Investigation of the relationship between 2D:4D finger ratios and internet and smartphone addiction in middle school children

Abstract

In humans, prenatal testosterone exposure affects a sexually dimorphic feature called the second-to-fourth digit ratio (2D:4D). Our research sought to better understand the connections among 2D:4D, Internet addiction (IA), and smartphone addiction (SPA) among middle school students. The study included 104 students aged between 10 and 14 years (mean age for girls: 11.3, the mean age for boys: 11.6), with 48 male and 56 female participants. Measurements of 2D:4D, hand length, and hand width were taken from the participants' hands. IA was assessed using the Young Internet Addiction Scale (YIAS), and SPA was assessed using the Smartphone Addiction Scale-Short Form (SAS-SF). In male participants, a negative correlation was found between the 2D:4D ratio and IA, while no correlation was observed in female participants. Both male and female participants showed a high correlation between IA and SPA. The study concludes that 2D:4D is an easily measurable and reliable marker for gender differentiation. It was found that male participants had higher levels of IA compared to female participants and that IA and SPA are strongly correlated in both genders.