Consciousness - An Introduction (ch11)

In what way can consciousness be seen as a unit? - Chapter 11

The whole

It seems like we only have one consciousness. If you look at the brain, then you see that there is complexity and diversity. Often there are multiple processes that take place simultaneously through different brain routes. Yet we feel that everything forms a unity. We feel that only one exists and that we experience things not as isolated but as a whole. How come?

Dualists believe that everyone has a consciousness that is something other than their brains. Eccles believed as dualist that the mind plays an active role in selecting and integrating neural activity. This would result in a unified whole. But how should this happen? Where does the interaction between the mind and the brain take place? This problem recurs in all dualistic theories. The dualist Libet has the answer that the feeling of unity is achieved through a mental field of consciousness. That is why split brain patients still behave as one person.

The binding problem 

When you pick up a coin and throw it in the air, there are immense things happening in your brain. For example, various brain areas are active for observing color, movement and shape. There are also auditory processes under way. There is no specific place or a specific moment in which all this information comes together so that the falling coin can be seen as a unified whole. Yet we do have the feeling that everything is processed as a whole and that the coin falls, as it were, in one go. How can you see the coin as one moving object?

This problem is described as the visual binding problem and more generally as the 'binding problem'. This problem can be described at different levels, for example at the neural level and at the phenomenological level. Some people think that the binding problem is the same as understanding how attention works. So if you focus your attention on a cast coin long enough, the characteristics of the coin will be merged.

When the attention is overloaded, the wrong characteristics can be connected to each other. However, it is not the case that connecting characteristics and attention are the same. For example, binding can also occur unconsciously. There is a relationship between attention, awareness and bonding, but this relationship is not yet well exposed.

Binding and simultaneity (synchrony)

Malsburg stated that the simultaneous, coordinated firing of neurons in the visual cortex is the basis of visual binding. All neurons that process certain characteristics of an object (for example color or shape) would come together, and fire at the same time. This would ensure that we experience characteristics of objects as unified. Crick and Koch think that this may be the neural translation of visual consciousness. They believe that consciousness depends on a kind of short-term memory and on successive attentional processes. The thalamus would lead the attention by making a choice from the object characteristics that should be connected to each other. This would be done by letting neurons fire.

Crick states that this has been useful in evolutionary terms. He states that it is better to have one representation of an object than to always send information to different parts of the brain. He says that the unity of consciousness really exists. Later Crick and Koch adjusted their opinion. According to them, there is no question of a single brain area where it all comes together.

Micro-consciousness

Zeki doubts whether there is a unity of consciousness. He believes that there are many micro-consciousnesses. According to him, the visual system consists of many separate and specialized systems that function in parallel. Each system is independent and achieves an endpoint at a different time. Some characteristics must be observed before other characteristics can be observed. Zeki states that all these systems go together with a separate form of consciousness. He finds this because there is no 'end station' found in the brain where all the information comes together. This should therefore mean that there is not only one form of consciousness. Zeki can be seen as a Canestian materialist, because he states that there is a finish line where unconscious processes become aware.

Multisensory integration

Integration of information that enters multiple senses depends on neurons that respond to input from more than one sense. These neurons are found in different parts of the brain, but mainly in the superior colliculus in the midbrain. Neurons who find themselves there are already responding to multiple senses from birth, but this continues to improve as someone makes more use of his or her senses. It is not clear how integration of information from different senses produces a sense of subjectivity (ie consciousness).

Reentry and the dynamic core

Edelman and Tononi are trying to explain two characteristics of consciousness. First of all, they want to know how the unity of consciousness is caused. In addition, they want to find out how complex and diverse the consciousness is. They state that consciousness ensures that we experience things as continuous and coherent. This applies even to people with damaged brains.

Based on their vision, the researchers have designed the theory of reentry by neuronal group selection. Here they state that consciousness depends on continuous, self-repeating, parallel processes between parts of the thalamus and cortex. In addition, they argue that this time is needed to bring the long, self-repeating routes to a successful conclusion. Activity in these routes is necessary for consciousness, but not enough. Other factors are also needed.

They distinguish between two forms of consciousness. First there is such a thing as primary consciousness that occurs in many animals. This form of consciousness goes together with a short-term memory and being able to deal with the here and now. Clusters would arise in the brain and connections within a cluster would be stronger than connections outside a cluster. These clusters may depend on interactions between many brain regions. They ensure that different characteristics of an object can be combined. In addition, according to Edelman and Tononi, there is something like higher order awareness. This form of consciousness would have been developed in evolution at a later stage. Higher order awareness depends on connections between language and conceptual systems. This would ensure that a 'dynamic core' can arise and that there is also a feeling of a coherent self. The dynamic core is a large functional cluster that always changes, but still maintains continuity and integration, because there are connections with the rest of the system. The dynamic core can be involved at different moments in different parts of the brain. Other parts of the brain can then remain active, but are not part of the dynamic core.

This theory does not explain how the dynamic core creates subjectivity.

Unity as illusion

One way to escape the idea that consciousness is a unity is to think in terms of actions as unity. Cotterill believes that consciousness is a result of the interaction between the brain, the body and the environment. Hurley states that perception, action and the environment are closely linked. The unity of consciousness would arise through a dynamic flow of causal processes and multiple feedback routes that link input and output to each other.

These scientists see consciousness as a way of doing or acting, rather than a way to perceive information. They therefore believe that consciousness is connected with interaction with the world. Then the question remains why it gives a specific feeling when we perform an action. Some scientists believe that the unity of consciousness is only an illusion.

Resources: Blackmore; Susan. (2010). Consciousness, Second Edition An Introduction. Abingdon, Oxon: Taylor & Francis.