Dik Zak writes with word of a paper published in the journal Hormones and Behavior. A study found that women take greater care over their appearance when they are at peak levels of monthly fertility
. The researchers took two photos of each of 30 women, one near ovulation and one at the other end of her cycle. They then showed the paired photos (with faces obscured) to a group of observers, who were asked to judge in which photo the women were trying to look more attractive. The observers chose the "high fertility" subject nearly 60% more of the time than would be expected by chance.