Finger length 'key to aggression'
Finger length is linked to testosterone exposure in the womb
The length of a man's fingers can reveal how physically aggressive he is, Canadian scientists have said.
The shorter the index finger is compared to the ring finger, the more boisterous he will be, University of Alberta researchers said.
But the same was not true for verbal aggression or hostile behaviours, they told the journal Biological Psychology after studying 300 people's fingers.
The trend is thought to be linked to testosterone exposure in the womb.
It has been known for some time that there is a direct correlation between finger lengths and the amount of the male sex hormone testosterone that a baby is exposed to in the womb.
In women, the two fingers are usually almost equal in length, as measured from the crease nearest the palm to the fingertip. In men, the ring finger tends to be much longer than the index.
Other studies looking at finger length ratio have suggested that, in men, a long ring finger and symmetrical hands are an indication of fertility, and that women are more likely to be fertile if they have a longer index finger.
Finger length can tell you a little bit about where personality comes from says researcher, Dr Peter Hurd.
One study found boys with shorter ring fingers tended to be at greatest risk of a heart attack in early adulthood, which was linked to testosterone levels.
In the current study, Dr Peter Hurd and his student Allison Bailey measured the fingers of 300 undergraduates at their university.
Men with the shortest index fingers scored higher on measures of physical aggression than those with longer index fingers, but the study's findings did not apply to women.
Dr Hurd is now looking at male hockey players to see whether there is any correlation between finger lengths and each player's penalty record for contact and fouling during matches.
Window to the soul?
He has also been looking at whether men with more feminine finger lengths might be more prone to depression.
He said: "Finger length can tell you a little bit about where personality comes from.
"A large part of our personalities and our traits are determined while we are still in the womb."
But he said finger length should not be used to draw too many conclusions about an individual person.
"For example, you wouldn't want to screen people for certain jobs based on their finger lengths."
I could predict reasonably well who was going to win based on their finger length says Professor John Manning, University of Central Lancashire.
Professor John Manning from the University of Central Lancashire's department of psychology, who first realised that sex hormone exposure in the womb influences finger length, agreed.
He said certain individual characteristics correlate better with finger length than others.
"For example, if you had a group of runners and they were about to start a race I could predict reasonably well who was going to win based on their finger length.
"But I would not be able to predict whether someone was neurotic or not."
He said Dr Hurd's findings were logical based on what we know about finger length, testosterone exposure and aggression, but said more research was needed to confirm the findings.
He said another recent study had found women exposed to higher levels of testosterone in the womb, and hence a more 'male' pattern of finger length, displayed more frustrated behaviour when answering challenging telephone calls than other women.
Monday, 22 October, 2001, 07:35 GMT 08:35 UK
Finger length heart attack clue
A long ring finger may be good news
The length of a young boy's finger may provide a clue as to whether he will be at risk of a heart attack in early adulthood.
Scientists at Liverpool University have established a link between the length of baby boys' fingers and their chances of going on to have a heart attack at an unusually young age.
They believe the link could provide doctors with a simple way to to spot potential heart disease victims at a very early age.
The longer your ring finger, the more protected you are against heart attack.
Dr John Manning's research shows that boys with shorter ring fingers tend to be at greatest risk.
This is because these boys tend to have lower levels of the male sex hormone testosterone, which is known to protect against heart attack.
The genes that are indirectly responsible for the production of testosterone and the female hormone oestrogen also control the development of the fingers.
Divide the length of your index finger by the length of your ring finger to give the ratio
For the average male in Britain, this figure is about 0.97
Below 0.9 an individual is unlikely to have a heart attack early in life. Above 1.00 the risk climbs
Lead researcher Dr John Manning told the BBC: "Males tend to have a relatively longer ring finger compared to the index finger than females.
"This is a very early trait and it is under the influence of sex hormones.
"For a man, the ring finger tends to be about 2% longer than the index finger. The longer your ring finger, the more protected you are against heart attack, because the more testosterone you have.
"There is a relationship between the ratio between these two finger lengths and the age at heart attack of people who do have heart attacks."
The ratio between the two fingers remains the same throughout life.
Short ring fingers did not necessarily mean that boys would go on to have heart attacks, but should alert their parents to do what they can to lessen the risk.
Dr Manning said: "This is an indicator of risk independent of things like smoking and diet, so you can adjust your diet and stop smoking and so on, if you are in a high-risk group."
Dr Manning and Dr Peter Bundred examined 151 male heart attack victims in Merseyside.
They found the age range for heart attacks in men where the index finger was relatively long was 35 to 80 years of age, but in those with relatively long ring fingers it was 58 to 80.
Dr Manning has previously uncovered links between finger-length and vulnerability to depression and sporting ability.
The research is to be published in the British Journal of Cardiology.
Public release date: 20-Oct-2004
Contact: Makeda Scott
British Information Services
Academics find that finger of destiny points their way
Male scientists are good at research because they have the hormone levels of women and long index fingers, a new study says.
A survey of academics at the University of Bath has found that male scientists typically have a level of the hormone estrogen as high as their testosterone level.
These hormone levels are more usual in women than men, who normally have higher levels of testosterone. The study draws on research that suggests that these unusual hormone levels in many male scientists cause the right side of their brains, which governs spatial and analytic skills, to develop strongly.
The study, which as been submitted to the British Journal of Psychology, also found that:
these hormonal levels may make male scientists less likely to have children.
those men with a higher level of estrogen were more likely than average to have relatives with dyslexia, which may in part be caused by hormonal levels.
women social scientists tended to have higher levels of testosterone, making their brains closer to those of males in general.
The study drew on work in the last few years which established that the levels of estrogen and testosterone a person has can be seen in the relative length of their index (second) and ring (fourth) fingers. The ratio of the lengths is set before birth and remains the same throughout life.
The length of fingers is genetically linked to the sex hormones, and a person with an index finger shorter than the ring finger will have had more testosterone while in the womb, and a person with an index finger longer than the ring finger will have had more estrogen. The difference in the lengths can be small – as little as two or three per cent – but important.
A survey of the finger lengths of over 100 male and female academics at the University by senior Psychology lecturer Dr Mark Brosnan has found that those men teaching hard science like mathematics and physics tend to have index fingers as long as their ring fingers, a marker for unusually high estrogen levels for males.
It also found the reverse: those male academics with longer ring fingers than index fingers – the usual male pattern – tended not to be in science but in social science subjects such as psychology and education.
A further study also suggests that prenatal hormone exposure, and hence index finger length, can also influence actual achievement levels. In a survey of male and female students on a JAVA programming course at the University, the researchers found a link between finger length ratio and test score. The smaller the difference between index and ring finger - the higher the test score at the end of the year.
"The results are a fascinating insight into how testosterone and estrogen levels in the womb can affect people's choice of career and how these levels can show up in the length of fingers on our hands," said Dr Brosnan.
In the general population, men typically have higher levels of testosterone than women, but the male scientists at the University of Bath have lower testosterone levels than is usual for men – their estrogen and testosterone levels tend to match those of women generally.
This research now suggests that lower than average testosterone levels in men lead to spatial skills that can give a man the ability to succeed in science. Other research has in the past also suggested that an unusually high level of testosterone can do the same thing by encouraging the development of the right hemisphere.
This right brain development is at the expense of language abilities and people skills that men with a more usual level of testosterone develop and which can help them in social science subjects like psychology or education.
Dr. Brosnan said that men having levels of testosterone very much higher than normal for males would also create the right hemisphere dominated brain, which could help in science. The extremes of low testosterone and high testosterone for men would create the scientific brain, and the normal range in the middle would create the 'social science' brain.
The question also arises as to why more women, who have this lower level of testosterone, are not in science, which is male-dominated, with only one in 40 science professors being a woman.
The short answer is that we don't know: the high levels of estrogen in women may act differently on the brain and not give them the spatial skills that men with similar levels of the hormone have.
There may be social reasons: science has been male-dominated the past and this may be putting women off entering it, even though they are able to. Why male scientists should have fewer children is not known.
"The study of my colleagues at the University of Bath was also interesting in that it shows that women in social science tend to have a higher level of testosterone level relative to their estrogen level, making their brains closer to those of men in general, said Dr. Brosnan."
Finger shows rational thought
08/02/2005 10:03 - (SA)
London - An unusually long index finger is an indication of male superiority at rational scientific thought and reasoning, according to a team of British scientists, all of whose first digits presumably meet the qualifications.
Their findings showed that male scientists are good at research because they have higher than average levels of the female hormone oestrogen which aids analytical skills.
The survey, conducted at the University of Bath, found that male scientists tended to have longer index fingers than other men, showing high levels of oestrogen present in their bodies.
Men had levels of oestrogen as high as their testosterone levels, which caused the right side of their brains responsible for spatial and analytical skills, to develop more strongly.
Because of the high levels of oestrogen, male scientists were less likely to have children and were more likely to have relatives with dyslexia, which may be in part caused by hormonal levels.
Findings also revealed that female social scientists tended to have higher than average levels of testosterone, making their brains similar to those of males.
The study drew on past research, which has found that finger length is genetically linked with the sex hormones oestrogen and testosterone.
A person whose index finger is shorter than their ring finger will have received more testosterone while in the womb than a person with a longer index finger, who will have had more oestrogen.
Psychology lecturer Dr Mark Brosnan studied 100 male and female academics at the University of Bath.
He found that men teaching traditional science subjects such as maths and physics had index fingers at least as long as their ring fingers, meaning they had high levels of oestrogen.
Men teaching social science, such as psychology and education, had ring fingers longer than their index fingers.
Choice of career decided in womb
Brosnan, whose index and ring fingers are the same length, said: "The results give insight into how testosterone and oestrogen levels in the womb can effect people's choice of career and how these levels can show up in the length of fingers on our hands.
"In the general population, men typically have higher levels of testosterone than women, but the male scientists at the University of Bath have lower testosterone levels than is usual for men their oestrogen and testosterone tend to match those of women generally.
"This research now suggests that lower than average testosterone levels in men lead to spatial skills that can give a man the ability to succeed in science.
"Other research in the past also suggested that an unusually high level of testosterone can do the same thing by encouraging the development of the right hemisphere."
Brosnan said that the lack of women working in science was a mystery.
"Science has been male-dominated in the past and this may be putting women off entering it, even though they are able to." - Sapa-dpa
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