You're thinking of something you have to do later tonight, but right as you walk into the next room -- BAM! You forgot what it was you were thinking about.
Science may now have an explanation for why exactly we can forget in such an instant -- and it likely has to do with the physical act of walking through the doorway.
"Entering or exiting through a doorway serves as an 'event boundary' in the mind, which separates episodes of activity and files them away," study researcher Gabriel Radvansky, a psychology professor at the University of Notre Dame, said in a statement.
"Recalling the decision or activity that was made in a different room is difficult because it has been compartmentalized," he added.
To come to this conclusion, Ravansky and his colleagues conducted three experiments, the results of which are published in The Quarterly Journal of Experimental Psychology. In the first, they had college students virtually move objects from a table at one side of a room to a table at the other side of the room, as well as to virtually move objects from one room to another room and crossing beneath the doorway.
The researchers found that the students were more forgetful when they moved between the rooms, versus when they were just moving from one table to another in the same room.
In the second experiment, researchers had college students do the same experiment, but in real life. They found that the results were the same as in the first experiment. And in the third experiment, researchers found that passing through a doorway might be how the mind is able to file away memories.
Previously in research into forgetfulness, scientists have found that if you forget a bunch of information and then re-learn only some of that information, the process of re-learning may make it more difficult to remember the rest of the forgotten information, The Telegraph reported.
"You make a shopping list of, say, 10 items in your head. A little while later, you get to the shop and recall some items, but you find that you cannot recall all 10 item(s)," that study's researcher, Dr. Jim Stone of the University of Sheffield, told The Telegraph. "This may be because, as each item is recalled, some degree of relearning of that item occurs. The theory states that any relearning of some items on a list reduces recall of the other items."