- Scientists have revealed an easy way to identify a psychopath in the real world
- People with a longer ring finger than their index finger are more likely to be psychopaths
From The Joker to Patrick Bateman, psychopaths have been featured in many famous blockbusters over the years.
Now scientists have revealed an easy way to identify a psychopath in the real world – and it’s all in their hands.
Research has shown that people with a longer ring finger than the index finger are more likely to have psychopathic tendencies.
Researchers from the Center de Recherche Charles-Le Moyne in Quebec say the findings suggest psychopathy may be “biologically rooted.”
The researchers wrote in their study: ‘Although individuals with such behavior are socially highly problematic and develop problems, such behavior may be biologically rooted and perceived as a rapid life history strategy.’
From The Joker to Patrick Bateman (pictured), psychopaths have been featured in many famous blockbusters over the years
Scientists have found that a low 2D:4D ratio, the ratio between your ring finger and index finger, is linked to psychopathy, substance addiction and antisocial behavior
The study, published in the Journal of Psychiatric Researchexamined the hands of 80 participants – 44 with a clinical diagnosis of amphetamine use disorder (AUD), antisocial personality disorder (ASPD) or both, and 36 healthy controls.
The researchers took detailed scans of the participants’ right hands and subjected them to several psychological assessments, including one designed to test for 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 longer ring finger than the index finger) and antisocial traits, as well as higher scores on the Dark Triad Personality Tests.
Researchers from the Center de Recherche Charles-Le Moyne in Quebec say the findings suggest psychopathy may be ‘biologically rooted’ (Photo: Heath Ledger as The Joker in The Dark Knight)
Previous studies have shown that finger length is affected by the amount of testosterone and estrogen a 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 us PsyPost: ‘The more an adult participant showed signs of psychopathology, the more it appeared that this adult was exposed to higher testosterone concentrations and lower estrogen concentrations during the prenatal phase of life.’
However, Mr. Brand also emphasizes that a low 2D:4D ratio is not a foolproof indicator of psychopathy.
He added: ‘It is important to understand that finger length ratio as a measure of a specific exposure to prenatal sex hormones should not be interpreted as the irrevocable fate 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 tend to have a lower 2D:4D ratio than women, regardless of any psychopathic tendencies.
Due to its connection with testosterone levels, having a longer ring than the index finger is also associated with better sports performance in both men and women.
For example, a study of 104 female Olympic athletes found that they had significantly lower 2D:4D ratios than members of the general public.
This is also associated with higher grip strength scores and an even higher jump height in football players.