Male–female differences in left-handedness in Sardinia, Italy

Abstract

Males were consistently found to be more likely than females to report left-hand preference in single-hand tasks, but the literature reports negative results too. Using data from a large sample in Sardinia, we aimed at testing the links of left-handedness with sex, age, residence, and seasonality of birth. A total of 4239 participants (males = 1589; females = 2650) were recruited in public places such as high schools, university classes, or gyms in one of the major islands of Italy. Hand preference was established with the question: Which hand do you normally use to write legibly? The monthly distribution of births was studied with the Rayleigh test. In the sample, 270 female participants reported left-hand preference in writing (10.2%) versus 161 male participants (10.1%). Left-hand preference in writing was negatively related to age, with increasing left-hand preference in the younger generations. Left-hand preference in writing was not more common in urban than in suburban or rural settings. The month of birth was found to have a seasonal effect on the left-handed (p=.031) but not on the right-handed (p=.80) participants, and this seasonal effect was more evident in males (p=.04) than in females (p =.26). In our sample males were not more likely to report left-hand preference in writing than females. On the other hand, left-hand preference does vary by age and, in all likelihood, this is an effect of the reduced cultural pressure to write with the right hand in the younger generations.

Keywords:

• Handedness
• Sex
• Age
• Seasonality of births
• Obstetric complications