Can A Test Really Tell Who's A Psychopath?
There's a story on NPR under the above heading. It discusses the accuracy of Hare's checklist for deciding who is a psychopath. The test is now widely used in the U.S. criminal justice system to decide who can safely be released on parole. NPR opposes that, of course.
But on what grounds? Their principal ground seems to be the case of one man: A man with a long record of violent crime who scores highly on the Hare test. Rather than seeing that long record of violent crime as excellent validation of the test (proof that the test measures what it purports to measure) they say: "Aha! But that is the man of yesteryear. After many years in prison he has now reformed."
Yet what they report of his behaviour they evaluate very naively. They report that the man realized he would have to adopt different behaviour to get out of jail and worked systematically on doing that. And he has really charmed lots of people by the new and caring man that he is.
What a laugh! That's exactly what psychopaths do. They are great actors when they need to be and charming people is their stock in trade. If the NPR writers knew anything about psychopaths, they would be embarrassed to write what they did. They have actually disproved their own case.