Dogs are man's best friend. They are one of the earliest domesticated animals and have been with us for thousands of years. If you had or have seen a pet dog, you know that it's possible for them to pick up on what humans are saying. Usually it's when a human is directly addressing the dog and giving it some kind of command.

But there was a question as to whether dogs understood actual human words, or just the emotional cues in a human voice. Clearly dogs do understand specific words in some cases. If you've ever seen one becomes suddenly depressed at the mention of the vet, or overly excited at the prospect of a walk or a treat. Still, for the average dog and the average command, do they understand us?

That's what a psychologist from the University of Sussex intended to figure out, as reported on NPR. Not only did this experiment attempt to see whether dogs could understand human speech, but roughly what area of the brain processed it.

To do this, 250 dogs had speakers on each side of their head, and the command to come was played in both. The commands started out normal but then the audio was modified. Sometimes the meaningful words were completely removed and only the inflection was preserved. Other times the inflections were totally removed and just the exact words of the command were said.

The results were that when the inflection was removed, roughly 80% of the dogs turned their head to the right. A similar pattern emerged with dogs turning their head to the left when only the inflections were played. That might not sound like a big deal but it implies that dogs both understand speech and process it in at least two distinct parts.

In humans, our understanding and interpretation of speech is extremely complex and handled by different areas of the brain. Like in humans, it would seem dogs split the task of processing speech in two parts on each side of the brain. Obviously this is just a first study, but it would appear processing the meaning of words happens on the left side of the brain and emotions in speech on the right. Also like in humans, the parts of the body that are governed by certain parts of the brain are reversed left to right.

This was a relatively simple experiment, so it will take some time before the exact areas of the brain that process these two kinds of speech are specifically identified. And the researchers gave no intention of attempting this experiment on cats.