Cats know what they want, and a new study shows they know how to get it by purring
If your cat knows just what to do to convince you it's feeding time, a new study will help explain the scientific reason why. For the study, to be published in Tuesday's edition of the journal Current Biology, researchers identified and examined a particular type of vocalization they termed "solicitation purring."
Solicitation purring "is producing the low fundamental frequency and its harmonics by muscular activation ... but also voicing a cry, probably with the inner edges of the vocal folds, which is then superimposed on the sound's frequency spectrum," the study's lead author, Karen McComb of the University of Sussex, told Discovery News.
The resulting purr is not just any purr but also contains the hint of a more high-pitched cry that, the researchers suspect, reminds cat owners on some level of a crying human baby. Most important, the researchers found, solicitation purring was effective in conveying urgency to human listeners.
The researchers learned that cats produce the solicitation purr only when they're with a human they know well. "Remember, these cats have years to train up their owners," McComb told U.S. News & World Report. "They learn to dramatically exaggerate this cry embedded within the purr because it proves effective in getting their owner to respond." So in order to conduct further testing, it was necessary to have cat owners record their pets' vocalizations.
The team then played the recorded cat sounds for 50 human listeners. Almost all, they reported, identified the solicitation purr as the most urgent (and the most unpleasant). Next, the researchers used the magic of technology to remove the high-pitched sound component from the solicitation purr. The human listeners reported that the digitally altered purrs sounded less urgent.
Apparently, whether they're able to master the fine art of string or not, cats understand one thing -- human manipulation -- very well indeed.
-- Lindsay Barnett
Photo: Max, one of the carol-singing Jingle Cats, performs. Credit: Scott Rathburn / For The Times