The influence of relatedness proportion on the joint relationship among word frequency, stimulus quality, and semantic priming in the lexical decision task

In the lexical decision task, the additive effects of stimulus quality and word frequency have been used to infer the presence of independent processing stages in visual word recognition. Importantly, this pattern can be moderated by semantic priming, suggesting the presence of a retrospective prime retrieval mechanism that is selectively engaged based on task context (i.e., utility of the primes). We examine the sensitivity of this mechanism in two lexical decision experiments that manipulate stimulus quality, word frequency, and semantic priming. Critically, we studied these joint effects when the proportion of related primes was set at.50 or.25. Results indicated that with a.50 relatedness proportion, a three-way interaction was obtained such that additivity between frequency and stimulus quality was found following related semantic primes, but an overadditive pattern was exhibited following unrelated primes. When the relatedness proportion was reduced to.25, this interaction was eliminated. Furthermore, relatedness proportion affected the magnitude of the stimulus quality by priming interaction but not the frequency by priming interaction. These results are interpreted within the context of a flexible lexical processer that adaptively engages processes in response to task context.