The Times of Ira Hirsh: Multiple Ranges of Auditory Temporal Perception.

Ira Hirsh was among the first to recognize that the auditory system does not deal with temporal information in a unitary way across the continuum of time intervals involved in speech processing. He identified the short range (extending from 1 to 20 milliseconds) as that of phase perception, the range between 20 and 100 milliseconds as that in which auditory patterns emerge, and the long range from 100 milliseconds and longer as that of separate auditory events. Furthermore, he also was among the first to recognize that auditory time perception heavily depended on spectral context. A study of the perception of sequences representing different temporal orders of three tones, by Hirsh and the author (e.g., Divenyi and Hirsh, 1978) demonstrated the dependence of auditory sequence perception on both time range and spectral context, and provided a bridge between Hirsh's view of auditory time and Bregman's view of stream segregation. A subsequent search by the author for psychophysical underpinnings of the cocktail-party phenomenon (e.g., Divenyi and Haupt, 1997) suggests that segregation of simultaneous streams of speech might rely on the ability to follow spectral changes in the demisyllabic-to-syllabic (100 to 200 milliseconds) range (i.e., Hirsh's long range).Learning Outcomes: As a result of this activity, the participant will be able to (1) describe the importance of temporal processing in hearing; and (2) identify time ranges where the auditory system will spontaneously adopt different analysis techniques.