LISTEN 
Dr Geoff Bunn features comic book heroes and science in his history of the lie detector.
A QR code is a type of barcode which can contain links to webpages. Mobile phones with a camera and an appropriate application are able to read these codes and take you to the address contained within it.
This code will link to the page for Christmas Meditation when read using a QR code reader.
You may save, print or share the image. Also available in: small, large
BBC © 2013 The BBC is not responsible for the content of external sites. Read more.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.
