This article starts out by talking about an evolutionary trait found in domesticated dogs. When something is hidden under one of two cups and a human points at the correct cup, an untrained puppy will unwaveringly knock it over to retrieve the treat. This seems simple enough, but when placed in the exact same situation, a chimpanzee, a much smarter animal, has no clue which one to pick. This is evidence in favor of evolution through the selection of desired traits in dogs (domestication).
It goes on to talking about a farm in Russia in which they have, since 1959, been domesticating foxes. The traits that were selected for were non-aggressiveness and non-fearfulness towards humans. After a few generations, they began noticing certain traits in the foxes, such as narrower jaws, smaller size, and increased sex-drive, similarly, traits like these have supposedly been seen to evolve in humans as civilization has advanced. There is speculation in the article that we have self-domesticated ourselves and that docility is a prerequisite for civilization, however there is no substantial proof to back up this claim.
Perhaps the most interesting component to this article, at least in my eyes, was that they actually determined what, biologically, causes this increase in docility in the foxes and in humans. Serotonin. The levels of serotonin in the blood of the domesticated foxes was substantially higher than that of the wild ones. This is also the case in humans. Aggressive people have less sensitive receptors for serotonin in their brains, and in turn, less serotonin in their blood.
I found this article especially interesting because it gives a biological explanation for the difference in temperament amongst animals. I always figured that things like temperament and emotions were simply acquired throughout ones life, and were not related to the biology of an organism. It was eye-opening to find out that how aggressive you are can actually be determined by how the receptors for such a small particle in your brain work.
One thing I found peculiar was the suggestion that we self domesticated ourselves. Not so much that we did, i guess, but more of the traits that we supposedly selected for. I have heard multiple times that some of the traits that a woman looks for in a man are the exact opposite of the traits that were seen in the population of foxes. I think it has been shown that men with broader shoulders and a wider jaw are more desirable, but these are traits that signify a higher level of testosterone, and in turn aggressiveness. It seems counter instinctive to select for narrower jaws and smaller proportions.