"These results indicate that dogs pay very close attention to human signals," lead researcher Gregory Berns, director of the Emory Center for Neuropolicy, explained. "And these signals may have a direct line to the dog's reward system."
In that study, the reward was food, but Custance and Mayer think canines over the thousands of years of domestication have been rewarded so much for approaching distressed human companions that this may somehow be hardwired into today's dogs.
The phenomenon in some cases could even have a subconscious element. Consider what happens when a person yawns and a dog is in the room.
"Dogs show contagious yawning to human yawns," Matthew Campbell, an assistant professor in Georgia State University's Department of Psychology, told Discovery News.
He said that "we have selected dogs to be in tune with us emotionally."
Custance and Mayer next hope to determine how empathetic wolves may be.
"It would be interesting to see how wolves who have been raised in human households would respond if they took part in our experiment," Custance said. "Would they behave like domestic dogs or show less response to a crying human? It would be fascinating to find out."