October 15, 2012
On october 9 (2012) Manning et.al. presented the very first 2D:4D digit ratio study in Klinefelter syndrome (XXY).
The results describe how Klinefelter syndrome is typically featured with a high 2D:4D digit ratio + short fingers.
The ratio of second to fourth digit length (2D:4D) is a correlate of prenatal testosterone. High 2D:4D is associated with low prenatal testosterone, and reduced sensitivity to testosterone. Klinefelter’s syndrome (KS; 47 XXY) affects the endocrine system, such that low testosterone levels are found in KS foetuses, new-borns and adults. To date, there are no published data regarding the pattern of 2D:4D in KS males. Here we consider 2D:4D in KS individuals (n = 51), their relatives (16 fathers and 15 mothers) and an unaffected control sample of 153 men and 153 women. Adult KS individuals were taller than their fathers and had shorter fingers than fathers and male controls. Compared with fathers, male controls and mothers, KS males had shorter fingers relative to height. With regard to 2D:4D, KS individuals had higher 2D:4D than fathers (right and left hands), male controls (right and left hands) and mothers (left hands). Among KS males older than 13 years there were 34 individuals currently prescribed testosterone and nine not prescribed. In comparison to the former, the latter individuals had higher right 2D:4D and higher right–left 2D:4D. We conclude that KS males have mean 2D:4D values similar to those found in female population norms. In addition, testosterone supplementation in KS males may be most common for individuals with low right 2D:4D.
- digit ratio;
- Klinefelter’s syndrome;
- prenatal testosterone;
- testosterone sensitivity
September 6, 2011
For quite a few years researchers have assumed that finger length development and the 2D:4D digit ratio is directed by sex hormones. Nevertheless, until now direct experimental evidence was lacking. However, researchers from Florida have reported an important discovery. They discovered via a study of the limb buds in mice – which are known for having a digit length ratio similar to humans – that human fingers are likely to have likewise sex hormone receptors as seen in the paws of mice.
A few comments made by researchers Martin Cohn (one of the researchers from Florida) and ‘finger professor’ John Manning:
“The discovery that growth of the developing digits is controlled directly by androgen and estrogen receptor activity confirms that finger proportions are a lifelong signature of our early hormonal milieu,” Cohn said.
“I’ve been struggling to understand this trait since 1998,”said John T. Manning, Ph.D., a professor at Swansea University in the United Kingdom, who was not involved in the current research.“”When I read this study, I thought, thank goodness, we’ve attracted the attention of a developmental biologist with all the sophisticated techniques of molecular genetics and biology.” “When Zheng and Cohn blocked testosterone receptors, they got a female digit ratio,” Manning said. “I find this completely convincing and very useful,” Manning said.“We can now be more focused in our examination of the links between digit ratio and sex-dependent behaviors, diseases of the immune system, cardiovascular disorders and a number of cancers.” “He suggested that the 2D:4D ratio would be an interesting question, and I have to admit to being skeptical,” Cohn said. “When he came back with the initial results, I was blown away. We looked at each others hands, then got busy planning the next experiment.”
The new discovery provides a genetic explanation for a raft of studies that link finger proportions with traits ranging from sperm counts, aggression, musical ability, sexual orientation and sports prowess, to health problems such as autism, depression, heart attack and breast cancer.
The report about the new study appears in this week’s Proceedings of the National Academy of Sciences.
An overview of some key-reports about finger ratios:
May 24, 2011
Various studies have shown that babies exposed to higher levels of testosterone when developing in the uterus have longer ring fingers as adults, and higher levels of oestrogen typically result in longer pointer fingers. However, testosterone & oestrogen levels also affect the rest of the body, including a person’s physical appearance. The ratio between the length of the index and ring fingers has been found to be a good indication for a variety of social and economic factors, thought to be directly or indirectly related to the effects of the prenatal testosterone. These photographs are part of a study on beauty and sexual attraction.
In 2010 a Meta-analysis studyby researchers from the University of Ontario, Penn State, and the Centre for Addiction and Mental Health found that the second to fourth finger length ratio (2D:4D) serves as an indicator of sexual orientation. The study included 1.618 heterosexual men, 1.693 heterosexual women, 1.503 gay men, and 1.014 lesbians.
In addition to identifying the normative heterosexual sex difference in 2D:4D for both hands, the researchers found that heterosexual women had higher (more feminine) left- and right-hand 2D:4D than did lesbians. However… the researchers found NO difference between heterosexual and gay men (though moderator analyses by the researchers suggested that ethnicity explained some between-studies variation in men).
MORE FINGER & DIGIT RATIO REPORTS ARE AVAILABLE AT:
Since the classic Roman time the ring finger has been known to be associated with the wearing of rings in married men and women. The literature indicates that this early belief appears to origin in the idea that a nerve, vein or artery runs directly from the 4th digit to the heart, and therefore it became judged to be the seat of the emotions. Unfortunately medical science today appears not able to present any anatomical evidence that confirms this idea. Nevertheless, there are various other interesting explanations which describe how the ring finger became associated with marriage!
Despite the missing of anatomical evidence for a connection with the heart, there is alternative evidence which suggest that wearing a ring on the ring finger can be associated with the ‘control’ of brute emotions.
CASANOVA HAD THE LONG RING FINGER:
Anecdotal evidence is found in the memoirs of Giacomo Casanova from Venice, who became known as one of the most famous ‘womanisers’ of all times. Casanova’s life as an adventurous writer took him across Europe, and in his memoirs about his stay in Spain we learn of the relative length of his fingers. Casanova described a dispute with the painter Anton Raphael Mengs about the ‘human condition’ of the ratio between the index finger and the ring finger. While Menge was claiming that his longer index finger was the correct human condition, Casanova claimed that his long finger was ”like that of all the children descended from Adam’.
But Casanova was not aware that his claim was basically only true for men only!
COMMITMENT WITH MARRIAGE:
Professor John Manning from the UK presented two books devoted to the ‘2D:4D digit ratio’. In his first book, Manning presented some evidence that the wearing of rings in married women can be understood as an act of ‘advertising’ their commitment to their marriage.
Additionally, the study also demonstrated that a considerable lower percentage of the married men (29%) was wearing a ring on their ring finger – while the percentage was considerably higher for the married women (71%).
FINGER LENGTH REPRESENTS A PRENATAL MARKER:
Today especially the length of the ring finger became known as a prenatal marker for masculinity, and in all regions of the world studies have confirmed that in males the absolute length of the ring finger is usually longer than the absolute length of the index finger. And some studies have pointed out that the sexual dimorphism in finger measures is even more strongly expressed in the distal extent of fingertips than in the length of fingers.
In his second book ‘The Finger book’ Prof. John Manning describes a few references to scientific studies dating back to the 19th and early 20 century:
“The ‘Casanova pattern’ in the fingers is considered by some to be the mark of an ugly hand – an atavistic hand recalling brute instincts and behaviours, modelling the forms of the fingers of our monkey relatives. Thus the ‘beast’ in us is represented by the ring finger while the ‘beauty’ resides in the index finger. This notion has led to suggestions that the femininised ‘Mengs pattern’ is of a purer type, a hand which signifies emancipation from our primate ancestry. … Science, however, has been slow to identify the importance of such connections. That there is a sex difference in the relative length of men’s and women’s fing and index fingers has been known for more than a century. Compared to sex differences arising at puberty the finger ratio is modest in its size and visibility, and it has been neglegted.”
These considerations provide an explanation about why the 4th finger became known as the ‘ring finger’. The ringfinger became also known as the 4th finger or the annulus (digitus annularis).
The following books about fingers are highly recommended to read much more about fingers (presenting various elements that can be described as ‘building stones’ in Mult-Perspective Palm Reading):
• Fingerology (2010), authors: Hillary J. Kener & Michael Zeide
• The Finger Book (2008), author: John T. Manning
• Digit Ratio (2002), author: John T. Manning
Academic science has developed a new theory about how finger length is related to human biology & behavior. A significant part of theory is focussed on the so-called: ‘2D:4D digit ratio’, which concerns the full length ratio of only two fingers: index finger vs. ring finger. In women the length of both fingers is usuallly about equal, while in men the ring finger is usually slightly longer: a tiny sex difference.
NOTICE: This tiny sexe difference has been confirmed among many ethnic populations around the world, but one should also keep in mind that the finger length differences between ethnic populations are often larger than the finger length differences between males and females.
FINGER LENGTH & ATHLETIC ABILITY
Professor John T. Manning of the University of Liverpool (School of Biological Sciences, Liverpool, UK) explains the link between finger length & athletic ability as follows (see video: starting at 2m5s):
“Our fingers have information about how much testosterone and how much oestrogen we’ve been exposed to in the whomb. So, the longer one’s ring finger relative to one’s index finger, the more testosterone you’ve had. And that testosterone has an effect on the brain, and on the body. If a boy has a large amount of testosterone before birth, he is likely to be born with a very efficient heart and vascular system.”
“So the longer one’s ring finger relative to one’s index finger, the faster one can run.”
The BBC’s “Secret of The Sexes” confronted the ‘finger Professor’ with six athletes – all 5000 meter specialists, and asked him to “predict” the outcome of the race based on finger length only. Actually, the BBC provided Manning photocopies of the athletes hands, and in return Professor Manning risked his reputation by providing the results of a race that had yet to be run.
The outcome of the experiment is unvealed “LIVE” in the video (starting at 5m10s). And surprizingly… the theory appeared to be pretty accurate in practice. After Manning & the athletes are controfonted with the results Manning summarizes:
“… We’ve got four out of six right, but the two that are wrong were kind a quite close.”
The winner of the 5000 meter race responds:
“I thought… that finger thing is bullox because there are so many variables… I am very impressed”.
Manning’s theory was also confirmed by the results of various studies e.g. on endurance running & sprinting speed. And in another likewise experiment finger length correctly predicted the outcome of a 100 meters race with 5 young sprinters.
FINGER LENGTH & OTHER LIFE ISSUES
In his second book – titled ‘The Finger Book‘ – Professor Manning explains that because of the prental link with the androgens (testosterone & oestrogen), finger length studies have generally shown consequent sensible correlations with a rainbow of life issue. The tiny sex difference appears to be highly revealing, for hundreds of studies the ‘2D:4D digit ratio’ appears to correlate with a wide range of topics that are usually also known for a typical male-female difference, including: musical ability, personality, health, and even sexual preference.
The following two videos present other materials from the BBC’s “Secrets of The Sexes”: in the second video Manning explains how finger length is related to performance in spatial-visual tasks, and in the third video Manning demonstrates how finger length is related to another typical sexe-related aspect of personality: the ability to empathize!
HOW TO MEASURE DIGIT RATIO?
NOTICE: Measuring the ‘2D:4D digit ratio’ is really a matter of measuring the full length of both fingers. Two additional tips to avoid: 1 – don’t try to ‘judge’ the 2D:4D digit ratio with bare eyes only (conscientious measurment + calculation is a necessity) 2 – one can not find the ‘2D:4D digit ratio’ from the back of the hand, nor the tips of the fingers only.
Picture source: University of Cambridge.
IS THIS THE NEW ‘PALM READING’?
In 2008 Professor Chris McManus of the University College London (Psychology and Medical Education) characterized Manning’s finger research as follows:
“Chiromancy, the notorious pseudoscience that Sir Walter Scott bracketed with physiognomy, astrology and “other fantastic arts of prediction”, has for two decades been creeping back into scientific favour. And John Manning is its high priest. In The Finger Book, he [Manning] writes: “I believe that the pattern and nature of our decline in middle life and the disease which will eventually lead to our death, is dependent to a large extent on our experiences as a foetus”, a phrase that could almost have been written by Cheiro, the early 20th-century society palmist.”
Because of the obvious association with the divination aspect of palmistry (which is still very popular in various countries such as India & Pakistan), the issue of the ‘2D:4D digit ratio’ will probably continue to have a controversial status.
March 5, 2010
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:
“… 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)
SUGGESTIONS FOR FURTHER READING:
June 26, 2009
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.”
Are you tall, short, or got a small head?
Recently Roger Dobson – author at MailOnline.co.uk presented an informative article with the title: ‘Tall, short – or got a small head? Here’s what your physique reveals about your health’. The article describes how various body dimensions – varying from body length to foot size – can indicate useful information about your risk of developing certain conditions, varying from cancer through to dementia & heart disease.
Roger Dobson wrote in his article about the hand:
“IF YOU HAVE LONG FINGERS
Autism and ADHD, mental illness/depression
A range of disorders has been linked to the length of fingers, and in particular the ratio between index and ring fingers. The ratio is thought to be a marker of what was happening hormonally in the womb when the foetus developed.
It’s thought a relatively long ring finger is a sign that the foetus was exposed to higher levels of the male hormone testosterone, while a relatively long index finger is a marker of the female hormone, oestrogen.
Conditions associated with a long ring finger compared to the index include autism and ADHD. Those associated with a longer index include depression.
Males, who are more likely to develop autism and ADHD, tend to have a longer ring finger relative to their index finger.
Exposure to certain hormones might increase or reduce the risk of certain conditions and traits.
‘It has been suggested that autism may arise as the result of exposure to high concentrations of prenatal testosterone,’ say researchers at Liverpool University.”
March 13, 2009
John Manning is a professor at the University of Swansea and he wrote the book “The Finger Book”. Professor John Manning explains in his book how the ratio of the index finger and ring finger (= the ‘2D:4D digit ratio’ finger length) is related to the ‘Big five’ of life.
|FINGERS & EVOLUTION
The human thumb is known as a ‘marker’ for the evolution of human kind; however our relative long index finger – compared to the ring finger – is a likewise example. In the chimpanzee and gorilla, this hand feature is different: they always have longer ring fingers and a short index finger.
THE RING FINGER & SPORTS
Exceptional performances in sports are being linked to the amount of male hormones that people absorb before birth while they stay in the womb. The ‘digit ratio’ has frequently been used to predict performances in various sports leagues.
THE INDEX FINGER & SOCIAL BEHAVIOR
Interestingly, especially among children a short index finger may indicate a lack of empathic ability.
There is growing statistical evidence that our finger ratios are a reliable predictor of our receptiveness to diseases. However, in real life the findings have not yet shown to have a significant impact.
YOUR FINGERS & YOUR SEX-LIFE
Men with long ring fingers, consider themselves as attractive. Studies show that women in the general rule agree and confirm the judgements of these men. Surprisingly, a likewise result has been found in women.
READ FURTHER ABOUT MANNING’S FINDINGS: