Our final project is about the study of false memories in normal aging, using the DRM paradigm. This paradigm is made of lists of words in which every word of the list is linked to another word that is absent from the list which is named critical lure. For example, the list could be: rest, bed, nap, peace, etc. and the critical lure that is not part of the list would be “sleep”. The lists are presented one after the other to the participants. After each list, they have to recall as many words as possible.
Using this paradigm, the researchers made the impressive discovery that in spite of its absence, a lot of participants recall the critical lure. This effect is therefore a false memory, and it is even more prevalent in older adults. However, the cognitive explanations for these observations are not clearly established. Changes in cognitive processing were observed in young adults when using a modified version of the paradigm. This modified version involves a presentation of the critical lure directly in the DRM list. We, therefore, sought to replicate this experiment in an older population to better understand the cognitive functioning of older adults. We decided to base our study on two main theories: Activation-Monitoring theory and Fuzzy Trace theory.
The first one is the activation-monitoring theory. This theory implies that our knowledge is stored in our brain in the form of a network organized according to semantic proximity. The activation of a concept in the network would lead to a propagation of the stimulus activating also the words close to the initial concept within this network. Using this propagation of the activation, the critical lure is finally strongly activated. Then, during the recall task, each potential candidate is reviewed by the monitoring process. The role of this process is to recover the source of the memory to determine if the word was part of the list or not. In other words, the participant tries to remember if the candidate has really been presented to him or if it’s just him who thought about it when he heard the other words. It is when the monitoring process fails that a false recall happens. The monitoring process declines because of age-related changes, which explains why older adults produce relatively more false memories than younger adults.
Then, the fuzzy trace theory is also an explanatory theory of false memories. According to this theory, the memories are encoded, stored, and recovered through two types of processes: Gist and Verbatim. The Gist corresponds to the overall representation or the general meaning of the information and the Verbatim corresponds to its distinctive features. The information treated by the Gist is more stable over time than the information treated by the Verbatim, but they are also more sensitive to change and become false memories. In the DRM Paradigm, every word of the list would be treated by both processes. With regard to the critical lure, being itself the general meaning of the list, it is supported by the Gist process. However, as it is not part of the list, it has few distinguishing features and therefore benefits little from the Verbatim process. Moreover, the verbatim process seems to be defective in older adults. For this reason, older adults tend to rely more on the Gist which accentuates the proportion of false memories.
In our study, we use a modified version of this paradigm which consists of the explicit presentation of the critical lure in the lists. Our goal is to watch if there is an impact of this modification on the cognitive processing of young and older adults. We conducted an experiment with 80 participants, 40 young adults, and 40 older adults. To evaluate the impact of the presentation of the critical lure in the lists, we have made sure that half of our lists presented the critical lure and the other half did not. Every participant had to study 5 lists of each type of list.
We found that older adults recalled fewer list words than young adults in both conditions. Regarding the proportion of critical lure production, older adults produced more of them than young adults when the critical lure was not presented in the list. However, when the critical lure was presented, both young adults and older adults produced it at the same very high rate. In addition, the presented critical lure was more recalled than any other words on the list.
According to these results, it seems that the explicit presentation of the critical lure in the list had an impact on the cognitive processing of both groups, young adults and older adults. From the activation-monitoring theory, we can conjecture that the presentation of the critical lure would grant it a higher degree of activation and especially facilitate the recovery of its source. These elements would justify the significant increase in its production in both groups of participants. With regard to the Fuzzy Trace theory, we can make the assumption that being present in the list, the critical lure benefited from both the Gist and Verbatim processes, which significantly increased its production. In conclusion, our study contributes to bringing new knowledge on the profile of elderly people in the DRM paradigm. Our study participates in the advancement of knowledge on memory aging, and in particular on false memories.
Words we have learned:
In spite of = malgré; en dépit de
Distinguish = distinguer
Recovery = récupération
Assumption = hypothèse