Why people yawn when others yawn

Try to watch this video without yawning at least once

Another one of our science-explainer video pals is Vsauce, who presents this interesting video on why yawning is contagious - there's both a physical and mental reason as part of the explanation.

The real trick and fun with this video is to try and count how many times you yawn during the video - not because it might be dull, but rather for the explanations given. Try the ice pack trick too!

Keith Shaw rounds up the best in geek video in his ITworld.tv blog. Follow Keith on Twitter at @shawkeith. For the latest IT news, analysis and how-tos, follow ITworld on Twitter, Facebook, and Google+.

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