2D:4D digit ratios in males and females and its correlation with simple reaction time: A cross sectional Study at Combined Military Hospital (CMH), Lahore, Pakistan

A cross-sectional study was conducted on 86 medical students between the ages of 18 to 25 years studying at the Combined Military Hospital (CMH) in Lahore, Pakistan. They were assessed for height, weight, digit length of the 2nd and 4th fingers of both hands and reaction time (response time to auditory stimulus as measured by BIOPAC). Of the 86 students, 42 (49%) were male and 44 (51%) were female, with a mean age of 19.55±1.017 and 19.86±0.905 years, respectively. There was a significant difference in the height, weight and Body Mass Index (BMI) of the students. The mean 2D:4D ratio for males on the left hand was 0.958±0.029 and for females it was 0.979±0.363 (p=0.004). The ratio for the right hand for males was 0.958±0.031 and for the females it was 0.977±0.035 (p=0.011). There was a significant correlation between the 2D: 4D ratio in the left hand with the reaction time in the dominant hand at random intervals (r= -0.240, p= 0.027) and with reaction time in the non-dominant hand at fixed intervals (r= -0.232, p= 0.03). Our results concluded that there is a negative correlation between the digit ratio and the reaction time. Those individuals who had lower digit ratios had faster reaction times than those who had higher digit ratios.