The scent of vanilla brings back ice cream eaten during summer vacation. The smell of soap recalls a bath on a long-ago trip. In a study of Japanese adults, older participants rated such odor-evoked memories as more pleasant than younger participants did.
Published in 2023, the study asked whether the age-related positivity effect, a tendency to view the past more positively with age, also appears in personal memories cued by odors. It also examined qualities such as vividness and nostalgia, along with the questionnaire used to measure them.
Smelling eight scents at home, one per day
Adults aged 20–49 and healthy adults aged 60–79 were recruited through a Japanese research firm. After excluding four people who could not complete the full procedure, the analysis included 317 younger and 181 older participants. Health status and smell-related problems were checked through self-report.
The eight odors were peach, jasmine, mint, orange, bar soap, vanilla, hinoki wood, and rose. The mint fragrance came from natural spearmint essence; the other seven were blended fragrances. Odorless cellulose beads impregnated with each scent were mailed in small bottles labeled with codes that did not reveal the contents.
At home, participants smelled one odor per day and described the first personal event that came to mind, including their age at the time. If a memory arose, they answered 21 questions about it. If none arose, they rated only the odor itself. Four assessment days were followed by a three-day break and then the remaining four days. Participants were randomly assigned to one of four odor presentation orders.
Examples in the original paper include orange prompting a memory of eating tangerines with family in winter, vanilla evoking ice cream during summer vacation, and mint recalling chewing gum with friends in high school. The scenes associated with the same scent differed from person to person.
Overall memory pleasantness was higher in the older group
The central result concerned ratings of the memory’s overall impression on a seven-point scale from very unpleasant to very pleasant. The older group averaged 5.09 and the younger group 4.70, a significant difference. The effect size was r = .23.
This comparison used each person’s average rating across samples that evoked memories. Pleasant memories were common in both groups, but the older group’s average was more positive. This does not mean that every older person recalled only happy memories.
The authors also reported a higher rate of memory recall in the older group. However, the paper contains numerical inconsistencies between participant counts before and after exclusions, recall rates, total recollections, and averages per person. The greater frequency of recall should therefore be treated as the reported direction of the result, without relying on precise percentages or fold differences. The main conclusion concerns comparisons of ratings of the memories that were recalled.
Differences in vividness, nostalgia, and future action
The study’s questionnaire, the OEAMQ, assesses seven aspects of personal memories evoked by odors: their pleasant emotional impression, a sense of learning from the past, clarity, information about when the event occurred, future actions one wants to take, perceptual experiences such as taste and smell, and nostalgia.
The older group scored higher than the younger group on all seven aspects. For example, clarity was rated 4.23 versus 3.78, and nostalgia 4.16 versus 3.85. Ratings of future action, such as wanting to do something or forming plans or ideas after remembering, were also higher in the older group.
These are qualities participants felt their memories had. The researchers did not check the memories against records of the events to assess accuracy, or follow up on whether participants actually carried out their plans. Even so, the measures offer a multidimensional view of how odor-evoked memories involve not just images of the past, but present-day interpretations and thoughts about action.
Separating ratings of odors from ratings of memories
The age groups also differed in how they rated the odors themselves. Older participants rated odor-evoked emotion as more positive and emotional arousal as stronger. Younger participants, in contrast, rated odor intensity and familiarity higher. Confidence in naming the odors did not differ significantly between groups.
The results are therefore difficult to explain simply by saying that older participants gave higher scores to every question. Still, the study did not completely eliminate differences in response tendencies or age-related experience.
In both groups, more pleasant odor-evoked emotions were associated with higher ratings on all seven memory dimensions. Emotional arousal was also associated with many dimensions, but in the younger group its correlation with the factor concerning the memory’s pleasant emotional impression was not significant. Not every emotional measure was linked to every memory characteristic in the same way.
Checking the questionnaire as a memory measure
The OEAMQ had previously been studied mainly in younger people. In this study, responses to the questions making up each dimension were also closely aligned in the older group, showing high internal consistency. Together with the associations with emotional ratings, the findings support using the questionnaire to study odor-evoked memories in older participants.
However, the study compared people of different ages rather than following the same people as they grew older. Having more memories to draw on after a longer life, and differences in life experience between generations, could also matter. The authors discuss possible explanations involving perceptions of remaining time, changing motivations to prioritize emotion, and ways of retrieving memories, but the study did not directly measure these mechanisms.
The odors were generally rated as pleasant. There were no unpleasant-odor, odorless, or word-only cue conditions, and the home environments could not be fully standardized. These findings concern memories evoked by these eight odors in healthy Japanese adults. Preventing dementia or improving physical and mental health are separate questions requiring further testing before considering applications.
Summary
Personal memories cued by eight odors were rated as more pleasant by the older group than by the younger group. Older participants also scored higher on all seven questionnaire dimensions, including clarity, nostalgia, learning from the past, and thoughts about future action. Since younger participants perceived the odors themselves as stronger, odor intensity and the richness of memories cannot be captured by the same measure.
When considering the relationship between smell and memory, what people recall matters, but so does how they feel about that memory now. The study demonstrated such differences between age groups through multidimensional ratings of emotion and memory. High internal consistency in the older group’s questionnaire responses also supported its use as a measure of odor-evoked memories.
The research was funded by JSPS KAKENHI and Kao. An author employed by Kao at the time participated in study design, implementation, and manuscript revision, as disclosed in the paper.
References
Yamamoto, K., & Sugiyama, H. (2023). Influences of age-related positivity effect on characteristics of odor-evoked autobiographical memories in older Japanese adults. Frontiers in Psychology, 13, 1027519. Original research paper
