Imagine you are at a friend’s wedding and have been tasked with serving drinks at the tables. As an enthusiastic and responsible friend, you always want to please the esteemed guests who have come to celebrate.
However, among the many guests, there will be some you meet for the first time. Among these first-time guests, there will be those who can drink alcohol and those who cannot.
So how can you – just by glancing – tell who at a table can drink and who cannot?
The longer the ring finger, the higher the alcohol tolerance of the person. (Illustration).
A study published in the American Journal of Human Biology offers a little tip. According to it, you only need to look at the length of the ring finger to assess a person’s alcohol tolerance, especially if that person is male.
Surveys show that those with a longer ring finger compared to their index finger tend to drink more than those with a longer index finger. The longer the ring finger, the higher the alcohol tolerance of that person.
But why is there such a strange correlation?
The answer lies in the differences in gene expression related to sex. We know that some sex differences are influenced by social factors, but others stem from our biological nature.
For instance, there is a clear difference in the amount of alcohol that men and women can drink, with men usually consuming more than women.
Similar to many other sex differences, alcohol tolerance can be found in the exposure to sex hormones, including testosterone and estrogen, even in the womb.
When a mother is pregnant with a male child, the child’s testes are capable of secreting testosterone. At the same time, a small amount of sex hormones, including both testosterone and estrogen, also diffuses from the mother’s blood into both male and female fetuses.
Thus, in general, males have higher testosterone levels prenatally compared to females.
Testosterone causes changes in the brain and other organs in the fetus. These changes are then further activated in boys due to the increase of testosterone during puberty.
It is believed that the differences in testosterone and estrogen are reflected in the relative length of the index and ring fingers (the second and fourth digits referred to as D2:D4).
A long ring finger indicates high testosterone and low estrogen levels.
This means that your finger ratio, or D2:D4, reflects your exposure to sex hormones in the womb. Therefore, a long ring finger indicates high testosterone and low estrogen levels.
And this is not just true for humans.
Scientists have observed that many five-fingered animal species develop similar sexual characteristics to humans, including the ratio of length between the ring and index fingers.
In experiments on mice and monkeys, when testosterone was supplemented during the fetal stage, the male offspring were found to have longer ring fingers than index fingers, proportional to the amount of testosterone injected. The longer the ring finger, the higher the tendency for alcohol tolerance.
However, for ethical reasons, we cannot conduct these experiments on humans to confirm if the characteristics of the index and ring fingers are related to drinking ability. Nevertheless, scientists still have ways to test it.
Establishing the Relationship
In general, compared to women, men tend to consume more alcohol and suffer from more alcohol-related diseases. The annual incidence rate has increased from 4.6 to 7.0 cases per 100,000 people since the beginning of the decade.
The longer the ring finger, the higher the trend of alcohol tolerance.
Among the alcohol-related diseases, men also have a higher risk of death than women, up to nine times. So, could this sex difference be influenced in fetuses by testosterone-induced changes?
In a recent study published in the American Journal of Human Biology, scientists conducted a survey of 169 women and 89 men to find an answer.
They asked participants to measure the length of their fingers and then perform a test to determine alcohol use disorder, which included questions investigating people’s drinking habits.
The results showed that participants with a longer ring finger compared to their index finger reported higher alcohol abuse scores, with greater weekly alcohol consumption. This relationship holds true for both men and women but is stronger in men.
“Some current studies have found a relationship between the length of the ring finger compared to the index finger and the amount of alcohol consumed by a person. A large internet survey, where volunteers self-measured their finger lengths, showed that the difference in length between the ring and index fingers could predict the amount of alcohol consumed in the population, even on a national scale.“, the scientists wrote.
“Studies in Europe and Asia have discovered that alcohol-dependent patients have very long ring fingers compared to their index fingers. Our data supports these findings and extends them to non-alcoholic subjects.“
Beyond the relationship with alcohol consumption, the length of the ring finger also provides us a window to predict many health issues.
The good news is that those with longer ring fingers often have healthier hearts, and they tend to perform better in endurance sports, such as marathon running, soccer, basketball, skiing, and surfing.
The bad news is that longer ring fingers are associated with autism, ADHD, internet addiction, and a higher risk of prostate cancer.
Overall, the ratio between the ring and index fingers is an important expression related to testosterone levels even before you are born. It is a piece of the vibrant puzzle that highlights the powerful influence of sex hormones on our behavior and physiology.
So, the next time you attend a wedding party and want to know whether someone can drink or not, just look at the length of their ring finger.
