You can’t miss it. When it comes to the face, the nose is front and centre, and for some of us a very prominent feature. Yet compared with the hard-working drudge senses of sight and sound, or the refined and vaguely erotic senses of taste and touch, the nose and all the smelling it does has been relegated to an olfactory outland where it works overtime.
Swedish psychology professor Jonas Olofsson, in his new book The Forgotten Sense: The New Science of Smell, has undertaken to restore the nose to its rightful position. It’s a real eye-opener.
Olofsson assails the reader with one scientifically sourced and surprising revelation after another: humans smell as well as, if not better than, most animals; coffee has very little flavour; there is a firm link between odour disgust and right-wing political views.
What led him to this fragrant specialty – did he just follow his nose? Not exactly.
“I originally wanted to be a historian or some kind of social theorist,” says Olofsson, “but I got very fascinated by cognitive science.”
In his early days at university, he worked as an assistant in a nursing home, in some cases with people in the early stages of dementia. “And I learnt from one of my professors that the sense of smell might be a bit of a canary in the coal mine for Alzheimer’s disease. So I ended up doing my PhD studying that specific topic.”
The theory turned out to be correct for some varieties of Alzheimer’s.
It was not a crowded field, partly thanks to the ancient Greeks whose big-name thinkers looked down their noses at smell and considered it a baser faculty. “For example, Aristotle said we have a much less keen sense of smell than other animals. And I think that has been a myth that has stuck throughout the ages.”
Humans can, if we are really desperate for something to do, determine the sex of flies by their smell.
The belief that animals are generally better at smelling than we are is in fact completely wrong, he says, quoting research that shows we out-sniff rats, mice, vampire bats and spider monkeys. The dog beats us, but humans can, if we are really desperate for something to do, determine the sex of flies by their smell.
We can detect the odorant butyl mercaptan – a skunky-smelling chemical used in a wide range of consumer products – diluted to a concentration of 0.3 parts per billion. And, if we want to take on dogs, we can even train our noses for tasks like tracking.
So, why is the sense of smell still in such bad odour? Olofsson cites historian David Wootton, “who said that in medieval times, life was genuinely multi-sensory. But after the scientific revolution, sight became a dominant sense. With all the new technologies, and cartography mapping the world and describing it, and also literacy, people started to be able to learn how to read those things.”
Smell simply fell out of fashion. But it never really went away, lingering thanks to the central, if often misunderstood, part it plays in so many activities.
“The sense of smell is fundamentally a warning system,” says Olofsson. “It warns us of things that are new, so we react to new smells in a negative way.
“Some we react to more negatively than others, but the general point is that you don’t know where unfamiliar smells are from or what they signify. If you don’t have any other kind of explanatory information, then we tend to think they are disgusting or bad. But the more we get familiarised with them, they can become quite tolerable, if not enjoyable.”
Which is why, you guessed it, our own farts smell fine but the other person’s are intolerable. It’s also why the contents of our children’s nappies aren’t offensive to us, but other kids’ are disgusting.
“People like the smell of their own dog, but they don’t like the smell of other people’s dogs. There’s a lot of research [finding] smells tend to get better the more we smell them, or at least less bad. That is in line with the role of smelling as a survival function – if we have smelled it many times, it can’t be that bad for us.”
Think of smells as the teenage delinquents of the senses: not inherently bad, just misunderstood. “Even olfactory smell researchers sometimes tend to think that some odours are naturally bad and some are naturally good. But there’s many cases where we react differently if we know what it is.”
Such has been the incredible journey of garlic, once the go-to example of bad smells causing social death. “When I grew up, you would say that you shouldn’t eat garlic if you’re going to see people, because you’d smell bad. But no one is really saying that any more.”
He refers to a study that had people eat very strong garlic butter on white bread. Others’ reaction to the resulting odour was more positive than it had been previously.
The theory is that the smell signals garlic’s positive health effects. “I think that’s maybe far-fetched, but it could be that the smell of garlic now is just pervasive.”
However, telling someone – with love – that they, or their breath, stinks is still not socially acceptable, probably because smelling okay is so important.
“It’s a very intimate thing. And of course, few people walk around believing that they smell bad.” We spend a lot of money on counter-odours to mask our potentially stinky selves.
It’s more of a problem for men, who “tend to have stronger body odours than women, partly because men eat more red meat and that brings out a stronger body odour”.
Olofsson speaks from experience. “I was a vegetarian for many years. When I started eating meat again, I felt like my body odour was completely disgusting. It took me a week to get over that.”
For those self-conscious about body odour, help may be at hand. “I went to a conference in Japan where there was a talk about a Japanese invention that is basically a smell detector. It detects people’s sweat [and tells them] if they smell bad. It looks like a little electric razor.”
If it ever gets to market, depending on price point, this invention could save many of us a small fortune in deodorant costs, if not banish Lynx from supermarket shelves forever.
Practice makes perfume
It’s quite common for people to think they don’t have a good sense of smell. And it’s true that our sense of smell deteriorates, like our other senses, as we get older, but it’s equally true that we can do something about it. It turns out practice makes perfume.
“We see that in in older participants,” says Olofsson. “We devised a memory game with tea smells, and the task was to find pairs. It’s like the kids’ game memory, but with little tea jars instead.”
Olofsson says you can also play this game with your spice cupboard, doing blind guesses on what is in each box or jar. “A lot of improvement is possible because we’re very bad at saying what the smell is. Once you start training on that, you get better very quickly.”
Which is especially good for old people, as a deteriorating sense of smell is just as much a part of ageing as deteriorating sight and hearing and just as important to take action over, especially given its job in alerting us to dangers.
There’s more to smell than the nose.
“One thing that shouldn’t be forgotten is oral referral. That’s when you believe that something has a taste when, in fact, it has a smell. It has an aroma, but you perceive it retro-nasally through the oesophagus and out through the nose. When you’re eating and drinking, you say this milkshake tastes like cherry or whatever, but it’s actually an aroma. We think of it as coming from the mouth, so we call it a taste.”
Coffee doesn’t have much of a flavour, but it has incredibly interesting aromas. Try holding your nose when drinking coffee and taste the disappointment.
The nose has been such an under-researched area that many questions remain. Like: why do we have two nostrils? They’re right next to each other doing apparently the same thing. It’s not like having two eyes, which help us perceive depth, or two ears, which help us work out where the noise is coming from.
There is a theory, but it doesn’t pass the sniff test for Olofsson.
“I don’t write about it in the book, because I’m not sure if it’s true or not, but there is a theory that we smell different things with different nostrils. It’s a fascinating idea. We have something called a nasal cycle, so we are more congested in one nostril than the other, and this changes throughout the day. I think it’s a four-hour cycle and the idea is that we might be able to pick up certain molecules when it’s a narrow airflow, and other molecules with a bigger airflow. One study appeared to show that, but no one has been able to find that to be true.”
The existence of the nasal cycle, with our nostrils doing different jobs at different times, is indeed scientifically proven and implicated in everything from brain function to immune response and general nasal hygiene.
Political link
Equally counter-intuitive but scientifically backed is the link between odour disgust and political attitudes, which is a keen interest of Olofsson’s. In studies around the world, he and his colleagues have found a link between body odour disgust and political authoritarianism.
“We had people come in and actually smell body-related odours such as urine and armpit sweat.” This provided a way to measure people’s levels of disgust at various smells. “Once we validated the scale, it became very easy to use.”
In fact there is an “authoritarian cluster”, within which people “who value traditionalism, authoritarianism, having a strong leader, traditional gender norms and anti-immigrant sentiment tend to be more disgusted by body odours.
“The theoretical explanation is that authoritarian disposition is a type of disease-protection behaviour. There’s also less interaction between different groups, less mobility and less risk of being contaminated by viruses from abroad or whatever.”
Perhaps a case of “Make America smell great again.”
It’s well known that certain intimate odours can be difficult to talk about, but it’s a little miracle that we can talk about any with clarity because the vocabulary around smells is extremely limited, especially when compared with that for other senses.
“Linguists who have studied this argue that Western languages typically don’t have a designated smell vocabulary,” says Olofsson. Rather than having a specific word for a specific type of smell, we tend to explain it in terms of something we know; for instance, cinnamon or mandarin, rose or bacon.
“But there are languages that have more words that only describe smells. These words can be pretty abstract and they can pick out a quality [shared by] smells that come from very different sources.”
English also relies on metaphor – for example, “heavy” or “light” smells – but this is not as efficient.
“When we say that something smells like mandarin, we are very much in agreement, but when we use heavy or light, different people have different uses of that word, and the combination of those two types of description is not very functional.”
As Shakespeare almost said, “A nose by any other name would still smell as sweet.”
Go here to read an edited extract from The Forgotten Sense: The New Science of Smell.