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Can finger size tell us a lot about our personality? Yes, according to a new study that looked at the link between hormones, finger ratios, and narcissism. A surprising discovery.
Should we look for a person’s narcissistic traits in their fingers? Possibly. New research suggests that prenatal exposure to different levels of testosterone and estrogen, as estimated by 2D:4D finger length ratios, is indeed linked to narcissistic traits in adulthood.
Index-to-ring finger ratio, a sign of prenatal hormone exposure
In science, the 2D:4D ratio refers to the comparative lengths of the index finger (second digit) and the ring finger (fourth digit). This ratio is now considered a marker of prenatal hormone exposure:
- Lower ratios indicate higher prenatal testosterone levels;
- Higher ratios indicate higher prenatal estrogen levels.
Males typically have lower 2D:4D ratios than females. This ratio has been linked to various biological and psychological traits, reflecting how prenatal exposure to hormones influences development.
Can narcissism be pointed out?
Narcissism, a personality trait characterized by grandiosity, self-importance, and a lack of empathy, has also been examined in relation to 2D:4D ratios. Some studies have suggested a link between lower 2D:4D ratios and higher levels of narcissism, particularly in women, while others have found nothing.
However, most of these studies have measured narcissism as a one-dimensional construct within the “Dark Triad,” which also includes psychopathy and Machiavellianism, potentially overlooking nuances, such as the fact that narcissism manifests in different forms.
Two new forms of narcissism studied
The motivation behind the new study stems from the need to resolve these inconsistencies and provide a more nuanced understanding of the relationship between 2D:4D ratios and two dimensions of narcissism: grandiose narcissism and vulnerable narcissism.
- Grandiose Narcissism is characterized by traits such as dominance, self-confidence, and an exaggerated sense of self-importance, often accompanied by a need for admiration and a tendency to display aggressive or competitive behaviors.
- Vulnerable narcissismon the other hand, involves more fragile self-esteem, emotional instability, and sensitivity to criticism, with individuals often oscillating between feelings of superiority and inferiority and displaying defensive, withdrawn, or hostile behaviors.
Distinguishing between grandiose and vulnerable narcissism, the researchers sought to determine whether prenatal hormone exposure differentially influences these two dimensions of narcissism in men and women. Given the distinct gender differences in narcissism, with men typically exhibiting more grandiose traits and women more vulnerable traits, the study sought to examine these associations in a gender-specific manner.
Different results between men and women
The study involved 400 participants, mostly college students between the ages of 18 and 44, with a significant majority of them women (312 women and 88 men). The researchers conducted the study in supervised group sessions, during which participants completed a paper-and-pencil questionnaire and had both of their hands scanned to measure their 2D:4D ratios. As expected, women generally had higher 2D:4D ratios than men, reflecting higher prenatal estrogen exposure and various dominant traits.
- In terms of narcissistic traits, men scored higher on grandiose narcissism, while women scored higher on vulnerable narcissism, which is consistent with previous research;
- In women, a lower 2D:4D ratio (indicating higher prenatal testosterone exposure) was associated with higher grandiose narcissism. This suggests that prenatal testosterone may contribute to traits such as dominance and self-confidence in women;
- In men, a higher 2D:4D ratio (indicating higher prenatal estrogen exposure) was linked to more vulnerable narcissism, indicating that prenatal estrogen may influence traits such as emotional instability and sensitivity to criticism in men.
Feeling good in your body, feeling good in your head!
Narcissisms are different depending on gender
These findings are important because they demonstrate that prenatal hormone exposure can influence the development of different forms of narcissism in gender-specific ways. The study adds to the growing body of evidence suggesting that biological factors, such as prenatal hormone exposure, play a role in the formation of complex personality traits.
“By separating women and men in our sample, we provide evidence of relationships between narcissism and prenatal exposure to estrogen and testosterone” (…) This also fits well with the theoretical discussion of Green, et al. (2022) who described grandiose narcissism as more stereotypically masculine and vulnerable narcissism as more stereotypically feminine”the researchers wrote.
But the study has some caveats to consider. The sample included many more women than men, which could impact the generalizability of the results. Additionally, while the 2D:4D ratio is a useful indicator of prenatal hormone exposure, it is not a direct measure, and other factors could also contribute to narcissistic traits.
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