People have a tendency to treat technology and big data as neutral, sterile and immune to mortal failings. Yet the digital tools we use at schools, jobs and home don’t simply fall from the sky—humans produce them. And that means human biases can and do slip right into the algorithms. We talked with Ruha Benjamin, associate professor of African American Studies at Princeton University and author of new book “Race After Technology.” She points out that some people’s fantasies are other people’s nightmares.