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A comparison of self-measured and researcher-measured digit ratio (2D:4D)

Lookup NU author(s): Dr Gareth RichardsORCiD, Dr Trevor James



This is the authors' accepted manuscript of an article that has been published in its final definitive form by Taylor and Francis, 2019.

For re-use rights please refer to the publisher's terms and conditions.


The largest investigation of digit ratio (2D:4D), the BBC Internet Study, reported on finger lengths measured by participants themselves, yet data validating this technique are scarce and the reliability has been questioned. The current study aimed to calculate reliability and repeatability statistics for self-measured 2D:4D, and to examine the correlations with researcher-measures. 178 undergraduate psychology students attending a practical class self-measured their finger lengths with rulers; a researcher using digital Vernier callipers measured the second and fourth fingers of a random subsample (n=97). Reliability and repeatability of self-measured 2D:4D were high, as were correlations with researcher-measurements. In each case, lower values were observed for the right-left difference in 2D:4D (D[R-L]). Self-measured L2D:4D and M2D:4D were significantly higher than the equivalent researcher measurements, suggesting that direct comparison could be problematic. Self-measurements and directly made researcher-measurements of 2D:4D are strongly correlated, though self-measured D[R-L] is unreliable.

Publication metadata

Author(s): Richards G, James TK

Publication type: Article

Publication status: Published

Journal: Annals of Human Biology

Year: 2019

Volume: 46

Issue: 6

Pages: 527-530

Online publication date: 02/10/2019

Acceptance date: 28/08/2019

Date deposited: 03/09/2019

ISSN (print): 0301-4460

ISSN (electronic): 1464-5033

Publisher: Taylor and Francis


DOI: 10.1080/03014460.2019.1674380


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