AI, NN, and CNS

[Andrew J. Worth]

The main reason I posted the original "Connectionism vs. AI" question
was to imply that one should not gloss over the differences between
the two philosophies when combining them.  Many of the subsequent
postings illustrated the problem with the definitions used in the
question.  I believe that the question I was thinking of could have
been asked more succinctly by comparing the assumptions that lead to
"the explicitly symbolic nature of many AI endeavors" with a
connectionist approach that does not hold such assumptions.  But this
might unleash the symbol grounding debate.

In lieu of that, I would like to respond to Jim Bower's posting; do AI
and connectionism have anything to do with biology?  Again, it depends
on your definitions.  "Computational Neuroscience", as described by
Sejnowski, Koch, and Churchland [1] is an attempt to bring together
not just biology, but also psychology and other fields to explain
information processing in the brain using computational models.  The
results are "connectionist" models where emergent properties (not
explicit symbols and rules) become important.  Bower's assertion that
many neural networks have little to do with biology expresses a
regrettable fact.  But as Bower mentioned and as Sejnowski et al.
show, not all of connectionism ignores biology.

Other bodies of work that do not ignore biology are those by
Grossberg, et al. on vision and motor control [2,3].  Perhaps the most
painless introduction to some of these ideas can be found in [4].  A
practical demonstration of some of the vision work can be seen in [5].

It seems to me that the lure of connectionism is a haunting whispered
promise to go where no "AI" has gone before.  I consider attention to
biology in general, and Grossberg et al's techniques in particular, as
steps in the right direction.

[1] T.J. Sejnowski, C. Koch, and P.S. Churchland, Computational
    Neuroscience, Science, v.241, pp.1299-1306, 9 September 1988.
[2] S. Grossberg and M. Mingolla, Neural Dynamics of Perceptual
    Grouping: Textures, Boundaries and Emergent Segmentations,
    Perception & Psychophysics, v.38(2), 141-171, 1985.
[3] S. Grossberg & M. Kuperstein, Neural Dynamics of Adaptive Sensory-
    Motor Control, New York, Pergamon Press, 1989.
[4] S. Grossberg, Why do cells compete? UMAP Unit 484. The UMAP Journal,
    V.III, No.1 (Educational Development Center, 0197-3622/82/010101.)
   1982.
[5] S.M. Lehar, A.J. Worth, & D.N. Kennedy, Application of the Boundary
    Contour/Feature Contour System to Magnetic Resonance Brain Scan
    Imagery, Proc. of the International Joint Conf. on Neural Networks,
    v.I, p.435-440, 1990.

Andrew J. Worth                  worth at park.bu.edu
Cognitive & Neural Systems Prog. (617) 353-6741
Boston University                (617) 353-7857 (CAS Office)
111 Cummington St. Room 244      (617) 353-5235/6742 (CNS Grad Offices)
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