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Pheromones are kind of the slightly more grown up version of asking Jenny to tell Sam that you fancy him. They are chemicals that trigger a change in behaviour or certain response from someone else. Pheromones are thought to be released through your sweat and then others pick up on their scent. Animals use pheromones to communicate in lots of different ways but, in humans, research so far suggests they are used most commonly to send signals to the opposite sex.

What They Do…

The smart guys are still a little unsure whether us humans actually use pheromones or not but they think we do. There are definitely responses in humans that are present in other animals that use pheromones, but research has yet to find an actual human pheromone chemical. However, when human ancestors gained their ability to see in colour, they lost the organ used by many animals to detect pheromones (vomeronasal organ). If we do use pheromones they would work by communicating information about you to other humans.  Which (when they smell them on your sweat) they pick up on sub-consciously.

There are three main demonstrations of pheromones affecting humans:

  • Women can smell men’s sexual intentions
    • A study was done in which they collected the sweat of men after they had watched a pornographic movie and then normal sweat (gross, I know)
    • They then asked (some very brave) women to smell the sweat
    • As the women smelled the sweat they scanned their brains (with an fMRI machine – which means functioning magnetic resonance indicator to show what the brain is doing)
    • The sweat from men when they were turned-on activated a different part of the brain from normal sweat, the bit of the brain responsible for understanding emotions (right orbitofrontal cortex)
  • Men can tell when women are at their most fertile
    • They stuck a bunch of absorbent pads in the armpits of women (not on the birth control pills) at different times of the month
      •  During menstruation (period)
      • Onset of ovulation (when your ovaries release an egg)
      • Fertile stage
    • It found that men find the smell of the sweat most attractive when the women is in the ‘onset of ovulation’ stage as she is more likely to get pregnant and more  likely to be responsive to sexual advances (i.e. someone hitting on her)
  • Women sync the periods to other women
    • Women were given the sweat of menstruating women to smell. Their periods sped up or slowed down in order for them to sync with the women’s sweat they smelled.

There is also some suggestion that women may be able to smell a guy’s healthiness and suitability through his pheromones. In mice the pheromones of male mice communicate information about their immune system and health to female mice and females tend to pick males with an immune system that provides different immunity to their own. It has been proposed this is the reason humans kiss, as through kissing they get close enough to a possible mate to have a real good sniff and find out if he’s really suitable.

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