When I’m driving and a song comes on the radio from 1968, I sing along. I know all the words, even if it has been decades since I last heard them. I might even recall where I was, what I was doing, with whom I was doing it and, possibly, what I was wearing at the time. 

Yet, when I leave the den and walk into the kitchen, I cannot remember why I’m there. Looking around for clues, I come up empty. I return to the den, again looking for something to spur my memory as to why I left in the first place… Nothing.

Why can I remember the lyrics to a song from nearly fifty years ago, but I cannot remember why I just walked into the room? Is it an indication of my age-related, mental demise? Could it be signs of dementia? We often joke about this, but, beneath the surface, we genuinely wonder. So I did some research. 

What I learned, surprisingly, is that it’s called the Doorway Effect. Walking from one room to another actually causes us to forget. Now, before you start constructing your anti-doorway helmet or move to a studio apartment, here me out. It’s more complicated than that. 

It has to do with the way our brains collect and use information about our environment. Going back to my driving example, perhaps you are familiar with the concept of doing several things at once, like driving the car and planning a vacation or having a complex conversation with a passenger. Have you ever gotten to your destination and had no recollection of actually driving there? The subconscious can take care of routine things that we have done over and over again (like driving). Meanwhile, the brain takes in other information and processes it, at the same time (like vacation plans or conversations).

Your mind is always operating like this. You might be doing one thing, but you are taking in other data that you need, from your environment. This is called a “situational model” or, more practically, the room you are in. When you leave that room and enter a new one, your brain discards the temporary information it acquired because it no longer needs it. You automatically start collecting information about your new environment, or the next room into which you have walked. The reason you are there, however, might have been included in the mind-dump of data from the previous room.

That is also why returning to the original room doesn’t necessarily work – At least not right away. That information is gone and now you’ve caused your brain to dump another set of data and begin a third situational model. Eventually, you might take in the same date as the first time, like the fact that you need the watering can because your favorite houseplant is wilting. But, if it were a thought-driven idea that sent you on your mission instead of something you can see, you may not remember.

Interestingly, there have been studies that used virtual rooms. The subjects played a videogame where they picked up an object from a table and then walked from one room into another. The object, once selected, was hidden from the subject’s view while being carried, in a box or back pocket. When the subjects arrived in the new virtual room, they mostly could not recall what the object was that they had selected to bring with them. Returning to the original room did not help. The mind operated the same way, even when moving thru virtual doorways. 

I read a fable about a woman who comes upon three men and asks each “what are you doing?” The first replies, “I’m putting brick upon brick upon brick.” The second says, “I’m building a wall.” The last man answers, “I’m building a cathedral.” Every task we approach has multiple levels. Moving from one level to the next is like walking thru the doorway. Our minds compartmentalize much more than we realize. Moving between the levels, or thru the doorway, makes us forget.

So, I am not necessarily losing my mind when I arrive in the kitchen, clueless. Apparently, what happens in the den, stays in the den….