Figure 1. Cascaded lexical search model.

Clusters are thought to reflect the cascaded processing of semantic and phonological information: In this view, word search originates from the activation of semantic fields (A, B, C). During respective field scans a parallel phonological search stream is activated. In letter VF, words would be released if a semantic concept can be aligned with a suitable phonological representation. A cluster transition occurs upon completion of these automatic and therefore rapid operations per field, when the next semantic category has to be accessed and phonemic alignment is restarted.