Temporal- and stimulus-based constraints to interactive activation during visual word recognition in adult readers.

In models of visual word recognition that incorporate an interactive activation framework, activation spreads from orthographic and phonological units to semantic units and from semantic units back to phonological and orthographic units. The present research examined whether semantic feedback changes over the time course of lexical processing and as a function of stimulus quality. Using a mediated priming paradigm, prime-target word pairs were associatively related (frog-toad), homophonically mediated (frog-towed), or orthographically mediated (frog-told). Evidence of semantic feedback to both orthography and phonology was found when the prime duration was 146 ms (Experiment 1) and only to phonology when the prime duration was 253 ms (Experiment 2a). However, when the prime duration was 253 ms and target words were degraded (Experiment 2b), feedback spread only to orthography. The results suggest that the dynamics of semantic feedback change as the function of processing demands in the visual word recognition system.