By Léa Lomprez
Among the studies on false memories, the researchers found a factor to decrease their appearances. Only the modality of visual imaging to show significant results in their decreases. To date, with the exception of visual imaging, no other sensory modality has been studied, such as olfactory stimulation. The objective of this research is to assess whether olfactory stimulation decreases the appearance of false memories within the DRM paradigm.
Thirty participants aged nineteen to thirty-six were subjected to the DRM paradigm. Fifteen of them had to recall and recognize as many words as possible without exposure to an odor and fifteen other participants had to recall and recognize as many words as possible in a context of olfactory stimulation, of lavender smell. The choice of odour for olfactory stimulation is based on the results of a questionnaire proposed to 16 participants aged 18 to 24 who did not take part in the study. In this questionnaire, participants had 4 minutes to identify five smells that most reminded them of their childhood. Then they had 2 minutes to rank them according to their intensity and importance. The two most cited smells were those of cake and lavender. The smell of cake being difficult to maintain during the experiment, we opted for lavender whose smell in the form of essential oil is stable and intense. During the experiment, participants had to recall a maximum of words from ten lists of fifteen words each. The fifteen words in each list were strongly associated with a critical lure word that was never presented. Then, after an interfering task, the participants had to recognize the words studied in the recall task from among sixty words including: thirty words studied; ten critical lures; twenty distracting words not associated with the studied words and the critical lures. Finally, participants were asked to complete a multisensory imaging questionnaire to assess the ability of individuals to produce mental images of different sensory modalities (visual, auditory, somatic). For each image, participants were asked to indicate whether “yes” or “no” they were sure they had produced the requested image. Then, they evaluated the degree of liveliness of their mental image: 100% if their image was perfectly clear and as vivid as a real perception; 75% if their image was relatively clear and as vivid as a real perception; 50% if their image was half as sharp and vivid as real perception; 25% if their image was vague and imprecise; and 0% for no image.
Control participants and participants exposed to the smell reported as many false memories. The results did not indicate any effect of olfactory stimulation in decreasing false memories in the DRM paradigm. However, we were able to observe during the analysis of the results that are classically found in the scientific literature. Indeed, all the participants had better performance in task recognition than in task recall. Meaning that participants produce more false memories during recognition than during free recall. In addition, we performed a correlation matrix between the performance of the reconnaissance task and that of the multisensory imaging questionnaire on all participants. The analyses showed that participants with good somatic and/or global imaging ability (high percentage in the 3 sensory modalities), recall more critical lures words and therefore more false memories.
This study highlights that olfactory stimulation alone does not reduce the appearance of false memories. However, our study found that somatic imaging increased the propensity for false memories. Also, this work highlights new data in the research on false memories as the somatic imaging factor promoting their occurrence.