TLDR: it's Baskerville (below)
Errol Morris is a writer and filmmaker who once set a New York Times quiz with a secret purpose: to test the most trustworthy typeface.
The online test was ostensibly designed to deem whether the reader was an optimist or pessimist, asking users to read a passage from David Deutsch’s second book, The Beginning of Infinity and then agree or disagree with the statement "we are living in an era of unprecedented safety".
More than 45,000 people took the quiz and the passage was generated in a number of different fonts.
Analysis showed Baskerville (above) was the most agreeable font with Helvetica and Comic Sans being the least agreeable:
Speaking to Fast Company three years after the experiment, now the essay has been put into print as a Pentagram Paper, Morris told how the experiment has changed his life.
I'm drinking my own Kool-Aid now. I used to write all of my manuscripts in Bembo. Now I write them in Baskerville.