Men's finger length indicates how nice they are to women

A study released earlier this month relied on the "2D:4D" ratio to determine that 57 percent of men are inclined to be promiscuous. Now, a second study says the same ratio—which makes use of the length of the index and ring fingers—can also indicate how nice men are to women.

The study, published in Personality and Individual Differences, notes that a lower ratio "indicates greater androgen exposure"; in less scientific-speak, it means the longer a man's ring finger compared to his index finger, the more male hormones (chief among them testosterone) he was exposed to in the womb.

Over the course of 20 days, they selected which behaviors they exhibited in any social interaction of at least five minutes. The researchers mapped those behaviors as agreeable or quarrelsome, and discovered men with lower digit ratios reported roughly a third more agreeable behaviors with women, and also a third fewer quarrelsome ones.