Passing through a doorway from one room to another can, by itself, cause these memory lapses, psychology Professor Gabriel Radvansky of the University of Notre Dame said.
"Entering or exiting through a doorway serves as an 'event boundary' in the mind, which separates episodes of activity and files them away," he said in a university release Friday.
"Recalling the decision or activity that was made in a different room is difficult because it has been compartmentalized."
In several experiments in both real and virtual environments, subjects forgot more after walking through a doorway compared to moving the same distance across a single room.
That suggests the doorway or "event boundary" impedes one's ability to retrieve thoughts or decisions made in a different room, Radvansky said.