Scientists have long sought to explain why it is that humans sometimes go into a room to do something important, but forgetting the task as soon as they enter.
Previously, the phenomenon was attributed to the “doorway effect” – suggesting we tend to forget items of recent significance after crossing a boundary. The boundary may be physical like a door, or it could be a virtual one like switching between tabs on an internet browser. The explanation came to prominence in 2011 after a study by researchers at the University of Notre Dame.
But now a follow-up study by Bond University has found that the effect of “doorways” alone on forgetfulness was not as significant as earlier studies claimed it to be, thereby providing a new perspective on the phenomenon.
The scientists found that it was not just the door itself or the act of walking through it, but rather the change in context that caused the brain to drop the information that it considered irrelevant.
The research team conducted four studies – two using real-world locations and two in which participants wore virtual reality headsets and moved through various rooms in a 3D environment.
The participants were tasked with memorising objects (a yellow cross, a blue cone, and so on) on tables within each room and then move them from one table to the next in the same order. Crucially, sometimes the next table was in the same room, and at other times people had to move to another room by passing through an automatic sliding door.
The researchers found the change had no effect on memory and that people rarely forgot objects, regardless of whether they went through a doorway or not.
But when the researchers made the memory test harder, by asking the participants to perform the same task while simultaneously doing a separate counting task, the findings of the doorway effect were prominent.
“Essentially, the counting task overloaded people’s memory, making it more susceptible to the interference caused by the doorway,” explained Dr Oliver Bauman and Dr Jessica Mcfadyen, the authors of the study.
“This finding more closely resembles everyday experience, where we most often forget what we came into a room to do when we are distracted and thinking about something else,” they said.
Explaining the phenomenon, Dr Baumann said the brain compartmentalises memories from different environments and contexts.
“If the brain thinks it is in a different context, then those memories belong in a different network of information. Overall that gives us greater capacity than if you have just one gigantic workspace where everything is connected,” he explained.
“But there is a cost to that. By transitioning between compartments we can lose things.”
Dr Baumann said the Bond study also suggested it was possible to “immunise” yourself against forgetting.
“If we are single-minded in what we want to do, nothing will stop us from remembering. But if we have multiple things going on, forgetfulness becomes noticeable.”