Some people are ‘‘More Lexical” than others

Abstract

People can understand speech under poor conditions, even when successive pieces of the waveform are flipped in time. Using a new method to measure perception of such stimuli, we show that words with sounds based on rapid spectral changes (stop consonants) are much more impaired by reversing speech segments than words with fewer such sounds, and that words are much more resistant to disruption than pseudowords. We then demonstrate that this lexical advantage is more characteristic of some people than others. Participants listened to speech that was degraded in two very different ways, and we measured each person’s reliance on lexical support for each task. Listeners who relied on the lexicon for help in perceiving one kind of degraded speech also relied on the lexicon when dealing with a quite different kind of degraded speech. Thus, people differ in their relative reliance on the speech signal versus their pre-existing knowledge.