It's important to use critical thinking when looking at articles on science. That particular article was not scientific. I can't tell if this is a hypothesis, which has not been severely tested, or if it graduated to theory, where it will continue to be tested. We also have to be careful of the conclusions we draw from the data. Our education does not necessarily affect our genome, and that's the key. Just because we don't read sun dials anymore does not mean we have lost the ability to do so. We learn what we need to survive. I'd venture to say that if you took someone from the age of sundials and popped them on a computer with 3 windows open, they'd have a hard time, unless they were taught. We can teach a person to read a sun dial today, we just don't invest the time and resources into it because it is obsolete. Instead, we teach the kids how to log onto the internet, and then hopefully, also teach them to be critical of the information and how to determine if their sources are solid, etc.
Famers today probably don't know how to plow a field with oxen. We wouldn't call them dumber, because they hop up onto a John Deere and run a very dangerous piece of machinery instead. Kids today are not taught to flint knap---and that doesn't make them dumb. Instead, they are blending audio and video and making youtube videos. That is some pretty sophisticated thinking.
I did a quick search looking for this research, because taking a reporters word for things is never a good call. I didn't find anything, but I didn't look hard. I'd love to see Scientific American cover the story, because they will approach it in a scientific manner.
There are other pressures on natural selection, and that may play a role too. The more education a woman has, the less children she gives birth to. This could translate into our most intelligent people not passing on as many genes. But there are also plenty of intelligent people that don't get an education, so it may be difficult to measure. In countries where religion dicatates, and a curious or intelligent woman steps out of line, we may lose her genes from the gene pool. Think of Malala and her intelligence, and how they have tried to kill her, thereby preventing those genes from passing on. Start killing women for being intelligent, and stupider boys are being born too, since these women would also give birth to boys.
That's just a bit of hypothesis, as I have nothing to support it, but they are some of the thoughts I would have in mind when looking at research like this.
The big question is how much is genetic and how much is just cultural? That's difficult to determine at times, but culture does exert selective pressures.
Brain size is not necessarily an indication. Our brains have grown smaller. Populations that inhabit colder regions for many generations will have bigger brains. This has nothing to do with intelligence, but may be due to less sunlight and the extra room we need to process things visually.
It's a complex subject, and one study won't give us all the answers. I do know that we shouldn't look at what kids can do today and compare it to what the parents are able to do, and use that as evidence. Sure, grandparents may have been great at building barns, making quilts, building fires, hunting---whatever---but give them a video game control and let's see whose smarter then.
I'm sure the research will continue, and we will get our information from scientific sources with much less spin.
