The processing of duration and intensity cues to prominence

This paper presents results from two experiments designed to show how duration and intensity are processed during speech perception. Duration and intensity are two physical dimensions which are known to interact psychoacoustically in the perception of both length (a term that will be used for perceived duration) and loudness. The first experiment, a selective attention task, shows that length and loudness are processed as a unit [integrally, in the terms of Garner, The Processing of Information and Structure (Erlbaum, Potomac, MD, 1974)], but that the integrality is asymmetric: Extracting length information appears to be easier than extracting loudness information. The results of the first experiment make the prediction that listeners would not use loudness by itself in making prominence judgments, since the extraction of loudness in the presence of duration variation appears to require a (relatively) high processing load. The second experiment, a traditional trading relation experiment in which duration and intensity were varied orthogonally, appears to bear out this prediction. Listeners' responses were predicted from computed measures of length and loudness in a linear multiple regression analysis. Results show a negligible independent contribution of loudness to listeners' responses. Listeners' behavior is best predicted by computed measures of length.