Mind, Body, World- Foundations of Cognitive Science, 2013a

The discussion in this section would seem to place Pylyshyn’s (2003b, 2007)
theory of visual cognition squarely in the camp of embodied cognitive science.
Referential links between object files and distal objects permit visual information
to be accessible without requiring the constant updating of descriptive representations.
The postulation of indices that can guide actions and movements and the
ability to coordinate these indices with visual tags place a strong emphasis on action
in Pylyshyn’s approach.
However, Pylyshyn’s theory of visual cognition has many properties that make
it impossible to pigeonhole as an embodied position. In particular, a key difference
between Pylyshyn’s theory and enactive perception is that Pylyshyn does not believe
that the sole goal of vision is to guide action. Vision is also concerned with descriptions
and concepts—the classical cognition of represented categories:
Preparing for action is not the only purpose of vision. Vision is, above all, a way
to find out about the world, and there may be many reasons why an intelligent
organism may wish to know about the world, apart from wanting to act upon it.
(Pylyshyn, 2003b, p. 133)
8.8 Scaffolding the Mental Image
In Chapter 3 we introduced the imagery debate, which concerns two different
accounts of the architectural properties of mental images. One account, known
as the depictive theory (Kosslyn, 1980, 1994; Kosslyn, Thompson, & Ganis, 2006),
argues that we experience the visual properties of mental images because the format
of these images is quasi-pictorial, and that they literally depict visual information.
The other account, propositional theory, proposes that images are not depictive,
but instead describe visual properties using a logical or propositional representation
(Pylyshyn, 1973, 1979b, 1981a, 2003b). It argues that the privileged properties
of mental images proposed by Kosslyn and his colleagues are actually the result of
the intentional fallacy: the spatial properties that Kosslyn assigns to the format of
images should more properly be assigned to their contents.
The primary support for the depictive theory has come from relative complexity
evidence collected from experiments on image scanning (Kosslyn, 1980) and
mental rotation (Shepard & Cooper, 1982). This evidence generally shows a linear
relationship between the time required to complete a task and a spatial property
of an image transformation. For instance, as the distance between two locations on
an image increases, so too does the time required to scan attention from one location
to the other. Similarly, as the amount of rotation that must be applied to an
image increases, so too does the time required to judge that the image is the same
or different from another. Proponents of propositional theory have criticized these
394 Chapter 8