dwarren@ssc-vax.UUCP (David Warren) (04/22/89)
A single associative tag governs a whole memory-slice and associates it
with all the rest of the mind. It may look as though there is a tremendously
unworkable ratio of the vast information that can be contained in the slice
to the unitary, off-or-on information that can flow over the tag, but it will
be argued in this article that the vast information stored in any sensory
memory channel flows sideways to the core of the mind solely over aggregates
of these unitary, off-or-on "concrete associative tags." In other words,
each lifetime-long permanent sensory memory channel is quite isolated unto
itself and does not flow at its end into some region of further or final
processing of the sensory information. Wherever the sensory memory channel
comes to an end, it just stops. Let us hope that the end of our tabula rasa
memory channels is so remote that we never reach it in our natural lifetime.
(In an artificially intelligent robot we might recirculate
the memory channels by looping around and erasing the oldest memory-slices
just before reaching the end of the first full loop of the memory-slices.)
Each sensory memory channel is isolated unto itself, except for the
associative tags which lead awayat right (orthogonal) angles from the
time-dimension of the memory channel. Over an associative tag, you can go
from one sensory memory channel into the memory channels of all other senses.
For instance, you can go from vision to audition, or from olfaction to
vision. But you can go only at a right angle; you can not cross directly by
associative tag from a present memory-slice to one laid down years or even
minutes ago. Each associative fiber that interconnects all the senses is a
guarantee of simultaneity. The associative tags are laid down at each
successive moment of the fleeting present, and they can never after be
disconnected or altered. As the poet says, "The moving finger writes, and
having writ moves on."
You must have a thorough comprehension of the sensory and motor plane or
"grid" of the mind before you study the two levels of superstructure by which
mankind achieves rational intellect. You can maintain that thorough
comprehension as we examine the three levels of complexity which are
operative at the peak of the human central nervous system. The three levels
to be studied are:
1. The sentient plane of the sensory/motor grid. (The interface
between the external world and the core of the mind.)
2. The abstract core of the mind. (This core brings a central nervous
system to the level attained by "smart" mammals, such as dogs.)
3. The linguistic spiral in the abstract core of the rational mind.
It is important to go level by level so that you see clearly what the
mind is capable of at each level and what is still lacking. You should be
certain to understand the situation at each lower level before you study a
higher level. As with a ladder of evolution, each level makes sense by
itself and without reference to any higher level.
So far we have discussed the sensory input part of the sensory/motor
grid, which is the flat two-dimensional substratum of the mind. It remains
only to explain the role played by the motor-output side of the grid, and
then you should have a sufficient comprehension of the first of the three
levels of the mind.
Let us call this sensory/motor grid at the lowest level of mind the
"sentient grid." If we were to examine an animal or automaton that had only
such a "sentient grid" at the summit of its central nervous system, that
creature would be severely limited in its capabilities. It would have the
power of brute sensation, and its repertoire of motor behaviors might consist
of many reflex and instinctual actions which it would be able crudely to link
with sensory inputs as triggers for the initiation (or cessation) of motor
activity. Now let us examine the motor memory channels, in accordance with
the mind-diagram.
The motor memory channels are the polar opposite of the sensory memory
channels. The motor memory channels contain memory slices not of external
experience, but rather of internal, dynamic activation of themselves. This
difference is critical for your understanding of the sentient grid at the
bottom level of the mind. Motor memory is not passive, it is dynamic. If
you make associative access to a motor memory node on a motor memory fiber,
you unavoidably send out a signal to contract a muscle at the destination of
the associated motor nerve.
As you examine the mind-diagram, notice that the sensory memory fibers
flow in parallel with, but never touch, the motor memory fibers. Yet the
sensory side of the mind controls the motor side of the mind. "Concrete
associative tag fibers" flow between the sensory and the motor sides of the
sentient grid. As was discussed above with reference to the sensory
modalities, concrete associative tags flow at a right angle to all the
lifelong memory channels. Just as the memory fibers are all in parallel,
likewise all the associative tags in the flat sentient grid flow in parallel.
By flowing in parallel, the associative tags preserve the historical record
of each successive moment in time.
If a central nervous system did not have memory as a record of
experience (and as an enabling mechanism for learning), then its sensory
nerves would have to lead directly to its motor nerves. No variations of
behavior would be possible, and the whole organism would be pre-programmed
genetically to respond to stimuli always in the same way.
When evolution introduces memory channels, it is essential to buffer or
separate the sensory and motor systems so that they do not fuse together and
so that what intercourse occurs can occur with great discrimination and
precision. Therefore, the sensory and motor channels do not meet head-on,
but rather they attain a close proximity and then flow in parallel. At each
successive moment in time and experience, the sensory and motor memory
channels have the possibility of becoming linked by nodal fusing at both ends
of the particular concrete associative tag fiber which was provided
genetically for that moment in time. The whole lifelong tapestry of
experience has a fresh, new, blank, concrete associative tag fiber for each
moment of experience, like a corduroy road made out of logs.
But just how do the associative cross-tags link up sensory experience
with motor dynamism? Why do we call it motor "memory," when no experience is
recorded there?
The motor memory channel is like a giant keyboard of a piano. The
purpose of the motor memory is not to record events, but to cause them. Or,
we could say that the purpose of the motor memory is to cause an event and
then remember how to cause it again.
In the infant organism of our sentient being, a mechanism of "random
dynamics" permits various motor nerve cells to fire spontaneously. When a
motor nerve fiber in the motor memory channel fires, it causes
muscle-activation. Then information starts flowing in the sentient loop.
While the infant organism randomly moves its limbs, it experiences aspects
of that motion through its sensory apparatus leading into its sensory memory
channels. At each moment in time during the random motion, nodal fixation at
both end-regions of a concrete associative tag fiber is associating passive
sensory engrams with dynamic motor engrams. Before long, control of the
motor apparatus ceases to be random and spontaneous. Instead, associative
control passes over to the sensory side of the sentient grid.
In the mature organism, all motor activation occurs across associative
tag connections laid down in the past, and present associative tag
connections are made solely for the purpose of re-affirming or updating or
strengthening sensory-to-motor connections made in the past.
This immediately previous statement offers an explanation why
motor-learning time in infancy is crucial to the development of motor skill.
During infancy, the organism has the benefit of the random and spontaneous
firing of its motor control elements. The sensory side of the sentient grid
seizes upon these random firings and takes control of them. Once a
particular pattern of sensory memory has taken associative control of a
particular pattern of motor memory, all subsequent uses of that control-loop
are recorded and thus re-affirmed by concrete associative tag, and a habit of
routine or skill becomes entrenched.
Note that this mind-model offers an explanation for volition, although
the explanation is different for each of the three le
vels of mind. On the level of the sentient grid, and in the absence of any
higher superstructure, volition consists of automatic response to the stimulus
of a sensory pattern. No leeway is allowed in the response to a given stimulus,
but varying stimuli are allowed to elicit varying responses.
Notice something general about this information-loop in which the
sensory and motor pathways do not meet but instead launch into a parallel race
into the future. Remember, the interior of the mind is trying to mirror
the exterior of the environment. Well, just as things are not steadfast and
"hardwired" out in the environment, likewise on the inside the associative
sentient grid, by flowing through time and allowing all manner of novel
associative connections,can be just as varied and changeable internally as
the environment is externally. However, an organism with no nervous level
higher than the sentient grid is forced to learn unchanging laws from its
environment, and such a sentient being is not free to make its own decisions
by letting logical data freely interact internally. The sentient organism
lacks an abstract core of the mind where the strict bondage of
stimulus/response can be broken down on the one hand and goal-directedly
built back up again on the other hand.
In other words, if you now comprehend the associative sentient grid
which is the lowest of the three levels of mind, you are ready to proceed to
the examination of the second level of mind. That is the abstract core which
further buffers the sensory and motor memory channels to such a degree that
the formerly ironclad and inviolable principle of simultaneity in
stimulus/response is overruled in one way but kept intact in another.
The second level of mind is roughly on a par with the central nervous
system of dogs or monkeys or horses. Learning and Pavlovian conditioning are
possible. The organism can be so "smart" as to impress humans and generate a
sense of kinship.
After eons of evolution, when an organism attains the second level, the
sentient grid of the first level is still present and operative in the now
more evolved organism. The sentient grid neither withers away nor changes
significantly in its operation. Indeed, in the literature about brains you
will find a generally accepted principle to the effect that lower levels of
brains are designed to operate rather independently of higher levels
in theevent of successive breakdown or impairment starting from the topmost
levels.
The principle is that the higher level dominates by consistently inhibiting
the lower level, so that, if the higher level is damaged or removed, the
lower level is no longer inhibited and functions in a role perhaps of
inadequacy but certainly of the best coping ability that the impaired brain
has to offer.
The second level of the mind-model is that of the abstract core of the
mind. If this second level seems ridiculously simple to you, wait until we
fashion from it earth's most complex mechanism on the third level. But you
are correct if you deem simple the innovation worked upon the sentient grid
to raise it to the second level. The innovation is so simple that perhaps
you will now deign to consider how easily evolution (which "does not make a
leap") could have stumbled upon the wonderful innovation.
In the sentient grid of level one, there are two massive neuronal flows
at right angles to each other. The one massive flow is that of the permanent
memory channels, both sensory and motor. These memory channels flow along
the time-dimension of the grid. The other massive flow is that of the
concrete associative tag fibers which cover in blanket fashion all the memory
channels so as to provide their only internal avenue of connection. Every
associative tag fiber is at a right angle to whatever memory fiber it
touches. A memory fiber flows through the time-dimension, but an associative
fiber is frozen at, and indeed represents, a particular, concrete moment in
the lifetime of the organism.
The innovation in the second level - the tiny step in evolution -
involves the lifetime-long memory fibers that flow along the time-dimension.
On the merely sentient level, these fibers are supposed to contain either
sensory or motor memory, because they are connected either to sensory input
or motor output. In a level-one system, all memory fibers are "dedicated" -
either to sensation or to motor activation - and since the the fibers are not
free, the level-one organism is not free. If evolution had never progressed
beyond level one, we humans might still be starfish or barnacles. But the
step or stumble among the dedicated memory fibers was unavoidable, beckoningly
easyto make, and somehow somewhere long ago in the primordial eons the great
escape was made and they got loose! Some of the supposedly
dedicated memory fibers got away from their origin as elongations of the
pathways to the external world. Getting loose from the external world, they
became creatures of the internal world - and rational mind was on its way.
The mind-diagram of this article is actually more descriptive of level
two than of level one or three. Note the central core of time-dimensional
memory fibers which are not attached and not dedicated to either the sensory
or motor side of the brain-grid. Since these memory fibers at the core of
the mind are unattached and undedicated, we call them "abstract" fibers.