I am not an expert in cocktail parties, nor in discos, but I have to say I noticed that whenever I am in a crowd I have problem in hearing the person I am talking with because of the overwhelming noise. However, after a while, the noise seems to disappear and I can focus on my conversation.
This empirical “sensation” has now found an explanation by studies from researchers of the Columbia University and other universities, who managed to look “inside” the brain of people to see what happens when one wishes to concentrate on a sound in a noisy environment.
All sounds in the environment clearly get to our ears (we do not have the options of some dogs that can move their ears in the direction on a sound to better capture it and single it out from other sources).
This is shown in the activity of the brain that gets all sounds. Scientists have discovered, by experimenting with people suffering from epilepsy, that there are two regions in the brain involved with sound. One is basically capturing any sound detected by the ears, the other is focussing on a specific sound the person is paying attention to.
What they have further discovered is that it is this area that connects to the cortical neurones where perception of the sound arises. Hence, we perceive what we pay attention to. They also shown that the process of selectivity is a dynamical one. As our brain works out the meaning of a discourse it is able to create a representation that in turns further focus attention. Part of this representation fills in those sounds that get lost in the noise. In a way the brain reconstruct the meaning of a conversation by filling in what it is expecting to hear. This of course may generate false understanding from time to time, but in general it works pretty well.
It is just another example of the creation of a semantic network.
The research aims at helping people suffering from epilepsy by decreasing the burden of sounds that can originate an epilepsy episode as signals spread through the brain. A surgical intervention may interrupt the fibres spreading the signals thus decreasing the number of epilepsy episodes.
When reading this news I was attracted by the relation it has on semantic networks and the fact that we can really learn a lot by looking at how Nature can solve problems by working around them.
I was also interested by the connection I can see with the issues we have in wireless networks where the level of noise, that more and more is created by our own networks, is decreasing the amount of signals that can be transmitted.
In transmission we are constrained by the Shannon theorem that defines the ration between the signal and the noise that allows to transmit a certain amount of bits. With a semantic network we are not invalidating the Shannon theorem but we can find a reasonable work-around. By introducing an understanding of the message we can use less bit for the message and still work out its meaning, and then reconstruct it.
It is like saying in a discourse: “I will be going tomorrow from Rome to Milan” and because of the noise being unable to transmit the whole message. What if I am just sending ” I tomorrow from Rome Milan”? Well, if you place this into a context you will probably be able to work out the meaning and reconstruct the full sentence (this is just an example to give the basic idea, in reality it is much more complex, as more complex is the approach followed by the brain).
In the example given, the first sentence would have required 42 basic information (characters) to be sent, the second one achieves the same result with 25. And what if from the context you can tell that I am in Rome, and that I am talking about myself so that you just say “tomorrow Milan”. You would cut down the information transfer to 14 characters, 1/3 of the original sentence. In other words you might claim that using a semantic network you would be able to multiply by 3 the amount of information sent!
Once you move into the “semantic” space, you find yourself in a domain where correlations are as important, even more important, than the single pieces of information. In a future where we will have pervasive networks and thousands of objects creating connectivity, not just using it, you will have a structure that more and more resemble the wiring in the brain, with continuous alteration in the strength of each link that in turns represents a meta-information that can be used to assess meaning. We will change from a communications based on signals to a communications where signals change states of the network and this leads to new emerging properties (meaning) that can be perceived and that create the “message”, as it happens in the brain where our consciousness and perception is more a consequence of a brain state change than a response to external stimuli.