Certainly the game of getting smarter due to sociality had been going on for a long time before this. But it is still quite possible that something about thos

Certainly the game of getting smarter due to sociality had been going on for a long time before this. But it is still quite possible that something about those survivors gave them an edge in the following centuries. And since we can't see a fast change in anatomy around then, it is a fair guess that any such change was mental.