Hi
On Thu, 21 Jan 1999, Paul C. Smith wrote:
> Karen Yanowitz wrote:
> > Hi all-- In Cognitive this morning, I was explaining that information
> > can be encoded differently in stm depending on type of info etc -
> > student asked if there were developmental differences in ability to
> > encode- for example acoustic vs visual-- that stumped me!- anyone
> > have an answer?
With respect to Karen's question, I know the answer (but not
offhand a direct source ... let me know if that is important).
STM capacity (e.g., memory span) is highly correlated with speech
rate. Faster speakers have longer STMs, presumably because they
can keep more items in the articulatory or rehearsal loop. I
have seen a plot showing this relationship with people of
different ages providing the dramatic differences in speech rate.
That is, younger speakers talk more slowly and have shorter
memory spans.
> I don't have an answer, but I have a related question. I'm teaching a
> learning and cognition course this spring, using
>
> Bruning, R. H., Schraw, G. J., & Ronning, R. R. (1999). Cognitive psychology
> and instruction (3rd ed.). Upper Saddle River, NJ: Merrill.
>
> When the authors discuss the Sperling partial report study, they write that
> it appears that the capacity of the sensory registers is roughly 7-9 items.
> Later they say that it's a little more than 7 items. In the next chapter
> they say that it's around 7 items. (I'd provide exactly quotes, but I left
> the book out in my car).
>
> I believe that the authors have confused the sensory registers with the
> stm/working memory, and that we still generally believe that the sensory
> registers' capacity is huge (essentially briefly containing EVERYTHING that
> comes in through the senses). That's what John Anderson says in "Cognitive
> Psychology and Its Implications", where he writes that the Sperling study
> suggests "a memory that can effectively hold all the information in the
> visual display". And it's what I've always believed.
I would side with you up to a point. The classic studies of
Sperling gave estimates of 12 or so items as I remember.
Something like, reporting one row of 4 columns produced
approximately 3 items correct (i.e., 75%). That percentage of 16
cells gives an estimate of 12 items. I don't know offhand
whether estimates based on cuing single cells (avoiding masking)
provide higher estimates as there could be some memory loss
trying to report 3-4 cells when a row is cued. The "up to a
point" concerns whether we can effectively hold _all_ the
information in the visual display. I think resolution and
identification falls off dramatically as one moves away from
fixation, so it would be necessary, I assume, to restrict this
claim to some effective part of the visual display.
Best wishes
Jim
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James M. Clark (204) 786-9313
Department of Psychology (204) 774-4134 Fax
University of Winnipeg 4L02A
Winnipeg, Manitoba R3B 2E9 [EMAIL PROTECTED]
CANADA http://www.uwinnipeg.ca/~clark
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