Levels of perception

[From Bill Powers (920324.0300)]

Copy direct to Mark Olsen, plus CSGnet

My address is powers_d%flc@vaxf.colorado.edu. Between the powers and the d
is an underscore (shift hyphen) and between the d and the flc is a percent

Send Closed Loop orders to Mary Powers, $5 each copy.
73 Ridge Place, CR 510
Durango, CO 81301

Mark Olsen (920323) --

You ask about the functions relating one level of perception to another.
This is indeed the question that HPCT poses -- but doesn't answer. What
lies behind HPCT is not any proposal as to how each level of perception is
derived from the one below it, but a proposal as to what the levels of
perception are and how they are related. This is the phenomenon that any
model must in the end explain.

The "H" part of HPCT can be taken in two ways: first, as a general sketch
of a hierarchy of control in the abstract, with the communication between
levels consisting of a series of perceptual re-representations of reality
and a corresponding set of reference signals used to control lower levels;
second, as a series of proposed levels of perception (and control) based
directly on an analysis of experience with the hierarchical control concept
as a guide. This is a beginning model; there may well be other modes of
communication between levels, but the basic one is probably valid.

The definitions of levels define the modeling problem. We can see that the
sensation level is probably derived by weighted summations of intensity
signals, the weights defining a vector in a perceptual space having fewer
dimensions than there are different sources of intensity signals. But that
answer to the modeling problem comes after noticing that sensations seem to
depend on intensities in a particular way, a way that could be modeled as
weighted summation. The phenomenon to be modeled comes before the model.

And that's as far as I can go. I don't know how configurations are derived
from sensations -- how it is that we can get the sense of, say, a
particular person's face over a range of distances and orientations and
expressions. If signals standing for the dimensions of a face existed, then
it's possible to make a rough guess that transitions of the face from one
state to another would be sensed using time functions and partial
derivatives; that's a feeble start toward a functional model that you could
run on a computer. As to the rest of the levels, the kinds of computations
involved are mostly a mystery to me. The few guesses we have come up with
are strictly stabs in the dark. You can use words like "integration" to
describe how some kinds of perceptions are put together to create others,
but the word is just a noise. It doesn't tell us anything about the
processes involved.

Behind this exploration of perception lies a fundamental postulate; if you
don't internalize it, I don't think you can even get started on the problem
of modeling the brain's perceptual systems, or for that matter, in
understanding HPCT. The postulate, simply put, is this: it's all

By that I mean that no matter what you attend to in the world of
experience, whether you refer to inner or outer experiences, concrete or
abstract, verbal or nonverbal, the object of your attention is a
perception. You are looking at or otherwise experiencing the brain's
perceptual activities, not the objective world itself.

Vision is the most important sense to understand this way if you're
sighted; understand vision and the rest (touch, taste, sound, etc.) will
follow. The world you see begins as pixels (individual picture elements).
The pixels are so close together that you see no spaces between them,
although the sensory nerves do not overlap and in fact do not completely
fill the retina. There's a world between the pixels, but we don't see it
unless the view shifts slightly -- and then what we had been seeing
disappears into the cracks between the pixels. This is invisible to direct
experience; the world seems continuous over the whole visual field. We get
a sense of seeing the world at infinite resolution, and can't imagine what
the whole field would look like if we had, say, ten times as many retinal
receptors and the optical acuity and brain power to take advantage of them.
This would be like seeing the world through a magnifying lens, except that
the whole world would look that way, not just one little part of it (which
we still see at human resolution). The only way to imagine this is to go
the other way: view the world at a lower resolution, as in a halftone
photograph or a television screen seen close up, and imagine that the
result is the only world you can ever see. That's how our picture of the
world would look to a different organism with higher visual resolution. But
we experience it as having continuous detail right down to the level where
it appears smooth. I suppose the fly sees the world in the same way. But
its world is smoother than ours.

Building up definitions of the rest of the levels in the hierarchy is then
a matter of noticing persistent types of structure in this world of picture
elements. The first level above the pixels themselves is sensation, a type
of perception that can't be analyzed in any way except into variations of
intensity. Color is a sensation, as is shading.

Perhaps things like edges are sensations, derived in one step from the
pixel distributions. When analyzing perceptions, however, don't use any
data but your own experience. Theory and neural data will tell you that in
the visual field, in the retina itself, all edges are enhanced, so that
there is a strong outlining effect. But look at the edge of a sheet of
paper on a dark tabletop. There is no outline. The closer you look at the
edge, the more nearly it seems to be an infinitely sharp line separating
uniform white from uniform dark. The edge itself is there -- but you can't
see it as an object. It's just a sense of edgeness. Only under special
conditions, as in looking at a smooth gradient of illumination going over a
relatively short distance from white to black do you see edge effects like
the "Mach band", the only clear subjective evidence of edge enhancement.
However those neural signals enhanced at edges are processed, the result is
that step changes look like step changes, not outlines as in cartoons.
Whatever model we come up with for how the nervous system processes pixel
information, it must result in edges that look this way, without borders.
If it doesn't, the model is wrong.

The next step is to notice that the edges and corners and broad white areas
of the piece of paper add up to -- a piece of paper. If you've made this
transition properly, it will come as a surprise. Where did that piece of
paper, or piece-of-paperness, come from? It wasn't there in the edge, or
the corner, or the whiteness, or the darkness. It comes into being only
when all those elements are seen grouped into a thing, a configuration with
a familiar shape, orientation, distance, size, and so on. The Gestalt
psychologists of old spent a lot of time looking at things like these. They
should have kept going. Or perhaps they shouldn't have been cowed by the

You have to go slowly and by the smallest steps you can devise. If you go
too fast you'll miss the smallest steps; if you miss the smallest steps
you'll lose the sense of examining perceptions, and start projecting the
visual field into an external world again. You'll jump to the more abstract
levels and lose the connection from one level to the next. This is, if you
like, a form of meditation on experience in which you distance yourself
from experience and look at it merely as a display. You're not trying to
see anything about the world, but only something about the display. You're
trying to see what features the person who constructed it thought of
putting into it, just as when you read a program you think to yourself "Now
he's setting up an array to hold the results" instead of just reading the
code, or when you read a novel as a literary critic you think "Now he's
introducing tension" instead of just getting tense. Who the "he" is is
immaterial -- the point is to see what is before you as a construction that
has inner organization, and try to see how it is put together.

The general principle is that when you have found a level, like sensation,
the next level is going to depend on it; also, the current level depends on
the one below it. If you analyze a perception to see what it is made of, at
first you see just more perceptions of the same level -- big configurations
are made of little configurations. But when you analyze in just the right
way, you suddenly realize that all configurations, of whatever size or
kind, are made of sensations, which are not configurations of any kind. And
you realize that if it weren't for the presence of those sensations, there
couldn't be any configuration to see: a field consisting of a single
sensation, such as white, can't lead to any sense of configuration. There's
a relationship between these levels of perception. That gives us a hint
about building models of perception, a hint about how the brain's
perceptual system is constructed.

Sometimes you will identify what seems to be a higher level of perception,
some characteristic common to all perceptions, unconnected to lower levels
you have previously seen. Then you can use this kind of analysis to try to
fill in the gap. What is this new perception made of, besides smaller
perceptions of the same kind? When the gap is large, the missing steps are
obvious. You can, for example, look at spatial relationships such as "on"
-- something being "on" something else. You can see the on-ness clearly,
it's right in front of you. But what is it made of? If you said
"sensations" you would clearly be making too large a jump, because on-ness
involves objects, things, configurations. Some kind of object is "on" some
other kind of object. If it weren't for the impressions of distinct
objects, there couldn't be any sense of the relationship between them. But
is that step small enough? I've had to put two levels between relationships
and configurations: transitions (which can be zero), and events (which can
be as simple as mere duration). Seeing something "on" something else
involves more than a brief contact; there must be duration.

Perhaps someone else could find smaller steps still, or would characterize
the intervening steps differently. There's still a lot of room for
improving the definitions of the phenomena we're hoping ultimately to

I'm not talking here about the models themselves. I'm talking about the
attitude you take toward your own experiences when you're trying to notice
phenomena that need modeling. If you were a physicist you wouldn't be
taking this attitude. You'd treat the world of perception in the normal
unanalytical way as if it lay outside yourself where everyone could see it,
and you'd search for laws relating changes of one kind of perception to
other kinds of perceptions. You would call these "natural laws" or
"behavioral laws" and assume you were discovering truths about an objective

As a CT psychologist, however, you have a different objective: to grasp the
natural world as a manifestation of human perception (your own), and to
ferret out of it some regularities that tell us about perception rather
than about the world perceived. If you stumbled onto this attitude
accidentally, without understanding what you were doing, you might well
find yourself in a state with a clinical name: dissociation. I don't
recommend this attitude as one suitable for ordinary living. It's difficult
and uncomfortable, and it tends to strip the meaning from experience (until
you get past a certain point, after which you realize that meaning, too, is
perception, and let it back in). If you're afraid that understanding your
girl friend as a set of intensities, sensations, configurations,
transitions, events, relationships, categories, sequences, programs,
principles, and system concepts in your brain might strain your feeling
toward her (and hers toward you), don't do this with your girl friend. Do
it with somebody else's, or a laboratory rat. It doesn't matter who or what
you do it to, because you're really talking about your own perceptions.
This is a private experience valid only in one person's world. It can
become public only to the extent that different people independently arrive
at the same analysis. I've always hoped for that, but only a very few
people, to my knowledge, have tried this for themselves. Most people just
memorize my definitions, which unfortunately are in words. It's easier to
push words around than to shut up and examine direct experience.

You'll hear objections to this process alluding to introspectionism, which
failed to get anywhere a long time ago. But introspectionism didn't fail
because it looked at the kinds of things I'm talking about here. It failed
because it confused the subjective with the objective (and so did its
critics). The world that I'm speaking of examining here would be called, by
most conventional scientists, the objective world, not the subjective one.
I'm not recommnending shifting attention off the objective world and
plunging into the dim and uncertain world of inner phenomena -- or what we
imagine to be inner phenomena. I'm recommending a change of attitude toward
the world we normally consider to be the objective one, which includes the
world outside us and our bodies as we experience them. I'm saying that you
will learn something if you look on this world as directly experienced
evidence about the nature of your own perceptual system, and only in a
conjectural way about the world that is actually outside you.

Instead of treating relationships like on, beside, after, with, and into as
properties of the external world, look on them as perceptions constructed
on a base of lower-level perceptions. Instead of seeing categories as made
of things that are inherently alike, think of categories as ways of
perceiving that MAKE things appear to be alike -- things that are actually,
at lower levels of perception, different. Instead of seeing sequential
ordering as a fact of nature, see it as a way of putting ordering into an
otherwise continuous of miscellaneous flow. In short, take nothing about
experience for granted, as if some aspects of experience were really
outside and others were inner interpretations. Put the whole thing inside,
and see what you come up with when you understand that it's all perception.
All of it.

Final notes:

In HPCT diagrams, we show signals coming out of perceptual functions and
going into higher-level ones (as well as the local comparator, if the
signal is under control). I think of these lines as representing single
neural signals that vary in only one dimension: how much. This can be
confusing, because we don't experience single signals under normal
circumstances (when we do they cease to be meaningful). Instead we
experience all the signals within the scope of awareness, at every level in
the state we call conscious. To understand what the single-signal concept
means, you have to break this world of simultaneous perceptions into its
components, the individual and independent dimensions in which the totality
of perception can vary. You have truly identified one isolated perception
when it can vary only in the degree to which it's present, which we
experience as its state. If the perception varies without in the slightest
changing its identity, you have probably noticed a single signal.

This can be important when you talk about control. We talk loosely about
controlling "a dog," for example. But that way of talking is really lumping
many independently variable aspects of the dog together. You don't control
its species, or its eye color, or the length of its tail. You don't even
control its behavior. If it's behavior you're controlling, you always
control the radius within which it can move, by putting it on a chain. You
may control its speed of walking by saying "stay" or "follow," and its path
by saying "heel." Whatever you control, it must come down to a single
variable or small sets of variables independently controlled. If you're
controlling in more than one dimension, you must sense more than one
variable, and have a control system operating independently for each one.
That's because independent dimensions can be independently disturbed; you
need independent control systems so that a disturbance in one dimension can
be corrected without necessarily causing an error in another dimension.

None of this answers your question as to how perceptual signals in a
diagram depend on perceptual signals lower in the diagram. The only general
answer I can give is that some computation lies between them. The input
data consists of lower-level perceptions; the output data, the higher-level
perceptual signal, represents the value of the function being computed over
and over or continuously. At each level, I presume (judging from the way
the context changes every time you consider a higher level), a new type of
computation is involved, not simply a repetition of the kind of computation
at the lower level. The process of deriving categories from sets of
relationships can't be carried out by the same kind of computation that
derives relationships from sets of events or lower perceptions. There is no
one kind of computation that could serve at all levels.

But as I say, I am, we all are, a very long way from grasping what these
kinds of computations are. Every time people come up with a new computer
program for recognizing objects, they try to establish this new computation
as the blueprint for the whole perceptual system. This is a waste of time.
The blueprint changes with every level. Weighted algebraic summation is
simply not going to suffice to model our capacity to recognize and execute
a program described in words: a rule. Even though such networks are
purported to recognize categories, I think that the categoryness is read
into the results by a human observer. I don't think that any category-
recognizing back-propagation model will actually create what human beings
experience as categories -- for example, the category "wife." Of the eleven
levels of perception in my model, I think we know how model two of them,
the first two. All the rest of our modeling presents to us what a human
being might recognize as a higher-level perception, but which the circuit
or program itself does not recognize -- or control.

In that I could be wrong, of course, because I speak the truth when I say I
don't know how the higher levels of perception work. That means I don't
know how they don't work, too. I'm just expressing a hunch.

It's late and I've posted this so I could get to sleep (some ideas just
have to leak out through the fingers before they'll let you alone). I'll
get to comments on other interesting mail tomorrow.



Bill P.

[From Bruce Buchanan 950311.20:30 (EST)]

Bill Powers (950307.1625 MST) writes:

What we have now is an 11-level hypothesis in which each level is
supposedly dependent on the existence of the level below and is derived
from it. There is no way to prove that this dependency exists except by
looking at your own experiences and seeing if the idea still holds up.
There's no single rule that will allow you to deduce the next level up
from the existing levels; you just have to look and see what's there, in
your own experience. . . .

What all this suggests is that any level of perception can be a function
of perceptions of _any lower level_. Why not higher levels, too? Well,
I've tried that on, and all I can say is that I can't make sense of it.
Maybe someone else can.

I am not sure that I can make complete sense of the ways in which lower
level perceptions may be a function of higher levels but I think the
question is important. And some of the answers which have been given by
persuasive individuals and groups appear real enough to others to have
power in the world.

In approaching such a discussion I remind myself that, in trying to
understand a thinker (such as Bill Powers), it is useful to try to
understand (and this may be obvious to PCT in other terms) what particular
problems that thinker is addressing (implicitly or explicitly), and a
related question, what system boundaries are being assumed or drawn.

I am also aware, as are many others in the csgnet, of the implications of
Goedel's Theorem i.e. that is not possible to assess the adequacy and
completeness of any self-consistent theory or system of ideas from within
that system. Now, it may be considered that accepted methods of empirical
verification will allow for the necessary checks and tests. However to the
extent that methods are dependent upon a particular theory this may still
be problematic. As I say, I do not have the answers, but the problems are
there, and valid answers must take into account all aspects of the

So the question stands as to where the boundaries of one's conceptual
systems might most usefully be drawn. My own answer is that there should be
no arbitrary or preassigned limit, that the boundaries of human experience
are not limited to conceptual categories, and therefore cannot be
predefined or predicted. It also seems to me that, in the present state of
our understanding, we cannot with certainty predict from any particular
levels of perception what may be perceived at another level, either
subjectively or in others.

Returning to the point with with which I began, and acknowledging the
messiness or inherent uncertainties of societal values, it is a fact of
daily experience that personal and social values provide some of the
framework of context and purpose within which lower level perceptions do in
practice occur. While the lower levels may be primary requirements, most
if not all individuals learn to anticipate events and assess the
desirability and hazards of possibilities they face. Inevitably these
valuations provide a framework within which new experiences will be

These are realities of social life, and include economic and political
views and questions, as well as efforts by business to clarify values and
objectives to improve cooperation and efficiency, some at least of which is
generated by needs for conflict resolution, which is a function for higher
values and/or evaluative criteria which makes sense to me.

In summary I do not see the alternatives as being either a bottoms-up or a
top-down approach, but rather an approach which accepts a variety of
starting points involving different levels as potentially useful for a
variety of purposes, and particularly for conflict resolution.

Well, the question was posed (whether rhetorical or not), so I took the bait!

Cheers and best wishes.

Bruce B.

<[Bill Leach 950312.10:24 EST(EDT)]

[Bruce Buchanan 950311.20:30 (EST)]

And some of the answers which have been given by persuasive individuals
and groups appear real enough to others to have power in the world.

While I also feel that many ideas presented by serious 'thinkers' of the
present and past have merit the real question (from a PCT perspective) is
how much of their conclusions are based upon arbitrary assumptions.

Even the concept of 'individual survival' has at times been clearly of
lower priority than other goals. If there really was some 'natural law'
of survival then it seems unreasonable that some many people could have
violated such a law.

In approaching such a discussion I remind myself that, in trying to
understand a thinker (such as Bill Powers), it is useful to try to
understand (and this may be obvious to PCT in other terms) what
particular problems that thinker is addressing (implicitly or
explicitly), and a related question, what system boundaries are being
assumed or drawn.

Well, from a PCT point of view I suspect that 'the question' itself is of
little import. What is important is what inferences are being used and
to what extent is the 'thinker' recognizing such.

<[Bill Leach 950312.20:52 EST(EDT)]

[Bill Leach 950312.10:24 EST(EDT)]

Computers! Ha! Things have a 'mind' of their own.

For some reason, the computer decided that I did not like the majority of
my last message and also decided not to send it!

However, after having read Bill P.'s reply, I don't believe that what I
had to say would contribute anything worthwhile.


[From Bruce Buchanan 950313.23:30 (EST)]

Bill Powers (950312.0700 MST) writes:

(I wrote - 950311.20:30 (EST):

    boundaries of human experience are not limited to conceptual
    categories, and therefore cannot be predefined or predicted. )

I presume you're alluding to the question of individual versus social
systems. The properties of the system you study depend on where the
boundaries are drawn. When you study individual behavior, the most
useful place to draw the boundaries is at the input and output surfaces
of the individual.

No, I am really trying not to discuss systems at all, but rather to allude
to the actual phenomenology e.g. of perception, as described by e.g.
Merleau-Ponty and others (e.g. Popper, Jaspers) in more detail. I am
saying that placing boundaries or creating a clearly defined system for
purposes of description and analysis is entirely legitimate as a method,
but it does not exhaust the universe of possibilities.

(To be as explicit as possible, I am continuing to argue in what follows
for the philosophical position I would identify as phenomenological
existentialism. However I am not a professional philosopher, only a
problem-solving physician/psychiatrist trying to be clear about all my

      . . .The units of a social system are whole persons; the
social system does not have the same properties as the individual.

Right. A social system - or its component political, economic, legal, etc.
subsystems and their interactions - have their own logic and properties.
Their units may be whole persons, or they may be markets or interest
groups,etc. depending upon the problems selected and the analysis required.

When you say "... the boundaries of human experience are not limited to
conceptual categories, and therefore cannot be predefined or predicted,"
this is something of a non-sequitur. It sounds suspiciously like saying
that human experience is too vast and complicated to be explained, so we
shouldn't try at all. While I could agree that our theories have a long
way to go toward explaining it, I wouldn't agree that the effort isn't
worth while.. . .

I am not saying that attempts should not be made, but that useful attempts
are likely to be those most conscious of the methodological requirements.
(I know this will sound like preaching to the preacher again! ;-)) These
include an insistance on presupposition rather than conviction, so that any
boundaries drawn are provisional, i.e.subject to revision. I do not expect
disagreement with this in principle. However, it I contend that there are
human behaviors in the aggregate that cannot be understood and dealt with
in terms of a model that draws the boundaries "at the input and output
surfaces of the individual", then I am not so sure of agreement within csg.

There are areas of explanation that are useful and
possible, and I believe they can include considerably more than some
people have heretofore assumed is possible -- like explaining what a
"value" is.

Right. It is where we get into what I would call shared social values that
our discussions have seemed to me to get into trouble. To me, such
questions, which may also involve social responsibilities, may involve
something more, and more important, than the forcing of one person's
demands for compliance upon another. But I will not pursue that further

               . . . some of the answers which have
    been given by persuasive individuals and groups appear real enough
    to others to have power in the world.

That's a teaser -- how about laying out what some of these answers are?

This was not intended to be subtle or complicated. I meant the views that
the leaders of the great historical religions and nations and dominant
economic interests have severally and jointly used to structure societies
and the world as we know it.

On this point [Bill Leach 950312.10:24 EST(EDT)] also commented:

While I also feel that many ideas presented by serious 'thinkers' of the
present and past have merit the real question (from a PCT perspective) is
how much of their conclusions are based upon arbitrary assumptions.

I was not referring only to "serious thinkers" - unless these are thought
to include those who view truth in simplistic terms e.g. as "anything that
works", including the use of force, direct or indirect (e.g. via the law).

It also seems to me, however, that some human creations are the result of
decisions which might be termed arbitrary, in that they settle upon a
particular goal, to the exclusion of others, even on a roll of the dice.
Yet in some situations this may be the only strategy available to break a
paralyzing impasse.

In an experimental science there is always something outside the system
of ideas that works to expose inconsistencies of the system with nature,
as you hint.

Yes, it this were not so there would be no clear distinction between nature
and the models we can create, and clearly none of us is omniscient.

             . . .it is a
    fact of daily experience that personal and social values provide
    some of the framework of context and purpose within which lower
    level perceptions do in practice occur.

I think that this discussion would be more fruitful if you could give an
example or two of what you mean by "social values" as opposed to
"personal values."

Here again, I mean nothing very complicated. An example might be the
scientist's conception of criteria for truth, and presumably the Truth
value accepted by his colleagues, at least insofar as science is a social
enterprise (as in part it is, as recently discussed in the csgnet). I
guess I am supposing that, if social values are to be anything more than
impositions upon the inividual by parents and others, and are to be
anything more useful to members of a group than an outcome of anarchic
processes, then social values must involve their own level of effect and
justification ( - which I understand to be an unresolved problem - or
perhaps not a problem at all! - within PCT).

There is nothing in PCT that argues against personal
values; all that is problematical is whether any of them are inborn or
necessarily implicit in a given social situation, and perhaps where,
physically, they exist. Is there any difference between "reference
level" and "value" as you use the terms?

The difference I see here is that reference levels are individual and
derived from lower level perceptions and processes. I understand by values
superordinate criteria, mostly associated with language and culture, for
socially accepted ideas as to what is good, true, right and beautiful,
etc., which provide a basis and justification for many lower level
purposes. It seems to me that massive confusion in regard to values which
may be held to justify various human purposes are a source of many social
problems. I do not see many of these problems clarified by the view that
such values are no more than fictions which suit the convenience of those
in power, which has been my perception of some views on PCTers.

    These are realities of social life, and include economic and
    political views and questions, as well as efforts by business to
    clarify values and objectives to improve cooperation and
    efficiency, some at least of which is generated by needs for
    conflict resolution, which is a function for higher values and/or
    evaluative criteria which makes sense to me.

I'm puzzled as to why you keep returning to these noncontroversial
assertions. You seem to be implying that the subject of values has been
left out of PCT.

Once bitten, twice shy. I am not very sure of what is noncontroversial from
the point of PCT, which doubtless reflects my inexperience. For instance I
would have thought that the idea of social responsibility might have some
basis or justification in PCT thinking was noncontroversial, but some time
ago I found myself mistaken. as I thought, in that expectation.

an example of
"starting points involving different levels" would be helpful.

As I understand the various attempts to study man scientifically, from
genetics, through anatomy and physiology, individual behavior, family and
group dynamics, sociology, anthropology, economics, etc., each discipline
must start with the phenomena observed at its own level and attempt to
elucidate patterns and relationships. It may be that relationships among
levels can be discovered e.g. genetic factors in physiological development.
Reductionists have been wont to claim that someday everything will be
explained in terms of physics and chemistry, but at this stage of knowledge
that claim may be considered a matter of faith. Again, I did not intend
anything very abstruse.

As for conflict resolution, have you found the analysis of conflict in
PCT useful, as well as the implied methods of resolving conflicts?

Well, I have reread Chapt. 17 (Conflict and Control) in B:CP, with the
following reflections, which I offer not because I think they are
definitive but because I doubt that they are thoughts unique to one person,
and they may provide some basis for keeping the framework of discussion

I would acknowledge that, regardless of where conflicts may originate, if
they disturb human beings they involve perception. However, solution to
conflicts may also require attention to their more remote origins.

Re Logical conflicts - these may not only be logical. The Prisoner's
Dilemma may represent a type of real situation requiring interpersonal and
social strategies, in which computer gaming shows the tit-for-tat response
to be perhaps the most effective. And it seems to me that this is not
without interest in relation to the resolution of practical conflicts in
complex social situations involving many unknowns, including the issues of
war and peace studied by Rapoport.

In a similar vein, teachers of successful negotiation methods emphasize the
need to discriminate among relative priorities which the parties attach to
the various elements within a proposed agreement. It is recognized that the
desires of people differ, and on such grounds, because a deal means
different things in different ways to each party, a mutual win-win deal may
be devised. Here the social context provides a very real additional
dimension to the conflict and its resolution.

While there is no doubt that inner conflict may involve two or more
simultaneous and incompatible goals, and that the imposition of arbitrary
external demands or forces can create and add to this, there are also
conflicts with environmental forces which may require to be dealt with as
such. Of course hunger may affect intrinsic needs and variables, but if the
problem is theft and/or social oppression then recourse to physical force
may be seen as necessary, (as the text points out). And by the same token,
recourse to force may be seen as necessary by members of a group who wish
to protect themselves and their families from predators, including various
individuals, hence recourse to rules of law.

It seems to me an illusion to suppose that conflicts between individuals
and groups will ever be managed without some kind of appeal to physical
force, and circumstances which might require this do not appear to me to be
admitted by PCT, but perhaps I am mistaken in this.

Perhaps it is evident that I am still struggling with values as conceived
from a perspective of the social commons - of the shared assets and
requirements for social living - and the contributions of individuals to
the decisions made in this regard. While many wise heads have been shaken
over these problems in the past, what is recorded in books will not have
any effect except through those who seek to understand and apply the
principles. This is basically what I am trying to do, however

Cheers and best wishes!

Bruce B.

[Lars Christian Smith (950314 14:00 CET)]


To: Bill Williams, Bill Powers

Subject: Giffen Effect and Behavioral Ecology

Yesterday I got a disk from Dag Forssell with PCT goodies, including the
CROWD program, and posts from an economics thread. Here are
some ideas about how the two food resources in the Giffen
paradox, meat and bread, could be extended to a model with _n_ resources.

In optimal foraging theory an animal travels though a landscape,
encountering a number of resources. These resources are ranked in terms
of returns to effort.

The highest ranked resource should always be pursued upon encounter when
foraging. Lower ranked resources should be included in the set of
exploited resources until the next most profitable resource yields a
lower return upon encounter than could be obtained by continuing to
search for and pursue the more profitable items (the total number of
resources included in the optimal diet is referred to as 'diet breadth').

To see how this works, consider a forager walking across a landscape with
mango trees (large fruits, little preparation necessary) and walnut
trees (small fruits, hard to prepare). Should he climb every walnut tree
he encounters, or only the mango trees? The answer depends on how many
trees there are. If there are a lot, it wouldn't make sense to climb the
walnut trees. On the other hand, no matter how scarce the mango trees, if
he happens to encounter one, he should climb it.

So here is a proposed modification to the CROWD program. People move from
a home base (a camp) to goals, which are food resources (you can think of
them as plants). There a several kinds of plants. They sprout at
various intervals.

We need a daily energy requirement control system, and a control system
for the calculation of the overall foraging efficiency in order to decide
whether an encountered food item will increase or decrease overall
foraging efficiency.

The foragers will move through the landscape, decide which plants to eat,
and return to the home base when they have met their daily energy

An additional refinement would be to consider the case where the
resources are depleted faster than they sprout. The home base then needs
to be moved, e.g. to a distance 2 times the radius of the previously
exploited area.

What would be the most realistic way (i.e. closest to the way animals or
humans do it) of modelling the calculation of overall foraging efficiency?