Have you ever sat down to take a test and completely forgotten what you had studied,
or opened your fridge and not remembered what you came to get?
Quite often, we only remember these things once we return to the place where we studied, or to
where we had the initial craving for that snack. These experiences are so common that psychologists
have studied them for years, and attribute them to something called “context-dependent memory.”
What is context-dependent memory, and how does it work? To understand, let’s first have a look
at how memories are formed. This usually happens in three stages, encoding, storage, and retrieval.
When you learn something new or have a new experience -- say, you meet someone at a
party -- your brain takes this information -- the person’s face, the sound of their
voice -- and transforms it into a memory code, a pattern of activity in a network of nerve cells.
This is known as encoding. The encoded memories are temporarily stored in short-term memory,
and if you call upon them enough, they can get transferred to more permanent storage
called long-term memory, from where they can be recalled whenever you need to use them.
This process of accessing information from long-term memory is known as retrieval.
The interesting thing about forming memories is that your brain encodes and stores not only
the information that you are actively focused on but also some of the contextual information from
your surroundings. Things you might overlook -- like the music playing in the background,
a subtle aroma in the room, or the physical layout of the space -- are encoded in addition to your
new friend’s face and name. This link, between the context and the thing you want to remember,
is the basis for context-dependent memory. When you find yourself struggling to remember the
name of your dance partner, listening to the song that you danced to or revisiting
the location of the party might help you remember. If the context during retrieval
is similar to the context during encoding, you are much more likely to recall the memory.
The idea of context-dependent memory is not only intuitive, it has also been scientifically
supported with experimental data. In one of the classic studies on context-dependent memory,
researchers asked two groups of divers to memorize a list of words in two different contexts.
One group memorized the words while they were underwater,
and the other group did this on land. After the words had been memorized,
the researchers asked half the divers to recall the words in their original learning context,
and the other half to recall the words in the context where they did not learn the words.
The researchers found that words learned underwater were best recalled underwater,
and vice versa. Other studies have also shown that internal states and
moods -- such as the feeling of hunger, happiness or being caffeinated at the time of memory
encoding -- can help in the contextualization of memory and operate as the retrieval cue.
So what affects the strength of a context-dependent memory? Some of the factors
that enhance context-dependent memory at the time of encoding are the richness of the context -- if
a high number of cues stimulate many different senses, the memory will be better contextualized;
the uniqueness of the context -- say the high volume of the music playing; and the level
of attention you pay to small details in your surroundings. Among factors that interfere with
forming a strong context-dependent memory are high stress levels or fatigue at the time of encoding,
since these things decrease your attentiveness to contextual details.
Now that you know how a specific smell, sound, or feeling can influence the way you form and recall
memories, you can try to use context-dependent memory to your advantage. The next time you are
preparing for a test, try studying in a similar environment to the one you will take your test in.
And if you forget what you wanted from the fridge, try revisiting the place where you first
thought about what snack you wanted. Most likely, you’ll find the answers that you knew all along!