Lucid Dreaming

In a lucid dream, you realize you are dreaming while the dream is still running — and sometimes you can steer it. Surveys suggest about half of people have had at least one, while only a small share have them often. The trick is that your prefrontal cortex, the brain's planning hub, partly switches back on, handing you a little control inside the dream.

The most reliable way to train it is reality testing: several times a day, genuinely ask "Am I dreaming?" and check something that breaks in dreams, like rereading a sentence to see if the words stay the same. Do it enough while awake, and you will eventually do it in a dream.