Answer: The “Proust phenomenon” is an unintentional recollection of a memory after exposure to a stimulus.
Many times a day, we actively recall facts from memory. For example, if someone made a mental shopping list when they go to the grocery store, they may actively try to remember what they needed to buy. This type of memory is called a voluntary explicit memory: an intentional recall of a specific fact or piece of information.
However, sometimes exposure to some external stimulus may cause a person to unintentionally and recall a memory from the past. This memory may be such a vivid and powerful memory, that multiple sense modalities may be recruited. For example, they may not only visualize some moment in the past, but they might think of the accompanying smells or tastes that went along with their experience. They may also have an especially powerful emotional response that accompanies the recall of the memory, and may remember suddenly what they were feeling at the time.
Many people experience the Proust phenomenon when they taste foods that they had eaten when they were younger. It is the emotional response when someone eats their mom’s home cooking, for example. At this moment, they aren’t actively trying to recall any specific memories, but these memories return nonetheless. They may think of their emotional mindstate when the last time they had this food, or they may imagine they were sitting as a child at their childhood dinner table surrounded by their family.
A sudden recollection of the period of adolescence or early childhood is called a reminiscence bump, and is particularly prominent during the period of years where a person’s identity is being formed.
These Proustian memory recall events are not always pleasant memories. In fact, many of the emotional responses that are experienced by people who have post-traumatic stress disorder (PTSD) are believed the be a similar action of recall.
The Proust phenomenon is sometimes also called an involuntary explicit memory. Alternatively, because the memories that are recalled are often memories about a person’s past, they can also be called involuntary autobiographical memories.
There are not many studies related to studying the Proust phenomenon from a scientific standpoint. The studies that examine these involuntary memory recall events cannot be evaluated in animal models, so all research must be done in humans using imaging techniques such as positron emission tomography. One study (Brain regions supporting intentional and incidental memory: a PET study) indicates, expected, that the hippocampus mediates memory recall related to the Proust phenomenon. Some other brain structures that are relevant for these types of memory recall also include the left inferior frontal gyrus and the right superior occipital gyrus.
This type of memory recall is named after French author Marcel Proust. His major work, A la recherche du temps perdu, or “In search of lost time,” was a seven volume novel published between 1913 and 1927. The major theme of this work is the formation of memories through experiences.