Perceptual asymmetry between greater and lesser vowel nasality and VOT

This study explores whether there is an asymmetry with respect to the perceptual salience of an increase vs. a decrease of phonologically relevant features. A forced-choice discrimination experiment was conducted on stimulus pairs that included one member with unchanged phonetic features and the other with either increased or decreased degree of features (i.e., vowel nasality or VOT). The results revealed a perceptual asymmetry: participants were more accurate and in some cases faster in their responses to stimulus-pairs containing increasedfeature stimuli, suggesting that greater presence of these phonetic features is perceptually more salient than decreased presence. These findings demonstrate sub-categorical sensitivity for features known to be perceived categorically (VOT), as well as for features not primary to phonological contrast (vowel nasality). They also support a possible salience explanation for previously observed asymmetries in phonetic imitation.