The Brandeis University historian David Hackett Fischer makes a case for an enduring genetic basis for a "willingness to resort to violence" (citing especially the finding of high blood levels of testosterone) in the four main chapters of his book "Albion's Seed". He proposes that a Mid-Atlantic state, Southern and Western propensity for violence is inheritable by genetic changes wrought over generations living in traditional herding societies in Northern England, the Scottish Borders, and Irish Border Region. He proposes that this propensity has been transferred to other ethnic groups by shared culture, whence it can be traced to different urban populations of the United States.