"The National Geographic data also show significant variation in rates of left-handedness by U.S. state, with higher rates in the Northeast and lower rates in t

"The National Geographic data also show significant variation in rates of left-handedness by U.S. state, with higher rates in the Northeast and lower rates in the middle of the country." The actual accompanying data only describes white people born after 1950 which could be evidence of too many researcher degrees of freedom. Additionally, the legend to the map is showing single percentage points of difference which hardly speaks to a robust finding. And given the fact that the data was collected in a non-scientific manner, that 1% between New Jersey and Missouri may be as easily attributed to ambidextrous people fibbing to be more unique, or perhaps for some reason National Geographic appeals to different kinds of people than the underlying population. At least show me an r value or something. At any rate, the idea that since the Victorian era people have evolved to be less left-handed than in certain areas is absurd and without any scientific basis.