Bandwidth is the amount of information that can be carried through a system at a fixed amount of time.
The Bandwidth of the brain has been estimated in many ways with very different results. It is likely that the brain receives about 11 million bits/s only through the five known senses of perception. Yet this is only a very small part of its capacity.
Karl Küpfmüller once suggested 10.000 million bits/s, which was based on his estimation of the number of nervous cells in the brain. Then he assumed that each cell can handle 1 bit/s.
A better assumption would be something in the range of 100.000 million cells (or even more); while each cell has about 10.000 connections to other cells, and would be able to handle much more than 1 bit/s.
For the brain we would then end up with something in the range of 1000 million million bits/s. A "1" followed by 15 zeroes! 1.000.000.000.000.000!
However we choose to make the estimation, the number is astronomical.
This is not the place to discuss what consciousness is or can be; we might return to that on another occasion. For now it is the bandwidth of the consciousness we are interested in. Here I will rely on your intuitive grasp of what a consciousness is.
Just as with the brain, the bandwidth of the consciousness has been estimated in many different ways, with varying results; from 2.8 bits/s to 50 bits/s. There is no reason to discuss all these studies in detail here. Whatever we choose within the interval 2.8-50 bits/s, it is still almost negligible compared to the capacity of the brain. We will take a look at two examples, though; not because they are necessarily correct, but because they are theoretically interesting and provide some insight into the concepts we are dealing with.
[The content of this section is based on George A. Miller; "The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information", Psychological Review, 63 (1956).]
If you throw some matches on a table, you will be able to be aware of them all separately and simultaneously (at the same time), if there are seven or less of them. You will also be able to see how many there are without counting them.
If there are more than seven, you will see a set of matches, but you will not be able to be consciously aware of each one of them separately at the same moment, and you will not be able to see how many they are without some sort of counting procedure.
Certainly there is some variation as to ability, so instead of rigidly saying 7, we say "7 plus minus 2", which means a number between 5 and 9.
It is possible to be conscious of seven different words, numbers, concepts, thoughts, sounds, etc. at the same time, with some effort! With four or five it is still easy, but it is getting noticeably harder when you get to six or seven. When you reach ten (outside the 5-9 interval), you are certainly lost in confusion if you try to think of everything at the same time.
This does not mean that we cannot be conscious of more than seven things at a time; it means that we cannot be conscious of more than seven SEPARATE things, as separate, at the same time! We can still be conscious of them as a whole, a set. After all, when we read, we are not seeing words as separate letters, we are seeing whole words, sometimes whole phrases.
It is called "chunking", and it is necessary for us to be able to read, perceive a crowd (not separate individuals), or generally to see the whole, a set, instead of the individual parts.
But if we can be conscious of seven distinctive things, how many bits would that be?
"Bit" is the unit for information; in this context of our capacity to make distinctions.
Information can be defined as the logarithm of the number of separate things that are summed up in a set, in something whole. So if we can perceive seven separate things, but not more, we should take the logarithm of seven. Here it is a matter of 2-logarithms, so our question is: How many times do we have to multiply 2 by itself to get 7? The answer is: 2.8
According to Miller, this is our capacity: to be conscious of 2.8 bits of information at the same time.
But does that not seem very little? Well, by being conscious of seven distinctive things, we use 2.8 bits, but it can be misleading. If we think of a binary number (seven figures to remember), 1111010, it is 7 bits of information! A word of seven letters (if randomly chosen), would represent 35 bits!
Symbols increase our capacity. According to Miller, the consciousness is limited to the number of units or symbols it can handle, not by the amount of information each unit or symbol represents. So by structuring material intelligently, we can considerably increase the capacity of our consciousness.
Another theoretically interesting variant has been presented by professor Helmar Frank at Pädagogische Hochschule in Berlin, leading to a result of 16 bits/s. He defines a subjective time quantum [subjektives Zeitquant] SZQ, which is a psychological moment. It is the shortest time we can distinguish and perceive.
Frank noted that if the human ear is exposed to a sound with a frequency of 16 Hz or less (that is 16 pulses per second or less), the sound is perceived as pulses, you actually hear the "waves". If the frequency goes over 16 Hz, you hear one tone, and you cannot hear the "waves".
It is the same when we look at sight. If you are exposed to 16 or less pictures per second, you will see the separate pictures. Maybe not clearly, they will pass by too quickly, but you will notice them individually. If you are exposed to more than 16 pictures per second, you will see it as a film, a movie, and you will not see that there are many pictures.
Based on this, and other observations, Frank defines a time quantum, SZQ, as lasting exactly 1/16 of a second. Then he assumes that a human can handle exactly 1 bit/SZQ – which leads him to suggest that the bandwidth of the consciousness would be 16 bits/s.
However interesting it might be from a specialist's point of view, it is not really essential here to try to establish exact numbers for the discussed bandwidths. It is sufficient for us now to note two points:
1. The bandwidth of the consciousness is infinitely small compared to the bandwidth of the brain. Very, very little of the brain's activities pass through the consciousness. Most of it we are not aware of.
2. The limited capacity of the consciousness can be increased by a smart way to structure a material, or reality - by smart models.
All this information entering our brain through sensory perception but never passing through our consciousness, what happens to it? The theory is that it is stored somewhere forever. As I said above, one can train oneself to retrieve fragments of it, but only very small parts. Most of it remains hidden within us forever. Now and then, certain associations make something slip out into consciousness and we get insights we didn't know we had, but this is rare and the amount of information we become aware of in this way is so small that it is negligible. But is it useless?
Much of what takes place in the brain is unconscious, or subconscious (depending on how we want to define these words, it is enough to understand that it is something we are not consciously aware of). This is probably the most important part of its activity. It is there all processes supporting our conscious thinking occur; intuition, creativity, all those faculties which lie on the borderline between reality and imagination would be impossible without this part; and here our hidden memories certainly play an important role. We have to realise that we are aware of very little of what is happening in the brain; of what directs ourselves, our thoughts, emotions and actions.
Read the whole series:
1. Brain & Horror Vacui (Fear of the void)
2. History – Understand the Present by Understanding the Past
3. Memory as Soft or Hard History
4. Bandwidth Of Brain and Consciousness
Other related articles:
COLOUR & NEGATIVE REALITY: Do we sometimes see what is not?
What is Special with Number 7?
Words, Consciousness & Beyond
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