People exhibit less prejudice when they’re in the presence of a mirror, Dutch researchers have shown. Carina Wiekens
and Diederik Stapel said this effect occurs because mirrors make us
more aware of our public appearance, and therefore remind us of the
need to fall in line with social norms.
Here is more. Perhaps I have seen too many vampire movies, but in general I am of the opinion that mirrors have a real influence on our behavior.