As Gabriel Radvansky, Professor of Psychology at the University of Notre Dame in Indiana, USA, explains in a news article published on the University's website this last week:
"Entering or exiting through a doorway serves as an 'event boundary' in the mind, which separates episodes of activity and files them away."
"Recalling the decision or activity that was made in a different room is difficult because it has been compartmentalized," he added.
Radvansky and colleagues have been exploring this phenomenon for a while: the findings of their latest study were published recently in the Quarterly Journal of Experimental Psychology.
"Previous research using virtual environments has revealed a location-updating effect in which there is a decline in memory when people move from one location to another."
However, Radvansky and colleagues wanted to explore whether the "degree of immersion" in the environment had an effect on this.
For their latest study they carried out three experiments in real and virtual environments, the latter being where the subjects experience the "environment" on a display screen by means of a computer simulation. The participants, all college students, were given memory tasks to do while they just crossed a room and also while going out through a doorway.
The first experiment was done in a virtual environment using small display screens, to reduce the degree of immersion.
In this experiment, the students moved from one virtual room to another, picking up an object on a table and exchanging it for an object on another table. They then carried out the same task, "walking" the same distance, but without going through a doorway.
The researchers found the students forgot more after they went through a doorway than when they just walked the same distance across a room, suggesting the doorway or "event boundary" impeded their ability to retrieve thoughts or decisions they had made in a different room.
The second experiment was in the "real" world, not on a computer screen. The participants had to pick objects from a table and hide them in boxes and move either across a room, or go through a doorway into another room. As in experiment 1, they walked the same distance in both cases: whether across the room or through the doorway.
The results of the second experiment in the real world were the same as for the first experiment in the virtual world: walking through doorways appeared to impair memory.
In the third and final experiment, the researchers tested whether, if the participants were in the same environment as where they "created" the memory, even if they passed through several doorways, this would not impair memory: there is a theory that if you can put subjects in the same environmental context as when they did their learning, they retrieve the memories underpinning that learning better.
But this did not happen: the participants were asked to make a "decision" (select an object) in one room, then they walked through several doorways, eventually ending up back in the same room where they started. The results showed no improvements in memory, which the researchers said suggests the act of passing through doorways serves as a way for the mind to file away memories:
"In Experiment 3, the original encoding context was reinstated by having a person return to the original room in which objects were first encoded. However, inconsistent with an encoding specificity account, memory did not improve by reinstating this context," they write.
Perhaps one way to overcome the problem of forgetting what we went into the room for is to write little notes to ourselves, like Leonard Shelby, the man with anterograde amnesia, who was played by Guy Pearce in the award-nominated thriller Memento.
Written by Catharine Paddock PhD