An article in the September Scientific American discusses the longitudinal increase in intelligence we have been experiencing over the past 100 years (we don’t have much research for the periods before that). One of the findings that I find most intriguing is that many of our capabilities haven’t gotten better. The improvement over time is really narrow. Our abstract reasoning is what has improved. How are things related (remember those analogy questions on the SAT?)? And geometric pattern recognition.
Why these? I suspect that these capabilities are much more important now than they were 100 years ago when manual labor was what 99% of us did for a living (and to live). Now that we grow up in a world that involves lots of abstract reasoning, it is important to be able to do it well. And we need to see lots of 3-D shapes in 2-D artifacts like paper and computer screens. But basic skills, like working memory capacity, aren’t in much higher demand now than they were a century ago. Maybe even less necessary now that we have so many electronic toys to help us.
So the good news is that as the world changes around us, our brains have the capability to adapt and improve. But the bad news is that if the environment doesn’t push us to get better, we won’t.