On the scent

For Marcel Proust, the madeleine evoked childhood memories — a new treatment of the science of smell attempts to take our everyday experience of odour to a more insightful level, explains Gary Beauchamp.

What the Nose Knows: The Science of Scent in Everyday Life

• Avery Gilbert

Crown Publishers: 2008. 304 pp. £15.99, $23.95. 140008234X 9781400082346 | ISBN: 1-400-08234-X

In 2004, the Nobel Prize for Physiology or Medicine was awarded to Linda Buck and Richard Axel for their work on the science of smell. They discovered the family of more than a thousand olfactory receptors that recognize the volatile compounds that make up our scented world. To researchers in the field, this honour was neither surprising nor unanticipated. Many outsiders wondered: what is the social, biological and medical significance of this breakthrough that makes it so noteworthy?

Credit: SOLEIL NOIR/PHOTONONSTOP/PHOTOLIBRARY

Avery Gilbert's engaging book What the Nose Knows attempts to answer this question. Focusing on our experiences of scent in everyday life, it proclaims the importance and curious nature of the human sense of smell. Until the last chapter, which speculates on the future, Gilbert has little to say about the biological science underlying olfaction. He has even less to say about odours in other mammals and insects, where they have a greater role in regulating social and sexual activity than in humans. What this book lacks in basic biological science, it makes up for in psychological analysis, complemented throughout with literary allusions that Gilbert skilfully uses to illustrate his insights.

Gilbert draws on his personal experience, both anecdotal and scientific. He asks how many odours there are and how we might determine them, and describes the principles of perfumery. He addresses the psychological aspects of odour phobias and multiple chemosensory disorder, and explores odour memory within the literature of Marcel Proust. Gilbert seems especially fond of stories of the smell of dead bodies and human gaseous emanations. The book is perhaps overly larded with short, albeit fascinating, stories and olfactory anecdotes, and lighter on synthesis. Citations to the psychological literature abound, but they are listed at the end and the reader must flick back and forth to find a source.

The story of odorizing the movie experience is delightfully told. The 'battle of the smellies' between the scientifically based Smell-O-Vision, pushed by the impresario Mike Todd, and its rival AromaRama illuminates both the entrepreneurial spirit of the 1950s and the scientific and technological aspects of odour choice and delivery. The difficult task of odour removal is highlighted by cinema that, in the words of one reviewer, was filled with scent “strong enough to give a bloodhound a headache”.

Gilbert adopts a strong position on matters of controversy, sometimes trying hard to arouse disagreement. He persuasively dismantles the idea of Proust as poster boy for the profundity of odour memory, but I remain convinced that major research efforts to understand the phenomenon are still needed. When I encounter the scent of my grandfather's garage, I am not only reminded of the place — I am briefly transported there. Gilbert, too, calls attention to this power: “Like a nightclub mentalist, the mind presents us with a memory it picked from our pocket when we weren't looking.” The neural pathways unique to olfaction are probably involved but do not completely explain the experience.

Similarly, I question Gilbert's argument that smell makes a greater contribution to flavour than does taste. First, it is unclear what metric would be useful in measuring this. And there are many reasons to believe that taste — sweet, sour, salty, bitter and umami or savoury — is more potent as far as food selection and intake are concerned. Smell permits one to discriminate strawberry from cherry, but taste provides the information necessary to decide whether an object should be taken into the body or expelled.

Many years ago, when working with Gilbert at the Monell Chemical Senses Center in Philadelphia, I recognized his way with words as well as with scientific research. What the Nose Knows melds the academic and business worlds of smell into an entertaining and illuminating rumination on this almost magical sense that, even with a Nobel Prize to its credit, still holds many mysteries.