We all smell differently

Have you ever been debilitated by someone’s overpowering B.O. in the lift, train car, or lecture hall, while your friend sitting next to you doesn’t seem to notice it at all? What about swearing to your friends that you can smell someone barbecuing nearby and they think you’re going crazy?
Fear not – sensing odours is one of most variable neurological processes from person to person. An article about individual differences in odour perception has just landed on my virtual desk (in fact, it’s so hot that the fully formatted version isn’t even available yet!).
These authors wanted to look at individual odour perception in a diverse population: people living in New York City. I’m sure these individuals in general have had a wide range of exposure to good and bad smells; in NYC you can leave a Jewish bakery full of the smells of bagels and lox and then turn the corner into an alley way that a homeless guy has just made into his personal toilet.
Here were the main factors that seemed to influence smell perception:
  • Smoking – This one is a no-brainer, as it’s been apparent for a long time that smoking can decrease your ability to pick up on smells. But it’s certainly not the only factor…
  • Gender – Females are better. At sensing odours. So guys, next time your significant other tells you there is a dead possum in the chimney… believe her. This study also found that there was a gender difference across age (so women are better than men at odour perception no matter how old they are).
  • Age – Older people can’t sense odours as well as younger people – actually, we already knew this but the authors point out that it could either be part of the normal aging process or it could be damage over time by things like pollution. So I think it would be interesting to see another study like this where they compare people who live in the city to people living in rural areas.
  • Race – The found differences in odour perception between Caucasians, Asian, and African-Americans, but disappointingly, this finding wasn’t explored much.
  • Body Type – Here’s one I bet you didn’t expect. Both overweight and overweight people were not as good at detecting odours as people with a normal body type. I can’t emphasise enough how much new research is coming out every day about the link between mind/behaviour and body weight. It really looks like unhealthy body weight (in either direction) affects (and is affected by) so many things, including depression, sleep, inflammation, and now, odour perception. What was really interesting about this article is that they cited some previous research suggesting that decreased smell perception may be one of the causes of obesity rather than the other way around, and could have something to do with the way obese people make food choices.
This list is hardly exhaustive, and the article points out previous reserach that has found many other factors that influence odour perception, such as genetics, respiratory infections, and pollution, and prior exposure to an odour can influence detection of that specific odour.
The link to the article in BMC Neuroscience can be found here.

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