The Zeigarnik effect can be used deliberately to let ideas develop in our subconscious
Open tasks tend to occupy our short-term memory until they are done. That is why we get so easily distracted by thoughts of unfinished tasks, regardless of their importance.
The brain doesn’t distinguish between an actual finished task and one that is postponed by taking a note. By writing down, we literally get it out of our heads!
Conversely by letting an idea in our short-term memory, we let our subconscious crew on the idea and develop a “gut feeling”.
Relevant Note(s): Zeigarnik Effect