Re: Syntax and robot behavior

"RMDumse" <rmd@xxxxxxxxxxxxx> wrote:
An excerpt from "Flesh and Machines" by Rodney Brooks

"Dances with Machines

"What separates people from animals is syntax and technology. Many
species of animals have a host of alert calls. For vervet monkeys one
call means there is a bird of prey in the sky. Another means there is a
snake on the ground. All members of the species agree on the mapping
between particular sounds and these primitive meanings. But no vervet
monkey can ever express to another "Hey, remember that snake we saw
three days ago? There's one down here that looks just like it." That
requires syntax. Vervet monkeys do not have it."

In a previous thread, "Where is behavior AI now" we discussed time
domain based signals on simple inputs and outputs.

Isn't what Brooks saying above, that animals are not able to put such
time weighted concepts (i.e. snake we saw three days ago) into
communications? Isn't this parallel to the state information
discussion, to say, animals have very limited ability to remember
state?

I think the difference is that humans have the ability to manipulate
private state that is independent of the environment to an extent that is
far beyond all other animals. Before we can develop language to talk about
what happened yesterday, we first have to remember what happened yesterday,
or what happened 10 minutes ago. By this, I mean we have the power to call
up memories of the past. When we do that, all that I think is happening is
that our brain is partially activating old states, created from experience.

So, when sensory data flows in, it's decoded through a large parallel
network which specifies how the current sensory signals are different from
other sensory signals as well as decoded all the way to the correct actions
to take in response to this current sensory environment.

If we see/sense 100 things that are around us, it's because there are 100
different parts of the network activating at the same time in response to
this current sensory environment. I know there is a computer in front of
me only because parts of by brain that represent that idea have been
activated in response to this visual data. But at the same time, many
other lower level parts of the brain are being activated by the vision data
- the parts that detect simple edges, and areas of color, and shapes. It's
all this combined that creates our full experience of seeing a computer.

All that "state" is activated directly by our current and recent past
sensory inputs and all that state is also driving our behavior.

But, humans also have the ability to active some of that network state,
independent of the current sensory inputs. We can create a memory of
something that happened in the past by making part of that network activate
again. I can close my eyes, and still "think" about looking at the
computer. This memory is very weak and poor compared to the sensation of
actually seeing a computer because only a very small part of my brain is
being put back into that "seeing a computer" state when I have the memory.

If I remember seeing a snake yesterday, it's because my brain has sections
which are able to disconnect from the current sensory experience. It's
hard for example, for me to look at my computer screen, and have a past
memory of seeing a snake at the same time. I almost have to close my eyes
or at least, concentrate to block the sensory data in order to allow me to
have a past memory of seeing a snake. This is because the current sensory
data is trying to force the brain into the configuration of looking at a
computer monitor.

None the less, humans have a lot of power to do things like close our eyes,
and make our mind drift back to partial (very partial) recreations of past
experiences.

Our behavior however is a function of the entire state of the brain. So,
when parts of our brains are recreating state from past experience, our
behavior can also be a function of that part of our brain state, instead of
being a function of only brain state created from current sensory
experience. In other words, we can produce behaviors that are function of
our memories. We can say something like, "hey, that snake is like the one
I saw yesterday". That's because when we first saw the new snake, a small
part of the brain switched back to a state that represented what happened
yesterday. But not all of it switched back (not very much of it at all
really) which is why we can for the most part not be confused about what is
happening now and what is a memory. We only get confused about that if we
cut off our sensory inputs so that the memories are all we have to react to
- like what happens when we sleep and dream.

I think animals have nearly as much state information in their brain as we
do. It's just that most of their state is always a direct connection of
the current sensory inputs. Most of our state works that way as well.
It's how we know where we are and whats going on around us. But because we
have this percentage of the brain that flaps in the wind and can flip back
to old states it allows us to react now, as if we were reacting to
something that happened last week.

So I don't think we have that much more state. Or that we can can react in
ways all that more complex than the ways many higher animals can react to
their internal state, I just think that for some reason, some sections of
our brain has a bit more freedom to disconnect from current sensory inputs,
and switch to active configurations which represent states that were active
in the past. We constantly have memories of past events which allow us to
act in complex ways that many animals don't seem to have. Most of them
seem to be far more forced to react to only what is happening around them
instead of having a brain that can switch to a past experience (aka
daydream).

A dog for example shows clear signs of action that shows their behavior was
based on past experience. They run to the door to be let out because they
know that door is how they are let out. But this doesn't seem to happen
because they can recall a past memory of being let out that door. It seems
to happen simply by conditioning. I don't see any real signs of dogs day
dreaming. They only seem to react directly to what's happening around them
(except when they are sleeping and they do seem to have dreams in that case
but that's easy to explain if your body cuts off your sensory signals and
lets the brain free-wheel).

--
Curt Welch http://CurtWelch.Com/
curt@xxxxxxxx http://NewsReader.Com/
.

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