This post was previously on the Pathfinder Software site. Pathfinder Software changed its name to Orthogonal in 2016. Read more.
The Zeigarnik effect suggests people remember incomplete or interrupted things better than completed things. It’s human nature to want to complete a task or hear the end of a story, and when we don’t, a psychological tension result until the item is completed.
The effect has an interesting implication for digital interfaces. When a user involved in a long task encounters an interruption or an opportunity to complete a quick task, there’s a good chance the interruption or new task will get acted on. This can leave a lineage of uncompleted tasks and non-linear navigation trails.
One way to combat this that we have used in a variety of applications is to dynamically create a task queue. The queue stacks up incomplete tasks in one place so the user can get back to these tasks when he or she is ready. In a restricted domain, it’s usually possible to apply some intelligence as to how the queue is built so it reads fluidly and clearly.