The jury is still out on what this means because we aren't entirely sure what these genes do. It's possible they just control size and shape of the brain, rather than cognition. But the data is pretty compelling that the brain is evolving.

In a very short period of time, this class of variants arose from a single copy to many copies. That implies that this must have happened because of positive selection.

In another 10,000 or 20,000 years, I think the human brain may acquire a form that is quite different than the human brain today. Not necessarily in its shape, which may remain relatively the same. But the function may be different. It may be, on average, a little smarter. Or it may acquire certain skills that in its current form it isn't well-equipped to handle -- advanced cognitive abilities such as abstract reasoning. We don't really know for sure how -- but we are still evolving.

The next step is to find out what biological difference imparted by this genetic difference causes selection to favor that variation over the others.

They may have arisen in Europe or the Middle East and spread more readily east and west due to human migrations, as opposed to south to Africa because of geographic barriers. Or, they could have arisen in Africa, and increased in frequency once early humans migrated out of Africa.

We want to know how broad a trend these two genes represent. Did we get really lucky and hit on two rare examples of such genes? Or, are they representative of many other such genes throughout the genome. I would bet, though, that we will find evidence of selection in a lot more genes.

We don't know what these new variants do. But they might confer a selective advantage by improving cognitive abilities. This needs to be confirmed.

People like to think of modern human biology, and especially mental biology, as being the result of selections that took place 100,000 years ago. But our research shows that humans are still under selection, not just for things like disease resistance but for cognitive abilities.

I think a lot of people might consider humans to be at the pinnacle of evolutionary lineage -- that we have achieved an advanced state as a species, and we have basically become the end-game. But what we found indicates that the species -- particularly when it comes to the brain, which is perhaps our most defining feature -- is still evolving.

If we look at multiple genes, the ethnic variations such as the ones we found are likely to be counterbalanced by other differences. Just because these genes are still evolving, doesn't necessarily mean they make you any smarter. We've evolved genes for selfishness, violence, cruelty ??- all of which are in place because they may make survival easier.