September 7, 2009
While a few years ago early studies had identified a link between various hand characteristics and handness, last year the link was ‘officially’ confirmed in an Australian study that had used a new method for measuring finger length ratio. Now a new BBC internet study by the ‘finger professor’ John T. Manning has confirmed the earlier findings.
TITLE OF THE STUDY:
Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study.
SUMMARY OF THE STUDY:
“The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths.”
“We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference).”
“A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.”
READ FURTHER ABOUT FINGER LENGTH & HANDEDNESS:
August 6, 2009
Earlier this year TIME presented a photo essay of the hands of the last 9 US presidents. Let’s take a look at the finger ratio of their right hand!
Barack Obama’s finger ratio:
Barack Obama’s right hand clearly shows a very low ‘2D:4D digit ratio’. An earlier report on his left hand presented a ‘2D:4D digit ratio’ estimation close to 0.90-0.92, and various photos indicate that the same zone is indicated for his right hand.
NOTICE: though his inauguration photo appears to present a slightly higher ratio – but in that photo his fingers are obviously not ‘stretched’ and therefore that photo should be ignored).
George W. Bush’s finger ratio:
His inauguration photo shows that George W. Bush’s right hand shows a low ‘2D:4D digit ratio’, which is likely close to 0.90.
Bill Clinton’s finger ratio:
There are not many photos available that are suitable for measuring Bill Clinton’s finger length but various photos indicate that Bill Clinton’s ‘2D:4D digit ratio’ is close to 0.96-0.97, which could be described as normal for a white male.
George H.W. Bush’s finger ratio:
His inauguration photo shows that George H.W. Bush’s right hand shows a low ‘2D:4D digit ratio’, which is likely close to 0.95-0.96.
Ronald Reagan’s finger ratio:
Ronald Reagan’s right waving hand shows clearly a very low ‘2D:4D digit ratio’, which is likely close to 0.90.
Jimmy Carter’s finger ratio:
Jimmy Carter’s right waving hand shows also a very low ‘2D:4D digit ratio’, which is likely close to 0.90.
Gerald Ford’s finger ratio:
Gerald Ford’s inauguration photo shows that his ring finger is (much) longer than his index finger – confirmed by his right hand waving photo – but in his case it’s hard to make a more detailed estimation beyond that his finger length ratio can definitely be described as: ‘below average’.
Richard Nixon’s finger ratio:
Richard Nixon’s right hand waving photo shows that his ring finger is definitely longer than his index finger: ‘below average’ and close to 0.95-0.96.
Lyndon Johnson’s finger ratio:
Lyndon Johnson’s inauguration photo shows that lowest ‘2D:4D digit ratio’ of all presidential men – likely below 0.89.
Five out of the last nine US presidents (Obama, G.W. Bush, Reagan, Carter & Johnson) have a very low digit ratio – close to 0.90 or even lower!
Only in Clinton’s right hand the ‘2D:4D finger ratio’ can be described as normal.
SUGGESTION FOR FURTHER READING:
December 9, 2008
Earlier this year a Turkish study reported that in a sample of 386 right handed students, body height was found to correlate negatively with the right- and left hand digit ratios (significant for the left hand in men, and the right hand in women). This implicates that in both males and females evidence was found that a ‘low digit ratio’ is more frequently found in people who has a long body height.
|SOME ADDITIONAL POPULATION EVIDENCE:
‘Finger Guru’ John T. Manning presented in his first book Digit Ratio an overview of data related to the ‘digit ratio’ in various populations. This data (Manning, Barley, et al.; 2000) points out that e.g. in Spanish & British people (both populations for both men and women) a significant HIGHER ‘2D:4D digit ratio’ (the ratio between the index- and ring finger) was found, compared to for example the finger ratios in Finish & German people (again in both populations for both men and women).
Interestingly, especially Spanish people, and in a lesser degree British people as well, are known for their (relatively) short body height – while Germans & Fins are known for their moderelately longer body height (compared to the Spanish & British): see the figure below. This implicates that there appears to be a strong link between the Turkish study which was published in 2008, and the earlier population evidence mentioned by Manning!!
READ FURTHER ABOUT FINGER LENGTH & VARIOUS POPULATIONS: