The handedness of Leonardo da Vinci is controversial. Although there is little doubt that many of his well-attributed drawings were drawn with the left hand, the hatch marks of the shading going downwards from left to right, it is not clear that he was a natural left-hander, there being some suggestion that he may have become left-handed as the result of an injury to his right hand in early adu...

The objective of this study was to evaluate the relation between handedness, and the risk of malignant and benign brain tumors. Handedness has been hypothesized to serve as a behavioral marker of prenatal hormonal exposures or other factors that influence subsequent cancer risk. A case-control study was conducted at hospitals in three United States cities between 1994 and 1998. The cases were a...

While the Edinburgh Handedness Inventory has been widely used, there have been few studies assessing its factorial validity. There is evidence that the original instructions and response options are difficult to understand. Using simplified instructions and response options, the Edinburgh Handedness Inventory was administered on a sample of 1514 participants using an online questionnaire. In ac...

Conventional mirrors convert right-handed circularly polarized waves (RCP) into left-handed circularly polarized waves (LCP) and vice versa, see Fig. 1(a-c). Here we demonstrate a novel type of chiral mirror that will reflect one circular polarization without changing its handedness, while absorbing waves of the opposite handedness, see Fig. 1(d-f). This functionality, which fundamentally relie...

Medea factors or genes are maternal-effects mechanisms, found in many species, in which the mother’s body selectively kills embryos of a certain genotype. Humans have a similar genetic mechanism, the gene RHD which produces Rh-factor involved in blood type. Recently I proposed that RHD acts as a maternal-effects gene that determines handedness (i.e., right handed or non-right handed) in individ...

Once again there is a flurry of interest in handedness, this time in the guise of a question: whether a demonstrated increased ‘risk’ of left-handedness among those exposed to prenatal ultrasound denotes brain damage in such babies1,2. This is an old debate in a new vernacular in the sense that left-handedness has always been viewed with suspicion as far as the integrity of the brain of its pra...

An asymmetry in the prevalence of left-handedness vs. right-handedness society has supposedly resulted negative frequency-dependent advantages for left-handers interactive sports. The aim this study was to test whether these apply handball by examining being left-handed is beneficial when executing 7 m shots, a highly unimanual movement. All 1,625 shots at men’s 2016–2022 European championships...

purpose: the traditional view regards limb selection in reaching a hemispheric specialization and an permanent biological phenomenon. however, recent studies have questioned this idea. instead, they suggest that the task conditions is also an effective factor. the present study includes two experiments in right and left handed children examining the effect of object location as a task condition...

Competing theories have posited roles for foetal androgen exposure in the development of human handedness. However, due to practical and ethical considerations, few studies used hormonal measures examine this possibility. The current paper reviews literature reveals a generally inconsistent pattern results. We also present data from longitudinal study prenatal sex hormone subsequent More specif...