Do we really remember unfinished tasks better?

Probably not, or at least not reliably. The Zeigarnik effect is the idea that people remember unfinished or interrupted tasks better than completed ones. It's named after psychologist Bluma Zeigarnik, who published experiments on it in 1927. But several later attempts to replicate her results found no difference in memory, and a 2025 review of the accumulated research found no memory advantage for unfinished tasks. What it did find is a close cousin: a general tendency to go back to interrupted tasks and resume them.

The story began in a restaurant. Zeigarnik's mentor, Kurt Lewin, noticed that a waiter remembered orders in detail while they were still unpaid, then couldn't recall them once everyone had paid. Lewin's explanation was that starting a task creates a kind of tension that keeps its details close at hand. Finishing releases it; interruption keeps it going.

Zeigarnik's colleague Maria Ovsiankina looked at what that tension makes us do. When people were interrupted during a task and later given free time, they strongly tended to go back and finish it. That urge, the Ovsiankina effect, is the part the 2025 review found to be general.

You meet it daily. Apps show "Your profile is 64% complete" because people then take a few minutes to fill in the missing details, and series end episodes on cliffhangers to keep you coming back. It may not be memory that pulls you back, but the itch to finish.