsic existence. My conscious experience exists here and now, from my intrinsic perspective.
2. Composition. Consciousness is structured: it is composed of multiple phenomenal distinctions at different levels of generality, like a red colour, a traffic light, the left side, a red traffic light on the left, etc.
3. Information. Every conscious experience is specific and differentiated from other possible experiences; its distinctions specify spatial locations, as well as positive concepts – like road as opposed to no road, red as opposed to amber or green, etc. – and negative concepts – no red, no country lane, no beach, etc.
4. Exclusion. Each experience is definite in both content and spatio-temporal ‘grain’, making some phenomenal distinctions – driving along a road and coming to a red light – and not others, and flowing at one speed not another.
5. Integration. Seeing the red traffic light cannot be reduced to seeing the colour red plus a traffic light.

Basis to IIT lies the idea that consciousness is 100% guaranteed. Every inference to cause and possibility after that is based of that certainty. Also, Tononi – the owner of the theory – believes in the unity of consciousness too. He states that there is no way to reduce consciousness to multiple parts. Consciousness is incredibly informative, appearing to contain countless teeny tiny chunks of information. Yet what makes a conscious state informative is not how much information it may or may not contain, but the fact that it is just one of potentially millions of other possible states. Consider a human and a photodiode (yes, you’ll get it even if you don’t know what that is) facing a blank screen that is alternatively on or off. The photodiode can make only two distinctions: ‘light’ or ‘dark’. The human can distinguish the light screen not just from the dark screen, but also from a red and a green screen, and from other screens, showing any number of films, and from sounds, thoughts, and so on. This is a vast amount of information, for you can discriminate between all these states and each state has different behavioural consequences. So, you are way more conscious than the photodiode.

The five key parts, as mentioned before, are also called the axioms of integration. (Yes, eh, integration is a key part of integration, welcome to university people). Important is the aforementioned irreducibility. The less you can reduce an experience to separate parts, the more integrated it is (phi, Φ). This also  suggests that IIT allows the possibility of zombies because there could be systems which look identical to humans from an external perspective, but whose physical substrate consists of lots of mini-complexes of a low maximum Φ value rather than forming a large complex of high maximum Φ. (Why so complicated people??)

Like global workspace models, IIT insists on the importance of distributed dynamic processes and treats consciousness as a continuous variable. But in other respects, the theories differ. In GWTs, the contents of the workspace are conscious because they are displayed or made available to the rest of the system. In IIT there is no equivalent of this theatre or central area, other than the distributed power to affect other parts of the brain.

So, what is unity in action?

The theories discussed so far either don’t get involved with the hard problem or involve the ‘magical transformation’ again. Escaping completely from these problems is very difficult. The answer to this are enactive theories of consciousness. They treat consciousness as a kind of acting or doing, rather than representing or receiving information, so being conscious means interacting with the world, or reaching out to the world. This sidesteps the question of whether consciousness is really unified or not, for it is obvious that a single organism, whether an amoeba or a dog or a human, has to have unified action. An example of this is the sensorimotor theory of Noë back in chapter 3.

Is unity an illusion?

Finally, some people reject the notion that consciousness is unified at all. We have questioned whether the stream of conscious vision could be an illusion. Could the apparent unity of consciousness be an illusion too? This question is complicated by the fact that whenever we ask ourselves ‘am I conscious now?’, the answer always seems to be ‘yes’. We cannot catch ourselves out not being conscious, and when we do find ourselves being conscious there seems to be one me and one unified experience. And so, we never can be sure. (Which seems the point of this whole book, no?)

What are super unity and disunity?

So, an example of super unity is synaesthesia – which I’m not going to explain because if you are in your second year of psychology, you must already know what that means. Same goes for the example of disunity – the split brain scenario. In the most extreme version of disunity, there even is amnesia, if you squint a little.

Exercises

Yeah, so this chapter does not really have any exercises.