In which branch of science is the "Zeigarnik effect" known?

The Zeigarnik effect is a psychological phenomenon describing a tendency to remember interrupted or incomplete tasks or events more easily than tasks that have been completed.

The Zeigarnik effect was named after its founder, Russian psychiatrist and psychologist Bluma Wulfovna Zeigarnik. In one of her experiments, Zeigarnik asked a group of 138 children to complete a series of simple tasks, puzzles, and arithmetic problems. She allowed the children to complete half of the tasks and interrupted them during the remaining tasks. Zeigarnik investigated their recall after an hour’s delay and discovered 110 of the 138 children had better recall for the interrupted tasks than the completed tasks. In a related experiment involving adults, the participants were able to recall unfinished tasks 90% better than completed tasks. Her research report was published in 1927.

The Zeigarnik effect is employed in many aspects of modern culture. It may differ slightly by industry, but the underlying principles remain the same: (1) Initiate or draw attention to an interest-arousing event; (2) allow people to participate in some way; (3) terminate the event prematurely to create cognitive tension; (4) invite participants to return for the resolution.

Also, students who suspend their study to perform unrelated activities (such as studying a different subject or playing a game), will remember material better than students who complete study sessions without a break.