by Charles B. Brenner and
Jeffrey M. Zacks
December 13, 2011
Charles B. Brenner is a second year
graduate student in the
Laboratory at Washington University in St. Louis, where he
studies memory, language, and event cognition.
Jeffrey M. Zacks
is Associate Professor of Psychology at
Washington University in
laboratory studies perception, memory, brains, movies, and
The French poet Paul Valťry once
said, "The purpose of psychology is to give us a completely
different idea of the things we know best."
In that spirit,
consider a situation many of us will find we know too well:
You're sitting at your desk in your office at home.
something under a stack of papers, you find a dirty coffee mug
thatís been there so long itís eligible for carbon dating.
Better wash it. You pick up the mug, walk out the door of your
office, and head toward the kitchen.
By the time you get to the
kitchen, though, you've forgotten why you stood up in the first
place, and you wander back to your office, feeling a little
confused - until you look down and see the cup.
Are you a scientist who
specializes in neuroscience, cognitive science, or psychology?
And have you read a recent peer-reviewed paper that you would
like to write about? Please send suggestions to Mind Matters
editor Gareth Cook, a Pulitzer prize-winning journalist at the
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Turn the handle and
leave the past behind.
Scientists measure the
and it supports a novel model
of human memory
The French poet Paul Valťry once said,
"The purpose of psychology is to give us a completely different idea
of the things we know best."
In that spirit, consider a situation
many of us will find we know too well: You're sitting at your desk
in your office at home.
Digging for something under a stack of
papers, you find a dirty
coffee mug thatís been there so long itís eligible for
carbon dating. Better wash it. You pick up the mug, walk out the
door of your office, and head toward the kitchen.
By the time
you get to the kitchen, though, you've forgotten why you stood up in
the first place, and you wander back to your office, feeling a
little confused - until you look down and see the cup.
So there's the thing we know best:
common and annoying experience of arriving somewhere only to realize
what you went there to do.
We all know why such
we didnít pay enough attention, or
too much time passed, or it just wasnít important enough.
But a "completely different" idea comes
from a team of researchers at the University of Notre Dame. The first part of their paperís title sums it up: "Walking
Through Doorways Causes Forgetting."
Gabriel Radvansky, Sabine Krawietz and
Andrea Tamplin seated participants in front of a computer screen
video game in which they could move around using the arrow
In the game, 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.
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
As the title said, walking through doorways caused
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.
This "doorway effect" appears to be
It doesn't seem to matter, for instance, whether the
virtual environments are displayed on a 66" flat screen or a 17"
CRT. In one study, Radvansky and his colleagues tested the doorway
effect in real rooms in their lab. Participants traversed a
real-world environment, carrying physical objects and setting them
down on actual tables.
The objects were carried in shoeboxes to
keep participants from peeking during the quizzes, but otherwise the
procedure was more or less the same as in virtual reality.
enough, the doorway effect revealed itself:
Memory was worse after
passing through a doorway than after walking the same distance
within a single room.
Is it walking through the doorway that
causes the forgetting, or is it that remembering is easier in the
room in which you originally took in the information?
have known for a while that memory works best when the context
during testing matches the context during learning; this is an
example of what is called the
encoding specificity principle.
But the third
experiment of the Notre Dame study shows that it's not just the
mismatching context driving the doorway effect.
In this experiment
(run in VR), participants 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.
Radvansky and colleagues call this
sort of memory representation an "event model," and propose that
walking 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.
That thing in the box? Oh, that's from what I
was doing before I got here; we can forget all about
Other changes may induce a purge as well:
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
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 canít keep everything ready-to-hand,
and most of the time the system functions beautifully.
failures of the system - and data from the lab - that give us a
completely new idea of how the system works.