<http://www.npr.org/blogs/health/2010/09/16/129910351/how-your-brain-figures-out-what-it-doesn-t-know>Link
Metacognition is when people "assess how confident they are in the
cognitive processes in their own brain that produced [an] answer" -
how sure they are about a given fact or whether someone is
trustworthy. Some people are better at this than others, and "the
reason seems connected to a bit of brain just behind the eyes."
