Need to Complete
Unfinished tasks stay in mind until they are done.
What it is
Started but incomplete tasks occupy attention in a way completed ones do not. People remember them, return to them and feel a low-level pull to close them. Progress indicators, half-filled profiles and cliffhangers all rely on it. Digital Psychology listed it as Need to Complete; the underlying finding is the Zeigarnik effect.
The research
Waiters remembered unpaid orders in detail and forgot them almost immediately once the bill was settled; in the lab, interrupted tasks were recalled about twice as often as completed ones.
Zeigarnik, 1927
How to use it
Show what is unfinished
A checklist with one item open pulls people back. A checklist that is all ticked is closed in the mind, so add the next one.
Start the task for them
A draft that already exists gets finished. A blank page does not.
End emails and episodes mid-thought
A series that ends each part with the next question keeps people reading.
Related
Sources that shaped this entry: Digital Psychology, growth.design.