On the P and the D in PDP: is processing always parallel, and are representations always distributed?

Two major principles of the PDP or connectionist approach to understanding cognition is that all cognitive processing is parallel processing and that all cognitive representations are distributed representations. These are meant to be completely general principles and so to apply to all domains of cognition. We dispute the claim that there are any general principles that apply uniformly to all domains of cognition. One domain of cognition for which both principles are demonstrably false is reading. We present data from eight different kinds of investigation of reading all of which agree in revealing the existence of a serial processing system in human readers. And we present data from lexical decision tasks in intact readers and people with acquired disorders of semantics that we believe can only be explained if orthographic and phonological representations in the human language system are local rather than distributed. All of these results are predicted by the DRC computational model of reading aloud and are inconsistent with those computational models of reading aloud which are based on PDP principles.