Where there is CP, it is natural to asks what internal mechanism causes it. Some applications of a neural model. MIT Press, Cambridge, MA, US. 1988. A critical reappraisal. CP can be analysed behaviorally, by studying the way people discriminate and identify different stimuli, both naturally and as an outcome of learning.
Clues come from brain function as well as from computer modelling.
Again, this is not the whole story, but it provides some interesting pieces of it. Hemispheric specialization for categorical and coordinate relations. Frontiers in cognitive neuroscience. Compare the various models that have been proposed to explain categorical percption. Different models for CP exist, some very specialized, some quite general.