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 palm 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 palm reading to make sense of the heart and life lines and the shape of their hands. Although these tests and quizzes 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 palmistry in the category of a pseudoscience.
Despite the inaccuracy of palm 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 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. Stay tuned.
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