Age
related differences in memory have been widely cited as resulting from
deficits in specific memory processes. A popular technique for investigating
a cognitive ability, such as memory, is to compare the performance of one
group known to have decreased performance in this ability of interest with
a group of individuals who have normal levels of performance in the ability
of interest. From a theoretical standpoint these comparisons give insight
into the processes that possibly underlie normally functioning memory.
A well controlled, theoretically based study will introduce a manipulation
that should differentially influence rates of responding in one group but
not the other, and the differences in responding should be accounted for
by theoretically specified processes. This is the logic and rational underling
well done experimentation investigating cognitive processes through the
use of special populations.
Participants
watched a sequence of 62 slides depicting a theft. Half of the participants
viewed this sequence once, and the remaining participants viewed the sequence
twice. There was a five-minute delay between viewings in the two presentation
condition.
After
a 15 minute filler task in which participants completed measures of working
memory, they completed a questionnaire format recognition memory test for
information contained in the slides. Embedded within this questionnaire
was misinformation about items that were not present in the slide sequence.
After
another 5 minutes delay, participants completed a second questionnaire
format recognition test. This test contained target information from the
slides and critical items that were not presented in the slides but suggested
to have been in the question asked of the participants in the first questionnaire.
A
third questionnaire was administered asking participants to rate the characteristics
of their memories for the information they recognized as old in the second
questionnaire.
Younger
adults had higher rates of hits on the first questionnaire than the older
adults. There was no effect of repetition for either the younger or older
participants on questionnaire one.
Younger
adults had higher rates of hits on the second questionnaire than did the
older adults. There was a main effect for repetition for the younger adults.
Younger adults that viewed the sequence of slides twice had more hits than
the younger adults that only viewed the sequence of slides once. There
was no effect of repetition for the older adults.
Rates
of FALSE ALARMS
Older
adults had higher rates of false alarms to critical items than younger
and this difference was still present for the participants that viewed
the slides twice. In addition, older adults placed more confidence in their
false alarms than did the younger adults.
The
second exposure to the slide sequence served to attenuate the reported
vividness of false recognitions for young adults but not for older adults.
Younger
adults used more perceptual and location details when describing details
objects that were in the slides.
MCQ
levels differed between true and false memories.
Source
monitoring
Source
and reality monitoring have developed into a subset of a larger theory
of memory outlined by, most notably Marcia Johnson. Source monitoring is
the process of judging the origins of information.
As
briefly noted by the authors, source monitoring judgments have been linked
to the right anterior region of the prefrontal cortex. This area is activated
when graded judgments are being made on memory tests. In contrast recollection
has been identified with a different area of the prefrontal cortex. Activation
in this area accompanies recollection of targets and recollection rejection
of related distractors.
In
the present experiment participants were asked to only accept information
on the third questionnaire that was presented in the sequence of slides
presented at study. Source monitoring is required to make such a judgment.
Both targets and critical misinformation items suggested in the questions
used in questionnaire 2 were old in the sense that the participants had
experienced both of them in the context of the experiment. The critical
difference was the ability of the younger and older group to judge the
source of the information.
Older
participants had higher rates of false alarms to critical items than younger
items after
Feature Binding
Feature binding suggests that discrete pieces of an experience are bound together to form a coherent representation of the past. One interpretation of what results in a stronger memory trace would be to assume that more features from the original presentation are encoded into memory for the event. Feature binding is a process by which traces can become stronger and weaker. Furthermore, this process has been linked to the hippocampal—cortical tract that seems to perform similar functions in cognitive maps, and associative learning observed in animals as well as humans.
Note that the
repetition of information resulted in better memory for the younger adults
but not for the older adults.
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