4: Humans can Smell Fear

The sweet smell of fear

The sweet smell of fear

We’ve all heard that hideous cliche, “the smell of fear”. It’s a concept that will be familiar if you’ve read a few books, or watched a sufficient quantity of television. Dogs can smell fear, bears can smell fear, and evil villains that need to appear scary can smell fear. It seems every predator on the planet has evolved the ability to smell human fear – which kind of sucks for those of you that are … human. Luckily, the idea that animals can smell human fear is slightly inaccurate, and by “slightly inaccurate” I mean “completely wrong” –  which is surprising since television is normally always right. It is true that animals are able to sense the chemicals released by other animals of the same species under stressed conditions. These chemical signals, or “pheromones“, are usually warning signals to fellow critters that something fearful is hanging around. However, such chemical signals are widely accepted to be species-specific. In other words, if your mate claims his German Shepherd can smell your fear, then he’s talking out of his proverbial rear end.

Can Humans Smell Fear…?

I’m human, you’re human (probably), so does that mean you can smell my fear? No, obviously not, but that’s because I’m super-manly. Like Will Smith’s son in that God-awful movie they recently released, and I will never watch. You know, the one with the “fear is a choice” crap in the trailer? Anyway, a better question would be, could you smell the fear of some other weak and fear-filled individual – the kind of person I would never interact with. To answer this question, we will turn to a couple of relatively recent studies.

They did what?

That yellow spot is one terrified amygdala! Kind of...

That yellow spot is one terrified amygdala! Kind of…

How do you test if people can smell fear? Simple. You collect sweat from people just before they jump out of a plane, and then let other people smell it while you scan their brains with fMRI – described in fact 2. This imaginative study found that individuals smelling fear-fueled sweat (anything for science right) showed increased activity in the amygdala and hypothalamus – brain regions associated with fear – when compared with seat taken from individuals running on a treadmill. It is rather important to note that while the brain region activity could identify the fear-fueled sweat, the participants didn’t verbally identify any difference in the smells. It seems we don’t smell fear on a conscious level…

Of course, no solid result can be accepted without replication, so it’s lucky another group of eager scientists in the Netherlands did just that. Apparently tandem skydives aren’t popular over there, so instead this study gathered their precious fear-sweat from men watching a scary movie. They then presented this heady concoction to some lucky females – try to reign in your jealousy ladies – and found that the female facial expressions became more fearful when smelling fear-induced sweat. I know what your thinking, I want be paid for presenting sweat samples to people and watching their facial expressions. You and me both my friend.

Everyone should have "Able to Smell Fear" on their CV

Everyone should have “Able to Smell Fear” on their CV

What should I do now?

Humans can indeed smell fear, but how does this help you? Well, if you’re looking to go out on a hot date with that special someone, try to resist the urge to cover yourself in sweat beforehand, no matter how sensible the thought might be. Chances are that if you’ve just watched a scary movie, any potential suitors will be terrified by the smell of you. And to think I’ve been blaming my appearance all this time! If you enjoyed this fact, and want to keep abreast of the expanding list, then:

5 Comments

  1. Hmmm. Right. Smelling sweat. What kinda person signs up to be the “smeller,” I wonder? Sick. But interesting.

    Although I don’t know if I buy humans really being able to smell fear, I do think we can see it. As a fellow struggling writer, I’ve definitely described someone “feeling fear.” Tense shoulders. Wide eyes. Shallow breath. Etc, etc.

    Fear is a great thing; not only does it remind us we’re alive, but fear challenges us. Afraid to show your work to others? Do it anyway. You’ll feel high in the head once you’re done.

    Great post. Great writing.

    Reply
    • Hi Sara. Thanks for the comment, and the overly kind compliment :) Lord knows who signs up to take part in these studies, but I do worry for their mental health.

      It is definitely true that humans can see fear, and many psychophysical studies show that humans can identify “fearful” faces, regardless of the face’s sex or ethnicity.

      Interestingly, one study (that I did not mention here) has shown that if you make people smell “fear-fuelled” sweat, it will bias their facial recognition such that previously “neutral” faces now appear “fearful”. So on some level we do process these smells, even if we aren’t consciously aware of it.

      Thanks again for the comment, and good luck with your struggles!

      Reply
  2. Loved this post. Would love to use that test on Congress so I can figure out whether I will need to move my retirement money into an Alpaca farm or they will avoid the default. :)

    Reply
    • Ha! this actually made me laugh out loud, which is a rarity. Thanks for the kind words John, and for reading. I really like your website!

      Reply
      • Thanks! Yours as well. Keep writing!

        Reply

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