Chaser is a border collie who has a vocabulary of more than 1,000 words, that's like the same as a 4-year-old child.

But what makes Chaser even more special, is that he can even separate nouns from verbs.

Take lips. Take lips. Do it girl, do it! Good girl, good girl.

Paw lamb. Paw lamb, paw lamb, Chaser. Good girl, good girl!

Nose ABC, nose ABC. Good girl, good girl!

This is Oliver. Oliver, you think you're smarter than Chaser? What do you say? What do you say?

Yeah, let's go find out. Come on!

Get your ball. Where's your ball?

Get your bone. Where's your bone? Nope, that's your ball.

Where's your bone? Bone. Bone. Nope.

Find your bone? Where's your bone?

Okay, so maybe Oliver's not that good at this particular test, but the fact that we even try to communicate with dogs, and that they communicate back with us,

means that the human-dog relationship is truly something special.

Who's the best boy? Who's the best boy?

I… have been known to talk to dogs a little.

Who's the good boy? Who's the good boy?

Or... a lot.

Who is the smartest doggy in the world?

It's hard to know if they're responding to the words, or just the emotion in my voice, or the fact that I sound ridiculous.

Well, one recent study suggests it's both...or all three.

Researchers at the University of Sussex played sounds out of speakers on both sides of a dog.

When dogs heard commands stripped of their emotional context, they turned their head to the right, suggesting they process verbal meaning in their left hemisphere.

And when they heard the emotional sounds in the voice, but the words were jumbled, they turned to the left, suggesting they process emotional sounds on the right.

These experiments show that dogs can definitely separate the meaning of words from the emotions attached.

But how much information do they take from each?

When I ask my dogs "Do you want to go for a walk?" they aren't processing the real meaning of that sentence the way we do, like

Hmm, let me see, do I want to go for a walk right now? Get some exercise? Maybe I'm not feeling it today.

But I'm a dog, what does it even mean to want something?

As good as dogs are with words, in many of our interactions there's probably a good amount of Clever Hans at play.

In the early 1900's a horse named Hans was said to be able to solve simple math problems by tapping his hoof to represent numbers. 2 + 3?

Smart horse! It was later found, though, that Hans couldn't do math at all.

He was just responding to tiny cues from his handlers, maybe their facial expressions would tense as he got close to the right answer,

or they would exhale when he tapped the right number.

Clever Hans demonstrates that while we might think of language as something we experience mainly through our ears, we communicate meaning using more than just sound frequencies.

In his book The Expression of the Emotions in Man and Animals, Charles Darwin argued that the way that we outwardly express and interpret emotions evolved from animals,

and that our ability to recognize fear, happiness, sadness, even across species, is universal, and innate. It's something that we're born with.

Today, scientists are still debating whether Darwin was right, but recent research suggests that we do share one special bit of emotional intuition with our canine companions.

Dogs are the only non-primate animals that seek out eye contact with humans.

Their wolf ancestors, even tame ones, although they're close enough genetically to interbreed with dogs, won't look us in the eye… which is why you can never, ever trust a wolf.

How am I doing?

When reading emotions in other people we tend to look disproportionately and unconsciously to the right side of their face.

The dogs share this so-called left-gaze bias, but only when looking at human faces, not when they look at other dogs.

It seems like they genuinely want to understand what we're telling them and what it means.

And we seem to understand them too, or at least we think we do.

Researchers in Hungary tested people's ability to interpret the meaning of recorded dog barks, and found that many people really can speak dog.

What do you think this bark means?

Okay, that dog's angry. That's pretty easy.

What about this one?

Do you want to go for a walk?

Okay, that dog wants to go for a walk. One more.

I have no idea what that means.

If you think about it, this dog-human language connection makes a lot of sense.

We've co-evolved with these creatures for the past 10,000 years or so.

We've molded them from wolves into puppies with our hands and our brains, and our voices.

Even if we don't always understand each other, well, they're always there to listen, and that's the real meaning of a best friend. Isn't it buddy?

Wait a second. Sorry.

Hello? Um, yeah, sure. It's for you.

Hello? This is Oliver.

Hello. This is dog.

Oh, hey Luna!

Have you seen Vanessa? She's been out for hours! I miss her.

Ruh roh!

Um, thanks Luna! If you want to find out more about dog behavior, head on over to BrainCraft and find out if they really miss us when we're gone. Stay curious.

Good boy. Oh, and special thanks to Oliver.