Re: IS THIS A COGNITIVE QUESTION ?

In <4502bc51$0$24191$9a6e19ea@xxxxxxxxxxxxxxxxxxxx>, Wolf K
El_Lobo_Viejo@xxxxxxxxxxxxxx said:
: Kali wrote:
: > In <45021bab$0$24196$9a6e19ea@xxxxxxxxxxxxxxxxxxxx>, Wolf K
: > El_Lobo_Viejo@xxxxxxxxxxxxxx said:
: > : Kali wrote:
: > : > In <44fc766d$0$20445$ed362ca5@xxxxxxxxxxxxxxxxxx>, Glen M.
: > : > Sizemore gmsizemore2@xxxxxxxxx said:
: > : > :
: > : > : "Sharat Shastri" <sharatsastry@xxxxxxxxx> wrote in message
: > : > : news:1157385850.217456.8870@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
: > : > : >A variety of viewpoints is what makes a discipline like CS all the more
: > : > : > critical. CS mayn't be pleased with individuals' perspectives; rather a
: > : > : > system or a theory under which an individual's ideas flourish and come
: > : > : > to be accepted.
: > : > : >
: > : > : > I'm right now reading a bit of visual perception in which it is defined
: > : > : > as the acquisition of knowledge about environmental objects and events
: > : > : > by extracting information from the light emitted or reflected on them.
: > : > :
: > : > : Where did you read this? This is really, really funny. I'm serious. I would
: > : > : really like to know where you came upon this.
: > : >
: > : > Every college level sensation and perception text book will
: > : > explain it in depth.
: > :
: > : [...]
: > :
: > : It's amazing how far "explanations" of tautologies can go, isn't it?
: > :
: > : Glen was being not so gently ironic. The fact is that we don't "extract
: > : information from the light." If the notion of extracting information has
: > : any validity, it applies to the responses of the rods and cones: we
: > : "extract information" from the _differences_ between these responses.
: > :
: > : Think about it.
: >
: > I did. I think the criticism is picayune. It takes no scholarly
: > muscle whatsoever to ridicule a student for a slight
: > interpretive error.
:
: I don't think it's a slight error, but a serious one, because it
: misdirects your attention.

Empirically we can say that it misdirects *your* attention away
from the heart of the discourse to the linguistic surface of it.

: If we "extract information from the light",
: we would expect the same light to produce the same perception under all
: circumstances, because the information in the light of a certain colour
: is always the same. That is simply not the case. The same colour looks
: different when placed next to different colours - a fact that everyone
: working with colour takes account of, and exploits. Even the texture of
: the surface has an effect. Etc.
:
: > I am not impressed by Sizemore's sarcastic
: > chest thumping nor your rush to defend it. It's easy to see why
: > this group is so dead.
: >
: > Kali
:
: This group is dead because the same errors keep cropping up, and people
: get huffy when their errors are pointed out to them. Sorry about that.

To clarify my earlier statement: pouncing on a learner for
using terminology that is incongruent with your philosophy, and
then framing it as an "error" is unnecessary and hostile.

What you call "getting huffy" can alternatively be seen as an
appropriate reaction to hostility.

: And have you thought about it? There is a great deal of difference
: between claiming that the visual system extracts information from light,
: and the claim that the visual system extracts information from
: differences between sensors' responses to light, as alluded to above.

For a novice to be *riduculed* for not explicating such a
difference in his/her Usenet post is absurd.

: I'll try to explain further:
:
: "Blue" is not a property of light, wavelength is.

Yes.........

: When a physicist
: speaks of "blue light", (s)he means light of a certain range of wave
: lengths. (S)he does not mean "light that looks blue", even though most
: of the time that happens to be the case.
:
: If wavelength alone determined what colour we see, we would not see the
: same colours in different lighting conditions. Yet we do. So much so,
: that pretty well everybody is surprised when colour film does not see
: the colours we see. So much so, that it takes light with a surprisingly
: limited range of wavelengths for us to notice that someone "looks
: funny in this light." So much so, that digital cameras must calculate a
: colour balance in order to record an image that we will see as correctly
: coloured. (That's why digital cameras don't take the picture as soon as
: you press the button - it takes time for the software to execute.) So
: much so, that people whose profession involves colour selection and
: colour matching make sure they use light of a certain "colour
: temperature", because otherwise the visual system's ability to
: compensate for light differences would cause inconsistent colour
: selection. So much so that auto-body shops now use colour calibrators to
: match paint rather than relying on a human operator's visual system. And
: so on.
:
: So you see, if you shift your attention from the information "in the
: light" to how the visual system responds to light, you can explain a lot
: more. What's more, you can understand some of the questions about seeing
: a lot better.

All very nice.

The OP said (quoted?), "[visual perception is defined as]
acquisition of knowledge about environmental objects and events
by extracting information from the light emitted or
reflected..." You (and Sizemore) object to the use of the term
"extracting information".

ex·tract (k-strkt)
"To derive or obtain (information, for example) from a source"

"To derive information about the environment from wavelengths of
light or the reflection of wavelengths of light"

Tell me how this does not, in generic terms, define visual
perception? Please explain why this is "really, really funny"?

: Unsolicited advice: Beware of textbook definitions. Far too often they
: are truisms, tautologies, or high level abstractions. They give you the
: illusion of understanding because truism, tautology and high level
: abstractions are obviously true. Dig into them. Apply them to examples
: and see how far they get you.

I generally rely on published research, and experts like
Kosslyn, Coren, and Enns for information about the visual
system. I also find the questions more exciting than the
answers. Your mileage may vary.

: And just in case you wonder about my credentials, I was a teacher at
: University and High School levels for over 30 years - so I know far too
: much about text book definitions. :-)
:
: HTH

I'm a cognitive psychology Ph.D. candidate who has been teaching
S & P (lecture and laboratory) at two universities for over
three years. I find that the more I learn, the less I know. At
least I can hope that I don't ever become so bogged down in the
dogma of my preferred philosophy that I can no longer see the
forest for the trees.

Kali
--
There are in fact two things, science and opinion; the former
begets knowledge, the latter ignorance.
Hippocrates (c460-c.377 BCE) Greek physician. Law
.

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