A mind is like a parachute
It might save your life,
but you have to know how to use it first.

Sunday, May 5, 2013

Of Paramecia and Air-horns

Now that we have looked a little bit at how information is (or is not) converted to a signal, it may be useful to revisit the Airhorn Family  and see what they make of all this.

When the air-horn went off, it was simply a loud noise to the baby.  Babies find loud noises scary.  And the rumble of the earth from the blasting was no help either.  But it would be hard to view this information as something encoded in a language the baby could understand.  Or would it?

There must be a reason we find loud noises unsettling.  They make our heart pound and our adrenalin surge.  This can be a great thing when you are at a rock concert but is a very bad thing when you are a sleeping baby. Why would a sudden loud noises cause our heart to pound?  Where is the codebook that says what our brain is to make of this information.  To do anything with it at all, it must be a signal.  And if it is a signal, it must be encoded somehow.  So when did we all sit down and agree that loud noises should be a signal for our heart to beat faster?

To answer this question we must go way back in time and back to the very basic idea of what it means to have senses and to communicate with the outer world.

Suppose we have a single celled organism that lives in slightly salty water.  If the water gets too salty, it  dehydrates and if the water gets too fresh, it basically starves.   Now this little organism lives in salt water lagoons near the outlet of brooks and streams.  The fresh water flowing into the salt water provides the perfect salinity for it to thrive.

The cell uses tiny cilia to "swim" around in the water.  It can basically go forward in a spiral or backward in a spiral.  It would not be a stretch for us to imagine that it could develop the ability to swim back and forth between the saltier water and the fresh, constantly ensuring that the proper salinity is maintained.  Or if you prefer, take 300 of these little guys, with 100 of them always swimming toward the saltier water and 100 always swimming toward the fresh, and 100 of them spending their days swimming back and forth in the sweet spot.  Logic suggests that the 100 back and forth swimmers would find their conditions less hostile than the other two types and so would tend to reproduce more successfully than the others.  Over time, virtually the entire population of single celled swimmers would be the kind that swam away from inhospitable water.

So how would we describe this activity from a signal perspective?  Simply that the salinity of the water signaled to the cell whether it was safe to keep swimming forward or whether it should start swimming backward again.  But how is this signal encoded?  In this case, it is hardwired into the genetics of the cell.  All of the cells that didn't get the genetic memo, so to speak, died.  The ones who survived were all the ones who properly encoded salinity as a signal for how to move.

It doesn't matter whether the cell is conscious of the choices it is making.  All that matters is that, like the resistor that dutifully takes a current and impedes it, the paramecium responds to salinity in a consistent way, swimming forward for as long as the water is safe, backwards as soon as it is not.

This example could be extended quite a bit through many thousands of generations to a level of navigational sophistication that extended beyond our example, but we don't need to go any further to demonstrate the basic point.  On a very crude level, information can be converted into signals at the genetic level.

As Darwin so brilliantly pointed out, the basic method for "teaching" any gene pool how to behave is to simply kill off those who are behaving badly.  Only those who prosper will successfully reproduce (at least in large enough numbers to bother with), so over time genetic selection favors encoding that matches the environment.

Of course we all know this as "survival of the fittest", but this phrase has taken on a bastardization, especially in the social sciences.  To some the phrase means that only the grade A, prime cut members of a group survive -- that the weak ones all die horrible deaths in the big bad jungle.  But Darwin did not mean fit in this sense.  His expression was intended more as "survival of the most apt".  That is, the mechanism of evolution he described was one whereby the creatures who lived would be the ones who had properties and behaviors most suited to their environments.  To take our paramecia as an example, there may have been one really buff paramecium -- the envy of all the others and the starting QB on his high school team -- but if he had only the ability to swim toward fresh water without regard for its salinity, there will be no buff juniors running around any time soon.  His "fitness" does not matter.  His "aptness" (or aptitude) does.

So let's bring this on back to the baby human.  Is there any reason we can think of that sudden loud noises would be genetically encoded to cause a baby to cry?  Of course there is.  A sudden noise in most any natural context for most any creature we can think of would signal danger.  It could be the breaking of a branch to a bird or the sudden pounce of lion to a gazelle, but in most natural contexts, a sudden sound has a high likelihood of needing a quick response.

This means that those creatures who responded to sudden noises with a shot of adrenalin and increased heart rate for a boost of speed and strength would tend to out-live those who had a more laid back approach to sudden danger.  The fight or flight response is simply a genetic certainty.

Now, we could have easily said that the baby was predisposed to not like loud noises and that was why he cried.  But our little thought experiment has taken us beyond that.  Now we can suggest with a straight face that the baby human is genetically encoded to fire up his fight or flight response upon hearing the signal of a loud noise.  So why the crying?  Well that is the baby's response to all the built up energy.  His body just jolted him with energy.  That doesn't mean he is suddenly blessed with adult coordination and problem solving, however.  Those will come later.  For now, the jolt simply cries out for release.  The energy is burned off with a good cry.

I said previously that the baby had no context in which to place the information of the air horn and loud blast.  But that is not technically true.  His conscious brain did not have a context built yet, but on a much more basic level, the context was clear.  Loud noise signals danger.  In this case, the baby was not far off (even though the danger was not to him).  But it also explains why any loud noise, even a happy loud noise like celebratory party favors, may cause a baby to cry.  To know that a given sound is a good loud noise and not a dangerous loud noise takes context beyond the baby's capacity.

Now the cat is very much in the shoes of the baby, context-wise.  In our earlier piece we granted her some perspective she may or may not have had.  My assumption is that animals are generally smarter and more aware than we give them credit for, so I see no reason the cat couldn't learn some predictive elements about the noise -- such as that it never happened at night.  But in any case, the response was very similar to the baby's:  it fired up the cat's fight or flight response.  Again, this is because this signal was interpreted by a very deep part of the brain, encoded with ancient signals stretching back to the dawn of critters.  But the cat had the means to do something with all that adrenalin and she used it to run and hide behind the couch (seeing no obvious opponent to "fight", it was "flight" time).

When we treat information as something that becomes a signal when put into context, we realize more than ever the power and significance of what context is.  For even the baby who was still sizing up the world around him came pre-packaged with a context with which to view the world.  This would, in this case, be the context that is genetically encoded in his mind, his "instinct" for lack of a better phrase.  Only the Mother and Father had the experience and capacity to place the air-horn into a more sophisticated context. And there again, we should remember only the construction worker actually heeded the signal in its intended form.  That is, whatever else the air-horn meant or symbolized to him, when he was on the job site he took it "literally" -- as a warning that a blast was going to occur.   When the air-horn blast served to remind the construction worker's wife that he was at work nearby, it was still a signal.  But it was a signal in a context that she had created herself.  Her context was the result of her relationship to her husband and all of the significance and stress that she assigned to his job and career.  She could "hear him at work", which she found warmly reassuring.  But she was also reminded (not necessarily consciously all the time) that his job was sometimes dangerous.  She knew the air-horn could wake the baby. She knew it scared the cat.  She knew it was sometimes just an annoying distraction from what was on her mind.  The air-horn was all of these things to her.  And each of those meanings was associated with a context.  So for her perhaps more than any of the others, the information of an air-horn blast was a large number of signals.  Her mind quickly parsed each signal every time she heard the blast.  Depending on the facts of her environment (e.g. whether the baby was awake already or had just been put down to nap), her response to this signal would change.  But each time the information was received, her various contexts all played a role in deciphering the signal.

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