The fearless dominance associated with psychopathy may be an important predictor of U.S. presidential performance.
On the Medical Xpress website, Carol Clark relates the following story: "After a gunman shot him in the chest in 1912, Theodore Roosevelt went ahead and delivered a scheduled speech, blood leaking onto his shirt. ‘Friends,’ he began, "I don’t know whether you fully understand that I’ve just been shot. But it takes more than that to bring down a Bull Moose.’"
By comparing the testosterone levels of five-month old pairs of twins, both identical and non-identical, researchers were able to establish that testosterone levels in infancy are not inherited genetically but rather determined by environmental factors.