Don: Hi everyone. On this show we usually talk about other people's experiments, but today we're going to do an experiment of our own. Here's the deal: see if you can tell      if I'm smiling or not as I speak. Ready? Here's goes. Am I smiling now? How about      now? What about...

Ya?l: Wait, hold on. Don, what are you doing?

D: An experiment. Like I said, I want to see if our listeners can tell if I'm smiling just by  the sound of my voice.

Y: But how is that possible?

D: Researchers at the University of Portsmouth, in England, have worked on this. They recorded interviews with volunteers who were asked silly questions, the idea being to make them smile as they spoke. Then the researchers played the recordings for another set of volunteers and asked them to identify when the speakers were smiling. And more often than not, they could.

Y: Interesting. Is that because smiling affects the vocal cords or something?

D: Sorta. It's probably more that smiling can affect your pitch, making your voice sound   higher. So the listeners might have been picking up on that cue. They might also have  been concentrating on the intensity of the voices. It's not an exact science, obviously,  but something was tipping off the listeners.

Y: So does this have any practical application?

D: It could help improve voice recognition software and synthetic voices for things like computer games.

Y: Cool. OK, so let me try. I'm smiling now, can you tell? And now I'm not smiling. Do  I sound different?

D: Yes...and yes.