Back around the time I was born, anthropologists sometimes talked about some cultures being more advanced than others. This was before they decided that all cultures are equal, except that some are more equal than others.
Anyhow, that kind of comparison can be interesting. In the Old World, civilization arose first in the Middle East, and that heavily influenced later starts such as European and Chinese civilization. Civilization in the Americas seems to have arisen completely or almost completely independently: there may have been some pre-Columbian contacts, but it looks as if the Amerindians developed agriculture and technology on their own.
I’ve been trying to estimate the gap between Eurasian and Amerindian civilization. The Conquistadors were, in a sense, invaders from the future: but just how far in the future? What point in the history of the Middle East is most similar to the state of the Amerindian civilizations of 1500 AD ?
I would argue that the Amerindian civilizations were less advanced than the Akkadian Empire, circa 2300 BC. The Mayans had writing, but were latecomers in metallurgy. The Inca had tin and arsenical bronze, but didn’t have written records. The Akkadians had both – as well as draft animals and the wheel. You can maybe push the time as far back as 2600 BC, since Sumerian cuneiform was in pretty full swing by then. So the Amerindians were around four thousand years behind.