To make this question less of imho and more factual maybe we should look at GDP, standard of living, poverty indices, nobel prize winners, scientic advancement, political stability, well being and educational levels etc etc.
After factoring in population numbers obviously.
Will that then tell us if either hemisphere has a clear lead in the smartness/intelligence stakes.
Moved to IMHO.
Colibri
General Questions Moderator
Here’s a better idea. Look at those countries that straddle the equator and tell us if folks north of the line are smarter than folks south of the line. That’s a better way of controlling for factors not related to the equator itself. I suggest you start with Ecuador.
What do any of the factors you propose measuring have to do with intelligence?
The colder the climate, the dumber we are. 
Sounds like a dumb Northie question.
It sounds like a question that the book Guns, Germs and Steel answered. No, humans are more or less equal; the differences in tech innovation favoring northern white euros was due to environmental factors.
When these factors improve greatly over a period of decades, as they have (for example) in South Korea, does that mean the population got smarter? When they plummet, as they have done in Greece and Syria, does that mean the population got stupider?
Given that your entire premise is fatally flawed, no.
There’s actually a theory that claims the opposite - people in the north are smarter because they’ve spent more time inside and got book learning. The fact we willingly live where it snows seems to belie the idea.
What you me “we” Mr. snow-putter-up-with???
If you’re looking at human groups in the past the northern geography, particularly in the old world, was advantageous to sharing of information. The most important information you could share with people was information relating to agriculture. The people whom sharing agricultural knowledge is most advantageous are people at the same latitude as you are since a short trip north or south has a dramatic change on the types of plants that can be grown as well as the techniques required to improving that growth.
If you are on the Eurasian land mass there are a lot of people east and west of you with similar growing conditions and thus there are a lot of people trading information back and forth. The more people the higher likelihood of innovation and since knowledge is already being transferred even information that is not about agriculture would come along for the ride.
So it’s not that the people in the southern hemisphere have a lower IQ as much as it is that due to the skinny nature of the land masses in the southern hemisphere there is less trading of innovations and thus they didn’t advance the way that peoples of the northern hemisphere, especially Eurasia, did.
Thank-you, Jared Diamond.
Native Americans, Australian Aboriginals, Hawaiians, etc. are all from the same genetic population as the Japanese.
If you compare grades by ethnicity, your average Japanese kid will probably be near the top of the spectrum. Your average Native American kid will probably be near the bottom.
Just a few years before the first submarine was developed for the American Civil War, the Japanese were still living in the feudal ages. They were still living in an age where knights ride around on horses and swung swords at each other. A few decades later, large numbers of Japanese were convinced to move to Brazil, to work in their industrial sector. The Brazilians were ahead of the Japanese economically and technologically.
In the Americas before the Europeans came, most of the large, organized empires were in Central and South America. North Americans largely stayed as hunter gatherers (with exceptions). But since the land bridge from Asia to the Americas was in Alaska, everyone living in Central and South America are presumably the descendants of North Americans.
Basically, there’s no evidence that any particular ethnic group is inherently more or less intelligent than any other. Just following one ethnic group, there’s no particularly consistency in the level of social and technological development that was achieved among all the different political entities within that group. Nor is there any North/South divide. In the Americas, the Southerners tended to be more impressive.
More importantly, most of the Southern Hemisphere is water. Only 1/3rd (or less) of Africa is in the Southern Hemisphere. Most of Australia is a desert. Only 12% of the current human population exists in the Southern Hemisphere. On that basis alone, we can already expect 8 times more geniuses to be born in the Northern Hemisphere. When you add in access to education and a free economy, you wouldn’t expect to see much coming out of the South. But, as we’ve seen with Japan, things can change drastically in just a few hundred years.
Really?
Through whatever selection medium it came about people of Ashkenazi Jewish heritage are (an average) notably more intelligent than the US baseline and oddly have “below-average spatial intelligence” .
Eh, possibly you could select for higher intelligence, if it’s a small enough group. But I’d still vote that it’s more likely that you’re looking at a cultural phenomenon than a genetic one.
Other than maybe a higher percentage of Northern European blood, your average Jewish person is probably the same as your average Jordanian or Palestinian person, genetically. Are they particularly renowned for spawning geniuses?
The equatorial regions are the malarial regions, and malaria grinds societies down.
And it can cause brain damage leading to lowered intelligence, as can famine.
So, on average they probably are less intelligent - not because of generics, but from hunger and disease. Eradicate malaria and stop famine, and you’d fix that, presumably.
People always seem to think Mexico is not in North America, for some reason. And ignore the Missisipian which, while not an empire, was just as much a civilization as the Maya, Inca or Aztec.
Perhaps I am the first person to openly point out that the vast majority of human beings live north of the Equator. It’s a striking imbalance - something like 90% of all people are in the Northern Hemisphere. You are going to struggle to make a lot of valid comparisons because there aren’t enough comparisons to make.