I think it's really difficult to generalize on such an enormous question. Greeks and Romans clearly placed an enormous amount of prestige on those amazing individuals who seemed to transcend what we would consider "ordinary" and were not particularly collectivist in their thinking.

Some early Europeans venturing into the Americas sometimes commented on the apparent collective nature of the natives, but whether or not this is an accurate portrayal of what would be consider their "norm" is up for debate. It's entirely possible that after diseases from Europe destroyed so many native populations that once Europeans got there after the diseases had reached those populations first, Europeans were pretty much just seeing survivors, something akin to a refugee camp.

Confucianism in the east does promote a "social harmony" as Confucius sees it, but I doubt it always felt harmonious to those peoples in the lower social classes or positions. Westerners often like to generalize on the collective nature of eastern nations, but it's important to remember that at the end of the day, these people are human, past peoples were human, and individuality and a variety of values will bubble to the surface.

On another note, while not ancient peoples, you should perhaps look into the selfies of the American Civil War. Using early photography, check out how people like Frederick Douglass and Walt Whitman purposefully used photography and positioning to enhance their reputations. Another facet of the human need to be an individual!

Well, I can speak from the perspective of philosophy. Consider the beginning of Aristotle's Politics:

He who thus considers things in their first growth and origin, whether a state or anything else, will obtain the clearest view of them. In the first place there must be a union of those who cannot exist without each other; namely, of male and female, that the race may continue [Aristotle goes on to say an individual and his society share this same relationship, ie they cannot exist without each other]

And this other, much more famous passage:

He who is unable to live in society, or who has no need because he is sufficient for himself, must be either a beast or a god.

In modern times we are sympathetic to philosophers such as Thomas Hobbes or John Locke, who base political philosophy from a "State of nature" where man exists alone as an individual and is then brought into a social agreement. The idea is that the individual enters into a society for the sake of getting more out of it than what he sacrifices. Speaking in basics, for Hobbes this individual trades his liberty to get security, for Locke he gets the protection of Law, for Rousseau man was always more free outside of society, and it was a mistake to enter into anything but the smallest communities. Many of these modern philosophers, and thus modern political philosophy, is structured around the idea that a society is a covenant of fundamental individuals who enter into a mutual agreement for their own individual benefit.

Aristotle rejects this view outright. He states in the Politics that the state of nature, for man, is in a society. There is no "state of nature" where man exists alone, unless you want to go back to when we were complete beasts, which is not really "man" but rather "ape". And even then, man could not exist as an individual any more than a man can reproduce without a woman.

So, the answer to your question is that in the West (and to my knowledge elsewhere), the idea of basing political philosophy on a conception of man as fundamentally an individual only gained traction in modern times. Keep in mind that I am not addressing the entire ancient world nor the entire modern one.

The poster before me said that

Greeks and Romans clearly placed an enormous amount of prestige on those amazing individuals who seemed to transcend what we would consider "ordinary" and were not particularly collectivist in their thinking.

I would disagree. Heroes were, first of all, from myths that were very old during the time of Pericles' Athens, and second of all, almost every hero is either a God, related to a God, or he is a hero insofar as he was able to benefit his society. Hero exaltation does not indicate a conception of man as fundamentally individual.

EDIT: Removed a bad section on Ancient Greek which I was not qualified to speak about.

This is a good question for /r/askanthropology

You are most likely referring to [Bicameralism](https://en.wikipedia.org/wiki/Bicameralism_(psychology)), first postulated and popularized by Julian Jaynes.

There are a lot of problems with this theory, but for me the main one is how western-centric it is. Jaynes proposes that around 1000BCE (the time of The Iliad and the Old Testament) people considered their conscious thoughts to be external voices from gods. Shortly thereafter modern, western humans changed to think of those thoughts as coming from their own self.

So fine, let's say this is true. Then we'd expect to find evidence of this transition in other cultures, and where modern, western cultures subsequently encountered more archaic ones, we'd expect to find some amount of evidence of the former noting the bicameralism of the latter. As far as I know, there is no such evidence.