Trust Signals

What is a trust signal?
Let's say you're interested in a book you aren't familiar with-this book, for example.
Before you buy it, you wonder, “Can I trust this author?” Can you trust that their book will be worth your money and your time?
The author, in turn, tries to prove their trustworthiness in a number of ways:
An accomplished and relevant biography
Glowing praise from well-known people on the cover
Five-star reviews on Amazon
Acclaim on social media by people you follow
Coverage in news medi...