How the Brain Tunes Out Background Noise

Last year, Live Science published a nice little summary article (How the Brain Tunes Out Background Noise)) about our mental process and how our perceptual process will tend to phase out the aspects of our surroundings which are routine or predictable:

The "novelty detector neurons," as researchers call them, quickly stop firing if a sound or sound pattern is repeated. They will briefly resume firing if some aspect of the sound changes. The neurons can detect changes in pitch, loudness or duration of a single sound and can also note shifts in the pattern of a complex series of sounds.

"It is probably a good thing to have this ability because it allows us to tune out background noises like the humming of a car's motor while we are driving or the regular tick-tock of a clock," said study team member Ellen Covey, a psychology professor at the University of Washington. "But at the same time, these neurons would instantly draw a person's attention if their car's motor suddenly made a strange noise or if their cell phone rang."

I'm interested in how this applies to driving-- there's a lot we need to attend to, as drivers, and a lot we don't even notice on a conscious level. How much of what we do when driving is necessary and how much of it is background? Do some people tend to have more trouble with the distractions than others? Do some of us have the ability to better distinguish background noise from necessary information?

As I am known to do from time to time, I will use birding as an example. When I'm looking for birds, I pay a lot of attention to the sounds and calls of birds, but I suspect that, after a short while, I do not pay any attention at all to familiar birds. Once I know that there are American Robins around, do my ears pay attention to them any longer, or do I just mentally dismiss them?

Or, on the other hand, we can think about music: when I am listening to a fairly common and unoriginal melody, I may not notice it at all on the surface, but I may notice unusual harmonies or arrangements of that same melody. Or, alternatively, unless I specifically attend to it, I may not even notice the chord progression of a tune, once it's gone through once or twice. Unless the music does something interesting, it may fade entirely into the background-- how often have you not even realized what song was playing on an intercom until someone pointed it out to you?

What is consciousness?

I'm going to talk for a moment about the binding effect:

Think about how we perceive: you see a bird flying. This gives information to your brain through the eyes. Your eyes transmit that information through the retina, through the optic nerve to the occipital lobe and, eventually, to the frontal lobe.

Now... think about this for a moment: have you ever had the experience of seeing something and not being able to comprehend it for a moment? A part of you understands that you've seen it, but doesn't understand that you have seen anything at the same time. This happens when you see something that just doesn't fit your world, like a clown walking down the street or your grade school teacher in the grocery store. There's a moment of confusion there, and that's that delay between sight and consciousness.

But there's more to it in this. You see that bird and you have a name to connect to it. The name may simply be "bird!" (as opposed to "American Robin," "glossy ibis" or "black-crowned night heron"). So you have this word, and that word comes from your temporal lobe, communicated to the frontal lobe.

But, again, there's more... that bird is in motion. Another part of your brain, the parietal lobe, investigates the pattern of motion that the bird traverses. This, too, is communicated to your frontal lobe.

Your frontal lobe has basic roles here-- if you speak that it's a bird, your frontal lobe (which contains the motor strip) aids in that vocalization.

But it's got a much more important role-- that of central organizer.

What the frontal lobe does here is take -all- this information from all the other parts of your brain and organize it in a fashion which, from our point of view, seems absolutely integrated and instantaneous-- it's smooth enough and fast enough that, for most of us, we're not even -conscious- that it happens.

And yet, transparent process is a fundamental part of our consciousness. We couldn't serve as integrated human beings if we were incapable of processing information quickly and easily, even if the process isn't perfect.

But... we still are not entirely clear as to what consciousness is? What does it mean if the nature of our being can be fundamentally altered by an injury to the frontal lobe? What does it say about our identity? Are we simply machines that can be turned off or reprogrammed, or are we something more elaborate and complicated than that?