Is 2D:4D finger ratio research misleading?
June 26, 2009
This week Czech researchers presented a revision of their earlier reported results: “previously published results on the 2D:4D ratio are biased by its covariation with finger length”. But the Czech researchers also reported very explicitely: “We do not claim that the previous results for the finger length ratio are wrong”.
What can we conclude from the latests step in finger ratio research?
|What are the essentials of the Czech research? The Czech researchers claim that the fundamentals of the male-female 2D:4D finger length ratios can be related to male-female differences in finger length. Men usually have longer fingers (larger hand) than women – and there appears to be a negative correlation between finger length in general and the 2D:4D finger ratio.
The Czech research was presented under the title: ‘Differences in the 2nd to 4th digit length ratio in humans reflect shifts along the common allometric line’ – some quotes from the researchers about their finger ratio findings:
“Most studies agree that 2D:4D is sexually dimorphic.”
“Sexual differences in 2D : 4D are mainly caused by the shift along the common allometric line with non-zero intercept, which means 2D : 4D necessarily decreases with increasing finger length, and the fact that men have longer fingers than women.”
“We do not claim that the previous results for the finger length ratio are wrong”
“We conclude that previously published results on the 2D : 4D ratio are biased by its covariation with finger length. We strongly recommend regression-based approaches for comparisons of hand shape among different groups.”