When we think about memory, we
often focus on situations in which we encounter some information and then
recall it later. In many situations,
though, after we encounter the information, we talk about it with other people. That creates a shared recollection. This can happen both socially and in
education situations.
Much less is known about shared
recollection than about individual recall.
Cognitive psychologists tend to focus mostly on what individual people
do rather than groups of people, and so most memory studies involve individuals
who study information and then remember it later.
A fascinating paper by Adam
Congleton and Suparna Rajaram in the August, 2014 issue of the Journal of Experimental Psychology: General looked at factors
relating to shared memory.
One observation from previous
research on creating shared memories is that when groups work together to
recall information, they remember less information overall than the individuals
in the group would have remembered if they had worked alone. The idea is that the group discussion focuses
the group members on a subset of the information they were exposed to, and that
subset is smaller than what the individual group members would have thought
about if they had not been part of a group.
In this study, participants in a
room were exposed to 120 words on a projection screen. The words were chosen from 8 categories of
objects, so that there would be some way for remembering one word to remind
people of other words on the list. After
a brief delay, all participants were asked to remember as many of the words as
they could. Then, participants performed
three more recall tests in that session and one additional test a week
later.
Some participants worked alone in
all of the remaining recall tests. The
rest of the participants were put in groups of three. In one condition, the group did the second
recall task together. In a second
condition, the group did the third recall test together. In a fourth condition, the group did both the
second and third recall tests together.
The last recall test of the first day and the test a week later were all
done individually. There were some
subtle differences across these three group conditions, but I will gloss over
those for now.
When the group did recall, they
talked about the words they remembered, and one member of the group wrote down
each word that the group remembered.
What happened?
Looking at the last recall session
on the first day, groups of three individuals selected at random from the
individual condition remembered more overall than the groups that recalled a
list together. That is consistent with
the previous findings that I mentioned.
Recalling in a group increased the
similarity of what people from that group were able to remember. People in groups that worked together
recalled more of the same items than people who recalled alone. In addition, they tended to remember the
words in the same order. These findings
suggest that working together as a group made everyone’s memory of the words
more similar.
A particularly interesting result
was that the groups that showed the most similarity at the end of the study (as
measured both by the amount of overlap in what they remembered and the
similarity of the order or recall) was related to the difficulty that groups
have recalling information overall compared to individuals. Groups that remembered less when they worked
together were more similar later than groups that remembered more when they
worked together.
The idea is that when a group
really works together, they influence each other’s memory. The idiosyncrasies of what they would
remember drop away, and they end up with a shared memory of the set of words. So, everyone loses some details about the
list, but they end up with a strong shared memory.
A similar pattern of results was
observed after a one-week delay suggesting that working with the group
influenced the long-term memory of the list.
The researchers in this study used
lists of words, because that is a convenient way of comparing memories across
people. But, this work tells us
something about memories in general. When
we discuss an event with the people around us, it affects what all of us are
able to remember later. Over time, the
group’s memory for an event gets more similar, so that eventually all of the
group members remember the same details about the event. Even though they may have experienced the
event differently, recalling it with others makes everyone’s memory more
similar.
