The population in the United States is aging. That has created a lot of anxiety about the
cognitive effects of getting older. Lots
of research suggests that older adults are worse than younger adults on a
variety of different thinking tasks.
They remember fewer words from lists they see. They are slower to respond in many
situations. They have more trouble ignoring
distracting information.
An interesting paper in the April, 2013 issue of Psychological Science by Renee Biss,
Joan Ngo, Lynn Hasher, Karen Campbell, and Gillian Rowe suggests that—while
these factors may look like they are all aspects of cognitive decline—there are
times when these changes may actually be helpful.
In particular, there has been a long line of research in
psychology showing that older adults have worse basic recall memory than
younger adults. The typical way to
demonstrate this effect is to show participants a list of words and then have
them recall the words from that list after a short delay. College students remember a higher proportion
of the words on the list than adults in their 60s and 70s.
The researchers in this study speculate, though, that in
many situations there may be subtle reminders of what needs to be remembered in
the world. If older adults pay more
attention than younger adults to information that may seem distracting, then
that may actually help their memory.
To test this possibility, college students (with an average
age of about 20) were compared to older adults (with an average age of about
68. First, participants saw a list of 20
words that they were told to remember for later. After a brief delay in which everyone counted
backward by 3s starting with the number 74, participants were asked to remember
as many words as possible from the list.
After that, participants did a 1-back test. In a 1-back
test, a series of pictures are shown, and participants respond with one key
when the current picture was identical to the previous picture and with a
second key when the current picture was different from the previous
picture. The pictures in this test were
all line drawings of objects that were not related to the words that were
studied.
On each trial, though, there were words superimposed on the
pictures in a different color than the line drawing. Participants were told that the words were
irrelevant to the task and that they should be ignored. However, eight of those words were items that
had actually been presented on the study list.
After doing this 1-back test, participants were asked to recall the list
of words again.
On the initial test, the older adults recalled significantly
fewer of the words from the list than the younger adults. After the 1-back test, older adults recalled
more words that had been shown in the 1-back task than words that had not been
shown. In fact, they remembered just
about as many of those repeated words as younger adults did. The younger adults were not affected by the
1-back test. They remembered words
equally well regardless of whether they were repeated in the 1-back test. In fact, the older adults remembered the
repeated words just about as well as the younger adults did, allowing them to
overcome the age difference in memory.
Overall, people recalled a little over 30% of the items from the list,
so this is not a ceiling effect.
One other interesting finding in this study was that older
adults responded slightly more slowly to the pictures when the accompanying
word had appeared on the initial list than when it had not. Younger adults showed no difference in speed
to respond to these items. This finding
suggests that older adults were more distracted by items they had seen before
than younger adults. None of the
participants included in the analyses explicitly recognized that words from the
list had appeared in the 1-back test, so this distraction was happening without
awareness.
This research replicates previous work showing that older
adults remember less and are more distractible than younger adults. However, this work also suggests that there
is a silver lining to this combination.
If older adults need to remember a piece of information, they may be
more likely than younger adults to notice information in the environment that
helps them to remember it. This
combination may help them overcome some of their memory limitations.
