I was actually going to post something along these lines. Brain size != intellect. That's been shown through repeated tests. Even among humans, larger brains only equate to greater memory capacity. Intelligence is not a factor. Brain size has nothing to do with a person's ability to think. We actually have no scientific basis for understanding human consciousness. Despite everything we've learned about the human body, a person's ability to think remains pretty elusive. It's presumptuous at best to say that our ancestors would be smarter than us just because they had bigger brains. We have no reason to think that.