Seth Stephens-Davidowitz, a former data scientist at Google, used his data-analysis skills to learn what was really on Americans' minds. The result, a new book called Everybody Lies, shows how the terms and questions people type into search engines don't at all match what they claim on surveys.

"So for example," he recently told an interviewer, "there have historically been more searches for porn than for weather." But just 25 percent of men and 8 percent of women will admit to survey researchers that they watch porn. When asked if he had any big insights about Americans' personal lives, Stephens-Davidowitz said:

I think there's two. The book is called Everybody Lies, and I start the book with racism and how people were saying to surveys that they didn't care that Barack Obama was black. But at the same time they were making horrible racist searches, and very clearly the data shows that many Americans were not voting for Obama precisely because he was black.

I started the book with that, because that is the ultimate lie. … People can say one thing and do something totally different. You see the darkness that is often hidden from polite society. That made me feel kind of worse about the world a little bit.

But, I think the second thing that you see is a widespread insecurity. … I think people put on a front, whether it's to friends or on social media, of having things together and being sure of themselves and confident and polished. But we're all anxious. We're all neurotic. … I now assume that people are going through some sort of struggle, even if you wouldn't know that from their Facebook posts.