Subject:
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RE: Bump switches and "aggression"
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 5 Dec 2003 00:10:52 GMT
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Original-From:
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Rob Limbaugh <RLIMBAUGH@ihatespamGREENFIELDGROUP.COM>
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Viewed:
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1106 times
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> -----Original Message-----
> From: Jim Choate [mailto:ravage@einstein.ssz.com]
> Sent: Wednesday, December 03, 2003 12:49 PM
> To: Steve Hassenplug
> Cc: lego-robotics@crynwr.com
> Subject: Re: Bump switches and "aggression"
>
>
> On Wed, 3 Dec 2003, Steve Hassenplug wrote:
>
> > How exactly, do you want to trigger this 'fight or flight'?
>
> Easy the bump switch jumps into a RNG, and it's important to
> understand that the output of a RNG does -not- need to be
> equi-probable, and it decides. Watch animals when they're
> startled, they don't stop and think, they jump around for a
> second and then take off.
Creatures (animals and humans) do not scatter in a totally random
direction. They scatter at a random vector in a direction opposite the
source of whatever startled.
That implies that more than one sense is being used to determine source
direction AND it implies that the animals are doing something where a
sudden noise or vibration is not expected.
> > It seems to me that a rabbit (for example) would use both of the
> > methods above. If it's running along, and it's nose smacks • into a tree
> > (I mean bumps into a tree) the behavior is very deterministic.
>
> Here's the problem with your approach, blind rabbits don't
> live long enough to run into trees. What a real rabbit does
In the wild, a blind rabbit would die long before it had to fend for
itself.
> is either freezes or takes off in a pretty much random
> direction, if they happen to hit something (say a pet rabbit
> in a bedroom that's startled with the phone
> rings) like a wall they reverse their trajectory and begin
> their avoidance strategy again. They continue this until they
> get under cover or are caught.
I believe you are wrong.
Animals (and even humans) "freeze" to rapidly assess the situation and
then take off in a random vector *away* from the perceived source of
threat.
Experiment 1: Close your eyes and have someone randomly jab you with a
pencil. Count how many times you push yourself harder into the pencil.
Experiment 2: Buy a bunch of minnows or goldfish and put them in a
bathtub full of water. Use an infrared camera and turn off the lights.
Toss a small marble into the bathtub. Count how many "blind" fish swim
into the marble.
Experiment 3: Adopt a blind cat or dog (especially a young one) and
observe it's behavior.
>
> How does the rabbit determine cover? It's eyes. How does a
> robot determine cover? Changes in light intensity via optical sensors.
I believe this is also a wrong statement. What does the rabbit do if
there is no cover? Sometimes agility and stamina are the keys to
survival and the pursuer decides the energy expense for that meal is a
waste of time. This is why the sickly, old, and weak are targeted out
of animal groups. There could be multiple pursuers and hundreds of
rabbits, yet they will only target a select few. Man is an exception...
We tend to kill anything.
Some blind creatures can still detect darkness. A rabbit can use it's
ears and whiskers if it is blind to find a hole to crawl in.
Darkness can also be detected by temperature difference.
> Now, a rabbit obviously has a more complicated behavior
> pattern than this.
> Why?
I think the complication is in deciding which behaviorial response is
appropriate for the situation and perceived stimuli.
> Because it has higher levels of processing going on that gate
> or squelch these behaviours. An example is what a rabbit does
> once it's a bit away from whatever startled it, it keeps
> going in -roughly- the same direction.
> What does that mean? It means that the process that causes
> the random path changes is still going on. How might one
> model that? I'm working on another project for this. Consider
> a ball. It has a weight in it that makes one end come to the
> bottom. Around that weight there are effectors that will come
> out at random times and push the ball in some direction.
> How can we modify this with a 'cover' behavior? Let's assume
> we have three effectors, we need three light sensors. Do we
> want approach or avoidance to light? Most cover is dark, it
> blocks sight and therefore light. So, the RNG in the ball-bot
> (I call it "Rho") keeps on trying to trigger the effectors,
> but we gate them with a AND function that is based upon light
> intensity. We do a comparison of the three sensors, which
> ever is lowest tells the others to turn off their effectors.
> When the RNG next gets around to hitting the effector for the
> dark sensor (I assume the sensors are opposite their
> effectors) the ball rolls toward the dark.
So what do you do when the agressor passes by and blocks the light on
the last operating sensor?
>
> > But, if it detects ground vibration, or possibly a noise from an
> > unknown direction, that is when the 'fight or flight' kicks in.
That's just it... The direction, even in a blind animal, is known!
Small animals run AWAY from stampeeds, away from earthquake epicenters,
and away from the sounds of agressors!
>
> Actually not, I've hunted and had pet Rabbits for more than
> 40 years. What a Rabbit does do is run off directly away from
> the vibration if there is time. If not the Rabbit freezes.
> They're behavior is very predictible.
> It's what makes them easy to hunt.
My experiences and observations with the animal kingdom in general are
vastly different from what you describe. Your descriptions in animal
behavior are congruent with what I know of caged animals released in the
wild.
You must be doing "pretend" hunting where you rely on caged animals
released in the wild as the prey and/or use traps, dogs, and guns. Try
hunting a wild animal on it's turf without man-made weapons or unnatural
traps.
Why does the typical unarmed man behave the same in the presence of a
wild grizzly as a wild rabbit does to a coyote?
>
> I can't count the number of times I've been bopping along in
> a pasture with other hunters spread out in a line and
> actually kicked rabbits. Sometimes they run, sometimes they
> don't they just sit there and let you kick'em again. You can
> litteraly reach down and pick them up, if you don't mind the
> chance of having a buzz saw in your hand. Possums do this
> sort of stuff too.
That happens because the rabbits know a *group* of agressors is chasing
them and the action they deam appropriate is to sit still and hope they
are bypassed, or to run. Again, this is a decision that has to do with
the behavior instincts and decision making abilities of the creature.
As soon as you pick them up, they attempt to free themselves to run
because now they know exactly where the agressor is and the intention.
Even humans do this.
If my observations of the world are wrong, by all means, please correct
me with real-world examples. Reference material would be great!
- Rob
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