ABSTRACT
The ratio of 2nd to 4th digit length (2D:4D), the systemizing quotient (SQ) and the empathizing quotient (EQ) are commonly put forth as correlates of prenatal testosterone. However, the evidence that 2D:4D is related to SQ or EQ is mixed. Indirect finger measurements were used and no significant associations with 2D:4D and SQ or EQ was found, whereas significant correlations between 2D:4D and a composite measure of SQ and EQ using direct finger measurements was reported. This study aimed at reporting associations of traits largely determined in-utero (2D:4D), SQ, EQ and other anthropometric indices in participants from two ethnic groups, namely Bajju and Asholio of Kaduna state. SQ and EQ were assessed in 600 participants, 300 from each ethnic group consisting of both males and females, using a questionnaire of 120 questions. Body anthropometrics such as height, weight, hip, waist, chest circumference were measured using stadiometer and measuring tape. Digit lengths of the second and fourth fingers were directly measured from the proximal crease to the tip of the finger using vernier caliper. Digit ratio was found to be significantly lower in males than females in both ethnic groups (right hand; males: 0.964 � 0.050, females: 0.987 � 0.054, t = 2.579, p = 0.010, : left hand; males: n = 0.984 � 0.040, females: n = 1.011 � 0.039, t = 4.549, p = .0001).There was significant negative correlation between SQ and 2D:4D and this being stronger for right hand (right r = -0.18, left; r = -0.08, p < 0.01 and 0.05) and independent of weight, age, height, ethnicity, body mass index, waist-hip ratio, waist-chest ratio and education. There was no significant correlation between EQ and left and right 2D:4D (right r = 0.13, left; r = 0.11, p > 0.01 and 0.05) , right hand 2D:4D being the major predictor of SQ (B=0.154, p=0.00). Significant positive correlations was found between female's left and right hand 2D:4D, waist and hip circumference, and WCR (right r = 0.12, 0.26, 0.19 left; r = 0.10, 0.26, 0.25 p < 0.01 and 0.05). (v) BMI has no relation with right ratio in the female, is negatively related to left hand 2D:4D but insignificant (right r = 0.13, left; r = -0.013, p > 0.01 and 0.05). In xvi conclusion, it is found that right hand 2D:4D was negatively correlated with SQ in males and females. The relationship was strong to the effects of sex, age, height and education. This suggests that 2D:4D and SQ are influenced by Prenatal Testosterone at similar developmental times. There was no association between 2D:4D and EQ. Birth order and family size shows effect on SQ and EQ.