Hoffstader describes in his Prologue to chapter two a principle behind one design for parallel processing systems: layers of precondtions. A footnote in Fennel and Lesser's paper on Heresay-11 provides a description of this structure. Process are implemented when their preconditions are met. The preconditions of the preconditions (pre-pre-conditions) must be met for the preconditions to be met, and the pre-pre-preconditions must be met for those, and so forth. Hoffstadter gives an interesting example of this structure in Greek life and the reader is led to believe this structure maximizes parallel processing and prevents unnecessary processes from being run.
Hoffstadter describes how this processing might be present in the analysis and recognition of worlds. I'm curious about how might this be implemented in the visual system in general? Is there a precondition of a vertical line and a precondition of a horizontal line for recognizing a desk? Is there a pre-precondition for an edge in general? When recognizing a face, what would be the preconditions? Concentric circles for eyes? A nose? Obviously those preconditions do not have to be met for a face (case and point: :)). It seems each object might have several preconditions, and can be recognized without all of them being met. (At this point, do they cease to be precondtions because they are only suggestive, not necessary?) It seems definitions and recognition has a huge probabilistic and graded element, and that few of the preconditions are always necessary. Perhaps it's different for visual processing of words?
This prologue left me with questions and feeling rather unsatisfied, which only augments a desire to read-on. How is this design implemented? Can an object be recognized without meeting all of the preconditions? And how exactly does it fit into word recognition and Jumbo tasks?
No comments:
Post a Comment