Canine emotion detectors are quite similar to human voice processors!

How dogs know when to nuzzle:

Our four-legged friends have a little patch of their brain devoted to deciphering emotions in human and dog voices, scientists reported Thursday in the journal Current Biology.

And the neural circuitry acts surprisingly like the voice-detection device found in people's brains. The happier the barks or giggles, the more that brain region lights up. The sadder the growls or whines, the less it responds.