- Scientists have revealed a simple way to identify a psychopath in the real world
- People with ring fingers longer than index fingers are more likely to be psychopaths
From The Joker to Patrick Bateman, psychopaths have appeared in many famous blockbusters over the years.
Now, scientists have revealed a simple way to identify a psychopath in the real world… and it’s all in your hands.
A study has found that people who have a ring finger longer than their index finger are more likely to have psychopathic tendencies.
Researchers at the Charles-Le Moyne Research Center in Quebec say the findings suggest psychopathy may have “biological roots.”
In their study, the researchers said: “While individuals with such behaviors are very socially problematic and incur problems, such behavior could have biological roots and be understood as a rapid life history strategy.”
From The Joker to Patrick Bateman (played by Christian Bale, pictured), psychopaths have appeared in many famous blockbusters over the years.
Scientists found that a low 2D:4D ratio, the ratio between the ring and index fingers, has a link to psychopathy, substance addiction, and antisocial behavior.
The study, published in the Journal of Psychiatric Researchexamined the hands of 80 participants: 44 who had a clinical diagnosis of amphetamine use disorder (AUD), antisocial personality disorder (ASPD), or both, and 36 healthy control subjects.
The researchers took detailed scans of the participants’ right hands and subjected them to several psychological assessments, including one designed to assess Dark Triad personality types.
Higher scores on these tests indicated that the subject had higher levels of psychopathic and antisocial traits.
The results revealed a clear link between a lower 2D:4D ratio (a ring finger longer than the index finger) and antisocial traits, as well as higher scores on the Dark Triad personality tests.
Researchers at the Center de Recherche Charles-Le Moyne in Quebec say the findings suggest psychopathy may have “biological roots” (pictured: Heath Ledger as the Joker in The Dark Knight)
Previous studies have shown that finger length is influenced by the amount of testosterone and estrogen the fetus is exposed to in the womb.
Higher testosterone causes a lower 2D:4D ratio, while lower testosterone causes a higher 2D:4D ratio.
Serge Brand, lead researcher on the paper, told psychology news website PsyPost: ‘The more signs of psychopathology an adult participant had, the more it appeared that this adult had been exposed to higher concentrations of testosterone and lower concentrations of estrogen during the prenatal period of life.’
However, Brand also emphasizes that a low 2D:4D ratio is not a foolproof indicator of psychopathy.
He added: “It is important to understand that the ratio of finger lengths as an indicator of specific exposure to prenatal sex steroids should not be understood as the irrevocable destiny of a person.”
The 2D:4D ratio is not just a sign of antisocial personality traits.
Simply put, men tend to have longer ring fingers due to increased testosterone levels during development.
The results also showed that men tended to have a lower 2D:4D ratio than women, independent of any psychopathic tendencies.
Due to the connection with testosterone levels, having a ring finger longer than the index finger has also been associated with better sports performance in both men and women.
For example, a study of 104 Olympic athletes found that they had significantly lower 2D:4D ratios than the general public.
This has also been associated with higher grip strength scores and even higher jump height in soccer players.
HOW CAN YOU MEASURE YOUR 2D:4D RATIO?
To measure your finger, straighten it and look at the palm of your hand.
There will likely be wrinkles at the base of the index and ring fingers. Your index finger will likely have a fold, the ring finger is a band of folds.
Select the crease closest to the palm and choose a point on the crease halfway to the base of the finger.
Mark it with a pen. Measure it from the mark to the tip of your finger.
To measure your finger, straighten it and look at the palm of your hand. There will likely be wrinkles at the base of the index and ring fingers. Your index finger will likely have a fold, the ring finger is a band of folds.