Lexical access codes in visual word recognition: are the joint effects of context and stimulus quality diagnostic?

Is it possible to identify when lexical access in visual word recognition is based on an orthographic code and when it is based on a phonological code? Some researchers have argued that the joint effects of semantic context and stimulus quality in lexical decision are diagnostic. Their argument is that when phonological recoding is employed, it serves to keep the effects of stimulus quality and context from interacting. Semantic context and stimulus quality are therefore predicted to have additive effects on RT. In contrast, when lexical access is not mediated by a phonological recoding stage, then the effect of stimulus quality interacts with context, as commonly seen in the literature. A strong test of these claims was devised in which participants were forced to use phonological recoding for the purpose of lexical access. An interaction between context and stimulus quality was observed. This finding is taken as evidence that the joint effects of semantic context and stimulus quality are not diagnostic with respect to the nature of the lexical access code (i.e., orthographic versus phonological) for readers of English.