What is Zeigarnik Effect?
People remember unfinished tasks better than finished ones, and feel mild tension until they are completed. Progress bars like 'Profile 80% complete' use this to pull you through onboarding and upsell steps.
Where it comes from
Bluma Zeigarnik (1927)
How it hooks you
Exploits task tension: an incomplete progress bar creates mental friction. Users feel compelled to close this loop by finishing the setup, which usually means handing over more personal data.
What the research shows
Zeigarnik's original experiments found people recalled interrupted tasks about twice as well as completed ones.
How to resist it
Treat completion prompts as persuasion, not obligation. Ask whether the remaining steps benefit you or mainly the platform.