You smell happiness in someone's sweat

Humans seem to be able to tell if someone is happy or not, just by giving them aquick sniff! The sweet smell of happiness could also be contagious, making others happy after a quick whiff. Ginny Smith reports on the research, which was published in the journal of theAssociation for Psychological Science...

Ginny - Well, I found a paper that was in Psychological Science this week that showed that if you smell the sweat of someone who's feeling happy, it can actually make you feel happy as well.

Kat - Okay. I do not want to be smelling sweat. What on Earth is this about? How were they doing this?

Ginny - It's one of those studies that you kind of don't want to have signed up for. But they got some men - 9 of them - to watch videos that made them feel either happy, neutral or fearful while they had sweat collecting pads taped under their arms. And then the poor researchers cut up these pads into little sections and gave them to various women to smell and measured various things in those women to see if their mood was influenced.

Kat - Can a smell of a man's sweaty pits tell you whether he was happy or fearful?

Ginny - What's interesting is that, we're not always that good at telling how we feel. So, the researchers wanted to use a few different measures to see if they could detect even kind of subconscious happiness. So, they taped some electrodes to the women's faces to measure which muscles they were moving. So, they could actually measure really tiny facial movements that the women wouldn't necessarily know they were making.

They found that the women who were smelling the sweat of the happy men, showed the sort of happy side of things. so, they moved the muscle that you move when you smile.

Kat - What does this actually tell us though? Does it tell us that happiness is contagious via your smell?

Ginny - Well, it does seem to be, but only in some circumstances. So, there were other ones where they were asked to rate how pleasant the sweat was and there was no correlation. So, it's not that we find happy sweat more pleasant.

So, what they suggest is that these signals that you're getting from the happy sweat is sort of so subconscious that they don't work when you're asked to do anything that involves language processing. So, whether you have to say whether you like something or not, it doesn't work. But with the kind of subconscious tests, it does work. I can see your face. That sounds weird.

Kat - Why would we do this?

Chris - It's just my sweat.

Kat - Smell my pits.

Ginny - So, we know that the olfactory nerves, the nose is very closely linked with emotions, but not very closely linked with language. So, that's why smells can evoke memories and feelings but sometimes it's quite hard to put those into words. People who lose their sense of smell often suffer from depression. But they're not always able to sort of say what they're feeling.

So, we think that there's this really kind of evolutionary ancient link with emotions, that's hard for our kind of more modern language senses to explain. It makes sense when you think of it evolutionarily because a lot of animals communicate with smell. We know that animal scent mark places to leave messages for other animals.

So, the theory is that, that's kind of what we're doing here. And if you were a mother animal who suddenly saw something dangerous, you'd want to communicate that fear as quickly as possible to your cubs. And actually, maybe by smell would be faster than explaining to them that there's something dangerous around.