Role of rhythmic structure in the identification of environmental sounds

Anne Guillaume1 , Marie Rivenez1 , Lionel Pellieux1 , Claude Blancard1 , Véronique Chastres1 & Carolyn Drake2

1 Institut de médecine aérospatiale du service de santé des armées, Brétigny sur Orge, France 2Université René Descartes, Paris, France

Various studies (Warren and Verbrugge, 1984; Repp, 1987) focused on the influence of spectral and temporal properties on the identification of environmental sounds. Especially Warren and Verbrugge (1984) showed the importance of rhythmic models for the distinction between an object rebounding or breaking in several pieces. In order to study the influence of the rhythmic structure on the identification of environmental sounds, we carried out an experiment with 117 sounds including 42 sounds with a more or less regular rhythmic structure. The sounds were equalized in loudness and presented using a gated stimulus paradigm which has been employed in studies on word recognition. In our experiment, it consisted in presenting step by step (50 ms) increasing durations of the sound. Each time the listeners performed a free identification, then had to rate their confidence on a scale from 1 (not at all confident) to 7 (very confident). 18 listeners with normal hearing participated to the experiment. We expected that the rhythmic structure would influence the identification of environmental sounds. The first results showed that rhythmic sounds (278 ms) were identified later than continuous sounds (266 ms) (F(1,1537) = 3.59; p<.05). Further analyses are currently conducted in order to assess the effect of the temporal properties of the sounds (inter onset interval, burst duration, degree of irregularity).