A new study found a link between relative lengths of index and ring fingers in men and behavior towards women.
The study conducted by Mcgill University showed that men with short index fingers and long ring fingers are on average nicer towards women, and this unexpected phenomenon stems from the hormones these men have been exposed to in their mother's womb.
Men's index fingers are generally shorter than their ring fingers. The difference is less pronounced in women. Previous research has found that digit ratio defined as the second digit length divided by the fourth digit length is an indication of the amount of male hormones, chiefly testosterone, someone has been exposed to as a fetus: the smaller the ratio, the more male hormones.
Simon Young, a McGill Emeritus Professor in Psychiatry and coauthor of the study, said that it was fascinating to see that moderate variations of hormones before birth could actually influence adult behaviour in a selective way.
The study approached 155 participants for 20 days and filled out forms for every social interaction that lasted 5 minutes or more, and checked off a list of behaviours they engaged in. Based on prior work, the scientists classified the behaviours as agreeable or quarrelsome. Men with small digit ratios reported approximately a third more agreeable behaviours and approximately a third fewer quarrelsome behaviours than men with large digit ratios.
The researchers found out that no statistically relevant link between dominant behaviours and digit ratios and they suggested future research could study specific situations where male dominance varies such as competitive situations with other men to see whether a correlation can be established.