Mike Tintner wrote:
RL: One thing that can be easily measured is the "activation" of lexical
items related in various ways to a presented word (i.e. show the subject
the word "Doctor" and test to see if the word "Nurse" gets activated).
It turns out that within an extremely short time of the forst word being
seen, a very large numbmer of other words have their activations raised
significantly. Now, whichever way you interpret these (so called
"priming") results, one thing is not in doubt: there is massively
parallel activation of lexical units going on during language processing.
Thanks for reply. How many associations are activated? How do we know
neuroscientifically they are associations to the words being processed
and not something else entirely? Out of interest, can you give me a ball
park estimate of how many associations you personally think are
activated, say, in in a few seconds, in processing sentences like:
"The doctor made a move on the nurse."
"Relationships between staff in health organizations are fraught with
complexities"
No, I'm not trying to be ridiculously demanding or asking you to be
ridiculously exact. As you probably know by now, I see the processing of
sentences as involving several levels, especially for the second
sentence, but I don't see the number of associations as that many. Let's
be generous and guess hundreds for the items in the above sentences. But
a computer program, as I understand, will be typically searching through
anywhere between thousands, millions and way upwards.
I am not sure how many, but my understanding of the literature is that
very large numbers show priming, and that it is proportional to
association strength or semantic relatedness, measured some other way.
The speed is also interesting: the effect can occur within about 140 ms
of the word being shown. At the brain's clock speed, that would be
maybe 300 clocks. Not much time for anything except parallel processing
in that short a time.
On the one hand, we can perhaps agree that one of the brain's glories is
that it can very rapidly draw analogies - that I can quickly produce a
string of associations like, say, "snake", "rope," "chain", "spaghetti
strand," - and you may quickly be able to continue that string with
further associations, (like "string"). I believe that power is mainly
based on "look-up" - literally finding matching shapes at speed. But I
don't see the brain as checking through huge numbers of such shapes. (It
would be enormously demanding on resources, given that these are complex
pictures, no?).
It would be a problem if it were checking pictures. The standard model
is that there are links already established between concepts, as a
result of experience, and all it is doing is propagating activation
along links, in parallel.
It does depend on whether these are analogies or just associations.
(related, of course).
As evidence , I'd point to what happens if you try to keep producing
further analogies. The brain rapidly slows down. It gets harder and
harder. And yet you will be able to keep producing further examples from
memory virtually for ever - just slower and slower. Relevant images/
concepts are there, but it's not easy to access them. That's why
copywriters get well paid to, in effect, keep searching for similar
analogies ("as cool/refreshing as..."). It's hard work. If that many
relevant shapes were being unconsciously activated as you seem to be
suggesting, it shouldn't be such protracted work.
Generating analogies of that sort would not be the same effect. I make
no claims for that specific thing, only for the activation of
semantically related or associated concepts.
The brain can literally connect any thing to any other thing with, so to
speak, 6 degrees of separation - but I don't think it can conect that
many things at once.
That is just low-level (neuron connectivity). That doesn't speak to
higher level systems.
I accept that this is still neuroscientifically an open issue, (& I'd be
grateful for pointers to the research you're referring to). But I would
have thought it obvious that the brain has massively inferior search
capabilities to those of computers - that, surely, is a major reasonwhy
we invented computers in the first place - they're a massive extension
of our powers.
Too many imponderable here, but in general, no: the brain may still
have the edge for some types of parallel search.
And yet the brain can draw analogies, and basically, with minor
exceptions, computers still can't.
Now you skip to different issue: we don't know the *mechanism* involved
in analogy finding. That is why compters cannot do it. It is not that
computers lack the processing power or connectivity.
I think it's clear that computers
won't catch up here by quantitatively increasing their powers still
further. If you're digging a hole in the wrong place, digging further &
quicker won't help. (I'm arguing a variant of your own argument against
Edward P!). But of course when your education and technology dispose you
to dig in just those places, it's extremely hard to change your ways -
or even believe, pace Edward, that change is necessary at all. After
all, look at the size of those holes.. surely, we'll hit the Promised
Land anytime now.
P.S. In general, the brain is hugely irrational - it can only maintain a
reflective, concentrated train of thought for literally seconds, not
minutes before going off at tangents. It continually and necessarily
jumps to conclusions. Such irrationality is highly adaptive in a
fast-moving world where you can't hang around thinking about things for
long. The idea that this same brain is systematically, thoroughly
searching through, let's say, thousands or millions of variants on
ideas, seems to me seriously at odds with this irrationality. (But I'm
interested in all relevant research).
There are too many angles to address this.
Richard Loosemore
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