chertok%ucbkim%Berkeley@sri-unix.UUCP (04/04/84)
From: chertok%ucbkim@Berkeley (Paula Chertok)
[Forwarded from the CSLI bboard by Laws@SRI-AI.]
BERKELEY COGNITIVE SCIENCE PROGRAM
Spring 1984
IDS 237B - Cognitive Science Seminar
Time: Tuesday, April 10, 1984, 11-12:30pm
Location: 240 Bechtel
HOW THE MIND REFLECTS THE WORLD
Roger N. Shepard
Department of Psychology, Stanford University
Through biological evolution, enduring characteristics of
the world would tend to become internalized so that each
individual would not have to learn them de novo, through
trial and possibly fatal error. The most invariant charac-
teristics are quite abstract: (a) Space is locally three-
dimensional, Euclidean, and isotropic except for a gravita-
tionally conferred unique upright direction. (b) For any two
positions of a rigid object, there is a unique axis such
that the object can be most simply carried from the one
position to the other by a rotation around that axis
together with a translation along it. (c) Information avail-
able to us about the external world and about our relation
to it is analyzable into components corresponding to the
invariants of significant objects, spatial layouts, and
events and, also, into components corresponding to the tran-
sitory dispositions, states, and manners of change of these
and of the self relative to these. Having been internal-
ized, such characteristics manifest themselves as general
laws governing the representation of objects and events when
the relevant information is fully available (normal percep-
tion), when it is only partially available (perceptual fil-
ling in or perceptual interpretation of ambiguous stimuli),
and when it is entirely absent (imagery, dreaming, and
thought). Phenomena of identification, classification,
apparent motion, and imagined transformation illustrate the
precision and generality of the internalized constraints.
***** Followed by a lunchbag discussion with speaker *****
*** in the IHL Library (Second Floor, Bldg. T-4) from 12:30-2 ***