Bluma Wulfovna Zeigarnik (Russian: Блю́ма Ву́льфовна Зейга́рник; 9 November 1901 – 24 February 1988) was a Soviet psychologist and psychiatrist, a member of Berlin School of experimental psychology and Vygotsky Circle. She discovered the Zeigarnik effect and contributed to the establishment of experimental psychopathology as a separate discipline in the Soviet Union in the after-World War II period.
Life and career 
Born into a Lithuanian Jewish family in Prienai, Kovno Governorate, Zeigarnik matriculated from the Berlin University in 1927. She described the Zeigarnik effect in a diploma prepared under the supervision of Kurt Lewin. In the 1930s, she worked with Lev Vygotsky at the All-Union Institute of Experimental Medicine (AUIEM, aka VIEM). During World War II, she assisted Alexander Luria in repairing head injuries. She was a co-founder of the Moscow State University Department of Psychology and the All-Russian Seminars in Psychopathology. She died in Moscow at the age of 87.
The Zeigarnik Effect 
In psychology, the Zeigarnik effect (less common: Ovsiankina-Effect) states that people remember uncompleted 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.
Zeigarnik first studied the phenomenon after her professor, Gestalt psychologist Kurt Lewin, noticed that a waiter had better recollections of still unpaid orders. However, after the completion of the task – after everyone had paid – he was unable to remember any more details of the orders. However, several studies attempting to replicate Zeigarnik's experiment, done later in other countries, failed to find significant differences in recall between finished and unfinished (interrupted) tasks (e.g. Van Bergen, 1968).
The advantage of remembrance can be explained by looking at Lewin’s field theory: a task that has already been started establishes a task-specific tension, which improves cognitive accessibility of the relevant contents. This tension that has formerly been established is being relieved upon completion of the task. In case of task interruption the reduction of tension is being impeded. Through continuous tension the content is easier accessible and it can be easily remembered.
The Zeigarnik effect suggests that students who suspend their study, during which they do unrelated activities (such as studying unrelated subjects or playing games), will remember material better than students who complete study sessions without a break (Zeigarnik, 1927; McKinney 1935).
- Van Bergen, A. (1968) Task interruption. Amsterdam: North-Holland Publishing Company.
- (Russian) Biography of Zeigarnik on the website of the MSU Department of Psychology
- A.V. Zeigarnik, "Bluma Zeigarnik: A Memoir" in Gestalt Theory (2007), no 3, pp. 256–268.
- Yasnitsky, A. (2011). Vygotsky Circle as a Personal Network of Scholars: Restoring Connections Between People and Ideas. Integrative Psychological and Behavioral Science, doi:10.1007/s12124-011-9168-5 pdf