in his post A pathway to pro-social behavior, peter frost references this article Second-to-Fourth Digit Ratio Has a Non-Monotonic Impact on Altruism in which the authors say:

“We find an inverted U-shaped relation for left and right hands, which is very consistent for men and less systematic for women. Subjects with both high and low digit ratios give less than individuals with intermediate digit ratios.

the subjects were w.e.i.r.d.-ish, btw — university students from granada, spain.

peter comments:

“From one population to the next, digit ratios tend to cluster around different means, perhaps because altruism has been favored or disfavored to different degrees.”

i’m not familiar with those differences (will have to investigate), but i did post this from turkey in a recent linkfest:

“Inbreeding is associated with lower 2D:4D digit ratio”

“We compared the 2D:4D ratios of 122 male and 108 female consanguineous (children of first cousin marriages) high school and university students to those of 142 male and 122 females controls. Across hands and sex, consanguineous parentage was consistently associated with lower, more masculine-typical, digit ratios. Digit ratios were 1.3–1.9 times more variable among the consanguineous group than the control group. While socio-economic status cannot explain the effects seen in our data, we found that lower, more masculinized, digit ratios were associated with lower family income.”

inbreeding leads to…whatever genotypic/phenotypic package that results in lower 2d:4d digit ratios *and* lower rates of altruistic behaviors? dunno. Further Research is RequiredTM.

ftr — i come from a population that has been inbreeding up until fairly recently, and i’ve got a low 2d:4d digit ratio. uh oh.

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