[Cleo]

Misleading message in a woman's walk

The sway of a woman's hips is not intended to impress men. So say researchers who have found that women have the sexiest walk during the part of the monthly cycle when they are least fertile. The finding implies that women use a variety of signals to advertise their fertility to men, using some signals to advertise when they are ovulating and others to conceal the fact.

Meghan Provost at Queen's University in Ontario, Canada, and colleagues dressed female volunteers in suits adorned with light markers placed along the joints and limbs. This allowed them to film each woman as she walked and then analyse her gait. They also collected saliva samples to find out whether each woman was in the more or less fertile phase of her menstrual cycle.

This showed a correlation between the way the women walked and their time of the month. The women who were fertile walked with smaller hip movements and with their knees closer together.

Similarly, when 40 men were shown the images of the women walking, they rated those in the less fertile part of their cycle as having the sexiest walks. "This was so surprising, I replicated the study with two more independent groups of men to make sure," says Provost, who will publish the results in the journal Archives of Sexual Behavior.

The results appear to run counter to other recent research, which has shown men responding more markedly towards women at ovulation. For example, researchers in the US have found that lap dancers earn more tips in their fertile period (New Scientist, 13 October, p 17).

However, Provost and her colleagues say there is in fact no contradiction between this research and other studies, as they are investigating two different kinds of signal. The previous research investigating men's response to fertile women focused on signals such as smells and facial expressions, which can only be detected at close range. That makes evolutionary sense, as it would benefit a woman to advertise her fertility to a man that she has decided is worth having children with and has therefore allowed to get close to her.

In contrast, men can pick up on the attractiveness of a woman's walk from long distance, and it can therefore act as an unwitting signal to less appealing males who she might not want to choose. So the advantage of having a less sexy walk around the time of ovulation becomes clear: it allows a woman to hide her fertile period from undesirable men who might take advantage of her at that time.

“Men pick up on the attractiveness of a woman's walk from long distance, so it may act as an unwitting signal”
"If women are trying to protect themselves from sexual assault at times of peak fertility, it would make sense for them to advertise attractiveness on a broad scale when they are not fertile," says Provost, who now works at Mount Saint Vincent University in Nova Scotia, Canada. To signal their fertility to people they choose to be with, it makes sense for women to use other means, she says.

"More and more research is being published indicating that ovulation perhaps should be considered unadvertised instead of concealed," she says.

Personally I think we are nothing more then rather clever monkeys.