It would be the ultimate perfume: a scent that evokes universal happiness. While we鈥檙e not there yet, a method of identifying scents that provoke the same response in everyone who smells them has brought that ideal a step closer.
For years, sensory scientists had assumed that our reactions to smell were hopelessly entwined with our cultural background. 鈥淲hen I came to the UK I was shocked that the smell of chrysanthemums evokes romantic feelings in people here,鈥� says Phillipe Durand, a perfumer at fragrance development company Quest International in Ashford, Kent. 鈥淚n France we associate it with graves and death.鈥�
However, there is mounting evidence from brain scans that our responses to some smells, particularly bad ones, are innate, says Tim Jacob, a smell expert at Cardiff University, UK. 鈥淭hat makes sense because if you had to wait and learn 鈥榯his smell kills you鈥� you鈥檇 be dead,鈥� he says.
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To investigate whether our responses to pleasant smells are also hard-wired, John Behan and Anne Churchill from Quest combined measurements of brainwave patterns on EEGs with questionnaires to gauge the responses of people from the UK, France, Germany and Japan while smelling a range of fragrances. 鈥淭he EEG data is an objective measure of emotional response to fragrance,鈥� says Churchill, which is important because verbal response can often be misleading.
They tested around 50 fragrances on between 20 and 30 people. In most cases, while people from the same country identified smells as producing the same feeling, for instance an 鈥渋nvigorating experience鈥�, the scans revealed varying levels of brainwave activity related to alertness. Even the fragrance of lavender, which is thought to relax most people, did not produce the same brain response in everyone. 鈥淭hat surprised me,鈥� says Churchill, who now believes that emotional responses to these smells are culturally dependent.
There was, however, a subset of 鈥渞elaxing鈥� fragrances that did produce a consistent pattern across her test group. 鈥淭he observations are consistent with the idea that while most responses to pleasant smells are learned, some are innate,鈥� says Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia. 鈥淭hat鈥檚 exciting.鈥�
Behan suggests that in evolutionary terms, sweet and musky smells might fall into the same bracket because they are reminiscent of breastfeeding.
While the technique won鈥檛 replace the human perfumer, who is still needed to concoct new fragrances, it may help predict which ones will stand the test of time, says sensory psychologist Steve van Toller of the University of Warwick, UK. 鈥淧erfumers need to marry fragrance with science if they want to create long-term commercial hits,鈥� he says.
A headache for perfume makers
Chanel No 5 is considered to be the epitome of a timeless fragrance, but its subtleties may have changed over the years. 鈥淩egulations introduced since it was created in 1921 have forced many of the original ingredients out of the perfumer鈥檚 palette,鈥� says John Ayres, Chairman of Fragrance Foundation UK, in London. If new European legislationis passed in December, other cosmetics may have to be reformulated or removed from the shelves entirely.
Last week, members of the European parliament鈥檚 environment committee voted in favour of a draft version of Registration, Evaluation, Authorisation and Restriction of Chemicals. REACH calls for manufacturers importing more than 1 tonne of a chemical substance per year to test it for safety and then register it in a central database.
Many chemical manufacturers worry that this will force them to retest chemicals they have been using safely foryears. Smaller companies may have to stop producing some cosmetics ingredients completely because they are unable to afford the tests, warns Chris Flowers of the Cosmetic Toiletry and Perfumery Association in London. 鈥淚nevitably, there will be a range of everyday products that suddenly won鈥檛 be available on the shelves because we won鈥檛 be able to make them,鈥� he says.
REACH has to pass two more rounds of voting before it can become law, so modifications could still be made.
