[I know most of you are waiting for Baby News, but as that has not yet been forthcoming, I have to improvise.]
A series of experiments at Notre Dame sheds light on on the perennial "Why did I come into this room?" question. Here are some excerpts from the Scientific American article, Why Walking through a Doorway Makes You Forget. Most of the experiments were done in a video-game context, but the same effect was seen in real-life versions as well.
[Participants played a video game in which] they would walk up to a table with a colored geometric solid sitting on it. Their task was to pick up the object and take it to another table, where they would put the object down and pick up a new one. Whichever object they were currently carrying was invisible to them, as if it were in a virtual backpack. Sometimes, to get to the next object the participant simply walked across the room. Other times, they had to walk the same distance, but through a door into a new room. From time to time, the researchers gave them a pop quiz, asking which object was currently in their backpack. The quiz was timed so that when they walked through a doorway, they were tested right afterwards. Their responses were both slower and less accurate when they'd walked through a doorway into a new room than when they'd walked the same distance within the same room.
Usually, returning to the room I started from will remind me of why I left in the first place. But the researchers did not find that to be the case in their experiments.
[P]articipants sometimes picked up an object, walked through a door, and then walked through a second door that brought them either to a new room or back to the first room. If matching the context is what counts, then walking back to the old room should boost recall. It did not.
The doorway effect suggests that there's more to the remembering than just what you paid attention to, when it happened, and how hard you tried. Instead, some forms of memory seem to be optimized to keep information ready-to-hand until its shelf life expires, and then purge that information in favor of new stuff. ... [W]alking through a doorway is a good time to purge your event models because whatever happened in the old room is likely to become less relevant now that you have changed venues. ... Other changes may induce a purge as well: A friend knocks on the door, you finish the task you were working on, or your computer battery runs down and you have to plug in to recharge.
Why would we have a memory system set up to forget things as soon as we finish one thing and move on to another? Because we can’t keep everything ready-to-hand, and most of the time the system functions beautifully.
Take heart, distracted mothers! That which frustrates you so badly was apparently designed to help with the rapid context-switching essential to your vocation.
