The Zeigarnik Effect

This is a new one to me.
Called after the original promulgator of the phenomenon the Russian psychologist Bluma Zeigarnik
The cliff-hanger. People remember an interrupt task, thought etc. about twice as effectively as a completed task. And that can be a useful device to keep a reader powering from chapter to chapter or scene to scene.
It is also used in marketing and TV a lot when you are given a nibble of what may be to come. A teaser if you will.
It’s also a great study aid in that you will remember more by breaking before completion that coming to a natural break.
Maybe Ernest Hemingway intuitively knew this when he said, “The best way is always to stop when you are going good and when you know what will happen next.”