Compression effects and perceptual asymmetries

This paper reports the results of two English experiments on timing and perception. The finding is that temporal patterns in production correspond to asymmetries in perception. We argue that these phenomena are best described in terms of auditory rather than articulatory representations. The production data concern compression effects, whereby, in syllables with a greater number of segments, each one of the segments is shorter than in syllables with fewer segments. The first experiment demonstrates that the amount of vowel compression found in English monosyllabic words depends in part on which consonants occur adjacent to the vowel in that word: words with liquids generally allow more vowel compression than words with nasals or obstruents. To explain these asymmetries, we posit a recoverability target for vowels that can be partially satisfied by information about the vowel contained in the surrounding context; differences in compression, then, can be explained by differences in how much vowel information is contained in adjacent segments and transitions. A second study shows that the perceptual assumptions required to make this analysis work are indeed found in English; timing asymmetries in production mirror perceptual asymmetries. The results favor a theory of timing that includes auditory representations over one that includes only articulatory representations.