I've spent much time in one rural Mexican village, San Agustin Oapan, and spent much time chatting with the people there...
I'm also sure they if you gave them an IQ test, they would do miserably. In fact I can't think of any written test -- no matter how simple -- they could pass. They simply don't have experience with that kind of exercise.
When it comes to understanding the properties of different corn varieties, catching fish in the river, mending torn amate paper, sketching a landscape from memory, or gossiping about the neighbors, they are awesome.
I should note that Jared Diamond makes very similar observations in Guns, Germs, and Steel.
There are indeed multiple intelligences. The one in which I am weakest is sometimes called "naturalist." I would not understand the corn varieties or how to catch fish. If you left me alone in the woods, I would die. Heck, if you left me alone on a farm teeming with crops, cows, and chickens, I would die.
IQ probably tends to measure intelligences that relate to reading, logic, and math. Other intelligences include kinesthetic, music, and social.
But the reality is that the intelligences that feed into IQ are what drive economic success. I have an unwritten essay on the meadow and the food court. It's a way of capturing Gregory Clark's economic history in a metaphor.
In a meadow economy, the human race is a grazing herd. The naturalists are the ones who eat the best. This was the economy up until about 1800 everywhere, and it still applies in the underdeveloped world today.
In the West since 1800, we've been moving to the food court economy, where we use complex recipes and convoluted trading mechanisms to translate basic ingredients into fancy consumption goods. Overall, most of the value nowadays is in the recipes, not in the ingredients.
And the people who can best create value in the food court economy are people with high IQ's. I have not read the book IQ and the Wealth of Nations (it strikes me as an issue that is not worth an entire book), but my guess is that Tyler's critique is not overly compelling.