NARRATION

Here's a question: is your dog a left-paw or a right-paw? And what does it mean?

Dr Jonica Newby

Well not only would being a leftie shape your dog's personality, it has a massive influence on whether this puppy will pass or fail Guide Dog school.

NARRATION

It's tough training to be a Guide Dog. Of all these puppies that start the course, only half will make it.

Dr Lisa Tomkins

Good boy …

NARRATION

Yet it's been hard to find screening tests to improve those odds. Until along came Lisa, with a left-field idea of looking at lefties.

Dr Jonica Newby

Tell me honestly, did it have anything to do with the fact that you are in fact a left-paw?

Dr Lisa Tomkins

[Laughs] I may have a little bit of a bias in there.

NARRATION

Okay, so step one - how do you know if your dog is a left-paw?

Dr Jonica Newby

Now you may think you know which hand your dog prefers, but we're going to show you how to test it for sure. And it starts with a bit of a cooking segment. Okay, so we have here a Kong, which is a typical dog toy that you stuff with treats.

Dr Lisa Tomkins

That's right, mm-hm.

Dr Jonica Newby

Mm-hm.

Dr Lisa Tomkins

So what we're going to do first …

Dr Jonica Newby

Yeah.

Dr Lisa Tomkins

… is we're going to measure out all the ingredients. Marinate for an hour, then we prepare our Kong. Plug up the small end with some peanut butter, and pour it in. Pop it in the freezer, let it set. And here's one we prepared earlier. [Laughs]

NARRATION

And now bring on the contestants. A trusting team of pet-owner volunteers, and a couple of trainee Guide Dogs for good measure.

Dr Jonica Newby

Okay, are you all ready for the Kong test?

Pet Owners

Yes.

NARRATION

A final dab of extra peanut butter to get the dogs going, and …

Dr Jonica Newby

Raise your Kongs, get set, go!

NARRATION

Each team has a sheet of paper with places for fifty paw scores. Mark 'L' for left, or 'R' for right. If they use both paws, it doesn't count. Test stops when all fifty places are filled.

Dr Jonica Newby

If they do hold it down for more than ten seconds, you move it out of their hands.

NARRATION

Mm, not working as well as we'd hoped.

Pet Owner

Caleb, you're a disgrace to the family, you're not using your paws.

NARRATION

And finally, by also substituting dog food for the peanut butter, we have lift-off.

Dr Jonica Newby

Okay, this one's finally got going.

Pet Owner

Right!

Dr Jonica Newby

How are we going?

Pet Owner

We're long done.

Dr Jonica Newby

Oh, you're long done? Oh, finished. First up of course, the labrador. Okay, well let's, let's tally them. Eighteen rights and thirty-two lefts. What does that mean?

Dr Lisa Tomkins

He's a leftie.

Dr Jonica Newby

We have our first leftie.

Dr Lisa Tomkins

Good girl …

NARRATION

Back in 2009, Lisa ran this test on a hundred and fifteen incoming trainee Guide Dogs, and then waited to see who made it through.

Dr Lisa Tomkins

Oh, good girl.

NARRATION

The result? Right-paws were twice as likely to succeed.

Dr Jonica Newby

When you finally got to look at your results, and saw what a massive difference it made, were you a bit shocked? Because I am.

Dr Lisa Tomkins

I thought it was awesome!

NARRATION

So how come? Well here's the theory.

Dr Jonica Newby

It's all to do with what's called brain lateralisation. That's where different hemispheres of the brain do different jobs. So the right brain is largely in charge of the fight-flight response - fear, anxiety. Whereas the left brain is largely in charge of jobs like eating. And because the nerves cross over, right-pawed means left brain biased, whereas left pawed means right brain biased.

NARRATION

In fact there's been decades of research in all sorts of species to show that right-handed animals tend to be more bold and inquisitive, while left-handed animals tend to be more fearful and cautious. So perhaps it's not surprising the more anxious lefties did worse. But Lisa's experiment didn't stop there. She also looked at eye preference.

Dr Jonica Newby

Now you might find this next test a little harder to do at home. That's because first of all you need to train your dog how to be a pirate.

NARRATION

Lisa covers each eye in turn, and then looks at how well they judge the jump and the distance. This time it was the left-eyed dogs who were more likely to succeed.

Dr Lisa Tomkins

Basically Guide Dogs are trained to work on the left side of their handler, and the vision in their right eye is often partially obscured. So I think that may have influenced the left-biased dogs in being more successful.

Dr Jonica Newby

But just when you think it couldn't get more interesting, here's one of the best guides to Guide Dog success. Believe it or not, it's all about good hair. Okay, so you need to go right in here and look for the test whorl. Is it clockwise, or anti-clockwise? Aha, anti-clockwise.

NARRATION

Famously, pioneering work in cattle found the position and direction of the hair whorl had a large bearing on how anxious or bold they were. No-one is sure exactly why, but it's something to do with skin and brain development in the embryo, and it's independent of paw preference. And it turned out that counter-clockwise dogs were twice as likely to graduate as the clockwise. Which astonished the Guide Dog school.

Dr Lisa Tomkins

They didn't believe me at first. They were, 'Hair swirls, what are they?' No. And yeah no, they were very excited.

NARRATION

So the perfect candidate for Guide Dog school would be right-pawed, left-eyed with an anti-clockwise whorl. And meanwhile, back at pet paw testing land …

Pet Owners

Left … right … that's it! Woo-hoo!

Dr Jonica Newby

You're done!

NARRATION

It looks like we will finish today.

Dr Jonica Newby

Whoa, the pug finished. Right, you all ready for your results?

Pet Owners

Yeah.

Dr Lisa Tomkins

Have a look at your right preferences, does anyone have thirty-two or higher?

Dr Jonica Newby

Okay, two right-paws.

Dr Lisa Tomkins

Between nineteen and thirty-one, your dogs are ambidextrous. Those dogs that have a score of thirty two or more for left-paw preference, hands up?

Pet Owners

Yep.

Dr Jonica Newby

So you are the south paws.

NARRATION

So they may not be as likely to pass Guide Dog school, but they're still lovely pets.

Dr Jonica Newby

Oh, very stylish. [Laughs]

NARRATION

And, let's face it, who wants a creative guide dog?