The digit ratio is the ratio of the lengths of different digits or fingers typically measured from the midpoint of bottom crease where the finger joins the hand to the tip of the finger. It has been suggested by some scientists that the ratio of two digits in particular, the 2nd (index finger) and 4th (ring finger), is affected by exposure to androgens e.g. testosterone while in the uterus and that this 2D:4D ratio can be considered a crude measure for prenatal androgen exposure, with lower 2D:4D ratios pointing to higher androgen exposure. The 2D:4D ratio is calculated by dividing the length of the index finger of the right hand by the length of the ring finger. A longer index finger will result in a ratio higher than 1, while a longer ring finger will result in a ratio of less than 1.
For the record, my index finger and ring finger are exactly the same, which supposedly means I should have average heterosexual female hormone levels. However spironolactone helped my acne when nothing else would.
Info from this article: http://www.viewzone.com/fingers.html
Scientists believe that the link is caused by different levels of the hormones testosterone and estrogen in the womb -- and the effect they have on both brain development and finger length. This is nothing new, since scientists have known for many years that elevated levels of testosterone -- or other hormones closely resembling testosterone -- can cause the brains of both males and females to be more "masculine."
It has long been known that boys tend to do better on math tests while girls do better at writing, reading and verbal tests.
"Testosterone has been argued to promote development of the areas of the brain which are often associated with spatial and mathematical skills," said Dr Mark Brosnan, Head of the Department of Psychology at the University of Bath, who led the study.
"Estrogen is thought to do the same in the areas of the brain which are often associated with verbal ability. "Interestingly, these hormones are also thought have a say in the relative lengths of our index and ring fingers.
"We can use measurements of these fingers as a way of gauging the relative exposure to these two hormones in the womb and as we have shown through this study, we can also use them to predict ability in the key areas of numeracy and literacy.
Edited by Green Gables, 10 March 2013 - 05:46 PM.