Phonotactics, density, and entropy in spoken word recognition

Previous research has demonstrated that increases in phonotactic probabilit y facilitate spoken word processing, whereas increased competition among le xical representations is often associated with slower and less accurate rec ognition. We examined the combined effects of probabilistic phonotactics an d lexical competition by generating words and nonwords that varied orthogon ally on phonotactics and similarity neighbourhood density. The results from a speeded same-different task revealed simultaneous facilitative effects o f phonotactics and inhibitory effects of lexical competition for real word stimuli. However, the nonword stimuli produced an apparently anomalous patt ern of results. In a subsequent experiment, we identified the source of thi s anomaly by estimating behaviourally the specific lexical competitors acti vated by our nonwords. Our results suggest that, under specific circumstanc es, neighbourhood density and probabilistic phonotactics may combine to pro duce non-additive or synergistic effects of lexical competition on processi ng times.