Why do we forget things when we walk through a door?

Hands up if this has happened to you. You are sitting in a room in your house and think of something you have to do or fetch in another room, or maybe in the car. So off you trot, out the door and before you know it you are standing at your destination wondering why you went there in the first place.

A bit of concentration usually prompts the answer, but why is it that we can so easily forget the reason for walking that short distance?

Research in virtual environments has found that when people pass through a doorway to move from one location to another, they forget more information than if they do not make such a shift, according to the authors of a recent study in Quarterly Journal of Experimental Psychology that ponders this puzzle.

Using their own virtual and real experiments, they carried out various memory tests on participants, including one that assessed memory when they walked through multiple doorways and returned to the original room.

And what they conclude is that walking through a doorway influences how the mind handles memories.

“Entering or exiting through a doorway serves as an ‘event boundary’ in the mind, which separates episodes of activity and files them away,” explains researcher Prof Gabriel Radvansky from the University of Notre Dame in a release.

“Recalling the decision or activity that was made in a different room is difficult because it has been compartmentalised.”