Escher said:
Sounds a bit like you've joined the "Know Nothings".
MDAO said:
Notice that genes don't enter into it at all at first. Simply historical experience. Genes only enter into the equation over successive generations, when the people who find solidarity in a common (real, imagined, or progressively a mixture of both) historical experience, tend to huddle together socially and therefore marry endogamously. The more endogamous and socially insular the group is (by their own choice and/or by ghettoization from without), the more well-defined the borders of the ethnic group becomes.
This is a good point, though I think it's an important caveat that genes never really enter the picture in any thorough-going way (except that family lineages might prove important in some contexts). If you have endogamy spanning tens of thousands of years (actually pretty rare for any given ethnicity), you get minor points of genetic distinction, like change in melanin production and facial structure...or concentration of a few specific genetic disorders (as with Ashkenazi Jews).
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I think that the key word in your description is "solidarity". That is, group formation has to take place in relation to other projects of identity formation, in particular in relation to other ascribed identities.
Eventually they reach a point where membership is determinable with reasonable accuracy with one quick look, and someone not an accepted member of the ethnic group, even if they were fortunate enough to have a phenotype common among that group, couldn't possibly fake the rich, subtle, and unique set of mannerisms of someone well socialized in that ethnic milieu.
We're actually pretty bad at identifying ethnicity from facial looks alone, at least according to a few studies that I've seen. Eg, most East Asians who purport to be able to readily discriminate Japanese from Korean from Han Chinese are pretty unreliable, having built an impression of competence out of confirmation bias.
I was seldom mistaken for a Russian local, even when I kept my mouth shut and wore clothes that were locally bought. It had to do with how I sat, how I walked and carried myself, what expressions I wore on my face, and so on.
Alternately, when I was teaching in Korea, my Vietnamese coworker (who doesn't look especially Korean except in terms of skin tone (ie, pale for a Southeast Asian)) was
very commonly mistaken for a Korean. Hell, my boss even imposed higher expectations of confirmation to Korean mannerisms on him than she did on me.
Ethnic identities are dynamic, though, and can dissolve away as easily as they form. When exogamy and friendship with out-group members becomes common, and/or successive generations stop caring about (or even frankly forget) being descended from people who lived through historical event(s) X, chances are they'll redefine themselves as something else, and disperse among other formed and vibrant ethnic identities.
Another good point that's rather easy to forget.
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One thing I'm wondering about is what specific conditions lead to ethnic formation rather than other processes of group-formation. Eg, why is it that the divide between the nobility and commoners in feudal Western Europe never took on an ethnic dimension? These groups were highly ascriptive, and certainly involved a rich set of status-performances, accompanying artifacts, role-specialization, and endogamy. Was it just a matter of time, in that these social structures failed to persist long enough for ethnic formation? Was it that these status-groups were too closely tied to economic class (relatedly, should we call Indian castes "ethnic")? Was it that these groups were not tied to wider patterns of human migration? Or did it matter that the two groups weren't distinct in physical features (I don't consider the latter likely...for example, most Ashkenazi Jews can pass as non-Jewish white in the vast majority of social settings)?
ebola
