Illusion - Is Seeing Really Believing?/Illusion - Is Seeing Really Believing (1998)(Marshall Media)[Mac-PC].iso/mac/ILLUSION/SROCK_TX.CXT/00350_Text_res19t.txt

Text File | 1996-12-31 | 2KB | 67 lines

    It is evident, then, that
investigators in perception
have not solved the problem of
the geometrical illusions,
although progress has been
made. Probably no one theory
can do justice to all of the
known illusions, and it may
well be the case that even a
single illusion is based on
several simultaneously
occurring factors. Of the
illusions considered here, it
seems warranted to suggest that
the Ponzo illusion (and the
corridor illusion, which is
similar to it) is jointly
determined by depth processing
and by contrast and
assimilation, that the
Poggendorff illusion is
explicable in terms of
unconscious depth processing,
and that the M├╝ller-Lyer
illusion is primarily the result
of an inability to isolate the
test lines or, otherwise stated,
of an incorrect comparison. But
these conclusions are put forth
only tentatively.

    To come back to a point made
at the outset, it does seem to be
true that we are learning
something relevant to the
problem of veridical perception
in daily life by the exploration
of these illusions and,
conversely, that what we have
learned from the study of
nonillusory phenomena has
helped us in trying to explain
the illusions. But even if we
learned nothing of value in
investigating illusions, they
would still constitute puzzles
that curiosity would drive us to
unravel.

    We have been concerned here
with what might be called
static illusionsΓÇöΓÇôthat is,
illusions of extent or line
direction in stationary
patterns. But many of the most
striking illusions are those
based on motion. While the
emphasis in the next chapter is
not on illusion but on the
search for general principles of
motion perception, it will be
seen that almost every
phenomenon considered there
is, in fact, an illusion of
motion.