Category perception as a level of perception

[From Bill Powers (931122.0830 MST)]

Just had a nice weekend visit by David Goldstein. We had some
long discussions of the medical view of psychopathology, a
subject that might make an interesting thread for the net.

Bruce Nevin (931118.1628) --

I am hungry. Any particular perception that would reduce that
error is a member of the category "things that assuage hunger."
Even if I have never encountered a particular given perception
before, after a suitable process of trial and (often) error I
recognize it as "food", not by some process of creating a new
perceptual function for it on the category level, certainly not
by any ratiocination, but simply by the very process of
satisfying hunger (without ill side effects), something I could
do only in memory and imagination while I was hungry and
looking for food.

As I think I experience perceptions of various levels, all
perceptions lower than what I call categories are particular
present-time experiences. At lower levels I do not experience
apples, but this particular apple with its particular taste,
color, weight, position, size, surface markings, crunchy feel
when bitten, and so on. I experience this bounce of this ball,
this distance of my hand from this glass of water. Each
experience is an aspect of the unique present-time world.

At the category level as I experience it, there are no unique
perceptions. A perception is simply an example of a category.
When I refer to a certain experience I no longer say "the apple,"
but "an apple." If I speak of unique perceptions, I refer to them
in the plural: mothers, apples, cars, nouns, verbs, phonemes. The
experiences to which such words point are not unique present-time
experiences, but collections in which the elements have great
variety, yet all strike me as somehow being examples of the same
"kind" of thing.

When I am looking for "food" I do not consider all objects that I
encounter to be "food." Experience has taught me that not all
objects can be treated alike when I am hungry (something I didn't
know in 1927). I have formed a perception of a category that
contains such things as chocolate milkshakes, steaks, celery,
peanuts, pizzas, mushrooms, milk, avacados, and many other
things. It does not include kippers, octopus tentacles, ants,
mandarin oranges, raw liver, whale blubber, Rocky Mountain
oysters, human flesh, blankets, rocks, or battery acid.

When I am searching for food, I am not searching for specific
perceptions, but for a class-perception. Any lower-level
perception that I have learned to accept as an example of food
will end the search. There is no need to nibble each object to
see if it assuages hunger, and indeed I probably reject many
objects that would assuage hunger because they are not members of
the right perceptual category for me.

At the lower levels, control always concerns particular
perceptions. A search for a yellow apple will reject a red apple.
A search for a screwdriver will reject a nail file or a dime, or
even a screwdriver with a handle of a color other than that of
the handle of the reference screwdriver I'm looking for.
If I'm looking for my work-gloves, I can be looking straight at
the new work-gloves I had momentarily forgotten buying and not
see them as "my work gloves." A low-level search is always a
search for one specific perception.

At the category level, we do not control specific examples of
perceptions. What we seek is any perception that will yield a
signal from a certain category-perceiver -- we seek only that
signal, not any specific item. Presence or absence of that signal
depends only on which possible inputs are connected to a
particular category-level input function.

The perception of a category is present whenever I imagine
controlling some perception without imagining precisely which
of diverse possible means I use for the purpose. "Something to
pry this cover up with."

How do you control without specifying a reference signal? Without
a specific reference signal there can be no specific error
signal. Without a specific error signal there's nothing to drive
the action to continue searching, and no way to end the search.
You're describing an indefinite action, which is no action at
all.

Also, you're overlooking the fact that when you're controlling a
category-level perception (find the "nouns" in this sentence),
there is no particular perceptual signal implied at lower levels;
any perceptual signal in the right category will do. Without the
ability to perceive categories, you would have no way of telling
whether different perceptions would serve equally well to
accomplish "the same thing." The very concept of "the same thing"
is a category perception.

ยทยทยท

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I do not see a need for a separate category level.

What am I missing?

What you're missing is your own ability to perceive categories.
You say you can detect them when they're present, but in saying
that you're implying that they're not perceptions -- they're
"really present." You're saying that you know they exist without
needing any perceptual function to detect them. If perception of
a category is present, I claim there must be a category-
perceiver. Otherwise you wouldn't know that a category is
present. A basic postulate of PCT is that all perceptions are
outputs of perceptual functions. Maybe that's not true, but if
you want to claim that it isn't, you take on the burden of
explaining how we know about something without any perceptual
function to create a signal representing it.

Remember the thesis I'm putting forth: to a person whose
awareness occupies a particular level, perceptions of the kind
generated by that level seem to be not perceptions, but objective
features of the experienced world. So if you're viewing the world
from the category level, the world of experience will seem to
contain objective categories that require no perceptual
interpretation. The feeling is, "This isn't a perception; it's a
real category."
--------------------------------------------------------------
It would be informative if participants in this net would say
which perceptual levels (as I've defined them) they accept as
self-evident types of perceptions, and which seem to be simply
aspects of the world. We've already had examples of different
people rejecting specific (and different) levels but accepting
others (which other individuals reject). The rejections have not
seemed to me to be rejections of the type of variable itself, but
more like an assumption that those variables are objective
aspects of the world rather than perceptions.
---------------------------------------------------------------
Best,

Bill P.

[From: Bruce Nevin (Mon 931122 14:30:20 EST)]

Bill Powers (931122.0830 MST) --

The perception of a category is present whenever I imagine
controlling some perception without imagining precisely which
of diverse possible means I use for the purpose. "Something to
pry this cover up with."

How do you control without specifying a reference signal?

The reference signal is a movement of hand and arm with some imagined
object in my hand. I observe that when I begin to search for the tool,
as often as not my hand and arm actually sketch the motion they would
make using the tool, oriented appropriately toward the thing that I want
to pry up. Observing the process, it seems to me that I create an
incomplete gestalt which I then seek to complete. (I don't intend the
term "gestalt" to be especially theory-laden, it's just handy.) If I
imagine the prying motion as using a fulcrum between me and the edge of
the object to be lifted, or under that edge, then my search is for
something like a pry bar. This kind of choice blinds me to other
possibilities, unless I stop and imagine other possibilities. I can be
looking right at something capable of hooking under the far side, say, so
that pushing down on the near end does the job, but not even see it. If
I imagine the prying motion as using a point beyond the near edge of the
object as fulcrum, then I look for a different sort of tool, probably a
specialized one like a bottle opener or a flat wrecking bar with its
nail-grabbing hole in the blade.

If I am looking for an apple, it may be the imagined act of eating it
that I am seeking to flesh out. In that case, I may reject a particular
apple because of a worm hole. Or it may be that I want it for a pie that
just needs a few more chunks before the top crust goes on, and that one
will do just fine after I cut out the bad parts. Or the side opposite
the worm hole is symmetrical with good color, so it is just the thing for
the harvest display I'm setting up on the sideboard. It is not a
particular apple, nor the category apple, but the imagined result
including the apple, that guides my search. In the last instance, a good
counterfeit of wax or even plastic may suffice.

I do not see a need for a separate category level.

What am I missing?

What you're missing is your own ability to perceive categories.

That's right. And yours.

You say you can detect them when they're present, but in saying
that you're implying that they're not perceptions -- they're
"really present."

I don't think I said either of those things. I think you're putting
words in my mouth (or my keyboard). I said, rather, that I cannot
identify my perceptions of categories other than the "categoryness of
perceptions" and the using of words and other labels for purposes of
social communication (real and imagined). And I did not make any
attributions to "boss reality" or in any other way say that categories
are "really present."

I asked what evidence there is for category perceptions apart from these
two (symbols, and the "categoryness of perceptions"). Your description of
"the category level as I experience it" fits essentially without change
my account of imagining controlling some perception without specifying
which of various possible means I am using to control that perception.
Something to pry this up with. Something to finish this pie with so I
can put the crust on. Something to fit in this harvest display so.
Something to snack on that smells thus, and crunches thus between the
teeth thus, and tastes thus--mmm! my mouth is watering!

I think Rick's response is to the point:

Rick Marken (931122.0800)

I think it would be pretty hard to find such evidence. Even if we
were able to show that a (non-verbal) organism were able to catagorize
(behaviorally) perceptions that it could not name, someone could
always say that there still "must" be some mental equivalent of a word
mediating the categorization. I think that "perception of a category"
will have to remain nothing more than a vague hypothesis until there is
considerably more data about ALL the _kinds_ of perceptual variables that
organisms control, including (if such things exist -- and are not simply
words) category perceptions.

Just so.

Since you need imagination in the model anyway, perhaps it is worth
taking a look to see if it can do what you're attributing to a category
level.

    Bruce
    bn@bbn.com