The Neuroscience of Nostalgia

fotoblend. Nostalgic photographs. Pixaby. 2022.

The yearning for the past, even for a time that did not hold especially fond or significant memories, is very common, especially in an age where the present seems to be regularly in decline. Nostalgia is a complex emotion and has been consistently seen as a dysfunctional disorder, previously having been seen as a disease in the 18th and 19th centuries, a psychiatric disorder in the early 20th century, and a form of depression by the end of the 20th century (1). Although nostalgia does include elements of depression, it is not an inherently negative emotion. In fact, nostalgia can function as a positive resource for the self by bringing about greater self-esteem and positive self-attribution (2). 

Nostalgia can be neurologically analyzed by being separated into four parts: self-reflection, autobiographical memory, emotion regulation, and reward processing (1). Each of these components is composed of various interacting brain regions and works to create a distinct bittersweet, reflective emotion. The first component, self-reflection, is inseparable from nostalgia. To feel nostalgic is to look back at the past through the lens of who you were, featuring the self as the protagonist. Although it often arises from negative emotional states, such as loneliness or stress, nostalgic memories typically contain more positive expressions, such as the redemption of a negative life event to a subsequent triumph (3). The depiction of the self in this positive light increases positive self-regard as well as social bonds (3). The self-reflection component of nostalgia can be linked to the medial prefrontal cortex (mPFC) region of the brain, which is responsible for using memory to interpret and respond to stimuli (1). 

Autobiographical memory is a blend of semantic and episodic memories about your entire life; from seemingly unimportant memories like your childhood best friend’s address to your high school graduation (4). This mental time travel is composed of more negative expressions, such as rumination and creating “what if” scenarios (1). However, nostalgia differs from these negative processes in that it is linked to positive outcomes rather than excessive dwelling and regret (1). Nostalgia tends to be self-affirming and reinforces the idea that every experience one has had, whether negative or positive, has contributed to one's personal growth. 

Even though nostalgia is commonly brought about by negative emotions, it has been found to regulate negative emotional conflict (1). Viewing negative memories in a rose-colored manner transforms them into something tolerable and easier to interpret if they were previously difficult to revisit. The mPFC and anterior cingulate cortex (ACC) are largely responsible for emotion regulation and cognitive processing, both of which are engaged during nostalgic reflection (1).

Figure 1. Brain regions involved in nostalgia and their relation to the four key components of nostalgia: self-reflection, autobiographical memory, emotion regulation and reward processing (1).

The final component of nostalgia is reward processing, which involves motivation and the pursuit of one’s goals (1). The reward system is composed of structures that reinforce survival-essential behaviours, such as eating and social interaction, by releasing dopamine and motivating one to repeat the action (5). Reward-related brain regions, such as the striatum, are activated by nostalgically satisfying stimuli, such as a picture of a loved one or personally meaningful music (1). This activation is responsible for the comforting and potentially motivating nature of nostalgia and could be a reason for which nostalgia often drives us to reconnect with significant people from our pasts.

Nostalgia can be triggered randomly, by photographs, music, scents, and personally meaningful memories. Each trigger is associated with distinct brain systems that shape how nostalgia is emotionally experienced. For example, visual and autobiographical cues activate the hippocampus, which produces vivid, detailed memory recollection (1). Emotional and sensory triggers, especially music and odors, engage the amygdala, which is responsible for assigning emotional significance to memories as well as the processing of negative emotion. Those who feel nostalgic more frequently are able to better regulate negative moods brought up by nostalgic music, shifting the experience to feel somewhat positive, or bittersweet (1). 

Like most things, nostalgia can be therapeutic, but excessive rumination can keep one obsessed with the past and dissatisfied with the present. Nostalgia involves viewing memories through a rose-colored lens, which can distort and filter out the actual reality of what you’re remembering. A childhood memory of skating, for example, may recall the crisp winter air and the untouched, fresh snow, while ignoring the sharp bite of the cold once the novelty faded. In this sense, excessive indulgence in nostalgia as a way to escape your current reality might produce more negative effects than positive ones. 

Nostalgia is particularly active in transition periods of your life (1) as a way to soften the new difficulties you’re dealing with. It is important to remember that the mind is a powerful and sometimes misleading storyteller, and that we have just as much capacity to adapt to the present as we do to retreat into the past.

References

1. Yang Z, Wildschut T, Izuma K, Gu R, Luo YLL, Cai H, et al. Patterns of Brain Activity Associated with Nostalgia: A Social-Cognitive Neuroscience Perspective. Social Cognitive and Affective Neuroscience [Internet]. 2022 May 13;17(12):1131–44. Available from: https://academic.oup.com/scan/article/17/12/1131/6585517

2. Vess M, Arndt J, Routledge C, Sedikides C, Wildschut T. Nostalgia as a Resource for the Self. Self and Identity. 2012 Jul;11(3):273–84.

3. Tim W. (PDF) Nostalgia: Content, Triggers, Functions. [Internet]. ResearchGate. 2006. Available from: https://www.researchgate.net/publication/6737405_Nostalgia_Content_Triggers_Functions

4. Daviddi S. Autobiographical Memory - an overview | ScienceDirect Topics [Internet]. Sciencedirect.com. 2015. Available from: https://www.sciencedirect.com/topics/neuroscience/autobiographical-memory

5. Lewis RG, Florio E, Punzo D, Borrelli E. The Brain’s Reward System in Health and Disease. Advances in Experimental Medicine and Biology [Internet]. 2021;1344(1344):57–69. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8992377/