Peter C. Whybrow of U.C.L.A. and John D. Gartner of Johns Hopkins University Medical School make their cases for an immigrant-specific genotype in their respective books, "American Mania" and "The Hypomanic Edge." Even when times are hard, Whybrow points out, most people don't leave their homelands. The 2 percent or so who do are a self-selecting group. What distinguishes them, he suggests, might be the genetic makeup of their dopamine-receptor system - the pathway in the brain that figures centrally in boldness and novelty seeking.
Why aren't Canada and Australia, where many immigrants and their descendants also live, as hypomanic as the United States? Whybrow answers that behavior is always a function of genetics and environment - nature with an overlay of nurture. "Here you have the genes and the completely unrestricted marketplace," he says - with the anything-goes rules of American capitalism also reflecting immigrant genetics. "That's what gives us our peculiar edge."Of course, the fact that a lot of the descendents of Australians did not choose to emigrate could also have something to do with it.
By coincidence, I was thinking about American hypomania recently, in the context of American culture having a propensity for maximality in various areas (the biggest cars, the fastest roller-coasters, the most exciting movies, the loudest, most attention-grabbingly garish TV); it came up in the context of the ongoing popularity of the death penalty in America, and the recent execution of Stanley "Tookie" Williams. Other than the ancient imperative for vengeance ("an eye for an eye and a tooth for a tooth", as it says in the Hammurabi codex the Bible), it is arguable that humanely euthanasing a convicted criminal is not a greater punishment than leaving them to contemplate their wrongdoing for some decades from within a cell with no hope of release. However, from an observer's point of view, the ritual of executing an evildoer is a grander statement of symbolic redressing of wrongs than the boringly administrative option of merely locking them up.