Valkenar wrote:What makes you say it's genetic?
Read "A Culture of Honor" in Gladwell's book "Outliers." He goes into considerable detail.
It gets down to two points of view that a good scientist can appreciate.FIRST PRINCIPLES
Have you ever pondered why there are so many redheads in Ireland and across the northernmost part of our hemisphere (e.g. Russia)? Conversely have you ever pondered why Africans are dark-skinned? It all has to do with the number of photons that hit your skin. If there are too many photons, you are at risk for skin cancer. If you have too few photons and aren't in the era of over-the-counter vitamin supplements and fortified milk, your body won't make enough Vitamin D. Those forces in dynamic tension with each other genetically select for fair-skinned people in the far north, and dark-skinned people near the equator. If you were to take a bunch of Africans and move them to Ireland, and a bunch of Irish and move them to the equator, and not allow either sunscreen or Vitamin D supplementation, then those two populations would not do well. Those that survived over a few hundred generations would look a lot different than the original seed populations - assuming there was enough genetic variability to allow for phenotype drift.
A similar discussion can be made to explain why descendants of West Africa have more fast twitch muscle (and so win the 100 meters at the Olympics) while Kenyans have more slow twitch muscle (and so are the winners of the Boston marathon year after year). It's all about their geography, and how Nature selected for those who were the best survivors in their respective countries.
The argument with Appalachian mountain people is that - for the most part - they come from similar Highland areas in northern Ireland and Scotland. Highlanders who lived on nonfertile soil were a lot different than the Irish who lived on the lowlands where the soil is coffee black. A Highlander is more likely to herd goats, and a lowlander is more likely to farm. Can you sneak in overnight and steal a farmer's yield? Nope... Can you sneak in overnight and steal a Highlander's herd? Yep... Would you steal a fellow's herd if you knew he and his kin 3 generations down would hunt you down and kill you and your kin, year after year? Nope... So which genetic type will flourish in the Highlands, and which will flourish where the soil is fertile and the farming is good?
On a personal note... It took me a long time to understand why my spouse and her Scotch-Irish dad held on to grudges for-e-ver. I mean... I'd hear the same story about how person A did him wrong year after year after year after... Same with the spouse. Do a bad thing and you will hear about it for the next 20 years. Can't let it go. So much emotional energy burned over so many years...
Now I get it. EXPERIMENTAL DATA
Read about the experiment in Gladwell's book here...... Insult, aggression, and the southern culture of honor: an "experimental ethnography"