The Wish to Know Who Is Safe

While reading the Guardian online, I noticed a headline:

How to spot a psychopath: "It's like the difference between a domestic cat and a wild cat."

It is difficult not to read on. The image is immediate. One cat curls beside the fire, familiar and companionable; the other may look similar, but belongs to a more dangerous world. The headline suggests that human beings also come in these two forms and that the difference, though concealed, can be discerned.