The idea that humans can somehow be unconsciously yanked around by pheromones – invisible, odorless, airborne chemicals – tends to make a lot of scientists guffaw and back away defensively. Lower animals? Sure, they can get influenced by these chemical traces! But not we mighty big-brained humans! We don’t even have a mating season! Except, as an experiment published in New Scientist suggests, maybe we do:
Geoffrey Miller and his team at the University of New Mexico, Albuquerque, compared the earnings of lap dancers who were menstruating naturally with those of dancers taking the hormonal contraceptive pill. During the non-fertile periods of their menstrual cycle, both sets of dancers earned similar tips. But when naturally cycling lap dancers entered their fertile period they earned significantly more in tips than their co-workers on the pill (Evolution and Human Behavior, DOI: 10.1016/j.evolhumbehav.2007.06.002).
Now, I should quickly point out that there’s no evidence that pheromones are specifically causing the increase in tips. All the researchers are saying is that something is invisibly signaling the males that certain females are fertile. They don’t know what it is, only that it’s there – and it’s altering human behavior.