How do you know what Adam and Eves brain sizes were?
I believe they were Cro Magnon or Neanderthal (both fully Human) and we know that both had larger brain cavities than humans today. I believe a compelling reason for this is that our skulls continue to grow as we age and people thousands of years ago lived a lot longer.
So you're saying that 7 million years before god created homo sapiens he created ape-like people?... Neanderthals were homo Sapiens but did not live 6000 years ago. The last neaderthals were absorbed and died off 30,000 years ago.
You have to have faith in evolutionist assumptions which are built into their dating methods to believe this... a faith i do not possess. Since their assumptions are wrong, their dating interpretations are worthless and in some cases billions of years becomes thousands. As I have mentioned in another post, 90% of dating methods point to a young earth and the 10% which point to an old earth are based in old earth assumptions so they are derived upon through circular reasoning. The majority of evidence points to all life existing 10,000 years ago or less.