Sex hormones and finger length: What does 2D:4D indicate?
Abstract
Much recent research has focused on the ratio of the lengths of the second to fourth manual digits (2D:4D) as a predictor of the degree of expression of sexually dimorphic and other sex-hormone-mediated traits. However, published findings are often contradictory or subject to various methodological problems. In the present study, we reassessed the relationships among three measures of 2D:4D (left hand, right hand, and mean) and several variables previously claimed to be related to 2D:4D, including sexual orientation, spatial ability, status, physical prowess, and components of reproductive success. In addition, we examined the relationship between 2D:4D measures and several other traits whose expression is thought to be related to sex hormones, including voice pitch, sociosexuality, mating success, and fluctuating asymmetry. 2D:4D measures showed highly significant sex differences, as did spatial ability, sociosexuality, components of reproductive and mating success, and fluctuating asymmetry. However, out of 57 correlations, 2D:4D correlated significantly in the predicted direction only with sexual orientation (for both sexes) and only for left hand 2D:4D. We discuss the recent 2D:4D literature in light of these findings and consider their implications for understanding the timing of developmental events.
- Publication:
-
Evolution and Human Behavior
- Pub Date:
- January 2004
- DOI:
- 10.1016/j.evolhumbehav.2004.03.005
- Bibcode:
- 2004EHumB..25..182P
- Keywords:
-
- 2D:4D;
- 2D/4D;
- Androgens;
- Digit length;
- Digit ratio;
- Sex differences;
- Sex hormones;
- Testosterone