Thank you! This is the the sort of thing I am looking for and couldn’t put into words. Maybe this will help people understand the question?
After a few days, you will pick out the unique features of the individual children and won’t see them as a bunch of different homogenous groups conspiring to confuse you. You’ll notice that this kid over there has a crooked nose and spiky hair and that one over here is knock-kneed and furrows his brow a lot. You’ll notice that while white people tend to vary more in hair color than they do in skin color, that it’s the other way around for other folks. You’ll notice that even within the same race, like those those little black boys you mentioned, that some will have different hair textures, face shapes, skin tones, and body frames. Also use your ears. When all else fails, people have unique voices.
There will be no need to categorize the kids based on their ethnic or racial origins. Just take them as the individuals they are.
I’d say that genetics do have a role in ethnicity, but it’s more than that. Ethnicity is a complex sociological phenomenon that involves a complex interplay of genetics (e.g. who your parents are), language, dress, religion, geography, citizenship, and other things, and involves both a person’s self-identification as a member of an ethnicity as well as that person’s level of acceptance as a member of that ethnicity both among people that claim the ethnicity and people that do not, etc.
One can argue that there is a non-genetic ethnicity in countries that have seen a lot of immigration from many different parts of the world, so one can be American, Canadian, French, or Brazilian with pretty much any ancestral background. It is a lot more difficult to become accepted as ethnically Korean if your parents aren’t Korean.
One could argue that “Appalachian Hillbilly”, and “Valley Girl” are ethnicities.
The taxonomy of ethnicity is an artificial one, like most taxonomies are, but that doesn’t mean it has no value.
The best way to determine whether an ethnicity is real or not is to ask whether people identify themselves by that ethnic identifier.
I don’t agree that there’s an “American” ethnicity - although I think there should be. I think that there are ethnicities unique to America - e.g. Tejano, African Amercan, Sioux, but I believe that the vast majority of Caucasians in the New World refer to themselves by their Old World ethnicity - e.g. Scottish, German, Dutch, Italian…
Hispanics don’t do that so much.
Ethnicity is situational. Take ten Americans from your different “ethnic” categories (Black, Tejano, African-American, Sioux, etc.) and fly them to Zimbabwe. You’ll soon discover that they have a lot of things in common that they do not share with the people of Zimbabwe. Of course there are still real ethnic differences between them, but that’s doesn’t take away from the fact that “American” is a real ethnicity as well as a nationality. I’d agree that it isn’t the most useful way to describe someone: most people have a smaller ethnic identity within “American” that more accurately represents who they are.
Zimbabwe has 2 “ethnicities”- tribes, really. Shona and Matabele. The Tejano, African-American and Sioux are likely to find that they have far more in common with the white English speaking Rhodesian than they are with either tribe.
Please read more carefully. I said “the people of Zimbabwe.” The composition of that people is irrelevant to the main point, which is that different ethnic groups in America still share enough cultural features to be classed as an ethnicity. They would still have more in common with each other than with the white Rhodesian.
Dude: Google Image search “[ethnicity] people” and you’ll get all the visual help you seem to think you’ll need. For example, image search for “Burmese people.” Look at the pictures for a while, Google image search another ethnicity/race/culture/blahblah, look at those pictures for a while, lather, rinse, repeat.
But really? If you suck at names, you suck at names. ('sokay. I totally suck at people’s names. Lotsa folks do.) What color the person’s name that you forgot is irrelevant - they’re still gonna be “hey, you,” right? 
I’ve been to South Texas and I’ve been to Zimbabwe. I’m not sure that I agree with you.
In Hawaii, there’s lots of Asians, and it can sometimes be hard to tell if someone’s Japanese, Korean, Chinese, or Vietnamese. When I used to work in tourism in Waikiki, lord help you if you thought a Japanese was Korean or Chinese, or vice versa. White on black racism, while more famous, has nothing on inter-Asian racism.
I’ve become pretty good at telling the difference, and yes, some of it could be called racism. The faces are “different”: the hair, skin tone, and (yes) eye slants. I can’t really describe it. It’s nothing brutally simple like “Chinese slants downward”, but you can just sort of tell, based on experience. Plus, groups tend to hang out among ethnic lines. So, if you can identify one, you can be reasonably sure the rest are.
My 6-year-old daughter has a funny way of telling the signs and labels apart: Japanese have less “squiggles” than the Chinese. And Korean has “zeros” in their letters.
My Thai wife (Chinese ethnicity) is always being mistaken by her fellow Thais for Japanese or Filipina.
It seem to me most white people do the “I’m a mutt” thing. And Hispanics certainly are big on what “kind” of Hispanic they are, almost to a fault. Don’t dare call a Cuban a Puerto Rican, or a Puerto Rican a Mexican. Really, don’t call anyone a Mexican. Unfortunately no one ever wants to be mistaken for that. Everyone’s got to get their hate on, it seems.
It varies where you are in the country, the white people thing. In NJ, I found that white people were more likely to play up their Polish or Italian or whatever heritage. But in Georgia, where I was born and raised, really only Jewish people would distinguish themselves in this way (I had a teacher in middle school who would constantly explain the etymology of her German-derived surname, as if a bunch of 12 year olds would even notice or care).
If I were white, I don’t know if I would feel comfortable claiming my old world ethnicity unless it was fairly recent (like my parents were immigrants or something). If I’ve never been to the “old country”, had relatives complain that I don’t speak the “old country” language, or really know that much about the “old country’s” customs, I’d probably just say “I’m American.” I think most people would know what that means more so than “I’m a German American.” I can kinda sorta picture what that person would be in a place like Michigan, but not so much down South.
OP, I have the same problem with white kids, and I’m white. I’m a high school teacher, so I have to learn 150 names each year. If there are, for instance, two white boys who are roughly the same height and build and have short blonde hair, it’s very easy for me to confuse them. I do get them sorted out–my goal is always no later than 2 weeks into the term.
The first few days, you likely WILL get some of them confused, but you would even if they each had obvious differences in hair or eye color. That’s OK–they’ll expect any adult meeting them en masse to get their names wrong at first because they’re kids and have been through this introductory phase before, most likely. What will clue you in will be their voices, personality traits, and eventually, subtle differences in their facial features. If you don’t stress about it, it’ll be even easier.
Best of luck.
The problem is that it isn’t a conscious process, but the way the brain works (and face recognition is a pretty complex process. It’s obvious to me that my mother is my mother, but if I had to explain exactly how to tell her apart from a similar looking female, it would be a bit more complicated, and certainly not instantaneous).
So, I don’t think you can really “learn” it. Rather, you’d have to be immersed in an area where there are a lot of “different looking” people until the part of your brain in charge of face recognition begins to automatically classify features other than what it’s currently accustomed to (instead of putting everybody in the same “guy with abnormally elongated eyes and abnormally high cheeks” folder).
By the way there are people who have a serious deficit in face recognition (can’t remember how this condition is called) and can only tell people apart by consciously noting obvious features (my wife has round ears, aunt Martha long curly hairs, etc…). Apart from that faces are for them essentially “blank”.
I’m one of those mutts. You name it in Europe, it’s probably in me. One direct ancestor was even knighted by Queen Elizabeth I and one Irish ancestor was at one time the richest man in New York (colonial days) and had farmland on what is now Greenwich Village (no riches passed down to me, alas :(), but I identify most with Swiss German, due to my surname. Plus the American branch of the family reestablished contact with the branch around Saint Gallen, and I’ve even visited them there.
My suggestion is to make all the kids from Pakistan wear a special armband.