The relationship between the 2D:4D ratio and lateral preference in a Ghanaian population

Abstract

Prenatal androgen exposure has suggested to be associated with lateral preferences in humans as per the Geschwind-Behan-Galaburda (GBG) theory, the Sexual Differentiation Hypothesis (SDH) and the Callosal Hypothesis (CH). The 2D:4D ratio is the putative marker of prenatal androgen exposure. The study aimed to determine the relationship between the 2D:4D ratio and lateral preferences. The study was cross-sectional from May to June 2021 that involved 206 participants (females = 112, males = 94), aged between 18 to 32 years. Computer-assisted analysis was used to measure the right (2D:4DR) and the left (2D:4DL) digit ratios while lateral preferences were measured using the Lateral Preference Inventory (LPI) questionnaire. The females’ 2D:4DL was significantly higher than males with a medium effect size (p = 0.033, d = 0.29). The odds that a male would have a preference for the left ear was greater relative to a female [AOR = 2.330 (95%CI: 1.034-5.251)]. There was a significant correlation between right-eye laterality and the 2D:4DR in females (r = –0.589, p = 0.030). Also, left-foot laterality significantly correlated with the 2D:4DL in males (r = 0.693, p = 0.046). Prenatal androgen exposure, as indexed by the 2D:4D ratio may be associated with lateral preferences of the eye in females and the foot in males. Further studies are however recommended.

Keywords

• the 2d:4d ratio
• prenatal androgen exposure
• lateral preference
• the lateral preference inventory (lpi) questionnaire
• ghana