Some pseudoscientific theories, such as palmistry, suggest that finger length reveals personality traits. While personality is influenced by genetics, environment, and psychology, some believe in the “digit ratio,” focusing on the index (2D) and ring (4D) finger lengths.

• Longer Ring Finger (Low 2D:4D Ratio): Associated with risk-taking, assertiveness, ambition, and high self-esteem.
• Longer Index Finger (High 2D:4D Ratio): Linked to empathy, compassion, communication, and conflict avoidance.
• Equal Length: Indicates a balance of assertiveness and empathy, blending competitiveness and cooperation.

John Manning, an evolutionary biologist, popularized this concept, inspiring over 1,400 studies linking digit ratios to personality, cognition, and disease risks. Researchers have even used finger ratios to infer ancient cave painters’ gender.

Emerging in the late 1950s, finger ratio studies offered a non-invasive method to examine traits influenced by prenatal hormones, such as aggression and sexual orientation, due to the risks of fetal hormone sampling.