Our sense of smell gives flavour to food, emotion to memories, and connects us to each other. But how exactly does it work?
I know the dangers of smoking. Tobacco is a leading cause of head and neck cancer, which can lead to life-changing disfigurement or, in the worst cases, death.
Speaking as an ear, nose and throat surgeon, this spectrum of disease has produced the most emotionally and technically challenging cases of my career: cigarettes were to blame the day I reluctantly broke the news to a patient on the morning round, blue paper curtains separating the dissolution of his world from a busy ward; cigarettes were to blame for the gradual suffocation of the swollen woman in the side room, whose visitors could no longer recognise her; and cigarettes were to blame when blood erupted from the carotid artery of a gentle grey-eyed man I’d met a few hours earlier. I know that ‘smoking kills’.
So why was it, when I recently visited the home of a smoker, with its lingering aroma of stale cigarettes, I involuntarily filled my lungs and sighed an illogical sense of calm? The answer eventually comes to me: ashtrays packed with Marlboro butts, balmy mosquito-filled evenings and the beautiful turquoise bracelets that bejewelled my breathless grandpa. A resolute smoker to the grave, this smell is my ‘echo of great spaces traversed’, and takes me back to the home of my mother’s father, where many childhood summers were spent.
In Swann’s Way, the first part of Marcel Proust’s lengthy – and for me as yet unconquered – À la recherche du temps perdu (1913-27), our narrator dips a madeleine into his tea:
No sooner had the warm liquid, mixed with the crumbs, touched my palate than a shiver ran through me … An exquisite pleasure had invaded my senses, something isolated, detached, with no suggestion of its origin … this essence was not in me, it was me … And suddenly the memory revealed itself. The taste was that of the little piece of madeleine which on Sunday mornings at Combray … my aunt Léonie used to give me, dipping it first in her own cup of tea or tisane.
But how do smoky corridors lead to tea-soaked cakes? The answer lies with sensory integration. Beyond the five true taste sensations from our tongue (sweet, salty, sour, bitter and umami), all the complex and delicate flavours of food can be attributed to their odours: volatile molecules that escape our oral cavity as we chew to stimulate smell receptors at the back of the nose, through a process called ‘olfaction’.
Therefore, what Proust’s narrator describes forms an eloquent template for what is now known as the ‘Proustian effect’: the seemingly unique ability of smells to unlock previously forgotten but vivid, emotional memories from our past.
Whether this poetic role of smell can be substantiated has interested psychologists, philosophers and neuroscientists for many years. The first to formally publish on the topic was Donald Laird, director of the psychology lab at Colgate University in New York state. Laird’s work usually focused on the burgeoning field of business psychology, with books such as Psychology and Profits (1929) and Why We Don’t Like People (1933).
But in 1935 he collaborated with his colleague Harvey Fitz-Gerald on the report ‘What Can You Do With Your Nose?’, analysing the olfactory experiences of 254 ‘men and women of eminence’. Of this cohort, 91.7 per cent of women, and 79.5 per cent of men had experienced odour-evoked autobiographical memories, and of these, 76 per cent of women and 46.8 per cent of men recounted such memories as among their most vivid.
Laird went on to provide personal anecdotes gathered from Fitz-Gerald’s participants. One such account comes from a ‘Southern attorney’ who said:
The sight of these things sometimes occasions the recalling of the facts but they come shapeless and indistinct – dead facts. The thing that is recalled by odour comes unasked and without effort upon my part; it seems more than a mere recollection; I am back there again in a world as it was, and I am as I was.
While lyrical and descriptively interesting, Laird’s study was just that: descriptive. His work provides no empirical evidence to support the superiority of odours over other sensory cues in eliciting vivid emotional memories. Whether odours are particularly potent in evoking such memories had yet to be proved.