Make no mistake that all things evolve. Whether or not they manage to hang onto their cognitive skills is another story altogether. I think Mrs. Gump said it best when she said that stupid is as stupid does. You see, you can educate the dimwitted by hitting them over the head with a book or two, but you can't fix retardation: which is something that proponents of de-evolution cling to.
As an example of this: there was a time when people began to suspect that the gods lived on-high. Problem was, they were just bright enough to realize that what goes up must also come down. How best to solve this little quandary? Why, put them in the trees - of course! This is why we still, to this day, knock on wood whenever we feel the need to tread carefully. It used to be that whenever someone needed something of god, they would approach the nearest tree and knock on it to get his attention.
Now I know it sounds like I'm making the argument for de-evolution, but just you hold on a few. That is because, yes, we also used to sacrifice human life to appease the gods. Had it "knot" been for evolution dragging spiritual maturation out of the mud with it, we would still be hard at it. While it's one thing to appease the gods over the idea of one's perceived sins, it's another altogether when you start doing it for the crops, the rain, the everyday bad luck...
While the argument could be made that we are getting dumber, we are certainly not de-evolving. As an added argument to help make my case, I give you the Sacropia plant. While a plant cannot make or break the case for human development, it lends itself to the nature of, well, nature.
Somewhere in time, leaf-eating insects took notice of this green, leafy plant. So much so, they began zealously attacking it as a food source. Over time, these insects passed this information on to their offspring via genetic code. The plant, being absolutely defenseless, began to die out only, something marvelous happened. Instead of going extinct, something with the power over life and death intervened on its behalf.
As a result of this unknown, yet highly targeted intervention known as evolution, the Sacropia plant began to make changes on the genetic level in an all out bid for survival. How? By producing small food nodules to attract a particular species of ant. You need to understand that these nodules are something this plant never had before - in its entire existence! Not only that, but these starchy nodules are a kind of hollow food, in that, they actually serve to increase the ants appetite and energize it for the hunt. No doubt it would have done little good to just stuff them into an "insecta siesta" by offering them a free lunch.
However, the force that acted on the plant's behalf did not stop there. It went a step further in the evolution process by creating hollow stems for these ants to live in. This re-engineering of the plant at the genetic level served a twofold purpose. (1). It kept its defenders close to home. (2). It protected the ants from those predators that would otherwise circumvent its protective measures. And, as we all know, the Sacropia plant now thrives because of the ants caring attentions.
More mysterious yet is how the plant even knew that ants existed at all. Not to mention this particular species that would, of all things, protect it. Without eyes to see, or a brain to reason, how did it "know" what taste preference this particular species of ant even desired that it could get the food formula right - is truly mind boggling! All of which, mind you, happened through some kind of alchemy as brewed on the genetic level.
So whether it be plant, animal or humankind, Mother Nature herself provides the answer we seek because, although the plant is itself dumber than a box of rocks - it evolved!