Re: Informational Masking

[Peter Lennox <peter@xxxxxxxxxxxxxxxxxxxxxxxx>]

Right.
I said I was probably mixing several phenomena in together. Unsurprisingly,
I underestimated how many!
Taking speech as an example, which is a very peculiar 'special case' kind of
listening (happy to expand/expound if necessary), I can think of many
examples where I'm able to repeat, after a period, a very reasonable
representation of the sound of the sentence which had been spoken to me,
even though so doing produces a sentence which is complete nonsense. On
re-hearing the original, one can hear the similarities, and in fact if my
long-suffering wife (who is admittedly annoyed by such antics!) doesn't
exactly repeat the sentence, but paraphrases in some way, I find it fairly
easy to arrive at the original, using 'meaning' to enrich the 'stored
approximation' of the *sound* of the sentence. Note that i find I can't do
this if I understood the original at the time of reception. Note also that,
in the 'gobbledegook' reconstruction of the sentence, it's usually the
consonants that I've got wrong (.....I think). The vowel sounds seem fairly
right, and the rhythm overall seems right, even though the division into
words has often gone awry.
Now this may be a slightly different thing to the experience of seeking out
something which has made a noise, then stopped. Here, (and I'm talking about
'real world' examples rather than psychophysics-lab examples) I find that a
sort of 'mental reiteration' of the sound may yield additional spatial
information (I don't particularly mean inter-aural difference information,
as this works even as one moves about), which may be used to 'home in' on
the likely position-and-source.
But both these examples may well relate to a finite storage capacity (even
if that capacity is able to re-iterate to itself in the absence of further
input), because new input seems to obliterate the phenomenon.

The point is that this sort of memory store may well be useful in holding
'undigested' chunks (sorry about the unappetising metaphor!) pending
apprehension of further, useful information which may well be of utility in
processing it. And to that extent, it does seem to relate to speech
processing (I think Jackendoff wrote something about this). Now, this may be
somewhat different to the way a sentence heard a few moments ago suddenly
makes sense in the light of a new sentence; here, we are talking about a
sentence which has been processed, but doesn't quite fit into an unerstood
scheme of things until new facts are revealed.
But, for me, the difficulty I've always had with Gibson's approach comes up
because this type of 'unprocessed-sensation storage' doesn't seem as
necessary in vision as in hearing. In insisting that all information is
external to the percipient, and allthough he stressed the notion of an
ambulant percipient, I never really got the sense of the role of various
types of memory in perception. Sorry if I've oversimplified this a bit.
But the idea that we perceive the 'now' only in the light of already
processed contexts from the past, a sort of unidirectional flow of
information-with-time, simply will not do (to quote Gibson!).  The
alternative is to say that memory (in various forms of sophistication of
processing) is a (the?) central part of 'real-world' perception, and in
which case doesn't this imply that some sort of internal scheme of things is
required, to map things onto? That this scheme-of-things might be highly
metaphorical seems fine (in other words we remember the 'meaning' of things
and events rather than the actuality of their physical characteristics), but
doesn't this absolutely seem to require a buffer storage for
'un-metaphoricised' sense-data?
regards,
ppl
----- Original Message -----
From: "Christian Kaernbach" <chris@PSYCHOLOGIE.UNI-LEIPZIG.DE>
To: <AUDITORY@LISTS.MCGILL.CA>
Sent: 02 March 2001 07:16
Subject: Re: Informational Masking


> Peter Lennox wrote:
> > I've also noticed what a complex phenomenon this information-masking
> > is, compared to signal-masking. If my wife speaks to me when I'm
> > trying to fix this blessed computer, it can take me 15 minutes to
> > respond! (if at all). I'm not just being facetious here; I seem to
> > observe that it is possible to 'store' apparently (fairly)
> > unprocessed 'sound chunks', and 're-listen' to them a short time
> > later, and *only then* understand them.
>
> I guess you are storing not unprocessed sound chunks but auditorily
> well-processed items on a priority-based schedule. Proof: tell your wife
> to intersperse once a week sentences like "I'm going to switch off the
> main fuse, so all electric devices will go down" in the same voice as
> she would say "I'm back in ten minutes but I just have to get this silk
> scarf." She should say both types of sentences in self-chosen wordings,
> and let action follow. I bet you will process the first type of sentence
> at quite a different speed.
>
>         ;-)  Christian Kaernbach
>