Servicios
Have you ever wondered why we feel the need to finish a survey as soon as we start it? What drives us to return to an abandoned shopping cart or complete a user profile? The answer may lie in a discovery from almost a century ago: the Zeigarnik effect.
The Zeigarnik effect was first described in 1927 by Soviet psychologist Bluma Zeigarnik, who observed that waiters remembered unpaid orders better than those already served and paid for. Intrigued, she conducted a series of experiments that showed that people tend to remember incomplete tasks more clearly than those they have already completed.
The human brain hates to leave things “open”. An interrupted task generates a kind of psychological tension that is only resolved when it is completed. This tendency, deeply rooted in our cognitive functioning, has direct implications for how we design digital experiences.
One of the most common uses of the Zeigarnik effect in UX is to display progress bars. When a user sees that they have completed “3 out of 5 steps,” it triggers a natural urge to finish. It’s not just design: it’s applied psychology.
“Progress bars not only indicate where you are, they create a psychological urge to move forward” – UX Planet
Platforms like Duolingo, LinkedIn or Trello apply this principle in small doses: completing tasks, leveling up or unlocking achievements. Each unfinished action remains as a “to-do” that the brain wants to cross off. It’s a subtle way to keep the user engaged without using intrusive techniques.
Social networks and work apps like Behance or Notion often remind you that your profile is “70% complete”. That exact figure generates a mild but effective discomfort. The Zeigarnik effect suggests that users are likely to return to finish what they started, especially if they see a clear and achievable goal.
Abandoned cart emails in e-commerce work because they appeal to the same principle: you interrupted a task (shopping) and the store takes care of reminding you. It’s like being told: “you still haven’t finished something you started”.
It is not a matter of leaving everything unfinished to provoke anxiety in the user. Misused, the Zeigarnik effect can lead to frustration or even abandonment. The design should offer a clear experience, without unnecessary steps, and with a real purpose behind the incentive to complete.
“Designing for task completion is not about manipulation; it’s about understanding human motivation and respecting their time” – UX Collective
The Zeigarnik effect reminds us that UX design is not just about beautiful interfaces, but about understanding how the human mind works. By applying this principle with intention, you can motivate users to move forward, complete and return… without forcing them to do anything. Because sometimes, the best conversion starts with a half-finished task.
Sources:
Zeigarnik, B. (1927). “Über das Behalten von erledigten und unerledigten Handlungen.” Psychologische Forschung.
Baumeister, R. F., & Bushman, B. J. (2017). “Social Psychology and Human Nature” (4th ed.). Cengage Learning.