Finding Sociopaths on Facebook

Original source

On his blog, Scott Adams suggests that it might be possible to identify sociopaths based on their interactions on social media.

My hypothesis is that science will someday be able to identify sociopaths and terrorists by their patterns of Facebook and Internet use. I’ll bet normal people interact with Facebook in ways that sociopaths and terrorists couldn’t duplicate.

Anyone can post fake photos and acquire lots of friends who are actually acquaintances. But I’ll bet there are so many patterns and tendencies of “normal” use on Facebook that a terrorist wouldn’t be able to successfully fake it.

Okay, but so what? Imagine you had such an amazingly accurate test…then what? Do we investigate those who test positive, even though there’s no suspicion that they’ve actually done anything? Do we follow them around? Subject them to additional screening at airports? Throw them in jail because we know the streets will be safer because of it? Do we want to live in a Minority Report world?

The problem isn’t just that such a system is wrong, it’s that the mathematics of testing makes this sort of thing pretty ineffective in practice. It’s called the “base rate fallacy.” Suppose you have a test that’s 90% accurate in identifying both sociopaths and non-sociopaths. If you assume that 4% of people are sociopaths, then the chance of someone who tests positive actually being a sociopath is 26%. (For every thousand people tested, 90% of the 40 sociopaths will test positive, but so will 10% of the 960 non-sociopaths.) You have postulate a test with an amazing 99% accuracy — only a 1% false positive rate — even to have an 80% chance of someone testing positive actually being a sociopath.

This fallacy isn’t new. It’s the same thinking that caused us to intern Japanese-Americans during World War II, stop people in their cars because they’re black, and frisk them at airports because they’re Muslim. It’s the same thinking behind massive NSA surveillance programs like PRISM. It’s one of the things that scares me about police DNA databases.

Many authors have written stories about thoughtcrime. Who has written about genecrime?

BTW, if you want to meet an actual sociopath, I recommend this book (review here) and this blog.