What a machine learning tool that turns Obama white can (and can't) tell us about AI bias

It's a startling image that illustrates the deep-rooted biases of AI research. Input a low-resolution picture of Barack Obama, the first black president of the United States, into an algorithm designed to generate depixelated faces, and the output is a white man. Get the same algorithm to generate high-resolution images of actress Lucy Liu or congresswoman Alexandria Ocasio-Cortez from low-resolution inputs, and the resulting faces look distinctly white. As one popular tweet quoting the Obama example put it: "This image speaks volumes about the dangers of bias in AI." But what's causing these outputs and what do they really tell us about AI bias?