Masking the information in multi-stream speech-analogue displays
Pierre Divenyi
(VA Northern California Health Care Systems, Martinez, and EBIRE)

The “cocktail-party” situation is understood as requiring segregation of the target speaker’s utterance from simultaneous utterances by speakers whom one wishes to ignore. But segregation can only take place if the salience of a given feature in one stream of speech is not interfered with—confounded with or masked—by the same feature in another simultaneous stream. Investigating this interference feature-by-feature is essentially impossible in speech itself because of the diversity and sheer number of features considered relevant. Therefore, we undertook the study of this interference psychophysically using two concurrent streams of non-speech stimuli that retained a small number of speech features, such as fundamental frequency, formant trajectory pattern, and/or syllabic rhythm pattern. This approach allowed us to define informational masking of a given feature in one stream by the same feature in the other and to see how the degree of informational masking compared with speech understanding performance in babble noise.

Relevant material:

Divenyi, P. L., Carré, R., and Algazi, A. P. (1997). Auditory segregation of vowel-like sounds with static and dynamic spectral properties. In D. P. W. Ellis (Ed.), IEEE Mohonk Mountain Workshop on Applications of Signal Processing to Audio and Acoustics (pp. 14.11.11-14). New Paltz, N.Y.: IEEE.
Divenyi, P. L. (2001). Dimensions of auditory segregation: What do they tell us about levels of auditory processing? In D. J. Breebart,A. J. M. Houtsma,A. Kohlrausch,V. F. Prijs, and R. Schoonhoven (Eds.), Physiological and Psychophysical Bases of Auditory Function (pp. 468-476). Maastricht (the Netherlands): Shaker Publishing BV.
Divenyi, P. L., and Brandmeyer, A. (2003). The “cocktail-party effect” and prosodic rhythm: Discrimination of the temporal structure of speech-like sequences in temporal interference, Proceedings of the 15th International Congress of Phonetic Sciences (pp. 2777-2780). Barcelona, Spain: The 15th ICPhS Organizing Committee.