Six years ago, on an early morning in September, Molly Birnbaum was out for her regular jog when she was hit by a car. Her pelvis was shattered, her skull fractured, her knee torn. Yet for her, the most serious damage was far less visible: she lost her sense of smell. Birnbaum, now 29, was an aspiring chef, and the loss meant the end of her career. It also meant something else, something that was potentially even more life-changing. “I felt like I lost a dimension of my memory,” she says. “It made me worried about the future. If I couldn’t smell ever again, was I losing this important layer?”
Memory comes in many forms. Every day we constantly receive and process sights, sounds, touches and smells from our surroundings, some of which will become our memories. The nature of those recollections, however, is inconstant. One memory can seem immediate and colorful, as if the event had just occurred, whereas another must be coaxed out of our brain little by little. Although a moment that excites our emotions is more likely to be recorded than a routine experience, the sensory qualities of the event we have buried in our brain also plays a part in how vividly and accurately we remember something.