Ever left a thrilling novel right before the great mystery was about to be unfolded?
The Zeigarnik Effect is the tendency to experience intrusive thoughts about an objective that was once pursued and left incomplete.
The automatic system signals the conscious mind, which may be focused on new goals, that a previous activity was left incomplete.
If you start working toward a goal and fail to get there, thoughts about the goal will keep popping into your mind while you are doing other things, as if to remind you to get back on track to finish reaching that goal.
Ever tried starting a game, and leaving it half-way without reaching the goal?
An interrupted or incomplete task leads to a strong motivation to complete the action, an extra argument for the success of an already started action. Ring any bell?
This effect is something many products leverage to make the user complete something. Especially video games.
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.