June 25, 2011
As a research scientist, Dr. Erina Lee is responsible for the international relationships research at eHarmony. In the following article she described how to use hands in building relationships!
Whether they’re soft and manicured, strong and calloused, weathered and wrinkled—hands come in all shapes and sizes and can often say a lot about you. They can reveal the tattered fingernails of nervous nail biter, the orange fingers of a cheese puff lover, or the worn hands of a grandmother. And when you look even closer at the many lines and wrinkles, is it possible that your hands can reveal even more? Some people believe that clues to our basic selves can be found in the details of our hands. But do our hands really tell us anything of importance about who we really are? Is it possible that the numerous bumps and ridges unique to every hand hold some insight into our level of intelligence or into our love lives?
In an eternal quest for self-discovery, people have looked towards hand readers, among other mystics, to see if the lines in their hands really tell them something meaningful about themselves and their future. In current times, people turn to internet quizzes and online hand reading to make sense of the heart and life lines and the shape of their hands. Although these tests and quizes can be fun, when put to the test of empirical science, most of these claims and predictions cannot be verified. Furthermore, these uncorroborated predictions about personality traits and future events leave palm reading in the category of a pseudoscience.
Despite the inaccuracy of palmistry readings, however, there are aspects of the hands that have been studied empirically, including finger length. When looking at the palm of your hand, fingers straight together, you will likely notice a difference between your second (index) and fourth (ring) fingers. On average women have longer index fingers, compared to ring fingers while men have longer ring fingers compared to index fingers. This association between the two fingers, called the 2D:4D ratio, is related to levels of androgen exposure (a sex hormone higher in men) in the womb. That means that the amount of male hormones a fetus is exposed to determines this very specific detail of finger length in the hands. The precise mechanism by which androgen works is not entirely clear, but in general most theorists believe that increasing androgen exposure will masculinize a fetus. There is also some evidence suggesting that either too much or too little androgen can be feminizing to the fetus.
Because androgen exposure is related to sexual development and masculinization, researchers have begun to wonder if the 2D:4D ratio, as a marker of hormone exposure, may also predict other characteristics. Hormone exposure has been linked to things like general physical health, cognitive abilities, personality, job preferences, attractiveness, and sexual orientation. While the 2D:4D ratio may relate to these developmental characteristics, thus far the evidence supporting such a link is at best described as mixed. For example, there has been much attention dedicated to whether the 2D:4D ratio relates to sexual orientation. While there have been several studies in this area, some have shown no differences between heterosexual and homosexual men in their 2D:4D ratios (e.g., Williams et al., 2000), and others, like Lippa, have shown heterosexual men having lower 2D:4D ratios compared to homosexual men. Similarly with other characteristics like personality and attraction, the research findings have been fairly inconsistent.
Another aspect of the hands that have been conclusively studied are the ridges, the ones that cover the palms and fingers, the ones that make up our unique fingerprints. The study of these ridges is called dermatoglyphics. Similar to the finger length, these ridges are known to be established earlier in the embryonic development, while the fetus is still in the womb. Researchers have shown dermatoglyphic differences between non-deficient people and those with cognitive or genetic abnormalities, like schizophrenia, Down’s syndrome, and intellectual disability. For example, individuals diagnosed with schizophrenia show fewer ridges between two specific points under the second and third fingers [a-b ridge count] compared to non-schizophrenic controls (Bramon et al., 2005). These findings support the idea that changes in the prenatal environment can display its effects in multiple ways, including changes in cognitive development and ridges of the hands. However, the findings do not assume that all people with fewer ridges have cognitive deficiencies.
To summarize, we do know that specific details in our hands are affected by early hormonal exposure and other environmental influences in the womb. And we know that this early exposure also affects other aspects of our development. While it is intriguing to speculate further that details in our hands can predict aspects of our personality or behavior, these conjectures have not been empirically supported. It’s also likely that there are more direct measures of personality, intelligence, and behavioral traits rather than the hands. But even though you can’t currently rely on your hands to unlock all of your mysteries, one thing you can count on is more studies and discussion about them to come.
December 29, 2010
Earlier this month, British researchers published new research presenting a link between the relative length of the index finger and the risk of developing prostate cancer. In men with an index finger longer than the ring finger the chances are 33% higher for not developing the disease.
Often such studies are qualified by non-experts as “nonsense” – initially because of the association with classical palmistry. Usually a main argument of concern is the seize of the studied sample: many ‘2D:4D digit ratio’ studies have been focused relatively small samples, and usually with the statistics were simly not strong enough to be applied to individuals. But those arguments can not be used to the describe the new British study!
The new British research involves a study where the hands of 1,524 prostate cancer patients were examined, which were compared with a control group of 3,044 men.
It can also be noted that Professor John Manning described in his second book ‘The Finger Book‘ with great details the suspected link between the ‘2D:4D digit ratio’ and prostate cancer – a complex theory about of role glutamine chains in the sensitivity of hormone receptors, which in their turn play a role in the activation of testosterone in the body:
“…The various forms of the androgen receptor have important consequences for our health and behaviour. For example, African-American men have shorter glutamine chains (high sensitivity to testosterone) than white men. Short glutamine chains are associated with an increased susceptibility to prostate cancer, and this may in part explain why the incidence of prostate cancer is higher in African-Americans than in white Americans. …”
In short, there seems to exist a triangular relationship between: 1) the high percentage of prostate cancer in Americans with African ancestry, 2) the length of the glutamine chains, and 3) the length ratio between index finger and ring finger.
The importance of the new British study can be recognized in the fact the use of preventive screening for prostate cancer – which is anno 2010 usually done through the use of a blood test – is still an object of confusion. Simply because the benefits of the screening devices are still very unclear. Meanwhile it is a fact that prostate cancer is known as the No. 1 cause of death from cancer in men (see picture below).
The British researchers therefore are speculating about how to add a practical application of their finger length study to the traditional methods of prostate cancer prevention screening!
November 14, 2009
Research at the universities of Liverpool and Oxford into the finger length of various primate species has revealed that cooperative behavior is linked to exposure to hormone levels in the womb!
The sientists have used finger ratios as an indicator of the levels of exposure to the hormone and compared this data with social behaviour in primate groups.
The team found that Old World monkeys, such as baboons and rhesus macaques, have a longer fourth finger in comparison to the second finger, which suggests that they have been exposed to high levels of prenatal androgens. These species tend to be highly competitive and promiscuous, which suggests that exposure to a lot of androgens before birth could be linked to the expression of this behaviour.
Other species, such as gibbons and many New World apes, have digit ratios that suggest low levels of prenatal androgen exposure. These species were monogamous and less competitive than Old World monkeys.
The results show that Great Apes, such as orangutans and chimpanzees, expressed a different finger ratio. The analysis suggests that early androgen exposure is lower in this groups compared to Old World monkeys. Lower androgen levels could help explain why Great Apes show high levels of male cooperation and tolerance.
HOW CAN WE UNDERSTAND THESE RESULTS?
Primate finger length researcher Emma Nelson explains:
“It is thought that prenatal androgens affect the genes responsible for the development of fingers, toes and the reproductive system. High androgen levels from a foetus or mother during pregnancy, may alter gene function and lead to subtle changes in relative digit length and the functioning of the reproductive system. Finger ratios do not change very much after birth and appear to tell us something about how very early androgens affect adult behaviour, particularly behaviour linked to mating and reproduction.”
ILLUSTRATION: A comparison of the human hand with primate hands reveals that only the human hand is featured with a long opposable thumb!
SUGGESTION FOR FURTHER READING:
• Finger length linked with social behavior!