A comparative assessment of speech sound discrimination in the Mongolian gerbil.

Abstract

The Mongolian gerbil is a small rodent with human-like absolute auditory sensitivity in the speech range below 4 kHz. Here, gerbil “speech DLs” (difference limens) are measured along several synthetic speech continua and compared with human data. Results show that gerbils are similar to humans in that they discriminate “within-category” information more easily for vowels than for consonants. However, gerbils are less sensitive to all the speech stimuli, with DLs about 2–3 times higher. Interestingly, gerbil speech DLs are not accurately predicted by their pure-tone frequency DL, which is 36 times that of the human at 1 kHz. Thus, gerbils are actually much more similar to humans in speech sound discrimination than in pure-tone discrimination. It is concluded that the gerbil offers a promising “small-mammal” model for the processing of spectral cues in human speech sounds.