Could finger length serve as a reliable predictor of athletic ability? Another experiment with five athletes – all specialized in 100 meters running… is John Manning able to predict the winner of the race?


This video – broadcasted in Spanish language – includes e.g. scenes from Discovery Channel. Professor John T. Manning explains how finger length is related to athletic ability. Finger length ratios are established in utero under the influence of testosterone. Testosterone plays an important role in the early development of the heart and lungs – the ‘motor’ of every athlete! But it is very hard to say how much in utero testosterone is involved in the early development of individuals. However, the 2D:4D finger length provides an indication for the amount of in utero testosterone.

In the second half of this video Mannings describes that the five athletes all must have had large amounts of testosterone during their early development in the whomb – because their ‘2D:4D finger ratio’ is rather low (for males). But in only one athlete the ‘2D:4D finger ratio’ is exceptionally low – and Manning explains why he expects that this athlete (no.5) has the best chance to win the race.

Then the moment of truth arrives… the athletes are prepairing to start the race. Who will win? The movie shows clearly that athlete no.5 was by far able to make the fastest start… during the race athlete no.2 becomes very competing… but at the finish athlete no.5 is still ahead, and wins the race. Manning made the right prediction!

At the end of the video Manning explains his prediction again, but he also points out that the proceses in the womb do not explain everything.

Feel free to watch the video again – knowing the succesfull outcome of the experiment should make you enjoy watching this video, and it should be easy to remember the outcome again!!!

Usain Bolt – the hand of the fastest runner ever!
Finger length: pointing a finger at athletic succes!
Finger length & sex I.D.: how fingers relate to your mind!

John T. Manning – ‘the finger Professor’!
John T. Manning - 'the finger Professor'!

What does finger length say about athletic ability? In a BBC project “Secrets of the Sexes” John T. Manning risked his reputation by participating in an experiment with six athletes: all 5000 meters specialists… the outcome is simply astonishing!

Professor John T. Manning explains how finger length relates to testosterone & athletic behavior.

Professor John T. Manning explains:

“… What I should be able to do is look at the differences between the ring finger and index finger, and on that basis rank these runners: first, second, third, fourth and so on. In theory that should work.”

Comment voice explains:

“In practice we’re providing professor Manning with photocopies of the athletes hands. And in return he’s risking his reputation by providing us with the results of a race that has yet to be run.”

You can now learn more about the fascinating ‘2D:4D digit ratio’: take a look at the outcome of this rather remarkable experiment – you will likely enjoy it, and probably… you will remember the outcome easily!!! (starting at 2:05 of the youtube video)

Finger length & sex I.D.: find out how your mind works!
Finger length & athletics: a secret your fingers reveal!
The hand of Usain Bolt – the fastest runner ever!

Usain Bolt has a low 2D:4D digit ratio.Jamaicans are known for having a low 2D:4D finger ratio.The olympic gold medal 4x 100m relay team from Jamaica.

Portrait of Giacomo Casanova by Anton Raphael Mengs.
Portrait of Giacomo Casanova by Anton Raphael Mengs (1768).

‘Giacomo Casanova had the long ring finger!’

Numerous references to variations in finger length patterns are found in the history of literature. However, none of the revelations are more lively than the informative comment in the memoirs of Giacomo Casanova (Jacques Casanova de Seingalt, 1725-1798) – who has been described as ‘world’s greatest lover’. Casanova where he recounts a conversation with the painter Anton Raphael Mengas (Casanova, 1794).

Peters et al. (2002) reported that Casanova made 2 clear statements: first, that the ring finger is relatively longer than the index finger and, second, that this is the case for both men and women. What follows is a quote from the work of Casanova (The Memoirs of Casanova: Spanish Passions) about one of his conversations with the German neoclassic painter Anton Raphael Mengs.


… Once I dared to tell him that he had made a mistake in the hand of one of his figures, as the ring finger was shorter than the index. He replied sharply that it was quite right, and shewed me his hand by way of proof. I laughed, and shewed him my hand in return, saying that I was certain that my hand was made like that of all the descendants of Adam.

“Then whom do you think that I am descended from?”
“I don’t know, but you are certainly not of the same species as myself.”
“You mean you are not of my species; all well-made hands of men, and women too, are like mine and not like yours.”
“I’ll wager a hundred doubloons that you are in the wrong.”

He got up, threw down brushes and palette, and rang up his servants, sayin,-

“We shall see which is right.”

The servant came, and on examination he found that I was right. For once in his life, he laughed and passed it off as a joke, saying-

“I am delighted that I can boast of being unique in one particular, at all events.”

BBC Test: finger length & sex I.D.!
Finger length & Cupid’s science!
The science of gaydar: finger length & sexual preference!
What they say about men with long ring fingers!

Giacomo Casanova's 'History of My Life' - part 1 to 12.

The right hand of Barack Obama!

Barack Obama.

The right hand of George W. Bush!

George W. Bush.

The right hand of Bill Clinton!

Bill Clinton.

The right hand of George H.W. Bush!

George H.W. Bush.

The right hand of Ronald Reagan!

Ronald Reagan.

The right hand of Jimmy Carter!

Jimmy Carter.

The right hand of Gerald Ford!

Gerald Ford.

The right hand of Richard Nixon!

Richard Nixon.

The right hand of Lyndon Johnson!

Lyndon Johnson.

Presidential palm readings: US presidents have a low 2D:4D finger ratio!

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.


Famous hands: the hand of celebrities!
More news reports related tothe  ‘2D:4D digit ratio’
The hands of Barack Obama: his finger length
What does the hand of a celebrity reveal?

Is 2D:4D finger ratio research misleading?

Is 2D:4D finger ratio research misleading?

Is finger ratio research misleading / deceptive?

This week Czech researchers presented a revision of their earlier reported results: “previously published results on the 2D:4D ratio are biased by its covariation with finger length”. But the Czech researchers also reported very explicitely: “We do not claim that the previous results for the finger length ratio are wrong”.

What can we conclude from the latests step in finger ratio research?

What are the essentials of the Czech research? The Czech researchers claim that the fundamentals of the male-female 2D:4D finger length ratios can be related to male-female differences in finger length. Men usually have longer fingers (larger hand) than women – and there appears to be a negative correlation between finger length in general and the 2D:4D finger ratio.

The Czech research was presented under the title: ‘Differences in the 2nd to 4th digit length ratio in humans reflect shifts along the common allometric line’ – some quotes from the researchers about their finger ratio findings:

“Most studies agree that 2D:4D is sexually dimorphic.”

“Sexual differences in 2D : 4D are mainly caused by the shift along the common allometric line with non-zero intercept, which means 2D : 4D necessarily decreases with increasing finger length, and the fact that men have longer fingers than women.”

“We do not claim that the previous results for the finger length ratio are wrong”

“We conclude that previously published results on the 2D : 4D ratio are biased by its covariation with finger length. We strongly recommend regression-based approaches for comparisons of hand shape among different groups.”

4D, Manning's index

Take a look at some of the international vocabulary + synonyms for the word ‘DIGIT RATIO‘:

The ‘DIGIT RATIO’ vocabulary in English language includes the words:
Finger ratio, 2D:4D ratio, 2nd to 4th ratio, 2th to 4th ratio, ring finger index finger ratio, finger length ratio, Manning’s index, Manning ratio, finger digit ratio, fingers ratio, finger size ratio

‘DIGIT RATIO’ synonyms in French language:
Indice de Manning

‘DIGIT RATO’ synonyms in Spanish language are:
Índice de Manning, ratio dedo de la mano

‘DIGIT RATIO’ synonyms in Porteguese language are:
Manning índice, dedo rácio

‘DIGIT RATIO’ synonyms in German language:
Finger-Verhältnis, Manning-Verhältnis

‘DIGIT RATIO’ synonyms in Dutch language:
Vinger ratio, vingerlengte ratio, Manning ratio

‘PALMISTRY’ synonyms in Rusian language are:
Соотношение палец

digit ratio

A short history of major the developments in the concept of ‘digit ratio’:

  • In 1888 antropologist and biologist Dr. Frank Baker noticed that the index finger is usually short than the ring finger:
  • More than a hundred years ago, a very entertaining paper concerning various customs and superstitions associated with the hand – titled: Anthropological Notes on the Human Hand (1888) – was presented to the Antropological Society of Washington by Frank Baker, Professor of Anatomy at the University of Georgetown. Following some fascinating tales, and a debunking of palmistry, he concluded by discussing the comparative lengths of the digits, and noted that the second (index) finger is usually shorter than the fourth (ring) finger.

  • In 1930 antropologist Ruggles George noticed a sex difference in the index finger and the ring finger:
  • Some years later R. George described in a paper – titled: Human Finger types (1930) – a sex difference in the distribution of finger length ratios in that males are more likely to show the 2 < 4 pattern (i.e. a longer ring finger relative to the index finger), while females are more likely to show the opposite pattern (2 > 4).

  • In 1952 antropologist V.R. Phelps discovered that finger length is stable throughout life:
  • Two decades later the sex difference findings reported by George (1930) were confirmed in the work of V.R. Phelps – titled: Relative index finger length as a sex-influenced trait in man (1952) – noting that such differences were observed in foetuses, and then appeared to be stable throughout life.

    Psychologist Glenn Wilson

    Psychologist Glenn Wilson

    * In 1983 Psychologist Glenn Wilson introduced the word ‘digit ratio’:

    Dr Glenn Wilson of King’s College, London published a study – titled: ‘Finger length as an index of assertiveness in women‘ – which introduced the 2D/4D ‘digit ratio’ as a marker of exposure to prenatal testosterone + examining the correlation between assertiveness in women and their digit ratio. This was the first study to examine the correlation between digit ratio and a psychological trait within members of the same sex.

    Psychologist John T. Manning

    Psychologist John T. Manning

    * In 1998 Psychologist John T. Manning presented a link between ‘digit ratio’ and testosterone + sperm counts:

    This link was described by Manning in a study – titled: ‘The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone‘.

    'Digit ratio' - the book

    Digit Ratio - the book

    * In 2002 Psychologist John T. Manning presented the book ‘Digit ratio’:

    Psychologist John T. Manning presented his first book about the 2D:4D ratio – titled: ‘Digit ratio: A Pointer to Fertility, Behavior and Health‘.

    In this book Manning presents a first overview of the digit ratio research which has been presented uptill the year 2002.

    The finger book

    The finger book

    * In 2008 Psychologist John T. Manning presented the book ‘The finger book’:

    Psychologist John T. Manning presented his first book about the 2D:4D ratio – titled: ‘The finger book‘.

    Quote from New Scientist:

    “According to evolutionary psychologist John Manning, who has spent years researching the secrets they betray, your digits reveal all sorts of things, from your sexuality to whether you are socially disadvantaged or likely to suffer a heart attack. They even, as the legend goes, give away the size of a man’s penis.”

    Take a look at your feet…

    What do you see? Most of us will see 5 toes … and very likely your inner toe will be the longest, the largest, AND the biggest! As a matter of fact, this a typical characteristic of the human foot!

    Now, let’s take a look at the feet of primates… (see the picture below):

    The primate foot and the human foot.

    Do you see the difference? The foot of these primates show quite a different picture: for, the inner toe is always the lowest set toe! This is a typical characteristic of the primate foot. And often the length of the inner toe does not pass the length of the other toes. 

    Another rather remarkable aspect is the fact that the ‘big toe’ of primates (the inner toe) shows quite some similarities with the thumb of our hands.

    These typical characteristics in human and primate foot were already described in 1920 in the work PRINCIPLES OF ANATOMY presented by Frederic Wood Jones. Wood Jones described these characteristics through the concept: DIGITAL FORMULA.

    The typical ‘digital formula’ for the human foot is: 1>2>3>4>5 – in the typical human foot the inner toe (toe 1) is usually the longest, and the little toe (toe 5) is usually the shortest.

    However, the typical primate foot is characterised by the so-called ‘simian digital formula’: 3>4>2>5>1 – in the typical primate foot the middel toe (toe 3) is usually the longest, and the ‘inner toe’ (toe 1) the shortest!

    Notice: Jones’ describes on page 30:

     “… the digital forumula*, and it must be remembered that such a formula does not express the relative length of the digits, but the relative projection of the tip of the digits from the extremity of the limb”.

    The ‘human digit formula’ for our hands…

    Interestingly, the typical ‘digital formula’ for the primate foot resembles the typical ‘simian digital formula’ for the primates hand: 3>4>2>5>1 – you see the confirmation in the picture below!

    How to measure digit ratio?

    As a matter of fact, the ‘digital formula’ of the human hand often resembles the typical ‘simian digital formula’: 3>4>2>5>1 – especially in the hand of human males! But also the hands of human females can often be characterized by the ‘simian digital formula’, however more often the hands of women can be described with the ‘human digital formula’: 3>2>4>5>1.

    The difference is that in human males the ring finger is more often larger than the index finger (or: pointer finger) – which resembles the  ‘simian digital formula’! In human females more often the index finger is longer than the ring finger – which resembles the ‘human digital formula’! These principles are visible in the picture below:

    Digit ratio in the male and the female hand

    The ‘digit ratio’ formula!

    However, both in human males and females the length difference between the index finger (digit 2) and the ring finger (digit 4) is often very small. And therefore the ‘ratio’ between the length of those fingers is often close to ‘one’ (1.00) – when both fingers have the same length, the ‘ratio’ between the 2 fingers is exactly ‘1.00’.

    Because of this situation scientists around the world are using the concept ‘digit ratio’ to study the relative length difference between the index finger (digit 2 = 2D), and the ring finger (digit 4 = 4D), which results in the formula: ‘digit ratio’ = 2D:4D.*

    * One should notice here that the concept of Wood Jones ‘digital formula’ is related to “… projection of the tip of the digits from the extremity of the limb” -see the 3th picture in this blog post). However, the ‘digit ratio’ is related to the absolute length difference between the index finger and the ring finger – see the picture below.

    How to measure digit ratio?