We take photographs to help us remember. Yet some of the experiences that stay with us most cannot be captured by a camera. What is it about certain moments that makes them memorable long after the image itself is gone?

A familiar scent can change a moment without warning. The smell of rain on warm pavement. Freshly cut grass. A particular perfume. Something cooking in a nearby kitchen. One moment, we are standing in the present. The next, we are remembering a place, a person, or a period of our lives we had not thought about in years. We do not always decide to retrieve these memories. They seem to arrive on their own—often carrying an emotion with them. Our sense of smell has an especially close...

Why do some experiences remain vivid for years while others quickly fade? Reflecting on my travels through cacao-growing regions in the Dominican Republic, I’ve often wondered why certain aromas, sounds, and seemingly ordinary moments stay with us long after the experience itself has ended.