First of all, his students measured clubbers’ ring and index fingers. The relationship between the two fingers is believed to be related to how much testosterone an individual was exposed to in the womb. If the ring finger is longer than the index finger, it suggests a high level of prenatal testosterone…

Lovatt then applied a filter to the footage so that the dancers could only be seen in silhouette, which meant that any viewer had to focus solely on their movements. He showed these films to students, who had to rate the dancers on a five-point scale from “very attractive” to “very unattractive.”

The results showed that women gave the highest attractiveness ratings to men with the highest levels of prenatal testosterone. The men with the lowest testosterone in turn got the lowest attractiveness ratings. “Men can communicate their testosterone levels through the way they dance,” Lovatt told SPIEGEL ONLINE. “And women understand it — without noticing it.”