| |
Abstract:
Contrasting with naive conceptions of perception as a pure
bottom-up process, the idea has been proposed by von Helmoltz that
perception results from unconscious inductive inferences (Gregory
1987). Although physiological studies of the visual system have
long been focused on how visual images are constructed through
hierarchically organized stages of processing, the same idea of a
dialogue between bottom-up and top-down processes is now being
applied to the understanding of vision (Salin and Bullier 1995,
Thorpe et al. 1996). This two-way description of vision and
perception in general is also widely acknowledged by psychologists
(e.g., Gregory 1987, Cave and Kosslyn 1989) and philosophers
(Dretske 1990, Jacob 1985), so much so that the idea that "there is
no such thing as immaculate perception" has been defended (Kosslyn
and Sussman 1995). The most cited experimental evidence for the
implication of descending influences on perception is the case of
ambiguous figures, for which perception can alternate between two
possible interpretations of the visual input, even though the
memorized image can be subjected to other interpretation (Peterson
et al. 1994). Visual illusions are also often considered as a clear
example of the interpretation (and contamination) of retinal
information involved in perception (Dretske 1990, Jacob 1985,
Gregory 1987, Meini 1996). In their attempt to rule out the
possibility for "immaculate perception," Kosslyn and Sussman (1990)
review evidence for the use of imagery in perception suggesting
that a match is being created between descending expectations and
ascending signals. Then they present possible anatomical substrate
of descending feedback from higher visual centers, and consider
possible ways to transform an internal image so as to match the
peripheral retinal image. This latter issue leads them to consider
the strong link between this mental transformation and
sensori-motor processing. This chapter will consider these and
other observations as a way to demonstrate that instances of
immaculate perception can be precisely found in the field of
action.
Full text of article
|
