sn13+@andrew.cmu.edu (S. Narasimhan) (12/10/89)
People seem to "visualise" things, events etc. What exactly is this "visualisation"? By visualisation I don't mean in the sense of "visionary". What I mean
is that "visualisation" seems to be some process of memory retrieval.But it is not same as "remembering".Visualisation seems something more direct representation of things and events rather than a coded "thought" form.Visualisation is not even "imagination". I consider imagination as an extension of visualisation.However, "dreams" are more akin to visualisation.
Let us try to describe the phenomenon first.It seems to be a process where one "relives" a previous experience of things or events passively.Since "living"
thru an experience in some sense means thatone'ssenses are active during the event, reliving should mean the activity of senses to the same degree.However, I've said "passively".I intend to mean that visualisation is a reliving only that some of the senses are active otherwise it is experiencing and not visualising.But which of the senses are active? For one, the eye.
The selection of the word "visualisation" is not chancy.For, people do feel
that they are "seeing" things when they visualise.In what sense is the eye active? This is the crux.Now,how do we look at objects? As the eye looks at the object there is a certain MOVEMENT associated with the eye.This MOVEMENT is required
so as *focus* at certain locations of the object.My claim is: It is this eye movement which is recorded. An equally good claim is:it could be that the whole picture ,say in terms of pixels, is recorded in the memory.But this fails to explain the visualisation process which is not exactly "seeing".
This eye-movement theory could explain the following:
(1)how people can reason about geometrical shapes
(2)how people tend to remember mostly the interesting details of the object
rather than the whole thing
(3)how dreams are triggered
(4)why people tend to remember colors of objects poorly
(5)why people always don't stare at things
(6)how blind people can "visualise" things.
(7)how people can gauge velocity of an object.
(8)why people see some things but don't "notice" them.
(9)why one object can remind us of another etc.,
To avoid making this article too long I'm not discussing all of these.But I want to mention about the dreams.
Dreams are always associated with Rapid Eye Movement.I'm not sure which is the cause and which is effect? Do dreams cause eye movement or is it the vice versa ? But one thing is sure. We feel dreams as reality because of the associated eye movements.One should consider the following theory: Suppose that the rapid
eye movements are caused by some physiological phenomena and these eye movements in turn retrieved events and objects, and the reasoning part of the brain tries desperately to make a "Story" of these objects and events...does this explain dreams to some extent?
To summarise, it is possible that the brain records or indexes objects and events in memory thru eye movements.
Addendum: Have you wondered how you can look at a person's eyes and tell about his feelings?
S.Narasimhan "My dear fellow,you see but I observe"
sn13+@andrew.cmu.edu -- Sherlock Holmesolson@antares.cs.Virginia.EDU (Thomas J. Olson) (12/12/89)
There is a fair amount of literature on these topics that you might want to check out. Your ideas have some merit, but you need to look at other views and at the psychophysical facts to tighten them up. An old but interesting and accessable treatment of what visualisation might be about is Ned Block's 'Imagery' (MIT Pr 1981). For more recent introductory material, pick up any current Cog Sci text and look up 'mental imagery' in the index. A classic and fun reference on eye momements is A.L. Yarbus 'Eye Movements and Vision', Plenum 1967. For the current standard theory on perception of velocity, see the Oct 1985 issue of J. Optical Society of America A. Have fun, Tom Olson