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

(Pylyshyn, 2007, p. 32). Part of Pylyshyn’s theory of visual cognition is also connectionist,
because he appeals to non-classical mechanisms to deliver visual representations
(i.e., natural computation), as well as to connectionist networks (in particular,
to winner-take-all mechanisms; see Feldman & Ballard, 1982) to track entities after
they have been individuated with attentional tags (Pylyshyn, 2001, 2003c). Finally,
parts of Pylyshyn’s theory of visual cognition draw on embodied cognitive science.
For instance, the reason that tracking element identities—solving the correspondence
problem—is critical is because Pylyshyn assumes a particular embodiment of
the visual apparatus, a limited-order retina that cannot take in all information in
a glance. Similarly, Pylyshyn uses the notion of cognitive scaffolding to account for
the spatial properties of mental images.
8.6 Indexing Objects in the World
Pylyshyn’s theory of visual cognition began in the late 1970s with his interest in
explaining how diagrams were used in reasoning (Pylyshyn, 2007). Pylyshyn and
his colleagues attempted to investigate this issue by building a computer simulation
that would build and inspect diagrams as part of deriving proofs in plane geometry.
From the beginning, the plans for this computer simulation made contact with
two of the key characteristics of embodied cognitive science. First, the diagrams created
and used by the computer simulation were intended to be external to it and to
scaffold the program’s geometric reasoning.
Since we wanted the system to be as psychologically realistic as possible we did not
want all aspects of the diagram to be ‘in its head’ but, as in real geometry problemsolving,
remain on the diagram it was drawing and examining. (Pylyshyn, 2007, p. 10)
Second, the visual system of the computer was also assumed to be psychologically
realistic in terms of its embodiment. In particular, the visual system was presumed
to be a moving fovea that was of limited order: it could only examine the diagram in
parts, rather than all at once.
We also did not want to assume that all properties of the entire diagram were
available at once, but rather that they had to be noticed over time as the diagram
was being drawn and examined. If the diagram were being inspected by moving
the eyes, then the properties should be within the scope of the moving fovea.
(Pylyshyn, 2007, p. 10)
These two intersections with embodied cognitive science—a scaffolding visual
world and a limited order embodiment—immediately raised a fundamental information
processing problem. As different lines or vertices were added to a diagram,
or as these components were scanned by the visual system, their different identities
had to be maintained or tracked over time. In order to function as intended,
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