This podcast first appeared on Pythagoras Trousers episode 144 on December 12th 2013

In this podcast I explore how our noses work through the science of smell.

“Follow your nose”

“Stop being Nosy”

I’m sure there are more phrases with “nose” in them (any suggestions?) but I can’t think of any right now…

This podcast explores the science of smell by looking at some of the nose research that is happening around the world.

Dr Darren Logan from the Wellcome Trust Sanger Institute has been looking at how much our ability to smell is determined by our genetics.

Darren, and others in the field of olfactory research, have found that there are two layers to your ability to smell:

Layer one: we each have about 400 different receptors in our olfactory bulb at the back of our noses that represent different smells we can detect. And between different human beings there is a 30% variation in who has which of these receptors activated. So we are al going around smelling the world slightly differently

The second layer of our smelling abilities, depends on how much of a certain gene you express. I’ll let Darren explain the rest in the podcast…

So, we can see by detecting light using our eyes, and we can predict what colour a certain light wave will have, by looking at it’s wavelength. We can similarly detect sounds by sound waves vibrating against our eardrums, and we can accurately predict the sound by examining the structure of the wave.

Dr Joel Mainland from the Monell Chemical Senses Center in Philadelphia has been working on finding a way to predict how molecules will smell, and earlier this week he had a paper published in Nature Nueroscience which (he hopes) will get him one step closer to finding out how to predict what a molecule will smell like.

The way it’s been traditionally thought that we can detect molecules that trigger our memories using a lock and key mechanism: a receptor in our nose is like a keyhole that only one specific key (the molecule which smells) can fit into. I speak to simon Simon Gane from London Centre for Nanotech who has worked with Luca Turin. They believe that quantum mechanics has a big part to play in predicting what a molecule will smell like.

What they think is that the receptors in our noses can probe the bonds of the molecules they detect, not just the shape. And it’s how these bonds are formed that determine what a smell smells like.

So there might be two molecules that have exactly the same shape, but different contents that we could determine as having a different smell. And if there are different contents, then there would be slightly different energies and vibrations within them. And its these vibrations that Gane and Turin think our receptors in our noses can detect. So they tried this with a musk molecule…

The last thing I look at in this podcast is the business end of our noses. The beauty industry, coffee shops, bakeries, even bookshops are using smells in marketing and influence our behaviours to suit their purposes. The reason they can do this is because we never really realise that we are smelling anything.

Have you noticed this? The only time you realise you smell something is when you notice a change in the surrounding smell. Soon after, you’ve forgotten about it.

Freelance olfactory researcher Irina Tudor has been working with industry for years, and she gives an example of how bookshops can manipulate our shopping movements.

Go to the orginal article here or listen below