Though I am not sure, I suspect that your student has run across references
to "Parallel Distributed Processing" possibly through references to a
semi-famous debate in cog science journals centered on modeling the
acquisition of the english past tense.
There is a fair amount to be untangled here: Parallel Distributed
Processing has become a term applied only to one school: centered around
Rumelhart and McClelland and the former PDP group originally at UC San
Diego. (I've always wondered about this.) Connectionism has become the
favored academic term and that is the way that the most recent references
will be indexed. It should be distinguished from "Neural Networks" which is
a highly technical, and technologized offshoot which is unlikely to be
helpful.
Literacy acquisition is not my field, and my interest in these ideas are
through my focus on trying to understand just what it is that changes when
we say something has been learned-and how that necessarily material process
constrains theories of learning and instruction. So if I say the obvious
just let me know.
The seminal reference in the past tense debate is: McClelland, James L. and
David E. Rumelhart. "On Learning the Past Tenses of English Verbs." In
Parallel Distributed Processing, Volume 2: Psychological and Biological
Models, eds. David E. Rumelhart, James L. McClelland, and the PDP Research
Group, 216-271. Cambridge: MIT Press, 1986. It is in part a reaction to an
earlier Pinker book which relies on hidden explicit rules. A variant is
supposed to have appeared in MacWhinney's "Mechanisms of Language
Acquisition."
A reference that discusses the debate and should help open out to other
sources and lines of research is: Bechtel, William and Adele Abrahamsen.
Connectionism and the Mind. Cambridge, MA: Blackwell, 1991.
Hope this helps, and touches on what your student is interested in.
____Some laignappe--something a bit extra.
There is an interesting bit of history here: Rumelhart is generally
acknowledged as the formulator of the most recent version of the
influential concept of "schemata." Rumelhart's work was then focused on how
children learn to read for meaning and more specifically to understand how
it is possible to "make up" and extend stories in various genres--an
ability that he felt had to be tied to children's ability to read a text
creatively and to insert their own meanings. (I suspect he might have been
more cautious in his characterization but that is the way I read the
direction.) From this, pulling on Chomsky's generative grammar, and the
emerging formalism of Artificial Intelligence he developed a structuralist
concept of schemata as an acquired data structure 'filled' with differing
specifics from experience. You'll still see many pro forma references to
his 77 or 80 work in the educational literature using this concept. (Though
he always felt that his intuition about schemata was never matched by the
models because the representations he was using were not active enough.)
His radical revision of this idea and the reason for it has received very
little play in educational or other practice-oriented fields. In
Rumelhart's view the problems with his early attempts to instantiate the
concept lay in the inflexibility of the data structures; it was hard to see
how anything approaching the flexibility of human learning could result.
For Rumelhart and his colleagues the solution lay in abandoning the idea of
data structures, their problematic storage and retrieval, and dubious
filling of default assignments altogether. Inspired by the massively
parallel and distributed nature of the architecture of the brain they
postulated a massively interconnected system linked to the world in such a
deep way that representations were better thought of evoked by experience,
with each evocation being an unique response to the situation based on
prior experience. With the caveat that we can provide ourselves with
evocative models and replays of experience, the notion is that the entire
system is based on constraint satisfaction, it reorganizes in significant
ways in response to each experience and that we don't retrieve memories but
recreate them in terms of the immediate problematic situation. This gave
Rumelhart the dynamic, active schemata he wanted but at the cost of what
most folks would understand as representation. The fundamental operation is
pattern completion, not formal logic over basically static representations.
_____and some ruminations:
When I ran across connectionist ideas it seemed to me that they were almost
tailor-made to fit into the framework put forward by the pragmatists and I
still think so. But the pragmatist vision was much broader and included a
strong sense of the role of activity and "ends in view" (goals) than
connectionists have put forward. (I have come to understand those operating
out of Vygotskian or several other practice-oriented traditions might make
the same objection.) In the first chapter of the book cited above Rumelhart
et al. introduce issues of external representation, formal logic and goal
seeking and do a credible job of laying out a program to research these
from within a connectionist perspective. To my knowledge the issue of
formal logic has been rather handily dealt with but the other two crucial
elements, goals and external representation, have languished. This,
especially external representation seems ideal for situated perspectives to
comment on. Pragmatism certainly had a finely graded series of "ends in
view" to add to the tool box. -----But few working in practice oriented
traditions seem interested in the material basis of learning within folks
(as opposed to communities) and the ways that it might powerfully constrain
the way we theorize. The political, policy and cultural implications are
very large--facts vanish in the connectionist story and the structure of
testing that organizes schooling will make little "scientific sense" if
this view prevails (and it is my judgement that it will prevail.) Nate a
bit back introduced some suggestive material and got no response.
My Question: Why isn't the material basis for learning (in-the-head
learning) interesting?
Thanks for your patience, John
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John St. Julien (stjulien who-is-at udel.edu)
Department of Educational Development
University of Delaware