[foal]

"Mirror neurons" are used to support simulation theory. That is, we make sense of the behavior and feelings of others... or "attribute mental qualities to others"... by simulating their experiences or at least attempting to in our own brain. This is in contrast to I think what is called the "theory theory" model which is that we have a theory of the mind of others that operates based on predictive power. I.e. if we attribute mental qualities to them, we can predict their behavior better.
It is a topic of debate, which model is better or more true. Personally I think they are not mutuality exclusive and that there is truth to both.