Péter Pongrácz, a biologist at Eötvös Loránd University in Budapest, recently demonstrated that humans have an innate ability to understand dog barks. Pongrácz played several artificial bark sequences that conveyed five emotional states—aggressiveness, fear, despair,playfulness, and happiness—to 90 human volunteers. The human listeners,regardless of their experiences with dogs, were able to translate each emotional state correctly by keying in on three basic acoustic qualities: tone, pitch, and timing. High-pitched barks separated by long time intervals were interpreted as happy and playful,deep-sounding, rapid-fire barks as aggressive.
While the repertoire is impressive, Pongrácz points out that it may not be all that surprising, given the closely entwined histories of the two species. “It’s interesting that dogs seem to have evolved this enriched barking behavior, because their most important communication is with humans.” It could be that dogs have been selected for better communication—for example, dogs that stood at the edge of a village and alerted human inhabitants of danger would most likely have been favored by humans, he says.