October 27, 2008
Look at the length of your index finger in relation to your ring finger. If your index finger is longer, you’re probably a ‘couch potato’. If your ring finger is longer, chances are you love to exercise.
Reuters Health reports that a number of previous human studies have linked finger length ratio to certain behaviors and personality traits, including aggression, athletic ability and even academic skills.
|Making a sweeping generalization, men tend to have a shorter index finger in relation to their ring finger, while the two fingers tend to be the same length in women. The so-called “male pattern”–whether it’s seen in men or women–often means there is more aggression and greater athletic ability, while the “female pattern” is associated with stronger verbal skills.
Now researchers at the University of Alberta in Edmonton in Canada have investigated the relationship in 1,000 white mice. When they selectively bred mice to enhance the trait of increased physical activity, those mice had a higher digit ratio. And although this behavior was clearly associated with digit ratio, the findings were the opposite of those observed in humans, reports Reuters. Specifically, the mice with a lower (or “male pattern”) digit ratio tended to be lazier than the mice with the “female pattern,” who took to their running wheels far more frequently.
If you’re lazy, can you blame it on the length of your fingers? Not a chance. Study co-author and associate professor of psychology Dr. Peter L. Hurd told Reuters Health, “The effect sizes for digit ratios on behavior in humans are really small, making it virtually impossible to tell anything about a single individual from their hands,” Hurd told Reuters Health. “The pattern only emerges when a great many people are examined.” He says comparing finger length to behavior is interesting because it says something about personality traits that are fixed during early development in the womb.
October 19, 2008
We all know that the body length of males is usually longer than the body length of females. Scientists call this difference between the sexes: a ‘sexually dismorphic trait’.
The picture below describes some details of this male-female dimorphic trait: about 75% of men are longer than about 75% of females.
John Manning reported in his first book, titled: Digit Ratio that a likewise ‘sexually dimporphic trait’ is noticed in the hands. In the hands of men, the index finger tends to be shorter than the ring finger. And in the hands of women the index finger tends to be the same size (or slightly longer) than the ring finger.
The picture below describes some details of this ‘sexually dimorphic trait’ in the hand: in about 75% of men the ring finger is longer than the index finger; however in females the percentage is about 50%.
Interestingly, John Manning also has pointed out that various studies have indicated that the relative lengths of our fingers offer a hint related to the sexual preference of a person!
For, as expected the index fingers of most straight men appear to be shorter than their ring fingers, while for most straight women the length of both fingers is closer to equal, or even reversed in ratio. But some researchers have noted that gay men are likely to have finger-length ratios more in line with those of straight women, and a study of self-described “butch” lesbians showed significantly masculinized ratios. An overview of these results is presented in the picture below:
An overview of the scientific sources which have found a link between finger length and sexual preference:
Illustration from the last study (Williams, 2000):
October 11, 2008
John Manning explains: “When we look at our fingers, we may think they are beautiful, ugly, refined, or stubby. We use them to eat, gesticulate, carry, point. But what do they tell us about our personalities?”
|“Our fingers provide us with a wealth of evidence about how men and women differ, and how they are programmed before birth to show certain behaviour patterns and likelihood of getting certain diseases.”
“As a fascinating new book explains, the length of our ring and index fingers can greatly influence our personality, health and abilities.”
“The early growth of our ring finger is sensitive to levels of testosterone – the so-called “male hormone”, in the womb (as the testosterone receptors are more densely packed along the finger), and the longer our ring finger the more “masculine” we will turn out to be.”
“The relative length of our ring and index fingers – our “finger ratio” – therefore speaks volumes about the balance of maleness and femaleness of our body and brain.”
“A long ring finger is not universal, but characteristic of men. A long index finger is found in many men, but overall it is characteristic of women as a group.”
“After years of research, during which I conducted many experiments, I have concluded that there are many fascinating different things our fingers can tell us.”
October 5, 2008
Anthropologist Helen Fisher explains what online dating sites can learn from the biology of love and what the length of your ring finger says about your sex life.
|Last year you may have seen ads for Chemistry.com, the ones about people who have been rejected by online matchmaking sites like eHarmony for being gay, depressed, or generally unmarriageable for murkier reasons. In one ad, a young man stares hopefully at heterosexual p o r n, only to conclude, “Nope, still gay.” At Chemistry, spokespeople like to crow, you can “come as you are” (as long as you come as someone who is over 18).
The company is an offshoot of Internet meet-market Match.com, which has been around since 1994. In 2004, Match approached anthropologist Helen Fisher about designing a site where, like at the successful but restricted eHarmony, members would not shop blindly for dates, but would be matched with each other based on personality profiles and compatibility.
Fisher, whose work on s e x, love and the brain had made her an authority on human mating, developed a theory that human beings fall into four categories – negotiators, directors, explorers and builders – and that your type helps determine who you fall for.
Passage in the interview:
RT: What is this thing about your fingers? It’s on the Chemistry questionnaire.
HF: It’s called ‘digit ratio’ (finger length ratio). In the womb – during pregnancy – the brain is washed over by estrogen and testosterone. If you have a lot more testosterone than estrogen in the womb, it is going to build a longer fourth finger than pointer finger. If you’ve got a lot more estrogen in the womb, the pointer finger will be longer.
RT: What does it say about your personality?
HF: If you have more testosterone in the womb and you have a longer fourth finger, you’re more likely to have musical ability, mathematical abilities, to be an engineer or architect or good at computer programming. You tend to have poorer social skills but be direct, decisive, ambitious, competitive.
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. This is because these boys tend to have lower levels of the male sex hormone testosterone, which is known to protect against heart attack.
|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 research shows that boys with shorter ring fingers tend to be at greatest risk.
Lead researcher Dr John Manning told the BBC:
“Males tend to have a relatively longer ring finger compared to the index finger than females.”
“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.”
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.
The research was published in the British Journal of Cardiology.
An overview of the scientific sources which have found a link between finger length (high ‘digit ratio’: >1.0) and heart problems:
According to recent news reports, the sight of lingerie or a sexy woman significantly impairs male decision making. But actually, the research under discussion … indicates the opposite!
The study involved a well-researched financial task known as ‘the ultimatum game’, where one participant is given a sum of money (10 euros in this study) and has to decide how to split it with another. If the other participant accepts the split, both get to keep the money. If they don’t, no one gets anything!
Researchers Bram van den Bergh and Seigfried Dewitte asked heterosexual male participants to play the game in pairs. Before they started the game, they were variously shown pictures of a sexy woman in bikini, landscapes, older women, younger women, or lingerie to handle.
The best write-up of the study’s details is from Nature, who do point out that the results actually CONTRADICT the idea that sexy images makes men less rational!
In the study, they actually made men more rational. The fact that men who saw sexy images were more likely to accept lower offers rather than reject them and get nothing at all, suggest that their short-term rationality was actually … enhanced!
October 1, 2008
The world’s most famous ‘digit ratio’ research, John T. Manning, has begun examining autism too. He teamed up with Simon Baron- Cohen and Svetlana Lutchmaya from the University of Cambridge, who have used samples of amniotic fluid to directly measure the levels of hormones that babies are exposed to in the womb.
|When the children reached their first birthday, the researchers measured their vocabularies and ability to make eye contact. Poor language skills and an unwillingness to make eye contact are early hallmarks of autism. They found that babies who’d been exposed to high levels of testosterone in the womb fared the worst.
“What we’re hoping to look at is whether finger ratios can be used as a proxy for hormones,” says Lutchmaya. Amniocentesis (sampling the amniotic fluic surrounding the unborn baby) is a risky procedure that only a few mothers choose to undergo, she says. But by measuring finger lengths instead, researchers can assess a random sample of children for possible early signs of impaired language and social skill development. Currently, they are checking the fingers of children for whom they have amniotic samples.
Meanwhile, Manning and Baron-Cohen have looked at the finger ratios of 49 children with firm diagnoses of autism, 23 with a mild form of the disorder called Asperger’s syndrome, and their families. The researchers found that autistic children tended to have very low 2D:4D ratios. Interestingly, children with Asperger’s syndrome had ratios that fell between those of autistics and unaffected children. “It fits exceptionally well with the theory,” says Manning.
Clearly genes play a role too in these conditions. But could fetal hormone levels explain other cognitive differences between the sexes? Janel Tortorice at Rutgers University in New Brunswick, New Jersey, thinks they may. She has measured finger ratios in 2D:4D ratio gay women and found that their hands were significantly different from those of heterosexual women-in fact, they tend to resemble those of heterosexual men.
But she has also found differences in the way these women’s brains work. “They have more masculine fingers and more masculine cognition,” she says. On tests of spatial and verbal ability, lesbian volunteers perform more like men than heterosexual women, she says. If this can be confirmed by further studies, perhaps Manning’s most recent suggestion is not as outrageous as it sounds. He claims that musical talent, too, is nurtured in the womb.
An overview of the scientific sources which have found a link between finger length (low ‘digit ratio’: 0.94) and autism:
* The 2th to 4th ratio and autism – 2001 (PDF)
* [Evaluation of the 2nd to 4th digit ratio in the patients with autism] – 2005 (Japanese study)