Environmental Sensitivity and Digit Ratio (2D:4D): Negative Results

The current study explored the associations between different levels of developmental plasticity factors—specifically, prenatal androgen exposure and the personality trait related to environmental sensitivity. We recruited participants from Japan (184 females and 90 males) and India (94 females and 86 males) and measured their personality traits of environmental sensitivity and an indirect indicator of prenatal androgen exposure, the ratio of the lengths of the index (2nd digit: 2D) and ring (4th digit: 4D) fingers (2D:4D). Overall, the analyses stratified by country and sex did not reveal a clear correlation between environmental sensitivity and 2D:4D ratios in any of the subsamples. In one subgroup, the environmental sensitivity of Japanese females showed a weak positive correlation with the left- and two-handed mean 2D:4D ratios; however, this correlation approached zero when outliers were removed and the data were reanalyzed. Finally, we considered possible explanations for the inconsistent findings regarding the associations among different levels of plasticity factors.