I'm writing a simulation game and I need to (crudely) model this. What do we know about how late hominids thought, compared to humans? I'm particularly interested in Homo erectus, Neanderthals, and the Denisovans, but more obscure ones are welcome as well, especially the Australopithecines. I understand that there's very little evidence that attests to this, but surely we can make conjectures based on found tools and possibly cranial volume/shape.