Читать книгу Applying Phonetics - Murray J. Munro - Страница 22

Our family cat, Owen, happens to be extraordinarily vocal when he is hungry, needs to play, or spots a squirrel through the window. The left panel of Figure 1.4 shows an acoustic representation of one of his productions, which you can compare with the much more complex, human‐produced word on the right. While it's tempting to attribute specific meanings to the sounds he makes, the available evidence does not allow researchers to say what exactly cats “mean” when they vocalize. Nonetheless, a wealth of studies of domestic feline behavior have helped shed light on the problem. It is well established, for instance, that cats vocalize differently when they are around humans than they do in feral conditions. Perhaps the most famous study of feline communication is Mildred Moelk's “Vocalizing in the House‐Cat: A Phonetic and Functional Study,” published in 1944 in the American Journal of Psychology. Moelk identifies three kinds of production: mouth closed, mouth gradually closing, and mouth tensely open. The resulting sounds fall into 16 different patterns, for which she even provides transcriptions using the International Phonetic Alphabet. According to Moelk, the patterns correspond to (among other things) greetings, acknowledgments, demands, begging, and bewilderment.

Several perceptual experiments have shown that humans can accurately interpret cat vocalizations, at least to some extent. Schötz and van de Weijer (2014) collected audio recordings of cats in two contexts: at feeding time and while waiting at the veterinarian. They played the meows in random order to 30 human listeners tasked with guessing the context of each token. Not only did the listeners perform correctly at above chance levels, but those having experience with cats as pets scored higher than those without. So, it seems that humans can learn to partially interpret feline messages through experience. In another study by McComb, Taylor, Wilson, and Charlton (2009), humans judged solicitation purrs (recorded during food‐seeking) as more urgent and less pleasant than non‐solicitation purrs played at equal volume. The listeners' ability to make the distinction, which occurred with or without cat experience, was due to a particular high‐frequency component within the solicitation purrs that has a surprising parallel in human infant cries. In the authors' words, the less pleasant purrs “may be exploiting an inherent mammalian sensitivity to acoustic cues relevant in the context of nurturing offspring” (p. R507). If so, then when Owen howls from the kitchen, it's not simply because he has learned what gets our attention. Rather, his biology may be calling out to our own!

Figure 1.4 Waveforms and spectrographic representations of a cat's meow (top) and a human production of the word “mouse” (bottom)