Interesting article from Discovery News!
Dog Barks Reveal Universal Language
Jennifer Viegas, Discovery News
What do dog barks have in common with bird tweets and human baby cries? All appear to communicate basic emotions, such as fear, aggression and submission, in somewhat the same acoustic way, according to a new Applied Animal Behavior Science study that suggests a primitive communication system may unite virtually all mammals.
The theory could help explain why previous research has found that many mammals, including humans, understand the vocalizations of different species.
For example, a Language Communication study determined young children can identify simple emotions conveyed in macaque calls. Another study, published in Primate Cognition, indicated that an African grey parrot could communicate with a bonobo.
For the recent research, Pter Pongrcz and colleagues studied how well people with varying dog experience could describe the emotional content of several artificially assembled bark sequences. The barks, which were based on sounds made by a Mudi (a Hungarian herding dog), covered five emotional states: aggressiveness, fear, despair, playfulness and happiness.
Pongrcz, a professor of ethology at Etvs Lornd University in Budapest, Hungary, and his team found that even people with little prior dog experience could correctly match the bark sequences with the previously determined emotional intent of the original barks.
The scientists discovered that changes in three basic sound qualities tone, pitch, and the time between barks determined how listeners perceived the barks. In general, high-pitched barks with longer intervals between each bark were rated as less aggressive than lower-pitched barks heard in frequent succession.
Human babies vary similar sound quality characteristics when they cry, except frequency range appears to be more important than pitch when they express their needs.
This link between pitch or frequency and perceived emotion appears to carry across many different species, according to Pongrcz, who cited an earlier theory proposed by avian expert Eugene Morton.
“His basic argument was that, according to the general physical laws, larger bodies emit sounds characterized by lower frequencies and these are also noisier/atonal, thus receivers can predict the size of the sender,” Pongrcz and his team wrote.
“This relationship could have formed the basis of an evolutionary ritualization process whereby low pitched vocalizations tended to signal aggression because larger animals are more likely to win contests…and high pitched vocalizations became predictors of submission or friendly intent.”
Since the dog study test subjects also correctly identified barks signifying despair, happiness and playfulness, the researchers suspect dogs and humans share a unique ability to communicate with one another that goes beyond the proposed universal mammal “language.”
The scientists believe years of domestication have improved the way that dogs, versus their wolf ancestors, can communicate with us. They point out that such communication isnt limited to vocalizations. It also includes visual signals, such as changes in looks.
Common house cats also appear to have evolved improved means of communicating with humans, according to a study conducted by Cornell University researcher Nicholas Nicastro. Cats, however, seem more intent on manipulating us.
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