Part of the show Forensic anthropology, and Facial Reconstruction - Naked Scientists
The sexual desire of women is boosted by the smells given off by breastfeeding women and newborn babies, researchers have found. The finding adds to the growing body of evidence suggesting that our natural smell influences other people on an unconscious level, supporting the idea that human pheromones exist and still exert a subtle influence over us. The study used childless women volunteers. Julie Mennella of the Monell Chemical Senses Center in Philadelphia and a team at the University of Chicago asked 26 nursing mothers to wear absorbent pads in their bras and under their armpits. The odours collected on the pads probably came from both the mother and the feeding baby. Another 45 women, who had never given birth, then spent the next three months undertaking a "sniff challenge". Four times a day for a month, all the women sniffed 'control pads' which were essentially clean pads dipped in a salt solution. This was to rule out the possiblity that the pads used might be producing an effect. For the next two months, some women were randomly chosen to sniff pads with the breastfeeding compounds, while others continued with the control pads. Each day the volunteers measured their temperature, took a urine sample and recorded sexual activity. In 2001, Mennella's group showed that exposure to breastfeeding odours disrupted the menstrual cycles of volunteers: longer cycles got longer and shorter ones got shorter. The new study revealed a more subtle effect. While the women smelling the breastfeeding compounds did not report increased sexual activity - this behaviour was most obviously influenced by the absence or presence of a partner - they did report significantly heightened and more enduring sexual desire and fantasies. "The data are pretty striking," says Mennella, who presents her evidence this week to a meeting of the Association for Chemoreception Sciences in Sarasota, Florida.