Why Do You Forget Why You Walked Into a Room?

Here’s a familiar scene: You need a pair of scissors from the junk drawer, so you head to your kitchen to grab them. You walk down the hall, step into the kitchen, and… nothing. Your mind goes blank. You open the refrigerator — you probably came to the kitchen for a snack, right? But that doesn’t feel right, and you just stand there staring at the fridge as if it owes you an explanation.

Most of us have intentionally gone into a room only to forget the reason just as soon as we arrive. It’s an incredibly common memory lapse that might be caused by… the doorway?

Your Brain Files Things by Scene

As humans, we make sense of our days by thinking about them in chunks; psychologists and neuroscientists call them “events.” Events include many contextual and environmental cues, such as where you are, what you’re doing, and why. When something significant changes, such as your location or your goal, your brain notes the change as an “event boundary.” It then closes that event, files it away, and opens a new, blank event to start a new recording session.

The majority of the time, this is a very useful way of thinking. You can’t have everything you’ve ever noticed at the ready all the time, so this is how your brain keeps its working memory from filling up with stale information. But it means that whatever you were thinking about in the previous event also gets filed away. So when you walk into the kitchen and begin a new event, the reason you did so has already been moved to long-term storage.

There are a lot of things your brain can consider an event boundary, such as turning on music, answering a doorbell, or even something as simple as walking through a doorway. In fact, your brain considers that last simple action to be a pretty convincing boundary.

In a series of experiments at the University of Notre Dame in 2011, psychologists had people pick up and drop off objects as they moved through both virtual and real rooms. Participants forgot more about what they were carrying after walking through a doorway than after walking the same distance within a single room. Researchers now call this the “doorway effect.”

Returning to the original place through a different route didn’t help, either. In one of the Notre Dame experiments, participants walked through doorways that led back to the room where they started, and their memory didn’t improve. This suggests the problem isn’t the new room so much as the act of crossing into one.

The doorway isn’t the whole story, though. When researchers tried to replicate the effect a decade later, the effect only appeared when participants were also juggling a second mental task: counting backward. In other words, a doorway is most likely to wipe your memory when your mind is already busy — planning dinner, answering a text, or thinking about what you’ll wear tomorrow.

So the next time you’re standing in the kitchen with no idea why, try not to think of it as your mind malfunctioning. Your brain’s actually doing its job too well and filing away information before you’re done with it.