## Monday, May 5, 2014

### How much Signal?

I have been chewing on the question, "How much signal is actually necessary?"

In the physical world, pulling the trigger on a firearm is the signal for the gun to fire.  A poor rifle trigger (Competitor #5) might have a pull of 5 pounds and a creep of 0.050 inches.  That works out to about 0.02 foot-pounds.  The .308 Winchester is a boringly pedestrian but highly effective big game cartridge.  It delivers about 2600 foot-pounds of energy when measured 10 feet from the muzzle.  That is a Action-Signal ratio (gain) of almost 125,000. For the best trigger the gain is closer to 2,000,000.

Precision and accuracy are associated with high gain signals.  The back-feed due to the signal is smaller and causes less distortion in the output.

In the social world a pretty girl smiling at you from 20 feet can change your life...I am speaking from personal experience.  That smile, estimated as 2.5" across by 0.625" high represents about 1.5 square inches.  The surface area of a sphere that is 20 feet in diameter is approximately 725,000 square inches for a signal content of one part in 460,000.

I am too lazy to run the calculations but the weight of the aroma molecules that enter your nostrils divided by the weight of the fresh donut indicates that olfactory signals have high gain.

#### Auto-calibration

Most people auto-calibrate.  Kirby uses the word "fuck" every third word for an average of 4 times in each sentence.  Flanders says "Dang!" after he saws three of his fingers off his hand.  Most people auto-calibrate.  We ignore Kirby because he continuously pegs the amplification on the coarse tuning knob.  We would grab our 72 hour kit and head to the fall-out shelter if Flanders said "Fuck".

I suspect that systems become insensitive to signals after they experience a few random, irrational requests-for-action.  It takes very few Tourette twitches to eviscerate the system's sensitivity to a particular signal.

#### Kids

Kids do dumb things as they grow up.  A huge part of parenting is deciding how much "signal", or pain, to let shine through our protective nature.  Absorbing all of the pain denies the child of any chance of learning.  Letting all of the pain through can be crippling.

I am chewing on why organisms and mechanisms can be so much more responsive to some kinds of signals (rifle triggers, pretty girl's smile, aroma from bakery) and so unresponsive to other kinds of signals.

#### Dogs

Kubota is getting quite a schooling with Zeus, his new dog.  He is starting to see things from a parent's perspective.  The fantasy of loving a dog into obedience is dying a quick and merciful death.

Dad:  "Don't feed the dog bacon."
Kubota: "He loves bacon."  Feeds dog bacon.  Dog barfs on Kubota.