Blink twice if you are a fake. Sophisticated fake videos created by artificial intelligence are getting better and better, so tools to identify the genuine article are needed. One solution is to look at the way fake faces blink.

In recent months, researchers have created eerily-realistic fake videos of Theresa May, Barack Obama, Vladimir Putin, and Donald Trump giving speeches, as well as of famous actresses superimposed into porn scenes. To make the footage, AI needs still images of the faked person, which are then mapped onto an …