Born to be wild: Second-to-fourth digit length ratio and risk preferences

Born to be wild: Second-to-fourth digit length ratio and risk preferences

Brian Finley, Adriaan Kalwij, and Arie Kapteyn

Journal paper

Economics & Human Biology

2022

The second-to-fourth digit length ratio of an individual’s hand (digit ratio) is a putative biomarker for prenatal exposure to testosterone. We examine the hypothesized negative association between the digit ratio and the preference for risk taking within a large U.S. population survey. Our statistical framework provides a cardinal proxy for the true digit ratio based on ordinal digit ratio measurements and accounts for measurement error under the assumptions of Gaussianity and time-invariant true digit ratios. Our empirical findings support the hypothesis and suggest a meaningful biological basis for risk preferences.