Smell is the most sensitive of the senses. People can remember smells with 65% accuracy after a year, while visual recall is about 50% after three months. Research has shown that smell is the sense most linked to our emotional recollection.



Smell begins at the back of nose, where millions of sensory neurons lie in a strip of tissue called the olfactory epithelium. The tips of these cells contain proteins called receptors that bind odor molecules. The receptors are like locks and the keys to open these locks are the odor molecules that float past, explains Leslie Vosshall, a scientist who studies olfaction at Rockefeller University.

People have about 450 different types of olfactory receptors. (For comparison, dogs have about two times as many. – so that’s why they can smell so well!) Each receptor can be activated by many different odor molecules, and each odor molecule can activate several different types of receptors. However, the forces that bind receptors and odor molecules can vary greatly in strength, so that some interactions are better “fits” than others.

“Think of a lock that can be opened by 10 different keys. Two of the keys are a perfect fit and open the door easily. The other eight don’t fit as well, and it takes more jiggling to get the door open,” explains Vosshall.

The complexity of receptors and their interactions with odor molecules are what allow us to detect a wide variety of smells. And what we think of as a single smell is actually a combination of many odor molecules acting on a variety of receptors, creating an intricate neural code that we can identify as the scent of a rose or freshly-cut grass.


This neural code begins with the nose’s sensory neurons. Once an odor molecule binds to a receptor, it initiates an electrical signal that travels from the sensory neurons to the olfactory bulb, a structure at the base of the forebrain that relays the signal to other brain areas for additional processing.

One of these areas is the piriform cortex, a collection of neurons located just behind the olfactory bulb that works to identify the smell. Smell information also goes to the thalamus, a structure that serves as a relay station for all of the sensory information coming into the brain. The thalamus transmits some of this smell information to the orbitofrontal cortex, where it can then be integrated with taste information. What we often attribute to the sense of taste is actually the result of this sensory integration. 

“The olfactory system is critical when we’re appreciating the foods and beverages we consume,” says Monell Chemical Senses Center scientist Charles Wysocki. This coupling of smell and taste explains why foods seem lackluster with a head cold.

You’ve probably experienced that a scent can also conjure up emotions and even specific memories, like when a whiff of cologne at a department store reminds you of your favourite uncle who wears the same scent. This happens because the thalamus sends smell information to the hippocampus and amygdala, key brain regions involved in learning and memory. 


For me personally, I am very intrigued about the psychological aspects of smell! For example, why does smell trigger certain memories in us?

There’s always a certain smell around ION Orchard, it’s some sweet and expensive smell, and it always puts me in a good mood to shop! Similarly for Abercrombie and Fitch! I heard that they spray the Fierce cologne- my favourite cologne, regularly around the shop. The result is that you’re able to smell the cologne from even across the street. And that always compels me to pop by and do some shopping!!

Incoming smells are first processed by the olfactory bulb, which starts inside the nose and runs along the bottom of the brain. The olfactory bulb has direct connections to two brain areas that are strongly implicated in emotion and memory: the amygdala and hippocampus.

The research — “The Cool Scent of Power: Effects of Ambient Scent on Consumer Preferences and Choice Behavior” — due to be published in the January edition of the Journal of Marketing, which is part of the American Marketing Association, carried out three laboratory and two store-based experiments. The researchers demonstrated that people spend more when they are in an environment with “warm scents” such as vanilla or cinnamon (as opposed to cool scents” such as peppermint). “Our findings provide practitioners with concrete insights on how different categories of scents work, and they can ultimately be translated into specific guidance for retailers’ strategy,” the study found.

But the researchers give a surprising reason why consumers spend more: A warm ambient scent leads people to perceive the environment around them as more “socially dense” or more crowded with people, says Adriana Madzharov, assistant professor of marketing at the Stevens Institute of Technology in Hoboken, N.J., and co-author of the study. “In other words, you can manipulate spatial perception and this is very important for retailers,” she says. People often shop to make themselves feel better and the more crowded a space, the less powerful they feel, Madzharov says. “People want to get out of this negative space and purchasing luxury products can give your status and power back.”


I think it’s super interesting that smell alone is so important to us. It’s something that most of us overlook too I’m sure! I remember before this project, I always ranked sense as the least important of the senses. But after researching about it, I realised that the sense of smell is equally as important as the rest. Used to imagine a world without the sense of sight, it is quite imaginable really- you just have to close your eyes. But having to imagine a world without the sense of smell would be so difficult! As a person, I am very- for lack of better words- ’empowered’ by the way I smell. That’s why I always have body mists and perfumes on hand! And on special days such as job interview days/ presentation days, I’ll take out my secret stash of perfumes (Victoria Secret’s Noir Tease, Marc Jacobs’ Honey and Ralph Lauren’s Midnight Romance are among some of my favourites!)

However, I am someone whose migraine gets triggered by smell. If someone literally bathes in perfume and sits beside me on public transport, it is safe to say that my head would start pounding like crazy. More often than not, my migraine gets triggered when I’m on an Uber. Dunno why 🙁

Osmophobia, or a heightened sensitivity or aversion to smells, is a commonly reported symptom of migraine headaches.

Headaches triggered by smells are characteristic of a particular headache syndrome called Migraine. It is practically pathognomonic of Migraine (i.e., diagnostic in and of itself). As for why odorants cause Migraine attacks, less is known, probably because the sense of smell is difficult to study.


All in all, smell is super interesting! And while unfortunate that it is my migraine trigger, I think it’s super useful and interesting that smell can influence so many factors such as our spending behaviour, our confidence… And love! (

Super cool facts I’ve found out while researching:

The smell of a new leather jacket or pair of shoes makes everyone happy. But a new car smells best of all. An artificial “new car smell” is sprayed inside cars that lasts for six weeks. (I LOVE THE SMELL OF NEW CARS!!!) And while not everyone can own a Rolls-Royce, at least you could get the smell. The car manufacturer reproduced the scent of the 1965 Silver Cloud and sprays it under the seats to recreate the smell of a classic Roller. The same goes for flying. Singapore Airlines recreated a scent of the Orient for its flights. The aroma of lotus flowers and bamboo forests is put on hot towels for passengers. (WHAAATTT I didn’t know that and will make a mental note to check the next time I’m on the plane!!!)

The answer to the question, can you smell in your sleep, is quite simply, no. As it turns out, the phrase wake up and smell the coffee is more true than you would imagine. When you are asleep, your sense of smell shuts down. You can only smell the coffee after you have woken up. (COOOL)


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1 Comment

  1. Super interesting smell facts!! 🙂 New car smell gives me headache tho ;( Didn’t know about our sense of smell shutting down when we sleep… Hmmm… That cld make us easy targets..

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