A young Chinese couple dance to techno music on Saturday night in the gay club “Destination”, Peking (Image: Flore–Ael Suran/Tendance Floue)

EVER had a feeling come over you that you just can’t explain? Like suddenly getting all warm and fuzzy when you meet someone for the first time, while somebody else who looks just as good leaves you cold? Or experiencing a sudden pang of fear on a plane even though you’re totally at ease with flying?

These seemingly unrelated and illogical human reactions may have a reasonable explanation after all, although one that not everyone will be happy to hear. They may be reactions to other people’s pheromones.

Pheromones are something of a sensitive subject in human biology. Though they are found across the animal world from insects to mammals, research into human pheromones has been dogged by flaky experimental designs and dubious commercial endorsements, with the result that the entire field has a whiff of the disreputable about it. “It’s not so much that the jury is out, but that the jury has been dismissed before the trial has begun,” says Mike Meredith, a neuroscientist at Florida State University in Tallahassee, who studies animal pheromones.

In recent years, though, this has begun to change. Evidence that animal pheromones don’t always work in they way we thought, backed up by a growing number of brain-imaging studies in humans, is convincing some researchers that we really do make and respond to pheromones. As a result some think it’s time to stop asking if human pheromones exist and start investigating exactly how they affect our behaviour.

The term pheromone was …