Joy Buolamwini is a researcher at the MIT Media Lab who pioneered research into bias that’s built into artificial intelligence and facial recognition. And the way she came to this work is almost a little too on the nose. As a graduate student at MIT, she created a mirror that would project aspirational images onto her face, like a lion or tennis star Serena Williams. But the facial-recognition software she installed wouldn’t work on her Black face, until she literally put on a white mask. Buolamwini is featured in a documentary called “Coded Bias,” airing tonight on PBS.