This study tested the feasibility of measuring the finger-length ratio of respondents’ second and fourth digit (2D:4D). 2D:4D has been proposed as a stable marker for prenatal testosterone exposure which in turn has organizational effects on human development and predicts a range of traits and outcomes later in life. Direct measurement of prenatal testosterone is expensive and invasive and can only be done on the embryo. Therefore 2D:4D as an indirect measurement is of potentially high value for researchers interested in human development and the life course. Given stability of 2D:4D as people age, measurement can occur ex-post at any panel wave with yet predictive value for respondents’ life course outcomes.
In the face-to-face interviews the lengths of the ring and index fingers of both hands were measured by interviewers using digital Vernier calipers; in the web survey respondents were asked to measure themselves. The procedure is described in detail in the fieldwork document IP6 Project Instructions for Interviewers.
In IP7 the measurement was repeated for new sample members, including the IP7 refreshment sample, and added to the youth self-completion questionnaire.
