Want to know what one of the most contagious human activities is? Don’t be surprised. It’s yawning. That’s right—opening your mouth so wide it feels like your jaw might drop off as you breathe in all the air around you—that six second (on the average) act of yours will lead 55% of the people who watched you yawn do it themselves within five minutes! In fact, you don’t even have to see someone do it. The blind will yawn simply from hearing an audio tape of someone else yawning. In fact, you don’t even need to hear a yawn. Just reading the word can cause you to yawn (a