Zeigarnik Effect Psychology Dissertation
Russian psychologist Bluma Zeigarnik found in 1927 that waiters remembered orders only as long as the order was in the process of being served.
When we hold multiple things in short-term memory, we have to rehearse them continuously, otherwise they would disappear. This requires a lot of cognitive effort, and the more things we are rehearsing the more effort.
Our brain usually tricks us, or rather we trick our brain into remembering only those things which are incomplete. Waiters had better recollections of still unpaid orders. However, after the completion of the task — after everyone had paid — they were unable to remember any more details of the orders.
Apart from a short-term effect, it also happens over a longer period as we worry about those things in which we have not achieved closure. Thus I might keep thinking about unresolved bug in my code over a whole weekend as it keeps coming back to haunt me.
This trick is very well applied by soaps and serials. The episode ends, but the story doesn’t. Thus you get stuck in a cliffhanger.
Zeigarnik Effect is a good method designers use to trick users into making them do certain things they wouldn’t do otherwise. LinkedIn uses this trick to make users complete their profiles.
An important feature of human memory is the ability to retrieve previously unsolved problems, particularly when circumstances are more favorable to their solution. Zeigarnik (1927) has been widely cited for the finding that interrupted tasks are better remembered than completed ones; however, frequent replications and non-replications have been explained in terms of social psychological variables (Prentice, 1944). The present study examines differences in memory for tasks based on completion status by appealing to cognitive variables such as the nature of interruption, time spent during processing, and set size. In one experiment using word problems, subjects were interrupted on half of the problems after a short interval of active problem solving, and completed tasks were in fact better remembered than interrupted ones. However, less processing time was necessarily spent on problems that were interrupted. A second experiment held time constant, allowing subjects to abandon tasks they could not complete. In this experiment, the opposite result occurred, replicating Zeigarnik and showing better access to unsolved problems in free recall. However, enhanced memorability in this study may have resulted from a subject-generated impasse in problem solving rather than "interruption" per se. This successful replication also included set size differences in favor of incomplete problems. Under these conditions, the status of completion can serve as a useful index to past problem situations. These experiments are successful in identifying cognitive variables that explain when one can suspend effort on a failed problem, and recall it at a later time.
Seifert, C. M., & Patalano, A. L. (1991). Memory for incomplete tasks: A re-examination of the Zeigarnik effect. In Proceedings of the Thirteenth Annual Conference of the Cognitive Science Society [refereed] (pp. 114-119). Mahwah, NJ: Erlbaum.