Fourteen men and 15 women, also aged 18 to 25, rated the photos for attractiveness, health and femininity. The group also rated two composite face images: one of the 10 women with the lowest peak-estrogen levels; the other of the 10 women with the highest levels. The study found a “very strong and direct” correlation between each woman’s estrogen level and how attractive they were found to be, and that the high-estrogen composite was more attractive. A further study by Law Smith's group, however, found that makeup erased the correlation between perceived attraction and estrogen levels. NewScientist.com first reported on Smith’s findings in November 2005.

Mammalian brains, when presented with a choice between survival and mating, will choose the former over the latter. The researchers made headway into understanding the circuitry of behavioral decision-making by studying mice that were simultaneously confronted with a threat and an opportunity to reproduce. David Anderson, professor of biology at Caltech, published his findings in the May 2005 issue of the journal Neuron.

We now know what happens in your brain when you get dumped. A new study of six men and 11 women by Dr. Helen Fisher’s research team uncovered which areas of the brain light up to reflect certain tendencies after being rejected by a lover. The tendencies include: a willingness to take risks to get the loved one back, obsessively thinking about the partner, controlling the inevitable “abandonment rage,” thinking about what the partner is doing/feeling, and actual physical pain. Details of these findings will be published in 2006.

Looking even further ahead, Fisher believes the future of the love science field is in the study of gender differences. “We come from a time where both men and women were considered to be exactly alike … [and] women thought finding differences could be used against them,” she says. “But we are going to understand, for example, that women are just as sexual as men—sex is just plain old different between genders.”