5. Prevarication and the Polygraph

Wouldn’t it be nice if we could take a video clip of someone talking and apply AI to determine whether or not they’re telling the truth? Such a tool would have myriad applications, including helping in the fight against fake news: a dissembling politician giving a dishonest speech would immediately be outed, as would a conspiracy theorist knowingly posting lies on YouTube. With the remarkable progress in deep learning in recent years, why can’t we just train an algorithm by showing it lots of videos of lies and videos of truth and have it learn which is which based on whatever visual and auditory clues it can find? In fact, for the past fifteen years, people have been trying this 21st-century algorithmic reinvention of the polygraph. How well it works and what it has been used for are the main questions explored in this chapter. To save you some suspense: this approach would create almost as much fake news as it would prevent—and claims to the contrary by the various companies involved in this effort are, for lack of a better term, fake news. But first, I’ll start with the fascinating history of the traditional polygraph to properly set the stage for its AI-powered contemporary counterpart.