Perception of phonemically-identical true prefixes and pseudo-prefixes in real words heard in noise

Abstract

This experiment assessed the perceptual salience of acoustic‐phonetic differences measured in the first syllables of words with initial syllables that differ in morphological, but not phonemic structure [Baker et al., Proc. 16th ICPhS (2007)]. Words began with true prefixes (Pr: e.g., mistimes, displease) or pseudo‐prefixes (Ps: e.g., mistakes, displays). The fourth phoneme was a stop. A woman recorded sentences, identical except for the critical word, e.g., I think she distrusts/destroyed them, in scripted dialogs for naturalness. Critical syllables (mis‐, dis‐), up to but excluding the stop burst, were cross‐spliced either into the ‘‘wrong’’ context (mismatched conditions, PrPsPr, PsPrPs) or into another instance of the same sentence (controls, PrPrPr, PsPsPs). In a counterbalanced design, four groups of ten listeners each heard eight mismatched and eight control sentences in cafeteria noise (SNR 2 dB), and wrote what they heard. Errors were greater for critical words in mismatched than control sentences, though the difference only achieved significance for dis‐ words. The data suggest that perceptual disruptions reflect the difference between the spectrotemporal pattern heard and that expected on the basis of the critical syllable’s morphological status (true‐ or pseudo‐prefix), the sentence prosody, and possibly the statistical distribution of the critical syllable’s duration.