I’ve always wondered where the term “counting sheep” came from. I’ve tried counting sheep to fall asleep, and it doesn’t work. In my case, the sheep don’t cooperate. Come to find out…
…counting sheep is actually an inferior means of inducing sleep. Subjects who instead imagined “a beach or a waterfall” were forced to expend more mental energy, and fell asleep faster than those asked to simply count sheep.
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Read more here](http://en.wikipedia.org/wiki/Counting_sheep)