[eno_]

Probably because earlier examples have not survived. If humans were anatomically "modern" 70,000 years ago, why should you expect them to be cognitively that different? I suspect there are layers of pre-Egyptian civilizations yet to be discovered, or, at least, their presence inferred.

[dubyagee]

That's my point, I wouldn't expect them to be cognitively different. So where are the 70,000 year old cave paintings? Where are the written "words" from that far back. If tools survived, surely etchings in stone would.

I'm sure now that they surmise humans weren't that different that far back, the 70,000 year old "writings" will not be far behind.