Best of Last Week—How humans really killed mammoths, making AI systems smarter, mitochondria fling their DNA

It was an interesting week for the study of human behavior as a team of cognitive scientists at MIT found what they believe is the reason that laws are written in an incomprehensible style—because it confers what they describe as a "special kind of authority" and because legislators feel compelled to follow tradition. And a team of archaeologists at the University of California, Berkeley, dispelled the myth of groups of early human hunters flinging spears at mammoths to bring them down—they found evidence that the large beasts were instead brought down by spikes planted into the ground at angles.