Separable effects of neighborhood density and phonotactic probability on word recognition in speech

Previous research on the effects of probabilistic phonotactics on spoken word recognition has typically confounded phonotactics and similarity neighborhood density. In the present research, the inhibitory effects of density and facilitative effects of probabilistic phonotactics on spoken word processing were manipulated simultaneously. Four sets of monosyllabic words and nonwords were created by orthogonally combining two levels of neighborhood density and two levels of probabilistic phonotactics. Speed and accuracy were examined in three different experimental paradigms: single-word shadowing, A-X same–different matching, and speeded neighbor generation. Words and nonwords were either blocked by lexicality or intermixed. Blocking and mixing of stimuli were used to manipulate participants’ focus on lexical and sublexical levels of processing. In part, our results demonstrate simultaneous effects (inhibitory and facilitative) of both density and phonotactics. The implications of our results for models of spoken word recognition and lexical access will be discussed.