The memory effect is deeply personal. The smell of cardamom might make one person think of festive desserts, while someone else may associate it with a completely different experience.
The emotional response to a smell is shaped by previous experiences and learned associations. According to a 2018 review published in Psychonomic Bulletin & Review, odor-evoked autobiographical memories tend to be older, rarer, and more emotionally intense than memories triggered by words or images. The review also found that smells can create a stronger feeling of being mentally transported back to the original event.
This is also why food can be particularly effective. Eating is rarely just about taste. Meals are tied to family, celebrations, routines, places and people, giving their aromas plenty of opportunities to become woven into memory.
