Digit extension: validation of a new biometric variable.

Abstract

This paper reports on a new biometric variable, namely digit extension. We calculated the average length of the second and fourth digit rather than their ratio and we entitled this biometric digit extension. In a first study, we showed that digit extension is related more strongly to a self-concept associated with vigor (masculine trait) than with supportiveness (feminine trait) in men, but not in women. In a second study we found that digit extension and risk seeking (masculine trait) were related in men, but not in women. In a third study we found that for both men and women a higher digit extension was related to more altruistic behavior in a situation where it is in accordance with either masculine or feminine traits. For all studies we show divergent validity with digit ratio, indicating that digit extension is independent of digit ratio. We speculate about the hormonal influences that determine digit extension.Altruism; Behavior; Digit extension; Finger lengths; Masculinity; Risk; Risk seeking; Studies; Validation;