Tuesday, May 4, 2021

The Sweet Smell of Memory

 

            There has been a lot of research behind the link between memory and the olfactory system which is no wonder because people experience the link every day. It could happen when walking in a mall, you smell a cologne and are transported to your grandparents house and are reminded of when you were near your grandpa. Maybe you are on a run and smell pine needles on the ground baking in the sun and suddenly you are back at summer camp when you were ten years old. There is no question smell plays an integral role in our most vivid memories, the question lies in what that role really is. Dr. Shanahan has spent her time researching this connection and the neural correlates behind the phenomenon. She has found evidence to suggest that olfaction has an influence on behavior and that behavior can have an influence on olfaction. Dr. Shanahan’s previous research focused on the former, where she found increased results on a memory task when the same odor was applied during the learning of the task and during slow-wave sleep. The findings of this study suggest being exposed to a specific odor while in slow-wave sleep can help with memory consolidation if the odor was also present while the brain was in its learning stage. In Dr. Shanahan’s current work, she found that hunger and satiety can influence olfactory. When hungry, participants were more biased towards food odors when exposed to a mixture of food and non-food odors which was not the case after they were full. Once fed either an odor matched meal or a non-odor matched meal the results were different. An odor matched meal meant the meal consisted of the food of the odor in the study. After full from the meal, those with matched meals were biased away from food odors and their neural correlates even showed the odor being processed as resembling a less food-like stimulus. This research indicates the way our olfactory processing can differ throughout time and ultimately affect our behavior. 

            The Harvard Gazette took a dive into this phenomenon from a different angle in their article “What the nose knows”, by Colleen Walsh. The article focuses on a few different ways in which olfactory is related to memory beginning with a passage meant to trigger memories based on the description of a sensory experience. Walsh connects this literary excerpt to the neuroanatomy behind processing smell and suggests the link behind memory and scent is due to the closeness of the olfactory bulb and the limbic system. Dr. Shanahan believes this aspect of neuroanatomy is likely a factor in the link as well although believes there are likely other neural correlates. Walsh’s main focus is to show how different industries are looking to capitalize on the sensation of odors triggering memory. The film industry worked to infuse specific scents during showings so the viewers could have a 4D experience at the theater, businesses have tried to introduce signature scents into their stores, and celebrities want their own signature scent. This marketing scheme is all based on the fact that people will remember more when they can associate a smell with the experience. 

            The work of Dr. Shanahan would support this notion, that it is more likely something would be remembered if there is a particular scent attached to it, however there are other factors involved. Dr. Shanahan’s work shows that the reintroduction of odors during sleep plays a large role in its memory consolidation which is not feasible for these brands. Her work also shows that people could be biased towards different scents depending on their satiety so where one scent could be more readily identified when someone is hungry, it could be less appealing when that same person is full. Dr. Shanahan’s research combined with the Walsh article show the growing interest in how we can use odor and our olfactory perception to our advantage as we aim to remember and learn in life. With the implementation of specific odors while we learn and while we sleep, we could set ourselves up for more success. Dr. Shanahan’s work gives researchers in the future a great base to work from when learning more about how we can implement odors into our lives to better our memories and learn about our behaviors. 

 

Citations: 

Shanahan, Laura & Gottfried, Jay. (2017). Scents and Reminiscence: Olfactory Influences on Memory                 Consolidation in the Sleeping Human Brain. 10.1007/978-3-319-45066-7_20.

Walsh, Colleen. “How Scent, Emotion, and Memory Are Intertwined - and Exploited.” Harvard Gazette, Harvard Gazette, 27 Feb. 2020, news.harvard.edu/gazette/story/2020/02/how scent-emotion-and-memory-are-intertwined-and-exploited/.


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