Multiplicative Effects on Sentence Comprehension for Combined Acoustic Distortions This study was designed to explore the effect on speech comprehension of combining two types of signal distortion. A tape of clearly-enunciated sentences in quiet was distorted in each of four ways: low-pass (LP) filtering, time compression, interruption, and noise masking. Data are reported on a population of normal-hearing young ... Research Article
Research Article  |   June 01, 1979
Multiplicative Effects on Sentence Comprehension for Combined Acoustic Distortions
 
Author Affiliations & Notes
  • Paul G. Lacroix
    Naval Submarine Medical Research Laboratory, Groton, Connecticut
  • J. Donald Harris
    Naval Submarine Medical Research Laboratory, Groton, Connecticut
  • Kenneth J. Randolph
    University of Connecticut, Storrs
Article Information
Research Articles
Research Article   |   June 01, 1979
Multiplicative Effects on Sentence Comprehension for Combined Acoustic Distortions
Journal of Speech, Language, and Hearing Research, June 1979, Vol. 22, 259-269. doi:10.1044/jshr.2202.259
History: Received July 3, 1978 , Accepted November 7, 1978
 
Journal of Speech, Language, and Hearing Research, June 1979, Vol. 22, 259-269. doi:10.1044/jshr.2202.259
History: Received July 3, 1978; Accepted November 7, 1978

This study was designed to explore the effect on speech comprehension of combining two types of signal distortion. A tape of clearly-enunciated sentences in quiet was distorted in each of four ways: low-pass (LP) filtering, time compression, interruption, and noise masking. Data are reported on a population of normal-hearing young men for multiple-choice answer tests of colloquial sentences of either LP filtered at 1, 2, 3, or 4 kHz, time compressed by computer at 250 words/min, interrupted (50 msec on—50 msec off), masked by speech-spectrum noise at +2 dB S/N, or given each of the 12 possible combinations of LP filtering plus the other three distortions. Individual distortion conditions were adjusted to reduce speech comprehension performance to about 90% accuracy. Low-pass filtering above 1 kHz reduced comprehension by no more than five to 10 percentage points, but when LP filtering was added to the other distortions in turn, latent effects were uncovered. The reduction in comprehension with the combined distortions was much greater than the simple additive effects of the distortion and LP filtering by themselves. For example, LP filtering above 2 kHz produced no measurable effect on sentence comprehension but this same distortion in combination with noise masking reduced performance from 89.4 to 59.7% correct (where 25% was chance). This study further validates the multiply-compounded nature of simultaneous types of distortion. The use of LP filtering extends the multiplicative principle to the simulated case of high-frequency hearing losses.

Order a Subscription
Pay Per View
Entire Journal of Speech, Language, and Hearing Research content & archive
24-hour access
This Article
24-hour access