Trading relations for puretone analogues of speech

This research investigated factors affecting the perceptual trading relation (TR)between first formant onset frequency and silent gap duration in pure-tone analogs of speech. Nonspeech analogs of /se/ and /ste/ were modeled after those used by Best etal. [Percept. Psychophys. 29, 191–211 (1981)]. Subjects’ descriptions of the stimuli and identification and discrimination performance before and after several hours of testing were examined. Based on identification performance and subjective stimulus descriptions, two groups of listeners emerged, similar to groups described by Best etal. Six of nine subjects described the nonspeech analogs as speech, exhibiting categorical perception and evidence of a TR. Three subjects described the stimuli as nonspeech sounds. In these subjects, a TR did not spontaneously develop following several hours of listening to the stimuli. The ‘‘nonspeech’’ listeners had more difficulty discriminating silent gap durations than did the ‘‘speech’’ listeners. It was hypothesized that the complex acoustic characteristics of these stimuli created a difficult perceptual task, interfering with integration of time and frequency cues by the ‘‘nonspeech’’ listeners. [Work supported by NIH DC00464 and BRSG ♯28-36.]