This article claims to be about decision-making during sleep, but it's actually about learning during sleep
. See this one for the part about decision-making
. Basically, your brain keeps going while you sleep. How sophisticated its behavior is during that time depends on a combination of innate talent and learned skill. Both of these things -- sleep-learning and decision-making -- are easy for some people, achievable for others, and out of reach for some. If you have the potential, you can develop it.
Sleep-learning is about backloading the subconscious part of your mind with information. In my experience, this is most effective with iceberg material, where the majority of import lies within the subconscious mind. For example, in learning a foreign language, vocabulary and grammar tend to go in the conscious mind but pronunciation, tone, native intuition, etc. go into the subconscious mind. So playing that language while you sleep will help you learn how it's supposed to sound, and then when you wake up, you speak it better.
Decision-making works the opposite. You go to sleep with everything already in mind, your subconscious processes it, and spits out an answer that comes to you when you wake up. This works by letting your mind mull over things without being distracted by what you think
you should be thinking.
And of course, if you're a writer or other creative person, you probably have the experience of waking up in the middle of the night with a really hot idea. Because your creative brain is kind of like a toddler just waiting for waking-you to fall asleep so it can pull everything out of the cupboards, see what fits together, and wake you up with a terrific crash
There are have been people who say these techniques do not work. That does not stop those of us who are using them from getting great results. They're just things that not everyone can do, and they're not in an easy place to study or measure. But there are starting to be glimmers of confirmation.