Left handed Barack Obama has a low ‘digit ratio’

Barack Obama will soon become the 7th ‘left-handed’ US president in history. The continued-discussion about the high number of ”left-handed’ US presidents became a little bit quite the past 8 years – George W. Bush was the first ‘right-handed’ US president after Jimmy Carter! (1977-1981) However, with the left-handedness of Barack Obama will likely fire-up this discussion again. By the way, John McCain is a ‘lefty’ as well!

Only recently a research was published at the University of Melbourne which reported that left-handednes can be linked to a ‘masculine’ digit ratio – which implicates that the length of the index finger is short than the length of the ring finger. The photo below illustrates that this hand-feature is also present in Barack’s left hand! And by the way, his right has the same characteristic.

Finger length shows your talent for math / literacy.

The Melbourne research finding is especially interesting in the perspective of the theory which links left-handedness to an overabundance of testosterone in the womb; this theory was published in 2004 in New Scientist. For, an important aspect of John Manning’s digit ratio research links low 2D:4D digit ratio to an overabundance of testosterone in the womb as well!

How to measure digit ratio!

The picture on the right provides some detailed guidelines to assess the digit ratio of Obama’s left. The 2D:4D digit ratio of his left hand is likely to be in the zone: 0.90 – 0.92. A very ‘masculine’ finger length ratio!


Barack Obama is the 7th left-handed US president!
The index/ring finger ratio (2D:4D) linked with hand preference.
Your finger length, handedness & chirality
Digit ratio & finger length news


all amino acids that make up proteins in all living things are 100% left-handed!

Handedness is not only seen in human beings, it is also an important concept in biology: all amino acids that make up proteins in all living things are 100% left-handed!

Handedness & your finger length ratio:

Earlier this year researchers from the University of Melbourne have tested a new method of measuring Mannings ‘finger ratio’. They e.g. found in the hands of 600 students that the hands of right-handed students are characterized by longer fingers in the right hand (compared to the left hand).

Interestingly, the researchers also observed an effect between hand preference and the index/ring finger ratio. Left-handed subjects appeared to have a more ‘masculine pattern’: they had a lower 2D:4D ratio compared to right-handed subjects. This implicates that relative finger length can predict a person’s gender or their hand preference!

The method of measuring the ‘finger length ratio’ included a tube-test, which was compared with measurements on photocopied hands. The tubes test yielded a longer estimate of ring finger length compared to the photocopy method. Despite this, there was a strong correlation between the tests and both showed an association with gender.

By the way, the link between handedness (laterality) and right-left finger length difference was already noticed a few years ago by a Dutch psychologist, who described that the combination leftward thumb length, finger length & handpalm asymmetry can provide a strong indication for left handedness.

Left handed men may think more like women
The origins of handedness
Your fingers reveal so much about you
Your left handed child – BOOK
The finger book – BOOK


* Source: Laterality