The Correlation between 2nd to 4th Digit Length Ratio and Characteristics of Temperament and Character in University Students

ABSTRACT

OBJECTIVES: The 2nd to 4th digit length(2D4D) ratio reflects the amount of exposure and sensitivity to the prenatal sex hormone and it is considered to be the most convenient and useful way to understand the influence of sex hormone in the determination of human behavioral traits. This study was carried out to find the correlation between the 2D4D ratio and characteristics of temperament and character in Korean university students. We assumed that 2D4D ratio would show a strong correlation with temperament which is defined to be an inclination of an automatical emotional response to a stimulus. METHODS: Participants were 104 university students who completed 2 self-report measures:Temperament and Character Inventory(TCI), Temperament Test. We examined the 2D4D ratio of each subject by measuring the lengths of the 2nd and 4th fingers using a photocopy measurement. We performed statistical analyses using correlation test and t-test to examine the relationship between 2D4D ratio and psychological characteristics. RESULTS: We found out the typical sex difference in 2D4D ratio. Women had significantly higher 2D4D ratio than men. TCI-Character factor(TCI-C) didn't show any significant correlation with the 2D4D ratio. TCI-Tempterament factor(TCI-T) and the item of Temperament Test showed a significant correlation with the 2D4D ratio. In correlation analysis of the total group including all women and men, the 2D4D ratio showed a significant positive correlation in a subscale(shyness with stranger) of harm avoidance scales in TCI-T. In correlation analysis of women's group, the 2D4D ratio showed a significant positive correlation in two subscales( fear of uncertainty) and[shyness to stranger] of harm avoidance scales in TCI-T. In correlation analysis of men's group, the 2D4D ratio showed a significant negative correlation with a sanguine temperament item of the Temperament Test. CONCLUSION: The results suggest that the amount of exposure to sex hormone in the prenatal period seems to have an impact on the determination of temperament and characteristics.