Named after Soviet psychologist Bluma Zeigarnik, in psychology the Zeigarnik effect occurs when an activity that has been interrupted may be more readily recalled. It postulates that people remember unfinished or interrupted tasks better than completed tasks. In Gestalt psychology, the Zeigarnik effect has been used to demonstrate the general presence of Gestalt phenomena: not just appearing as perceptual effects, but also present in cognition.
The Zeigarnik effect should not be confused with the Ovsiankina effect. Maria Ovsiankina, a colleague of Zeigarnik, investigated the effect of task interruption on the tendency to resume the task at the next opportunity.