2D:4D and Self-Employment Using SOEP Data: A Replication Study

SOEPpapers 1085, 25 S.

Frank M. Fossen, Levent Neyse, Magnus Johannesson, Anna Dreber


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The 2D:4D digit ratio, the ratio of the length of the 2nd digit to the length of the 4th digit, is often considered a proxy for testosterone exposure in utero. A recent study by Nicolaou et al. (2018) reported an association between the left-hand 2D:4D and self-employment (in a sample of about 1,000 adults). In this pre-registered study we replicate these results on a new and larger sample of about 2,600 adults from the German Socioeconomic Panel-Innovation Sample (SOEP-IS). We find no statistically significant associations between 2D:4D and self-employment and thus cannot confirm the findings of Nicolaou et al. (2018) for left-hand 2D:4D. Our estimated 99.5% confidence intervals are within an about 2 percentage points change in self-employment for a one standard deviation change in the 2D:4D when we pool results for men and women (the association does not differ significantly between men and women). Even larger studies are needed to rule out smaller effect sizes.

Levent Neyse

Research Associate in the German Socio-Economic Panel study Department

Keywords: Self-employment, entrepreneurship, hormones, testosterone, digit ratio