Moved by the Power of Speech

Chris - We often hear that people can move you by their words that they use.  Well, it turns out that that's actually physically true as well.  Bryan Gick is a researcher of the University of British Columbia and he's published a paper this week showing that actually we respond to the sensation of the breath of a speaker on our skin which helps to reinforce meaning.  He's with us now.  Hello, Bryan.

Bryan -   Hi.

Chris -   Welcome to the Naked Scientists.  Do tell us what have you been doing?

Bryan -   Well, we've just been aiming puffs of air at people basically and seeing how that affects their speech perception.

Chris -   So talk us through the experiment, what did you actually do?

Bryan -   Well, initially, we thought that there are certain things that we can pick up in our environment that help us to perceive speech.  And we haven't had so much insight into how the tactile sense works into this.

Chris -   So, in another words, we know that we're comfortable with the fact that people lip read, for example, and so they help their comprehension of what someone is saying by following the movements of someone's lips.  But there's an additional dimension to this which is the air coming out of their mouth.

Bryan -   Exactly.  And we aren't particularly fond of the air approach, it just happens that the air approach is the best way to get at what kind of information could somebody be conveying, that you can just sort of passively pick up from your environment.

Chris -   So how did you do this?

Bryan -   So we thought about these little puffs of air that people produce when you say a sound like "pah".  If you put your hand in front of your face, if you're an English speaker, you can feel a little puff of air in your hand.  And if you say "bah" you don't really feel a puff of air.  So we took little tiny puffs of air and put them on different places on people's bodies, and at the same time we played sounds that they could hear through headphones.

We found that if you if you play the sound "bah" to someone and at the same time, somewhere on the body, they feel a little gentle puff of air that's inaudible to them, they'll experience the sense of having heard "pah".

Chris -   Alright.  So you can completely throw them off the scent and you can make them think they're hearing a different sound because you're pairing a puff of air which they would normally associate with hearing the "pah" sound and in fact you played them a "buh"sound.

Bryan -   You're right.  So, a B will sound like a P, a D will sound like a T and so on.  And this is interesting to us, not just because it draws up your perception, but it suggests something, I think, bigger which is that we really seem to take all the information around us from whatever sense modality is available and we incorporate it into percepts of the world.

Chris -   Does it matter where on the person's body you give the puff of air when doing this experiment?

Bryan -   It doesn't seem to matter.  In the Nature paper, we looked at puffs of air on the neck and the hand and in other studies that we haven't published yet, we looked at the ankle, for example, and we get the same effect anywhere.

Chris -   So in other words, the brain is pretty clever in that it's integrating information coming in from all over the place to reinforce the information that would be coming in just from the spoken language?

Bryan -   Exactly.  And it sort of challenges this traditional idea that you see with your eyes and that gets processed by a particular part of your brain and you hear with your ears and that gets processed by another part of your brain.  It looks like our brains just perceive things and take everything in.

Chris -   And obviously, people who talk on the radio or listen to a podcast, TV programmes, they have no problem interpreting what people are saying.  So when would the body want to use this additional dimension of comprehension?

Bryan -   Well, the way I view it, we're biological parts of our environment and we, like everything, like the plants without chlorophyll, we use whatever we've got to get by.  And in our particular case, if we happen to only have one sense modality available to us, we'll get by.  If however we've got all of our senses and they can pick up information from our environment, we'll use it all and we'll do it seamlessly.

Chris -   So I guess that puts a whole new spin on the meaning "breathing down in someone's neck," doesn't it?

Bryan -   Yes, it does.

Chris -   Bryan, thank you very much.  That's Dr. Bryan Gick, who's a researcher at the University of British Columbia, paper in Nature this week, explaining how puffs of air can actually distort our perception of what people are saying.