Is digit ratio (2D:4D) different between sexual and non-sexual offenders, and non-offending men? Study of a Colombian sample

Abstract

One research line in criminal behavior studies 2D:4D ratio as predictor of aggressionand violent behavior has been established,given that there are sexually dimorphic behaviorsassociated with the influence of testosteroneon brain organization. However, resultshave been mixed. The aim of this study wasto explore the differences in the 2D:4D ratioamong offending and non-offending Colombianmen in four groups (N = 139). A comparativestudy was conducted with three groups of offenders sentenced in a Colombian penitentiary:(1) sexual offenders against children(n = 34), (2) sexual offenders against adultwomen (n = 31), and (3) non-sexual violentoffenders (n=26); as well as one group (4) menwith no criminal record (n = 48). The 2D:4Dratio was measured using the hand scanningtechnique and three digital measurementswere analyzed with the Autometric software:right hand ratio, left hand ratio, and differencebetween the right and left hand ratios (Dr -Iz). Although, in all groups, right-digit ratiowas lower that left-digit ratio (negative Dr–lratio) and, in non-offending men this differencewas not significant, no strong significantdifferences were found between groupsin any measure of 2D:4D ratio used (righthand, left hand or Dr−l). The results supportthe idea that these associations are too weak toconsider them predictors of sexual or non-sexualcriminal behavior. The risk factors determiningsexual or non-sexual criminal behavior,seems to go beyond intra-uterine effectsand involve complex interactions betweenheritability, epigenetics, and pre-natal andpost-natal life events