Time Factors in Perception of A Double Consonant

Abstract

A listening experiment was carried out to examine the perceptual distinction between a single stop consonant, /p/, and its double counterpart, /p-p/. The joint effects of two time factors are studied: (1) the duration of /p/-closure (silence) and (2) the rate of utterance of the surrounding test sentence. The test sentence, He was the topic of the year, was recorded on tape and then, in a number of recorded copies, the duration of the /p/-closure was altered by inserting or removing tape. A group of listeners judged each of the altered sentences to be either He was the topic of the year or He was the top pick of the year. Effects of ten closure durations (60, 100, 150, 200, 250, 300, 350, 400, 500, and 585 msec.) are studied in various combinations with five rates of utterance (2, 3, 4, 6, and 8 syllables per second). A threshold closure duration is defined to be the duration at which 60% of the judgments were topic. As the rate increased from 2 to 8 syllables per second, the threshold closure duration decreased from 320 to 140 msec, and at a progressively declining rate. This function of threshold closure duration vs. rate of utterance is found to be approximately parallel to the relation, for the unaltered sentences, between actual closure duration and rate of utterance.