[Bruce Nevin (2003.05.12 20:15 EDT)]
B:CP (under “The Principle of Addressing” pp. 211 ff) suggests
that reference signals come from memory. This introduces “… a new
property which accounts not only for perceptual remembering, but for the
ability of organisms to reproduce past perceptual situations through
actions. […] We do not need to create a special apparatus to take care
of these special reference signals. They are taken care of adequately by
a single postulate: all behavior consists of reproducing past
perceptions. … We will assume from now on that all reference signals
are retrieved recordings of past perceptual signals. This requires
giving the outputs from higher-order systems the function of address
signals, whereas formerly they were reference signals. The address
signals select from lower-order memory those past values of perceptual
signals that are to be recreated in present time. Thus the higher-order
output function still acts to select reference signals for lower-order
systems, but now it does so by way of addressing the memories of those
lower-order systems.” (p. 217).
Bill (2003.04.30.1309 MDT) referred me to this.
Associative memory, according to this postulate, constitutes the
reference input function or RIF that combines error outputs from above
and constructs from them a single reference signal below. So far as I
know this postulate is not tested in any extant simulation. Instead, in
the existing simulations error output values are transformed directly
into reference input values. They are not used as addresses for
recordings of past perceptual input values. Maybe I am wrong in this. (I
would be happy to be wrong!)
Imagination, according to the imagination switch hypothesis (stated on
the pages of B:CP immediately following the above quotation) is control
of a copy of the reference input as though it were (or in place of)
perceptual input. If reference input is a replay of memory this would
limit us to imagining only what we can remember. Since obviously we can
and do imagine novelties, it must be possible to construct new reference
signals. The existence of constructive imagination entails the existence
of constructive memory. Certainly we must store in memory what we control
in imagination. (I don’t think that we should postulate some mechanism to
distinguish imagination-control from real-time-input control so as to
prevent this.)
Subjectively, there is an associative character to memory – a kind of
passive, receptive connectivity – and there is a creative character to
imagination – an active, generative ramification of possibilities and
consequences that is deductive in character. But surely these are two
phases in the operation of the same thing, not separate mechanisms. It is
for this that Hofstadter’s ideas are appealing.
The context for my bringing this up is below.
[From Rick Marken
(2003.05.02.2130)]Marc Abrams (2003.05.02.0857)
A reference condition, in most, but not all cases, is an error signal
from a level above to a level below. I interpret that to mean that most
of our reference conditions are mostly ( not all ), but mostly, made up
of errors from higher levels.
I think I see your problem.
It’s true that the reference inputs to lower level systems are derived
from the error signals coming from higher level systems. But these
reference inputs still function as reference inputs (goal
specifications for the state of the perceptual input to the system). For
example, suppose the error signals, e3.1 and e3.2, from two third
level systems combined to produce the reference input , r2.1, to a second
level system: r2.1 = k(e3.1+e3.2). In this case the reference
signal (r2.1) is made up of two error signals but it doesn’t function
as an error signal. It functions as a specification for the perceptual
input to system 2.1, p2.1.
Rather, e3.1 somehow (!) evokes a set of stored perceptual signals {p2.h
… p.2i}, and e3.2 evokes another, perhaps intersecting, set of stored
perceptual signals {p2.j … p.2k}. Then “graded responses …
mutually inhibit one another so that the strongest response wins, or
alternatively … a threshold of response [intervenes] so that the
associative address must attain a minimum degree of match with a recorded
unit in order to trigger replay of the whole unit.” “Selecting
a unique experience from memory thus becomes a question of constructing
an associative address that evokes the strongest response from just one
recorded unit, and very few (or else mutually contradictory and hence
blurred-out) responses from other units. Mismatches may well act to
reduce the response from a given unit, further improving
discrimination.”
Marc Abrams (2003.05.03.1217)–
When a higher level “goal” is
“set” (whatever that currently means ) all “sub-goals” ( let’s use
reference conditions, please ) are errors from the levels above.
They are NOT “pieces” or “parts” of the original
“goal”. Any“piece” or “part” is itself a “goal” at
some higher level. Now“goals” and “sub- goals” do exist. But only at a
high, abstract level.
The several reference signals for systems at level n are stored
memories of perceptual inputs at at level n which were
recorded when the system at level n+1 was controlling its
perceptual input well. When those systems at level n control their
perceptual inputs to match those values, then the system at level
n+1 will again be controlling its perceptual input well.
That’s the theory as I read it.
From [ Marc Abrams (2003.05.03.1547) ]
[From Dick
Robertson,2003.05.03.1442CDT]The utilization of memory, on the other hand,
seems to be more a question under investigation in neuropsychology.
Or, am I missing the intent of the question?If you don’t believe that memory is a “proper question” for
HPCT we are in different universes in terms of our
“understandings” of HPCT model
I think you’re both right.
[From Rick Marken (2003.05.03.2230)]
Marc Abrams (2003.05.03.1217)–
I think these conflicts can be readily explained by PCT. No morphing
necessary.You need HPCT and a memory component to do that
We’ve got HPCT and a memory component (in B:CP). And the memory component
isn’t really necessary to explain the most interesting aspects of
conflict.
Bruce Nevin (2003.04.30 16:34 EDT)–
Bill Powers (2003.04.30.1309 MDT)–
See pp. 211 ff (The Principle of Addressing) in BCP for
a brief discussion of associative properties of memory and how they
mightfit into the hierarchy.
Thanks, it was good to re-read that. It’s been a few years. I had fogged
the use of error output as memory addressing, yielding reference input
out of memory. Rather than error outputs being combined directly in a
reference input function (my misconception), associative memory itself is
the reference input function, associating inspecific error signals with
specificvalues in memory. However, I don’t see that this “solves the problem
of translating an error in a higher-order variable into a specific value
of a lower-order perception”. There is still no particular reason
that error output at level n+1 should evoke memories at level n, or
indeed that it should evoke memories associated with the corresponding
perceptual input or reference input at all. Or at least no explicitly
stated reason.
The passage quoted above from B:CP continues: “This, incidentally,
solves the problem of translating an error in a higher-order variable
into a specific value of a lower-order perception, a problem that has
quietly been lurking in the background.” It is not clear to me that
this is true. the problem is simply transferred from perceptual input to
memory. It was previously a problem of translating error at level
n+1 to perceptual input at level n and it is now a problem
of translating error at level n+1 to memory at level n. The
only thing that maps diverse level n perceptual inputs to a single
level n+1 perceptual input is the perceptual input function (PIF)
at level n+1. Does the level n+1 PIF somehow guide the
associative memory process, breaking the level n+1 error output
signal out into level n memories?
We need to distinguish connectivity (neural connections or simulation
connections) from the generation of perceptual signals. The perceptual
input connections from level n to level n+1 presumably
already exist (modulo reorganization). The connections from level
n+1 error output to level n reference input are, according
to the above postulate, not neural connections of the same sort at all,
but rather the error output signal somehow evokes memories of perceptual
inputs which then – by way of associative memory processing of some sort
– enter each of those same comparators at level n (each of those
with ordinary connections back up to level n+1) as a reference
input signal of appropriate strength. “Control this perceptual
signal at this value.” I find this hard to fathom, even without
considering smoothly varying reference inputs. Are the curves of
variation remembered as well? Might account for development of skill and
style. But I’m still having trouble putting it together. A simulation
would help.
/Bruce
Nevin
···
At 12:27 AM 5/3/2003, Richard Marken wrote:
At 06:14 PM 5/3/2003, Marc Abrams wrote:
At 01:15 AM 5/4/2003, Marc Abrams wrote:
At 01:27 AM 5/4/2003, Richard Marken wrote:
At 03:16 PM 4/30/2003, Bill Powers wrote: