If brain size and intellectual abilities were correlated, dolphins would be much more intelligent than humans.
Believe me, they are not.
The average bottlenosed dolphin, displaying some of the most brutal social behaviour amongst cetaceans (and yes, its the "flipper" species), will find his match with an average 4 yr old kid. Which is all fine and well, but unless you just WANT to believe, there is not really much about it.
Likewise, some anomaly in skull size - untill otherwise proven - means that it was an anomaly, probably caused by a genetic defect.
We are not talking about a different species. Yes there is more to it than size, but size helps. These were also people that had a normal sized body but an enlarged brain - so that increased brain would not have to control more mass. I said as much in the article, if the increased size correlates to only a 10-20% it would indicate that they could have had an IQ of 149. This is not my data, but from the book Big Brain: The Origins and Future of Human Intelligence written by two highly respected neuroscientists - one teaches at UC-Irvine and the other at Dartmouth.
They broke from the mainstream group-think to put forth their theories on the Boskop people, and I applaud them for it.
Finally, what is evolution but a series of mutations, or what you call defects in your comment.
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.
I think it is presumptuous to think that science is ever final. Until the workings of the brain are completely understood I will never dismiss or accept anything about it. You may do what you want, but things change. You would be wise to never accept any study as gospel.