In an effort to prove the virtues of native advertising, the BBC is turning to facial-recognition technology. In the fall, the BBC used software from CrowdEmotion to measure 5,000 people’s conscious and subconscious emotional responses to content marketing digital campaigns from clients like HSBC, Dassault and Hainan Island Tourism. Now, the BBC is rolling out the capability broadly to clients of its StoryWorks content studio.