Have you ever realized that you're dreaming in the middle of a dream? If this happens during a nightmare (噩梦), you can wake yourself up. If it happens during a common dream, you can decide what to dream about next. Want to fly? Go right ahead! People call this type of experience a lucid dream (清醒梦)
Some people have lucid dreams naturally, while others need to practice. The key to lucid dreaming is realizing that you are in a dream. To do that, most people need a "reality check". One way of checking is to look at a clock or words on a page, look away, and then look back again. In a dream, words and numbers are often unclear, or change completely.
A lot of lucid dreaming devices (设备) promise an easy way to lucid dreams. These devices play sounds or shine red lights as reality checks. If these sounds or red lights appear in the dream, the user may realize, "Hey, I'm dreaming!"
Unluckily, a scientific report of lucid dreaming devices found that none of them were reliable (可靠的). For example, the Remee lucid dreaming mask was popular on Kickstarter when it came out in 2012. But many people complained that it didn't work. They didn't have lucid dreams, and didn't remember seeing any red lights. Another device, the $299 Aurora headband, which can record brain-waves as well as body movements, also made people unsatisfied.
What do you think? Have you ever had a lucid dream? Would you want to try a lucid dreaming device? Or are these devices just a lie?